Linux Audio

Check our new training course

Loading...
v3.5.6
 
   1/* Userspace key control operations
   2 *
   3 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
   4 * Written by David Howells (dhowells@redhat.com)
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the License, or (at your option) any later version.
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/init.h>
  14#include <linux/sched.h>
 
  15#include <linux/slab.h>
  16#include <linux/syscalls.h>
  17#include <linux/key.h>
  18#include <linux/keyctl.h>
  19#include <linux/fs.h>
  20#include <linux/capability.h>
 
  21#include <linux/string.h>
  22#include <linux/err.h>
  23#include <linux/vmalloc.h>
  24#include <linux/security.h>
  25#include <asm/uaccess.h>
 
 
  26#include "internal.h"
  27
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  28static int key_get_type_from_user(char *type,
  29				  const char __user *_type,
  30				  unsigned len)
  31{
  32	int ret;
  33
  34	ret = strncpy_from_user(type, _type, len);
  35	if (ret < 0)
  36		return ret;
  37	if (ret == 0 || ret >= len)
  38		return -EINVAL;
  39	if (type[0] == '.')
  40		return -EPERM;
  41	type[len - 1] = '\0';
  42	return 0;
  43}
  44
  45/*
  46 * Extract the description of a new key from userspace and either add it as a
  47 * new key to the specified keyring or update a matching key in that keyring.
  48 *
 
 
 
  49 * The keyring must be writable so that we can attach the key to it.
  50 *
  51 * If successful, the new key's serial number is returned, otherwise an error
  52 * code is returned.
  53 */
  54SYSCALL_DEFINE5(add_key, const char __user *, _type,
  55		const char __user *, _description,
  56		const void __user *, _payload,
  57		size_t, plen,
  58		key_serial_t, ringid)
  59{
  60	key_ref_t keyring_ref, key_ref;
  61	char type[32], *description;
  62	void *payload;
  63	long ret;
  64	bool vm;
  65
  66	ret = -EINVAL;
  67	if (plen > 1024 * 1024 - 1)
  68		goto error;
  69
  70	/* draw all the data into kernel space */
  71	ret = key_get_type_from_user(type, _type, sizeof(type));
  72	if (ret < 0)
  73		goto error;
  74
  75	description = strndup_user(_description, PAGE_SIZE);
  76	if (IS_ERR(description)) {
  77		ret = PTR_ERR(description);
  78		goto error;
 
 
 
 
 
 
 
 
 
 
 
  79	}
  80
  81	/* pull the payload in if one was supplied */
  82	payload = NULL;
  83
  84	vm = false;
  85	if (_payload) {
  86		ret = -ENOMEM;
  87		payload = kmalloc(plen, GFP_KERNEL | __GFP_NOWARN);
  88		if (!payload) {
  89			if (plen <= PAGE_SIZE)
  90				goto error2;
  91			vm = true;
  92			payload = vmalloc(plen);
  93			if (!payload)
  94				goto error2;
  95		}
  96
  97		ret = -EFAULT;
  98		if (copy_from_user(payload, _payload, plen) != 0)
  99			goto error3;
 100	}
 101
 102	/* find the target keyring (which must be writable) */
 103	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
 104	if (IS_ERR(keyring_ref)) {
 105		ret = PTR_ERR(keyring_ref);
 106		goto error3;
 107	}
 108
 109	/* create or update the requested key and add it to the target
 110	 * keyring */
 111	key_ref = key_create_or_update(keyring_ref, type, description,
 112				       payload, plen, KEY_PERM_UNDEF,
 113				       KEY_ALLOC_IN_QUOTA);
 114	if (!IS_ERR(key_ref)) {
 115		ret = key_ref_to_ptr(key_ref)->serial;
 116		key_ref_put(key_ref);
 117	}
 118	else {
 119		ret = PTR_ERR(key_ref);
 120	}
 121
 122	key_ref_put(keyring_ref);
 123 error3:
 124	if (!vm)
 125		kfree(payload);
 126	else
 127		vfree(payload);
 128 error2:
 129	kfree(description);
 130 error:
 131	return ret;
 132}
 133
 134/*
 135 * Search the process keyrings and keyring trees linked from those for a
 136 * matching key.  Keyrings must have appropriate Search permission to be
 137 * searched.
 138 *
 139 * If a key is found, it will be attached to the destination keyring if there's
 140 * one specified and the serial number of the key will be returned.
 141 *
 142 * If no key is found, /sbin/request-key will be invoked if _callout_info is
 143 * non-NULL in an attempt to create a key.  The _callout_info string will be
 144 * passed to /sbin/request-key to aid with completing the request.  If the
 145 * _callout_info string is "" then it will be changed to "-".
 146 */
 147SYSCALL_DEFINE4(request_key, const char __user *, _type,
 148		const char __user *, _description,
 149		const char __user *, _callout_info,
 150		key_serial_t, destringid)
 151{
 152	struct key_type *ktype;
 153	struct key *key;
 154	key_ref_t dest_ref;
 155	size_t callout_len;
 156	char type[32], *description, *callout_info;
 157	long ret;
 158
 159	/* pull the type into kernel space */
 160	ret = key_get_type_from_user(type, _type, sizeof(type));
 161	if (ret < 0)
 162		goto error;
 163
 164	/* pull the description into kernel space */
 165	description = strndup_user(_description, PAGE_SIZE);
 166	if (IS_ERR(description)) {
 167		ret = PTR_ERR(description);
 168		goto error;
 169	}
 170
 171	/* pull the callout info into kernel space */
 172	callout_info = NULL;
 173	callout_len = 0;
 174	if (_callout_info) {
 175		callout_info = strndup_user(_callout_info, PAGE_SIZE);
 176		if (IS_ERR(callout_info)) {
 177			ret = PTR_ERR(callout_info);
 178			goto error2;
 179		}
 180		callout_len = strlen(callout_info);
 181	}
 182
 183	/* get the destination keyring if specified */
 184	dest_ref = NULL;
 185	if (destringid) {
 186		dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
 187					   KEY_WRITE);
 188		if (IS_ERR(dest_ref)) {
 189			ret = PTR_ERR(dest_ref);
 190			goto error3;
 191		}
 192	}
 193
 194	/* find the key type */
 195	ktype = key_type_lookup(type);
 196	if (IS_ERR(ktype)) {
 197		ret = PTR_ERR(ktype);
 198		goto error4;
 199	}
 200
 201	/* do the search */
 202	key = request_key_and_link(ktype, description, callout_info,
 203				   callout_len, NULL, key_ref_to_ptr(dest_ref),
 204				   KEY_ALLOC_IN_QUOTA);
 205	if (IS_ERR(key)) {
 206		ret = PTR_ERR(key);
 207		goto error5;
 208	}
 209
 210	/* wait for the key to finish being constructed */
 211	ret = wait_for_key_construction(key, 1);
 212	if (ret < 0)
 213		goto error6;
 214
 215	ret = key->serial;
 216
 217error6:
 218 	key_put(key);
 219error5:
 220	key_type_put(ktype);
 221error4:
 222	key_ref_put(dest_ref);
 223error3:
 224	kfree(callout_info);
 225error2:
 226	kfree(description);
 227error:
 228	return ret;
 229}
 230
 231/*
 232 * Get the ID of the specified process keyring.
 233 *
 234 * The requested keyring must have search permission to be found.
 235 *
 236 * If successful, the ID of the requested keyring will be returned.
 237 */
 238long keyctl_get_keyring_ID(key_serial_t id, int create)
 239{
 240	key_ref_t key_ref;
 241	unsigned long lflags;
 242	long ret;
 243
 244	lflags = create ? KEY_LOOKUP_CREATE : 0;
 245	key_ref = lookup_user_key(id, lflags, KEY_SEARCH);
 246	if (IS_ERR(key_ref)) {
 247		ret = PTR_ERR(key_ref);
 248		goto error;
 249	}
 250
 251	ret = key_ref_to_ptr(key_ref)->serial;
 252	key_ref_put(key_ref);
 253error:
 254	return ret;
 255}
 256
 257/*
 258 * Join a (named) session keyring.
 259 *
 260 * Create and join an anonymous session keyring or join a named session
 261 * keyring, creating it if necessary.  A named session keyring must have Search
 262 * permission for it to be joined.  Session keyrings without this permit will
 263 * be skipped over.
 
 264 *
 265 * If successful, the ID of the joined session keyring will be returned.
 266 */
 267long keyctl_join_session_keyring(const char __user *_name)
 268{
 269	char *name;
 270	long ret;
 271
 272	/* fetch the name from userspace */
 273	name = NULL;
 274	if (_name) {
 275		name = strndup_user(_name, PAGE_SIZE);
 276		if (IS_ERR(name)) {
 277			ret = PTR_ERR(name);
 278			goto error;
 279		}
 
 
 
 
 280	}
 281
 282	/* join the session */
 283	ret = join_session_keyring(name);
 
 284	kfree(name);
 285
 286error:
 287	return ret;
 288}
 289
 290/*
 291 * Update a key's data payload from the given data.
 292 *
 293 * The key must grant the caller Write permission and the key type must support
 294 * updating for this to work.  A negative key can be positively instantiated
 295 * with this call.
 296 *
 297 * If successful, 0 will be returned.  If the key type does not support
 298 * updating, then -EOPNOTSUPP will be returned.
 299 */
 300long keyctl_update_key(key_serial_t id,
 301		       const void __user *_payload,
 302		       size_t plen)
 303{
 304	key_ref_t key_ref;
 305	void *payload;
 306	long ret;
 307
 308	ret = -EINVAL;
 309	if (plen > PAGE_SIZE)
 310		goto error;
 311
 312	/* pull the payload in if one was supplied */
 313	payload = NULL;
 314	if (_payload) {
 315		ret = -ENOMEM;
 316		payload = kmalloc(plen, GFP_KERNEL);
 317		if (!payload)
 318			goto error;
 319
 320		ret = -EFAULT;
 321		if (copy_from_user(payload, _payload, plen) != 0)
 322			goto error2;
 323	}
 324
 325	/* find the target key (which must be writable) */
 326	key_ref = lookup_user_key(id, 0, KEY_WRITE);
 327	if (IS_ERR(key_ref)) {
 328		ret = PTR_ERR(key_ref);
 329		goto error2;
 330	}
 331
 332	/* update the key */
 333	ret = key_update(key_ref, payload, plen);
 334
 335	key_ref_put(key_ref);
 336error2:
 337	kfree(payload);
 338error:
 339	return ret;
 340}
 341
 342/*
 343 * Revoke a key.
 344 *
 345 * The key must be grant the caller Write or Setattr permission for this to
 346 * work.  The key type should give up its quota claim when revoked.  The key
 347 * and any links to the key will be automatically garbage collected after a
 348 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
 349 *
 
 
 350 * If successful, 0 is returned.
 351 */
 352long keyctl_revoke_key(key_serial_t id)
 353{
 354	key_ref_t key_ref;
 
 355	long ret;
 356
 357	key_ref = lookup_user_key(id, 0, KEY_WRITE);
 358	if (IS_ERR(key_ref)) {
 359		ret = PTR_ERR(key_ref);
 360		if (ret != -EACCES)
 361			goto error;
 362		key_ref = lookup_user_key(id, 0, KEY_SETATTR);
 363		if (IS_ERR(key_ref)) {
 364			ret = PTR_ERR(key_ref);
 365			goto error;
 366		}
 367	}
 368
 369	key_revoke(key_ref_to_ptr(key_ref));
 370	ret = 0;
 
 
 
 
 371
 372	key_ref_put(key_ref);
 373error:
 374	return ret;
 375}
 376
 377/*
 378 * Invalidate a key.
 379 *
 380 * The key must be grant the caller Invalidate permission for this to work.
 381 * The key and any links to the key will be automatically garbage collected
 382 * immediately.
 383 *
 
 
 384 * If successful, 0 is returned.
 385 */
 386long keyctl_invalidate_key(key_serial_t id)
 387{
 388	key_ref_t key_ref;
 
 389	long ret;
 390
 391	kenter("%d", id);
 392
 393	key_ref = lookup_user_key(id, 0, KEY_SEARCH);
 394	if (IS_ERR(key_ref)) {
 395		ret = PTR_ERR(key_ref);
 
 
 
 
 
 
 
 
 
 
 
 
 396		goto error;
 397	}
 398
 399	key_invalidate(key_ref_to_ptr(key_ref));
 
 400	ret = 0;
 401
 
 
 
 
 402	key_ref_put(key_ref);
 403error:
 404	kleave(" = %ld", ret);
 405	return ret;
 406}
 407
 408/*
 409 * Clear the specified keyring, creating an empty process keyring if one of the
 410 * special keyring IDs is used.
 411 *
 412 * The keyring must grant the caller Write permission for this to work.  If
 413 * successful, 0 will be returned.
 414 */
 415long keyctl_keyring_clear(key_serial_t ringid)
 416{
 417	key_ref_t keyring_ref;
 
 418	long ret;
 419
 420	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
 421	if (IS_ERR(keyring_ref)) {
 422		ret = PTR_ERR(keyring_ref);
 423
 424		/* Root is permitted to invalidate certain special keyrings */
 425		if (capable(CAP_SYS_ADMIN)) {
 426			keyring_ref = lookup_user_key(ringid, 0, 0);
 427			if (IS_ERR(keyring_ref))
 428				goto error;
 429			if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
 430				     &key_ref_to_ptr(keyring_ref)->flags))
 431				goto clear;
 432			goto error_put;
 433		}
 434
 435		goto error;
 436	}
 437
 438clear:
 439	ret = keyring_clear(key_ref_to_ptr(keyring_ref));
 
 
 
 
 440error_put:
 441	key_ref_put(keyring_ref);
 442error:
 443	return ret;
 444}
 445
 446/*
 447 * Create a link from a keyring to a key if there's no matching key in the
 448 * keyring, otherwise replace the link to the matching key with a link to the
 449 * new key.
 450 *
 451 * The key must grant the caller Link permission and the the keyring must grant
 452 * the caller Write permission.  Furthermore, if an additional link is created,
 453 * the keyring's quota will be extended.
 454 *
 455 * If successful, 0 will be returned.
 456 */
 457long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
 458{
 459	key_ref_t keyring_ref, key_ref;
 460	long ret;
 461
 462	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
 463	if (IS_ERR(keyring_ref)) {
 464		ret = PTR_ERR(keyring_ref);
 465		goto error;
 466	}
 467
 468	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK);
 469	if (IS_ERR(key_ref)) {
 470		ret = PTR_ERR(key_ref);
 471		goto error2;
 472	}
 473
 474	ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
 475
 476	key_ref_put(key_ref);
 477error2:
 478	key_ref_put(keyring_ref);
 479error:
 480	return ret;
 481}
 482
 483/*
 484 * Unlink a key from a keyring.
 485 *
 486 * The keyring must grant the caller Write permission for this to work; the key
 487 * itself need not grant the caller anything.  If the last link to a key is
 488 * removed then that key will be scheduled for destruction.
 489 *
 
 
 490 * If successful, 0 will be returned.
 491 */
 492long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
 493{
 494	key_ref_t keyring_ref, key_ref;
 
 495	long ret;
 496
 497	keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE);
 498	if (IS_ERR(keyring_ref)) {
 499		ret = PTR_ERR(keyring_ref);
 500		goto error;
 501	}
 502
 503	key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
 504	if (IS_ERR(key_ref)) {
 505		ret = PTR_ERR(key_ref);
 506		goto error2;
 507	}
 508
 509	ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
 
 
 
 
 
 
 510
 511	key_ref_put(key_ref);
 512error2:
 513	key_ref_put(keyring_ref);
 514error:
 515	return ret;
 516}
 517
 518/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 519 * Return a description of a key to userspace.
 520 *
 521 * The key must grant the caller View permission for this to work.
 522 *
 523 * If there's a buffer, we place up to buflen bytes of data into it formatted
 524 * in the following way:
 525 *
 526 *	type;uid;gid;perm;description<NUL>
 527 *
 528 * If successful, we return the amount of description available, irrespective
 529 * of how much we may have copied into the buffer.
 530 */
 531long keyctl_describe_key(key_serial_t keyid,
 532			 char __user *buffer,
 533			 size_t buflen)
 534{
 535	struct key *key, *instkey;
 536	key_ref_t key_ref;
 537	char *tmpbuf;
 538	long ret;
 
 539
 540	key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
 541	if (IS_ERR(key_ref)) {
 542		/* viewing a key under construction is permitted if we have the
 543		 * authorisation token handy */
 544		if (PTR_ERR(key_ref) == -EACCES) {
 545			instkey = key_get_instantiation_authkey(keyid);
 546			if (!IS_ERR(instkey)) {
 547				key_put(instkey);
 548				key_ref = lookup_user_key(keyid,
 549							  KEY_LOOKUP_PARTIAL,
 550							  0);
 551				if (!IS_ERR(key_ref))
 552					goto okay;
 553			}
 554		}
 555
 556		ret = PTR_ERR(key_ref);
 557		goto error;
 558	}
 559
 560okay:
 561	/* calculate how much description we're going to return */
 562	ret = -ENOMEM;
 563	tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 564	if (!tmpbuf)
 565		goto error2;
 566
 567	key = key_ref_to_ptr(key_ref);
 
 568
 569	ret = snprintf(tmpbuf, PAGE_SIZE - 1,
 570		       "%s;%d;%d;%08x;%s",
 571		       key->type->name,
 572		       key->uid,
 573		       key->gid,
 574		       key->perm,
 575		       key->description ?: "");
 576
 577	/* include a NUL char at the end of the data */
 578	if (ret > PAGE_SIZE - 1)
 579		ret = PAGE_SIZE - 1;
 580	tmpbuf[ret] = 0;
 581	ret++;
 582
 583	/* consider returning the data */
 584	if (buffer && buflen > 0) {
 585		if (buflen > ret)
 586			buflen = ret;
 587
 588		if (copy_to_user(buffer, tmpbuf, buflen) != 0)
 589			ret = -EFAULT;
 590	}
 591
 592	kfree(tmpbuf);
 593error2:
 594	key_ref_put(key_ref);
 595error:
 596	return ret;
 597}
 598
 599/*
 600 * Search the specified keyring and any keyrings it links to for a matching
 601 * key.  Only keyrings that grant the caller Search permission will be searched
 602 * (this includes the starting keyring).  Only keys with Search permission can
 603 * be found.
 604 *
 605 * If successful, the found key will be linked to the destination keyring if
 606 * supplied and the key has Link permission, and the found key ID will be
 607 * returned.
 608 */
 609long keyctl_keyring_search(key_serial_t ringid,
 610			   const char __user *_type,
 611			   const char __user *_description,
 612			   key_serial_t destringid)
 613{
 614	struct key_type *ktype;
 615	key_ref_t keyring_ref, key_ref, dest_ref;
 616	char type[32], *description;
 617	long ret;
 618
 619	/* pull the type and description into kernel space */
 620	ret = key_get_type_from_user(type, _type, sizeof(type));
 621	if (ret < 0)
 622		goto error;
 623
 624	description = strndup_user(_description, PAGE_SIZE);
 625	if (IS_ERR(description)) {
 626		ret = PTR_ERR(description);
 627		goto error;
 628	}
 629
 630	/* get the keyring at which to begin the search */
 631	keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH);
 632	if (IS_ERR(keyring_ref)) {
 633		ret = PTR_ERR(keyring_ref);
 634		goto error2;
 635	}
 636
 637	/* get the destination keyring if specified */
 638	dest_ref = NULL;
 639	if (destringid) {
 640		dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
 641					   KEY_WRITE);
 642		if (IS_ERR(dest_ref)) {
 643			ret = PTR_ERR(dest_ref);
 644			goto error3;
 645		}
 646	}
 647
 648	/* find the key type */
 649	ktype = key_type_lookup(type);
 650	if (IS_ERR(ktype)) {
 651		ret = PTR_ERR(ktype);
 652		goto error4;
 653	}
 654
 655	/* do the search */
 656	key_ref = keyring_search(keyring_ref, ktype, description);
 657	if (IS_ERR(key_ref)) {
 658		ret = PTR_ERR(key_ref);
 659
 660		/* treat lack or presence of a negative key the same */
 661		if (ret == -EAGAIN)
 662			ret = -ENOKEY;
 663		goto error5;
 664	}
 665
 666	/* link the resulting key to the destination keyring if we can */
 667	if (dest_ref) {
 668		ret = key_permission(key_ref, KEY_LINK);
 669		if (ret < 0)
 670			goto error6;
 671
 672		ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
 673		if (ret < 0)
 674			goto error6;
 675	}
 676
 677	ret = key_ref_to_ptr(key_ref)->serial;
 678
 679error6:
 680	key_ref_put(key_ref);
 681error5:
 682	key_type_put(ktype);
 683error4:
 684	key_ref_put(dest_ref);
 685error3:
 686	key_ref_put(keyring_ref);
 687error2:
 688	kfree(description);
 689error:
 690	return ret;
 691}
 692
 693/*
 694 * Read a key's payload.
 695 *
 696 * The key must either grant the caller Read permission, or it must grant the
 697 * caller Search permission when searched for from the process keyrings.
 698 *
 699 * If successful, we place up to buflen bytes of data into the buffer, if one
 700 * is provided, and return the amount of data that is available in the key,
 701 * irrespective of how much we copied into the buffer.
 702 */
 703long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
 704{
 705	struct key *key;
 706	key_ref_t key_ref;
 707	long ret;
 708
 709	/* find the key first */
 710	key_ref = lookup_user_key(keyid, 0, 0);
 711	if (IS_ERR(key_ref)) {
 712		ret = -ENOKEY;
 713		goto error;
 714	}
 715
 716	key = key_ref_to_ptr(key_ref);
 717
 
 
 
 
 718	/* see if we can read it directly */
 719	ret = key_permission(key_ref, KEY_READ);
 720	if (ret == 0)
 721		goto can_read_key;
 722	if (ret != -EACCES)
 723		goto error;
 724
 725	/* we can't; see if it's searchable from this process's keyrings
 726	 * - we automatically take account of the fact that it may be
 727	 *   dangling off an instantiation key
 728	 */
 729	if (!is_key_possessed(key_ref)) {
 730		ret = -EACCES;
 731		goto error2;
 732	}
 733
 734	/* the key is probably readable - now try to read it */
 735can_read_key:
 736	ret = key_validate(key);
 737	if (ret == 0) {
 738		ret = -EOPNOTSUPP;
 739		if (key->type->read) {
 740			/* read the data with the semaphore held (since we
 741			 * might sleep) */
 742			down_read(&key->sem);
 
 743			ret = key->type->read(key, buffer, buflen);
 744			up_read(&key->sem);
 745		}
 746	}
 747
 748error2:
 749	key_put(key);
 750error:
 751	return ret;
 752}
 753
 754/*
 755 * Change the ownership of a key
 756 *
 757 * The key must grant the caller Setattr permission for this to work, though
 758 * the key need not be fully instantiated yet.  For the UID to be changed, or
 759 * for the GID to be changed to a group the caller is not a member of, the
 760 * caller must have sysadmin capability.  If either uid or gid is -1 then that
 761 * attribute is not changed.
 762 *
 763 * If the UID is to be changed, the new user must have sufficient quota to
 764 * accept the key.  The quota deduction will be removed from the old user to
 765 * the new user should the attribute be changed.
 766 *
 767 * If successful, 0 will be returned.
 768 */
 769long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
 770{
 771	struct key_user *newowner, *zapowner = NULL;
 772	struct key *key;
 773	key_ref_t key_ref;
 774	long ret;
 
 
 
 
 
 
 
 
 
 
 775
 776	ret = 0;
 777	if (uid == (uid_t) -1 && gid == (gid_t) -1)
 778		goto error;
 779
 780	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
 781				  KEY_SETATTR);
 782	if (IS_ERR(key_ref)) {
 783		ret = PTR_ERR(key_ref);
 784		goto error;
 785	}
 786
 787	key = key_ref_to_ptr(key_ref);
 788
 789	/* make the changes with the locks held to prevent chown/chown races */
 790	ret = -EACCES;
 791	down_write(&key->sem);
 792
 793	if (!capable(CAP_SYS_ADMIN)) {
 794		/* only the sysadmin can chown a key to some other UID */
 795		if (uid != (uid_t) -1 && key->uid != uid)
 796			goto error_put;
 797
 798		/* only the sysadmin can set the key's GID to a group other
 799		 * than one of those that the current process subscribes to */
 800		if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
 801			goto error_put;
 802	}
 803
 804	/* change the UID */
 805	if (uid != (uid_t) -1 && uid != key->uid) {
 806		ret = -ENOMEM;
 807		newowner = key_user_lookup(uid, current_user_ns());
 808		if (!newowner)
 809			goto error_put;
 810
 811		/* transfer the quota burden to the new user */
 812		if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
 813			unsigned maxkeys = (uid == 0) ?
 814				key_quota_root_maxkeys : key_quota_maxkeys;
 815			unsigned maxbytes = (uid == 0) ?
 816				key_quota_root_maxbytes : key_quota_maxbytes;
 817
 818			spin_lock(&newowner->lock);
 819			if (newowner->qnkeys + 1 >= maxkeys ||
 820			    newowner->qnbytes + key->quotalen >= maxbytes ||
 821			    newowner->qnbytes + key->quotalen <
 822			    newowner->qnbytes)
 823				goto quota_overrun;
 824
 825			newowner->qnkeys++;
 826			newowner->qnbytes += key->quotalen;
 827			spin_unlock(&newowner->lock);
 828
 829			spin_lock(&key->user->lock);
 830			key->user->qnkeys--;
 831			key->user->qnbytes -= key->quotalen;
 832			spin_unlock(&key->user->lock);
 833		}
 834
 835		atomic_dec(&key->user->nkeys);
 836		atomic_inc(&newowner->nkeys);
 837
 838		if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
 839			atomic_dec(&key->user->nikeys);
 840			atomic_inc(&newowner->nikeys);
 841		}
 842
 843		zapowner = key->user;
 844		key->user = newowner;
 845		key->uid = uid;
 846	}
 847
 848	/* change the GID */
 849	if (gid != (gid_t) -1)
 850		key->gid = gid;
 851
 852	ret = 0;
 853
 854error_put:
 855	up_write(&key->sem);
 856	key_put(key);
 857	if (zapowner)
 858		key_user_put(zapowner);
 859error:
 860	return ret;
 861
 862quota_overrun:
 863	spin_unlock(&newowner->lock);
 864	zapowner = newowner;
 865	ret = -EDQUOT;
 866	goto error_put;
 867}
 868
 869/*
 870 * Change the permission mask on a key.
 871 *
 872 * The key must grant the caller Setattr permission for this to work, though
 873 * the key need not be fully instantiated yet.  If the caller does not have
 874 * sysadmin capability, it may only change the permission on keys that it owns.
 875 */
 876long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
 877{
 878	struct key *key;
 879	key_ref_t key_ref;
 880	long ret;
 881
 882	ret = -EINVAL;
 883	if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
 884		goto error;
 885
 886	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
 887				  KEY_SETATTR);
 888	if (IS_ERR(key_ref)) {
 889		ret = PTR_ERR(key_ref);
 890		goto error;
 891	}
 892
 893	key = key_ref_to_ptr(key_ref);
 894
 895	/* make the changes with the locks held to prevent chown/chmod races */
 896	ret = -EACCES;
 897	down_write(&key->sem);
 898
 899	/* if we're not the sysadmin, we can only change a key that we own */
 900	if (capable(CAP_SYS_ADMIN) || key->uid == current_fsuid()) {
 901		key->perm = perm;
 902		ret = 0;
 903	}
 904
 905	up_write(&key->sem);
 906	key_put(key);
 907error:
 908	return ret;
 909}
 910
 911/*
 912 * Get the destination keyring for instantiation and check that the caller has
 913 * Write permission on it.
 914 */
 915static long get_instantiation_keyring(key_serial_t ringid,
 916				      struct request_key_auth *rka,
 917				      struct key **_dest_keyring)
 918{
 919	key_ref_t dkref;
 920
 921	*_dest_keyring = NULL;
 922
 923	/* just return a NULL pointer if we weren't asked to make a link */
 924	if (ringid == 0)
 925		return 0;
 926
 927	/* if a specific keyring is nominated by ID, then use that */
 928	if (ringid > 0) {
 929		dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
 930		if (IS_ERR(dkref))
 931			return PTR_ERR(dkref);
 932		*_dest_keyring = key_ref_to_ptr(dkref);
 933		return 0;
 934	}
 935
 936	if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
 937		return -EINVAL;
 938
 939	/* otherwise specify the destination keyring recorded in the
 940	 * authorisation key (any KEY_SPEC_*_KEYRING) */
 941	if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
 942		*_dest_keyring = key_get(rka->dest_keyring);
 943		return 0;
 944	}
 945
 946	return -ENOKEY;
 947}
 948
 949/*
 950 * Change the request_key authorisation key on the current process.
 951 */
 952static int keyctl_change_reqkey_auth(struct key *key)
 953{
 954	struct cred *new;
 955
 956	new = prepare_creds();
 957	if (!new)
 958		return -ENOMEM;
 959
 960	key_put(new->request_key_auth);
 961	new->request_key_auth = key_get(key);
 962
 963	return commit_creds(new);
 964}
 965
 966/*
 967 * Copy the iovec data from userspace
 968 */
 969static long copy_from_user_iovec(void *buffer, const struct iovec *iov,
 970				 unsigned ioc)
 971{
 972	for (; ioc > 0; ioc--) {
 973		if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0)
 974			return -EFAULT;
 975		buffer += iov->iov_len;
 976		iov++;
 977	}
 978	return 0;
 979}
 980
 981/*
 982 * Instantiate a key with the specified payload and link the key into the
 983 * destination keyring if one is given.
 984 *
 985 * The caller must have the appropriate instantiation permit set for this to
 986 * work (see keyctl_assume_authority).  No other permissions are required.
 987 *
 988 * If successful, 0 will be returned.
 989 */
 990long keyctl_instantiate_key_common(key_serial_t id,
 991				   const struct iovec *payload_iov,
 992				   unsigned ioc,
 993				   size_t plen,
 994				   key_serial_t ringid)
 995{
 996	const struct cred *cred = current_cred();
 997	struct request_key_auth *rka;
 998	struct key *instkey, *dest_keyring;
 
 999	void *payload;
1000	long ret;
1001	bool vm = false;
1002
1003	kenter("%d,,%zu,%d", id, plen, ringid);
1004
 
 
 
1005	ret = -EINVAL;
1006	if (plen > 1024 * 1024 - 1)
1007		goto error;
1008
1009	/* the appropriate instantiation authorisation key must have been
1010	 * assumed before calling this */
1011	ret = -EPERM;
1012	instkey = cred->request_key_auth;
1013	if (!instkey)
1014		goto error;
1015
1016	rka = instkey->payload.data;
1017	if (rka->target_key->serial != id)
1018		goto error;
1019
1020	/* pull the payload in if one was supplied */
1021	payload = NULL;
1022
1023	if (payload_iov) {
1024		ret = -ENOMEM;
1025		payload = kmalloc(plen, GFP_KERNEL);
1026		if (!payload) {
1027			if (plen <= PAGE_SIZE)
1028				goto error;
1029			vm = true;
1030			payload = vmalloc(plen);
1031			if (!payload)
1032				goto error;
1033		}
1034
1035		ret = copy_from_user_iovec(payload, payload_iov, ioc);
1036		if (ret < 0)
1037			goto error2;
1038	}
1039
1040	/* find the destination keyring amongst those belonging to the
1041	 * requesting task */
1042	ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1043	if (ret < 0)
1044		goto error2;
1045
1046	/* instantiate the key and link it into a keyring */
1047	ret = key_instantiate_and_link(rka->target_key, payload, plen,
1048				       dest_keyring, instkey);
1049
1050	key_put(dest_keyring);
1051
1052	/* discard the assumed authority if it's just been disabled by
1053	 * instantiation of the key */
1054	if (ret == 0)
1055		keyctl_change_reqkey_auth(NULL);
1056
1057error2:
1058	if (!vm)
1059		kfree(payload);
1060	else
1061		vfree(payload);
1062error:
1063	return ret;
1064}
1065
1066/*
1067 * Instantiate a key with the specified payload and link the key into the
1068 * destination keyring if one is given.
1069 *
1070 * The caller must have the appropriate instantiation permit set for this to
1071 * work (see keyctl_assume_authority).  No other permissions are required.
1072 *
1073 * If successful, 0 will be returned.
1074 */
1075long keyctl_instantiate_key(key_serial_t id,
1076			    const void __user *_payload,
1077			    size_t plen,
1078			    key_serial_t ringid)
1079{
1080	if (_payload && plen) {
1081		struct iovec iov[1] = {
1082			[0].iov_base = (void __user *)_payload,
1083			[0].iov_len  = plen
1084		};
1085
1086		return keyctl_instantiate_key_common(id, iov, 1, plen, ringid);
 
 
 
 
 
1087	}
1088
1089	return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1090}
1091
1092/*
1093 * Instantiate a key with the specified multipart payload and link the key into
1094 * the destination keyring if one is given.
1095 *
1096 * The caller must have the appropriate instantiation permit set for this to
1097 * work (see keyctl_assume_authority).  No other permissions are required.
1098 *
1099 * If successful, 0 will be returned.
1100 */
1101long keyctl_instantiate_key_iov(key_serial_t id,
1102				const struct iovec __user *_payload_iov,
1103				unsigned ioc,
1104				key_serial_t ringid)
1105{
1106	struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
 
1107	long ret;
1108
1109	if (_payload_iov == 0 || ioc == 0)
1110		goto no_payload;
1111
1112	ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc,
1113				    ARRAY_SIZE(iovstack), iovstack, &iov);
1114	if (ret < 0)
1115		return ret;
1116	if (ret == 0)
1117		goto no_payload_free;
1118
1119	ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid);
1120
1121	if (iov != iovstack)
1122		kfree(iov);
1123	return ret;
1124
1125no_payload_free:
1126	if (iov != iovstack)
1127		kfree(iov);
1128no_payload:
1129	return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1130}
1131
1132/*
1133 * Negatively instantiate the key with the given timeout (in seconds) and link
1134 * the key into the destination keyring if one is given.
1135 *
1136 * The caller must have the appropriate instantiation permit set for this to
1137 * work (see keyctl_assume_authority).  No other permissions are required.
1138 *
1139 * The key and any links to the key will be automatically garbage collected
1140 * after the timeout expires.
1141 *
1142 * Negative keys are used to rate limit repeated request_key() calls by causing
1143 * them to return -ENOKEY until the negative key expires.
1144 *
1145 * If successful, 0 will be returned.
1146 */
1147long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1148{
1149	return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1150}
1151
1152/*
1153 * Negatively instantiate the key with the given timeout (in seconds) and error
1154 * code and link the key into the destination keyring if one is given.
1155 *
1156 * The caller must have the appropriate instantiation permit set for this to
1157 * work (see keyctl_assume_authority).  No other permissions are required.
1158 *
1159 * The key and any links to the key will be automatically garbage collected
1160 * after the timeout expires.
1161 *
1162 * Negative keys are used to rate limit repeated request_key() calls by causing
1163 * them to return the specified error code until the negative key expires.
1164 *
1165 * If successful, 0 will be returned.
1166 */
1167long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1168		       key_serial_t ringid)
1169{
1170	const struct cred *cred = current_cred();
1171	struct request_key_auth *rka;
1172	struct key *instkey, *dest_keyring;
1173	long ret;
1174
1175	kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1176
1177	/* must be a valid error code and mustn't be a kernel special */
1178	if (error <= 0 ||
1179	    error >= MAX_ERRNO ||
1180	    error == ERESTARTSYS ||
1181	    error == ERESTARTNOINTR ||
1182	    error == ERESTARTNOHAND ||
1183	    error == ERESTART_RESTARTBLOCK)
1184		return -EINVAL;
1185
1186	/* the appropriate instantiation authorisation key must have been
1187	 * assumed before calling this */
1188	ret = -EPERM;
1189	instkey = cred->request_key_auth;
1190	if (!instkey)
1191		goto error;
1192
1193	rka = instkey->payload.data;
1194	if (rka->target_key->serial != id)
1195		goto error;
1196
1197	/* find the destination keyring if present (which must also be
1198	 * writable) */
1199	ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1200	if (ret < 0)
1201		goto error;
1202
1203	/* instantiate the key and link it into a keyring */
1204	ret = key_reject_and_link(rka->target_key, timeout, error,
1205				  dest_keyring, instkey);
1206
1207	key_put(dest_keyring);
1208
1209	/* discard the assumed authority if it's just been disabled by
1210	 * instantiation of the key */
1211	if (ret == 0)
1212		keyctl_change_reqkey_auth(NULL);
1213
1214error:
1215	return ret;
1216}
1217
1218/*
1219 * Read or set the default keyring in which request_key() will cache keys and
1220 * return the old setting.
1221 *
1222 * If a process keyring is specified then this will be created if it doesn't
1223 * yet exist.  The old setting will be returned if successful.
1224 */
1225long keyctl_set_reqkey_keyring(int reqkey_defl)
1226{
1227	struct cred *new;
1228	int ret, old_setting;
1229
1230	old_setting = current_cred_xxx(jit_keyring);
1231
1232	if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1233		return old_setting;
1234
1235	new = prepare_creds();
1236	if (!new)
1237		return -ENOMEM;
1238
1239	switch (reqkey_defl) {
1240	case KEY_REQKEY_DEFL_THREAD_KEYRING:
1241		ret = install_thread_keyring_to_cred(new);
1242		if (ret < 0)
1243			goto error;
1244		goto set;
1245
1246	case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1247		ret = install_process_keyring_to_cred(new);
1248		if (ret < 0) {
1249			if (ret != -EEXIST)
1250				goto error;
1251			ret = 0;
1252		}
1253		goto set;
1254
1255	case KEY_REQKEY_DEFL_DEFAULT:
1256	case KEY_REQKEY_DEFL_SESSION_KEYRING:
1257	case KEY_REQKEY_DEFL_USER_KEYRING:
1258	case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1259	case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1260		goto set;
1261
1262	case KEY_REQKEY_DEFL_NO_CHANGE:
1263	case KEY_REQKEY_DEFL_GROUP_KEYRING:
1264	default:
1265		ret = -EINVAL;
1266		goto error;
1267	}
1268
1269set:
1270	new->jit_keyring = reqkey_defl;
1271	commit_creds(new);
1272	return old_setting;
1273error:
1274	abort_creds(new);
1275	return ret;
1276}
1277
1278/*
1279 * Set or clear the timeout on a key.
1280 *
1281 * Either the key must grant the caller Setattr permission or else the caller
1282 * must hold an instantiation authorisation token for the key.
1283 *
1284 * The timeout is either 0 to clear the timeout, or a number of seconds from
1285 * the current time.  The key and any links to the key will be automatically
1286 * garbage collected after the timeout expires.
1287 *
 
 
1288 * If successful, 0 is returned.
1289 */
1290long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1291{
1292	struct key *key, *instkey;
1293	key_ref_t key_ref;
1294	long ret;
1295
1296	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1297				  KEY_SETATTR);
1298	if (IS_ERR(key_ref)) {
1299		/* setting the timeout on a key under construction is permitted
1300		 * if we have the authorisation token handy */
1301		if (PTR_ERR(key_ref) == -EACCES) {
1302			instkey = key_get_instantiation_authkey(id);
1303			if (!IS_ERR(instkey)) {
1304				key_put(instkey);
1305				key_ref = lookup_user_key(id,
1306							  KEY_LOOKUP_PARTIAL,
1307							  0);
1308				if (!IS_ERR(key_ref))
1309					goto okay;
1310			}
1311		}
1312
1313		ret = PTR_ERR(key_ref);
1314		goto error;
1315	}
1316
1317okay:
1318	key = key_ref_to_ptr(key_ref);
1319	key_set_timeout(key, timeout);
 
 
 
 
1320	key_put(key);
1321
1322	ret = 0;
1323error:
1324	return ret;
1325}
1326
1327/*
1328 * Assume (or clear) the authority to instantiate the specified key.
1329 *
1330 * This sets the authoritative token currently in force for key instantiation.
1331 * This must be done for a key to be instantiated.  It has the effect of making
1332 * available all the keys from the caller of the request_key() that created a
1333 * key to request_key() calls made by the caller of this function.
1334 *
1335 * The caller must have the instantiation key in their process keyrings with a
1336 * Search permission grant available to the caller.
1337 *
1338 * If the ID given is 0, then the setting will be cleared and 0 returned.
1339 *
1340 * If the ID given has a matching an authorisation key, then that key will be
1341 * set and its ID will be returned.  The authorisation key can be read to get
1342 * the callout information passed to request_key().
1343 */
1344long keyctl_assume_authority(key_serial_t id)
1345{
1346	struct key *authkey;
1347	long ret;
1348
1349	/* special key IDs aren't permitted */
1350	ret = -EINVAL;
1351	if (id < 0)
1352		goto error;
1353
1354	/* we divest ourselves of authority if given an ID of 0 */
1355	if (id == 0) {
1356		ret = keyctl_change_reqkey_auth(NULL);
1357		goto error;
1358	}
1359
1360	/* attempt to assume the authority temporarily granted to us whilst we
1361	 * instantiate the specified key
1362	 * - the authorisation key must be in the current task's keyrings
1363	 *   somewhere
1364	 */
1365	authkey = key_get_instantiation_authkey(id);
1366	if (IS_ERR(authkey)) {
1367		ret = PTR_ERR(authkey);
1368		goto error;
1369	}
1370
1371	ret = keyctl_change_reqkey_auth(authkey);
1372	if (ret < 0)
1373		goto error;
1374	key_put(authkey);
1375
1376	ret = authkey->serial;
1377error:
1378	return ret;
1379}
1380
1381/*
1382 * Get a key's the LSM security label.
1383 *
1384 * The key must grant the caller View permission for this to work.
1385 *
1386 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1387 *
1388 * If successful, the amount of information available will be returned,
1389 * irrespective of how much was copied (including the terminal NUL).
1390 */
1391long keyctl_get_security(key_serial_t keyid,
1392			 char __user *buffer,
1393			 size_t buflen)
1394{
1395	struct key *key, *instkey;
1396	key_ref_t key_ref;
1397	char *context;
1398	long ret;
1399
1400	key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
1401	if (IS_ERR(key_ref)) {
1402		if (PTR_ERR(key_ref) != -EACCES)
1403			return PTR_ERR(key_ref);
1404
1405		/* viewing a key under construction is also permitted if we
1406		 * have the authorisation token handy */
1407		instkey = key_get_instantiation_authkey(keyid);
1408		if (IS_ERR(instkey))
1409			return PTR_ERR(instkey);
1410		key_put(instkey);
1411
1412		key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1413		if (IS_ERR(key_ref))
1414			return PTR_ERR(key_ref);
1415	}
1416
1417	key = key_ref_to_ptr(key_ref);
1418	ret = security_key_getsecurity(key, &context);
1419	if (ret == 0) {
1420		/* if no information was returned, give userspace an empty
1421		 * string */
1422		ret = 1;
1423		if (buffer && buflen > 0 &&
1424		    copy_to_user(buffer, "", 1) != 0)
1425			ret = -EFAULT;
1426	} else if (ret > 0) {
1427		/* return as much data as there's room for */
1428		if (buffer && buflen > 0) {
1429			if (buflen > ret)
1430				buflen = ret;
1431
1432			if (copy_to_user(buffer, context, buflen) != 0)
1433				ret = -EFAULT;
1434		}
1435
1436		kfree(context);
1437	}
1438
1439	key_ref_put(key_ref);
1440	return ret;
1441}
1442
1443/*
1444 * Attempt to install the calling process's session keyring on the process's
1445 * parent process.
1446 *
1447 * The keyring must exist and must grant the caller LINK permission, and the
1448 * parent process must be single-threaded and must have the same effective
1449 * ownership as this process and mustn't be SUID/SGID.
1450 *
1451 * The keyring will be emplaced on the parent when it next resumes userspace.
1452 *
1453 * If successful, 0 will be returned.
1454 */
1455long keyctl_session_to_parent(void)
1456{
1457	struct task_struct *me, *parent;
1458	const struct cred *mycred, *pcred;
1459	struct task_work *newwork, *oldwork;
1460	key_ref_t keyring_r;
1461	struct cred *cred;
1462	int ret;
1463
1464	keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK);
1465	if (IS_ERR(keyring_r))
1466		return PTR_ERR(keyring_r);
1467
1468	ret = -ENOMEM;
1469	newwork = kmalloc(sizeof(struct task_work), GFP_KERNEL);
1470	if (!newwork)
1471		goto error_keyring;
1472
1473	/* our parent is going to need a new cred struct, a new tgcred struct
1474	 * and new security data, so we allocate them here to prevent ENOMEM in
1475	 * our parent */
1476	cred = cred_alloc_blank();
1477	if (!cred)
1478		goto error_newwork;
 
1479
1480	cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
1481	init_task_work(newwork, key_change_session_keyring, cred);
 
1482
1483	me = current;
1484	rcu_read_lock();
1485	write_lock_irq(&tasklist_lock);
1486
1487	ret = -EPERM;
1488	oldwork = NULL;
1489	parent = me->real_parent;
 
1490
1491	/* the parent mustn't be init and mustn't be a kernel thread */
1492	if (parent->pid <= 1 || !parent->mm)
1493		goto unlock;
1494
1495	/* the parent must be single threaded */
1496	if (!thread_group_empty(parent))
1497		goto unlock;
1498
1499	/* the parent and the child must have different session keyrings or
1500	 * there's no point */
1501	mycred = current_cred();
1502	pcred = __task_cred(parent);
1503	if (mycred == pcred ||
1504	    mycred->tgcred->session_keyring == pcred->tgcred->session_keyring) {
1505		ret = 0;
1506		goto unlock;
1507	}
1508
1509	/* the parent must have the same effective ownership and mustn't be
1510	 * SUID/SGID */
1511	if (pcred->uid	!= mycred->euid	||
1512	    pcred->euid	!= mycred->euid	||
1513	    pcred->suid	!= mycred->euid	||
1514	    pcred->gid	!= mycred->egid	||
1515	    pcred->egid	!= mycred->egid	||
1516	    pcred->sgid	!= mycred->egid)
1517		goto unlock;
1518
1519	/* the keyrings must have the same UID */
1520	if ((pcred->tgcred->session_keyring &&
1521	     pcred->tgcred->session_keyring->uid != mycred->euid) ||
1522	    mycred->tgcred->session_keyring->uid != mycred->euid)
1523		goto unlock;
1524
1525	/* cancel an already pending keyring replacement */
1526	oldwork = task_work_cancel(parent, key_change_session_keyring);
1527
1528	/* the replacement session keyring is applied just prior to userspace
1529	 * restarting */
1530	ret = task_work_add(parent, newwork, true);
1531	if (!ret)
1532		newwork = NULL;
1533unlock:
1534	write_unlock_irq(&tasklist_lock);
1535	rcu_read_unlock();
1536	if (oldwork) {
1537		put_cred(oldwork->data);
1538		kfree(oldwork);
1539	}
1540	if (newwork) {
1541		put_cred(newwork->data);
1542		kfree(newwork);
1543	}
1544	return ret;
1545
1546error_newwork:
1547	kfree(newwork);
1548error_keyring:
1549	key_ref_put(keyring_r);
1550	return ret;
1551}
1552
1553/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1554 * The key control system call
1555 */
1556SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1557		unsigned long, arg4, unsigned long, arg5)
1558{
1559	switch (option) {
1560	case KEYCTL_GET_KEYRING_ID:
1561		return keyctl_get_keyring_ID((key_serial_t) arg2,
1562					     (int) arg3);
1563
1564	case KEYCTL_JOIN_SESSION_KEYRING:
1565		return keyctl_join_session_keyring((const char __user *) arg2);
1566
1567	case KEYCTL_UPDATE:
1568		return keyctl_update_key((key_serial_t) arg2,
1569					 (const void __user *) arg3,
1570					 (size_t) arg4);
1571
1572	case KEYCTL_REVOKE:
1573		return keyctl_revoke_key((key_serial_t) arg2);
1574
1575	case KEYCTL_DESCRIBE:
1576		return keyctl_describe_key((key_serial_t) arg2,
1577					   (char __user *) arg3,
1578					   (unsigned) arg4);
1579
1580	case KEYCTL_CLEAR:
1581		return keyctl_keyring_clear((key_serial_t) arg2);
1582
1583	case KEYCTL_LINK:
1584		return keyctl_keyring_link((key_serial_t) arg2,
1585					   (key_serial_t) arg3);
1586
1587	case KEYCTL_UNLINK:
1588		return keyctl_keyring_unlink((key_serial_t) arg2,
1589					     (key_serial_t) arg3);
1590
1591	case KEYCTL_SEARCH:
1592		return keyctl_keyring_search((key_serial_t) arg2,
1593					     (const char __user *) arg3,
1594					     (const char __user *) arg4,
1595					     (key_serial_t) arg5);
1596
1597	case KEYCTL_READ:
1598		return keyctl_read_key((key_serial_t) arg2,
1599				       (char __user *) arg3,
1600				       (size_t) arg4);
1601
1602	case KEYCTL_CHOWN:
1603		return keyctl_chown_key((key_serial_t) arg2,
1604					(uid_t) arg3,
1605					(gid_t) arg4);
1606
1607	case KEYCTL_SETPERM:
1608		return keyctl_setperm_key((key_serial_t) arg2,
1609					  (key_perm_t) arg3);
1610
1611	case KEYCTL_INSTANTIATE:
1612		return keyctl_instantiate_key((key_serial_t) arg2,
1613					      (const void __user *) arg3,
1614					      (size_t) arg4,
1615					      (key_serial_t) arg5);
1616
1617	case KEYCTL_NEGATE:
1618		return keyctl_negate_key((key_serial_t) arg2,
1619					 (unsigned) arg3,
1620					 (key_serial_t) arg4);
1621
1622	case KEYCTL_SET_REQKEY_KEYRING:
1623		return keyctl_set_reqkey_keyring(arg2);
1624
1625	case KEYCTL_SET_TIMEOUT:
1626		return keyctl_set_timeout((key_serial_t) arg2,
1627					  (unsigned) arg3);
1628
1629	case KEYCTL_ASSUME_AUTHORITY:
1630		return keyctl_assume_authority((key_serial_t) arg2);
1631
1632	case KEYCTL_GET_SECURITY:
1633		return keyctl_get_security((key_serial_t) arg2,
1634					   (char __user *) arg3,
1635					   (size_t) arg4);
1636
1637	case KEYCTL_SESSION_TO_PARENT:
1638		return keyctl_session_to_parent();
1639
1640	case KEYCTL_REJECT:
1641		return keyctl_reject_key((key_serial_t) arg2,
1642					 (unsigned) arg3,
1643					 (unsigned) arg4,
1644					 (key_serial_t) arg5);
1645
1646	case KEYCTL_INSTANTIATE_IOV:
1647		return keyctl_instantiate_key_iov(
1648			(key_serial_t) arg2,
1649			(const struct iovec __user *) arg3,
1650			(unsigned) arg4,
1651			(key_serial_t) arg5);
1652
1653	case KEYCTL_INVALIDATE:
1654		return keyctl_invalidate_key((key_serial_t) arg2);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1655
1656	default:
1657		return -EOPNOTSUPP;
1658	}
1659}
v5.4
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* Userspace key control operations
   3 *
   4 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
   5 * Written by David Howells (dhowells@redhat.com)
 
 
 
 
 
   6 */
   7
 
   8#include <linux/init.h>
   9#include <linux/sched.h>
  10#include <linux/sched/task.h>
  11#include <linux/slab.h>
  12#include <linux/syscalls.h>
  13#include <linux/key.h>
  14#include <linux/keyctl.h>
  15#include <linux/fs.h>
  16#include <linux/capability.h>
  17#include <linux/cred.h>
  18#include <linux/string.h>
  19#include <linux/err.h>
  20#include <linux/vmalloc.h>
  21#include <linux/security.h>
  22#include <linux/uio.h>
  23#include <linux/uaccess.h>
  24#include <keys/request_key_auth-type.h>
  25#include "internal.h"
  26
  27#define KEY_MAX_DESC_SIZE 4096
  28
  29static const unsigned char keyrings_capabilities[2] = {
  30	[0] = (KEYCTL_CAPS0_CAPABILITIES |
  31	       (IS_ENABLED(CONFIG_PERSISTENT_KEYRINGS)	? KEYCTL_CAPS0_PERSISTENT_KEYRINGS : 0) |
  32	       (IS_ENABLED(CONFIG_KEY_DH_OPERATIONS)	? KEYCTL_CAPS0_DIFFIE_HELLMAN : 0) |
  33	       (IS_ENABLED(CONFIG_ASYMMETRIC_KEY_TYPE)	? KEYCTL_CAPS0_PUBLIC_KEY : 0) |
  34	       (IS_ENABLED(CONFIG_BIG_KEYS)		? KEYCTL_CAPS0_BIG_KEY : 0) |
  35	       KEYCTL_CAPS0_INVALIDATE |
  36	       KEYCTL_CAPS0_RESTRICT_KEYRING |
  37	       KEYCTL_CAPS0_MOVE
  38	       ),
  39	[1] = (KEYCTL_CAPS1_NS_KEYRING_NAME |
  40	       KEYCTL_CAPS1_NS_KEY_TAG),
  41};
  42
  43static int key_get_type_from_user(char *type,
  44				  const char __user *_type,
  45				  unsigned len)
  46{
  47	int ret;
  48
  49	ret = strncpy_from_user(type, _type, len);
  50	if (ret < 0)
  51		return ret;
  52	if (ret == 0 || ret >= len)
  53		return -EINVAL;
  54	if (type[0] == '.')
  55		return -EPERM;
  56	type[len - 1] = '\0';
  57	return 0;
  58}
  59
  60/*
  61 * Extract the description of a new key from userspace and either add it as a
  62 * new key to the specified keyring or update a matching key in that keyring.
  63 *
  64 * If the description is NULL or an empty string, the key type is asked to
  65 * generate one from the payload.
  66 *
  67 * The keyring must be writable so that we can attach the key to it.
  68 *
  69 * If successful, the new key's serial number is returned, otherwise an error
  70 * code is returned.
  71 */
  72SYSCALL_DEFINE5(add_key, const char __user *, _type,
  73		const char __user *, _description,
  74		const void __user *, _payload,
  75		size_t, plen,
  76		key_serial_t, ringid)
  77{
  78	key_ref_t keyring_ref, key_ref;
  79	char type[32], *description;
  80	void *payload;
  81	long ret;
 
  82
  83	ret = -EINVAL;
  84	if (plen > 1024 * 1024 - 1)
  85		goto error;
  86
  87	/* draw all the data into kernel space */
  88	ret = key_get_type_from_user(type, _type, sizeof(type));
  89	if (ret < 0)
  90		goto error;
  91
  92	description = NULL;
  93	if (_description) {
  94		description = strndup_user(_description, KEY_MAX_DESC_SIZE);
  95		if (IS_ERR(description)) {
  96			ret = PTR_ERR(description);
  97			goto error;
  98		}
  99		if (!*description) {
 100			kfree(description);
 101			description = NULL;
 102		} else if ((description[0] == '.') &&
 103			   (strncmp(type, "keyring", 7) == 0)) {
 104			ret = -EPERM;
 105			goto error2;
 106		}
 107	}
 108
 109	/* pull the payload in if one was supplied */
 110	payload = NULL;
 111
 112	if (plen) {
 
 113		ret = -ENOMEM;
 114		payload = kvmalloc(plen, GFP_KERNEL);
 115		if (!payload)
 116			goto error2;
 
 
 
 
 
 
 117
 118		ret = -EFAULT;
 119		if (copy_from_user(payload, _payload, plen) != 0)
 120			goto error3;
 121	}
 122
 123	/* find the target keyring (which must be writable) */
 124	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
 125	if (IS_ERR(keyring_ref)) {
 126		ret = PTR_ERR(keyring_ref);
 127		goto error3;
 128	}
 129
 130	/* create or update the requested key and add it to the target
 131	 * keyring */
 132	key_ref = key_create_or_update(keyring_ref, type, description,
 133				       payload, plen, KEY_PERM_UNDEF,
 134				       KEY_ALLOC_IN_QUOTA);
 135	if (!IS_ERR(key_ref)) {
 136		ret = key_ref_to_ptr(key_ref)->serial;
 137		key_ref_put(key_ref);
 138	}
 139	else {
 140		ret = PTR_ERR(key_ref);
 141	}
 142
 143	key_ref_put(keyring_ref);
 144 error3:
 145	if (payload) {
 146		memzero_explicit(payload, plen);
 147		kvfree(payload);
 148	}
 149 error2:
 150	kfree(description);
 151 error:
 152	return ret;
 153}
 154
 155/*
 156 * Search the process keyrings and keyring trees linked from those for a
 157 * matching key.  Keyrings must have appropriate Search permission to be
 158 * searched.
 159 *
 160 * If a key is found, it will be attached to the destination keyring if there's
 161 * one specified and the serial number of the key will be returned.
 162 *
 163 * If no key is found, /sbin/request-key will be invoked if _callout_info is
 164 * non-NULL in an attempt to create a key.  The _callout_info string will be
 165 * passed to /sbin/request-key to aid with completing the request.  If the
 166 * _callout_info string is "" then it will be changed to "-".
 167 */
 168SYSCALL_DEFINE4(request_key, const char __user *, _type,
 169		const char __user *, _description,
 170		const char __user *, _callout_info,
 171		key_serial_t, destringid)
 172{
 173	struct key_type *ktype;
 174	struct key *key;
 175	key_ref_t dest_ref;
 176	size_t callout_len;
 177	char type[32], *description, *callout_info;
 178	long ret;
 179
 180	/* pull the type into kernel space */
 181	ret = key_get_type_from_user(type, _type, sizeof(type));
 182	if (ret < 0)
 183		goto error;
 184
 185	/* pull the description into kernel space */
 186	description = strndup_user(_description, KEY_MAX_DESC_SIZE);
 187	if (IS_ERR(description)) {
 188		ret = PTR_ERR(description);
 189		goto error;
 190	}
 191
 192	/* pull the callout info into kernel space */
 193	callout_info = NULL;
 194	callout_len = 0;
 195	if (_callout_info) {
 196		callout_info = strndup_user(_callout_info, PAGE_SIZE);
 197		if (IS_ERR(callout_info)) {
 198			ret = PTR_ERR(callout_info);
 199			goto error2;
 200		}
 201		callout_len = strlen(callout_info);
 202	}
 203
 204	/* get the destination keyring if specified */
 205	dest_ref = NULL;
 206	if (destringid) {
 207		dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
 208					   KEY_NEED_WRITE);
 209		if (IS_ERR(dest_ref)) {
 210			ret = PTR_ERR(dest_ref);
 211			goto error3;
 212		}
 213	}
 214
 215	/* find the key type */
 216	ktype = key_type_lookup(type);
 217	if (IS_ERR(ktype)) {
 218		ret = PTR_ERR(ktype);
 219		goto error4;
 220	}
 221
 222	/* do the search */
 223	key = request_key_and_link(ktype, description, NULL, callout_info,
 224				   callout_len, NULL, key_ref_to_ptr(dest_ref),
 225				   KEY_ALLOC_IN_QUOTA);
 226	if (IS_ERR(key)) {
 227		ret = PTR_ERR(key);
 228		goto error5;
 229	}
 230
 231	/* wait for the key to finish being constructed */
 232	ret = wait_for_key_construction(key, 1);
 233	if (ret < 0)
 234		goto error6;
 235
 236	ret = key->serial;
 237
 238error6:
 239 	key_put(key);
 240error5:
 241	key_type_put(ktype);
 242error4:
 243	key_ref_put(dest_ref);
 244error3:
 245	kfree(callout_info);
 246error2:
 247	kfree(description);
 248error:
 249	return ret;
 250}
 251
 252/*
 253 * Get the ID of the specified process keyring.
 254 *
 255 * The requested keyring must have search permission to be found.
 256 *
 257 * If successful, the ID of the requested keyring will be returned.
 258 */
 259long keyctl_get_keyring_ID(key_serial_t id, int create)
 260{
 261	key_ref_t key_ref;
 262	unsigned long lflags;
 263	long ret;
 264
 265	lflags = create ? KEY_LOOKUP_CREATE : 0;
 266	key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
 267	if (IS_ERR(key_ref)) {
 268		ret = PTR_ERR(key_ref);
 269		goto error;
 270	}
 271
 272	ret = key_ref_to_ptr(key_ref)->serial;
 273	key_ref_put(key_ref);
 274error:
 275	return ret;
 276}
 277
 278/*
 279 * Join a (named) session keyring.
 280 *
 281 * Create and join an anonymous session keyring or join a named session
 282 * keyring, creating it if necessary.  A named session keyring must have Search
 283 * permission for it to be joined.  Session keyrings without this permit will
 284 * be skipped over.  It is not permitted for userspace to create or join
 285 * keyrings whose name begin with a dot.
 286 *
 287 * If successful, the ID of the joined session keyring will be returned.
 288 */
 289long keyctl_join_session_keyring(const char __user *_name)
 290{
 291	char *name;
 292	long ret;
 293
 294	/* fetch the name from userspace */
 295	name = NULL;
 296	if (_name) {
 297		name = strndup_user(_name, KEY_MAX_DESC_SIZE);
 298		if (IS_ERR(name)) {
 299			ret = PTR_ERR(name);
 300			goto error;
 301		}
 302
 303		ret = -EPERM;
 304		if (name[0] == '.')
 305			goto error_name;
 306	}
 307
 308	/* join the session */
 309	ret = join_session_keyring(name);
 310error_name:
 311	kfree(name);
 
 312error:
 313	return ret;
 314}
 315
 316/*
 317 * Update a key's data payload from the given data.
 318 *
 319 * The key must grant the caller Write permission and the key type must support
 320 * updating for this to work.  A negative key can be positively instantiated
 321 * with this call.
 322 *
 323 * If successful, 0 will be returned.  If the key type does not support
 324 * updating, then -EOPNOTSUPP will be returned.
 325 */
 326long keyctl_update_key(key_serial_t id,
 327		       const void __user *_payload,
 328		       size_t plen)
 329{
 330	key_ref_t key_ref;
 331	void *payload;
 332	long ret;
 333
 334	ret = -EINVAL;
 335	if (plen > PAGE_SIZE)
 336		goto error;
 337
 338	/* pull the payload in if one was supplied */
 339	payload = NULL;
 340	if (plen) {
 341		ret = -ENOMEM;
 342		payload = kmalloc(plen, GFP_KERNEL);
 343		if (!payload)
 344			goto error;
 345
 346		ret = -EFAULT;
 347		if (copy_from_user(payload, _payload, plen) != 0)
 348			goto error2;
 349	}
 350
 351	/* find the target key (which must be writable) */
 352	key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
 353	if (IS_ERR(key_ref)) {
 354		ret = PTR_ERR(key_ref);
 355		goto error2;
 356	}
 357
 358	/* update the key */
 359	ret = key_update(key_ref, payload, plen);
 360
 361	key_ref_put(key_ref);
 362error2:
 363	kzfree(payload);
 364error:
 365	return ret;
 366}
 367
 368/*
 369 * Revoke a key.
 370 *
 371 * The key must be grant the caller Write or Setattr permission for this to
 372 * work.  The key type should give up its quota claim when revoked.  The key
 373 * and any links to the key will be automatically garbage collected after a
 374 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
 375 *
 376 * Keys with KEY_FLAG_KEEP set should not be revoked.
 377 *
 378 * If successful, 0 is returned.
 379 */
 380long keyctl_revoke_key(key_serial_t id)
 381{
 382	key_ref_t key_ref;
 383	struct key *key;
 384	long ret;
 385
 386	key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
 387	if (IS_ERR(key_ref)) {
 388		ret = PTR_ERR(key_ref);
 389		if (ret != -EACCES)
 390			goto error;
 391		key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
 392		if (IS_ERR(key_ref)) {
 393			ret = PTR_ERR(key_ref);
 394			goto error;
 395		}
 396	}
 397
 398	key = key_ref_to_ptr(key_ref);
 399	ret = 0;
 400	if (test_bit(KEY_FLAG_KEEP, &key->flags))
 401		ret = -EPERM;
 402	else
 403		key_revoke(key);
 404
 405	key_ref_put(key_ref);
 406error:
 407	return ret;
 408}
 409
 410/*
 411 * Invalidate a key.
 412 *
 413 * The key must be grant the caller Invalidate permission for this to work.
 414 * The key and any links to the key will be automatically garbage collected
 415 * immediately.
 416 *
 417 * Keys with KEY_FLAG_KEEP set should not be invalidated.
 418 *
 419 * If successful, 0 is returned.
 420 */
 421long keyctl_invalidate_key(key_serial_t id)
 422{
 423	key_ref_t key_ref;
 424	struct key *key;
 425	long ret;
 426
 427	kenter("%d", id);
 428
 429	key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
 430	if (IS_ERR(key_ref)) {
 431		ret = PTR_ERR(key_ref);
 432
 433		/* Root is permitted to invalidate certain special keys */
 434		if (capable(CAP_SYS_ADMIN)) {
 435			key_ref = lookup_user_key(id, 0, 0);
 436			if (IS_ERR(key_ref))
 437				goto error;
 438			if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
 439				     &key_ref_to_ptr(key_ref)->flags))
 440				goto invalidate;
 441			goto error_put;
 442		}
 443
 444		goto error;
 445	}
 446
 447invalidate:
 448	key = key_ref_to_ptr(key_ref);
 449	ret = 0;
 450	if (test_bit(KEY_FLAG_KEEP, &key->flags))
 451		ret = -EPERM;
 452	else
 453		key_invalidate(key);
 454error_put:
 455	key_ref_put(key_ref);
 456error:
 457	kleave(" = %ld", ret);
 458	return ret;
 459}
 460
 461/*
 462 * Clear the specified keyring, creating an empty process keyring if one of the
 463 * special keyring IDs is used.
 464 *
 465 * The keyring must grant the caller Write permission and not have
 466 * KEY_FLAG_KEEP set for this to work.  If successful, 0 will be returned.
 467 */
 468long keyctl_keyring_clear(key_serial_t ringid)
 469{
 470	key_ref_t keyring_ref;
 471	struct key *keyring;
 472	long ret;
 473
 474	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
 475	if (IS_ERR(keyring_ref)) {
 476		ret = PTR_ERR(keyring_ref);
 477
 478		/* Root is permitted to invalidate certain special keyrings */
 479		if (capable(CAP_SYS_ADMIN)) {
 480			keyring_ref = lookup_user_key(ringid, 0, 0);
 481			if (IS_ERR(keyring_ref))
 482				goto error;
 483			if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
 484				     &key_ref_to_ptr(keyring_ref)->flags))
 485				goto clear;
 486			goto error_put;
 487		}
 488
 489		goto error;
 490	}
 491
 492clear:
 493	keyring = key_ref_to_ptr(keyring_ref);
 494	if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
 495		ret = -EPERM;
 496	else
 497		ret = keyring_clear(keyring);
 498error_put:
 499	key_ref_put(keyring_ref);
 500error:
 501	return ret;
 502}
 503
 504/*
 505 * Create a link from a keyring to a key if there's no matching key in the
 506 * keyring, otherwise replace the link to the matching key with a link to the
 507 * new key.
 508 *
 509 * The key must grant the caller Link permission and the the keyring must grant
 510 * the caller Write permission.  Furthermore, if an additional link is created,
 511 * the keyring's quota will be extended.
 512 *
 513 * If successful, 0 will be returned.
 514 */
 515long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
 516{
 517	key_ref_t keyring_ref, key_ref;
 518	long ret;
 519
 520	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
 521	if (IS_ERR(keyring_ref)) {
 522		ret = PTR_ERR(keyring_ref);
 523		goto error;
 524	}
 525
 526	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
 527	if (IS_ERR(key_ref)) {
 528		ret = PTR_ERR(key_ref);
 529		goto error2;
 530	}
 531
 532	ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
 533
 534	key_ref_put(key_ref);
 535error2:
 536	key_ref_put(keyring_ref);
 537error:
 538	return ret;
 539}
 540
 541/*
 542 * Unlink a key from a keyring.
 543 *
 544 * The keyring must grant the caller Write permission for this to work; the key
 545 * itself need not grant the caller anything.  If the last link to a key is
 546 * removed then that key will be scheduled for destruction.
 547 *
 548 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
 549 *
 550 * If successful, 0 will be returned.
 551 */
 552long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
 553{
 554	key_ref_t keyring_ref, key_ref;
 555	struct key *keyring, *key;
 556	long ret;
 557
 558	keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
 559	if (IS_ERR(keyring_ref)) {
 560		ret = PTR_ERR(keyring_ref);
 561		goto error;
 562	}
 563
 564	key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
 565	if (IS_ERR(key_ref)) {
 566		ret = PTR_ERR(key_ref);
 567		goto error2;
 568	}
 569
 570	keyring = key_ref_to_ptr(keyring_ref);
 571	key = key_ref_to_ptr(key_ref);
 572	if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
 573	    test_bit(KEY_FLAG_KEEP, &key->flags))
 574		ret = -EPERM;
 575	else
 576		ret = key_unlink(keyring, key);
 577
 578	key_ref_put(key_ref);
 579error2:
 580	key_ref_put(keyring_ref);
 581error:
 582	return ret;
 583}
 584
 585/*
 586 * Move a link to a key from one keyring to another, displacing any matching
 587 * key from the destination keyring.
 588 *
 589 * The key must grant the caller Link permission and both keyrings must grant
 590 * the caller Write permission.  There must also be a link in the from keyring
 591 * to the key.  If both keyrings are the same, nothing is done.
 592 *
 593 * If successful, 0 will be returned.
 594 */
 595long keyctl_keyring_move(key_serial_t id, key_serial_t from_ringid,
 596			 key_serial_t to_ringid, unsigned int flags)
 597{
 598	key_ref_t key_ref, from_ref, to_ref;
 599	long ret;
 600
 601	if (flags & ~KEYCTL_MOVE_EXCL)
 602		return -EINVAL;
 603
 604	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
 605	if (IS_ERR(key_ref))
 606		return PTR_ERR(key_ref);
 607
 608	from_ref = lookup_user_key(from_ringid, 0, KEY_NEED_WRITE);
 609	if (IS_ERR(from_ref)) {
 610		ret = PTR_ERR(from_ref);
 611		goto error2;
 612	}
 613
 614	to_ref = lookup_user_key(to_ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
 615	if (IS_ERR(to_ref)) {
 616		ret = PTR_ERR(to_ref);
 617		goto error3;
 618	}
 619
 620	ret = key_move(key_ref_to_ptr(key_ref), key_ref_to_ptr(from_ref),
 621		       key_ref_to_ptr(to_ref), flags);
 622
 623	key_ref_put(to_ref);
 624error3:
 625	key_ref_put(from_ref);
 626error2:
 627	key_ref_put(key_ref);
 628	return ret;
 629}
 630
 631/*
 632 * Return a description of a key to userspace.
 633 *
 634 * The key must grant the caller View permission for this to work.
 635 *
 636 * If there's a buffer, we place up to buflen bytes of data into it formatted
 637 * in the following way:
 638 *
 639 *	type;uid;gid;perm;description<NUL>
 640 *
 641 * If successful, we return the amount of description available, irrespective
 642 * of how much we may have copied into the buffer.
 643 */
 644long keyctl_describe_key(key_serial_t keyid,
 645			 char __user *buffer,
 646			 size_t buflen)
 647{
 648	struct key *key, *instkey;
 649	key_ref_t key_ref;
 650	char *infobuf;
 651	long ret;
 652	int desclen, infolen;
 653
 654	key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
 655	if (IS_ERR(key_ref)) {
 656		/* viewing a key under construction is permitted if we have the
 657		 * authorisation token handy */
 658		if (PTR_ERR(key_ref) == -EACCES) {
 659			instkey = key_get_instantiation_authkey(keyid);
 660			if (!IS_ERR(instkey)) {
 661				key_put(instkey);
 662				key_ref = lookup_user_key(keyid,
 663							  KEY_LOOKUP_PARTIAL,
 664							  0);
 665				if (!IS_ERR(key_ref))
 666					goto okay;
 667			}
 668		}
 669
 670		ret = PTR_ERR(key_ref);
 671		goto error;
 672	}
 673
 674okay:
 
 
 
 
 
 
 675	key = key_ref_to_ptr(key_ref);
 676	desclen = strlen(key->description);
 677
 678	/* calculate how much information we're going to return */
 679	ret = -ENOMEM;
 680	infobuf = kasprintf(GFP_KERNEL,
 681			    "%s;%d;%d;%08x;",
 682			    key->type->name,
 683			    from_kuid_munged(current_user_ns(), key->uid),
 684			    from_kgid_munged(current_user_ns(), key->gid),
 685			    key->perm);
 686	if (!infobuf)
 687		goto error2;
 688	infolen = strlen(infobuf);
 689	ret = infolen + desclen + 1;
 
 690
 691	/* consider returning the data */
 692	if (buffer && buflen >= ret) {
 693		if (copy_to_user(buffer, infobuf, infolen) != 0 ||
 694		    copy_to_user(buffer + infolen, key->description,
 695				 desclen + 1) != 0)
 
 696			ret = -EFAULT;
 697	}
 698
 699	kfree(infobuf);
 700error2:
 701	key_ref_put(key_ref);
 702error:
 703	return ret;
 704}
 705
 706/*
 707 * Search the specified keyring and any keyrings it links to for a matching
 708 * key.  Only keyrings that grant the caller Search permission will be searched
 709 * (this includes the starting keyring).  Only keys with Search permission can
 710 * be found.
 711 *
 712 * If successful, the found key will be linked to the destination keyring if
 713 * supplied and the key has Link permission, and the found key ID will be
 714 * returned.
 715 */
 716long keyctl_keyring_search(key_serial_t ringid,
 717			   const char __user *_type,
 718			   const char __user *_description,
 719			   key_serial_t destringid)
 720{
 721	struct key_type *ktype;
 722	key_ref_t keyring_ref, key_ref, dest_ref;
 723	char type[32], *description;
 724	long ret;
 725
 726	/* pull the type and description into kernel space */
 727	ret = key_get_type_from_user(type, _type, sizeof(type));
 728	if (ret < 0)
 729		goto error;
 730
 731	description = strndup_user(_description, KEY_MAX_DESC_SIZE);
 732	if (IS_ERR(description)) {
 733		ret = PTR_ERR(description);
 734		goto error;
 735	}
 736
 737	/* get the keyring at which to begin the search */
 738	keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
 739	if (IS_ERR(keyring_ref)) {
 740		ret = PTR_ERR(keyring_ref);
 741		goto error2;
 742	}
 743
 744	/* get the destination keyring if specified */
 745	dest_ref = NULL;
 746	if (destringid) {
 747		dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
 748					   KEY_NEED_WRITE);
 749		if (IS_ERR(dest_ref)) {
 750			ret = PTR_ERR(dest_ref);
 751			goto error3;
 752		}
 753	}
 754
 755	/* find the key type */
 756	ktype = key_type_lookup(type);
 757	if (IS_ERR(ktype)) {
 758		ret = PTR_ERR(ktype);
 759		goto error4;
 760	}
 761
 762	/* do the search */
 763	key_ref = keyring_search(keyring_ref, ktype, description, true);
 764	if (IS_ERR(key_ref)) {
 765		ret = PTR_ERR(key_ref);
 766
 767		/* treat lack or presence of a negative key the same */
 768		if (ret == -EAGAIN)
 769			ret = -ENOKEY;
 770		goto error5;
 771	}
 772
 773	/* link the resulting key to the destination keyring if we can */
 774	if (dest_ref) {
 775		ret = key_permission(key_ref, KEY_NEED_LINK);
 776		if (ret < 0)
 777			goto error6;
 778
 779		ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
 780		if (ret < 0)
 781			goto error6;
 782	}
 783
 784	ret = key_ref_to_ptr(key_ref)->serial;
 785
 786error6:
 787	key_ref_put(key_ref);
 788error5:
 789	key_type_put(ktype);
 790error4:
 791	key_ref_put(dest_ref);
 792error3:
 793	key_ref_put(keyring_ref);
 794error2:
 795	kfree(description);
 796error:
 797	return ret;
 798}
 799
 800/*
 801 * Read a key's payload.
 802 *
 803 * The key must either grant the caller Read permission, or it must grant the
 804 * caller Search permission when searched for from the process keyrings.
 805 *
 806 * If successful, we place up to buflen bytes of data into the buffer, if one
 807 * is provided, and return the amount of data that is available in the key,
 808 * irrespective of how much we copied into the buffer.
 809 */
 810long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
 811{
 812	struct key *key;
 813	key_ref_t key_ref;
 814	long ret;
 815
 816	/* find the key first */
 817	key_ref = lookup_user_key(keyid, 0, 0);
 818	if (IS_ERR(key_ref)) {
 819		ret = -ENOKEY;
 820		goto error;
 821	}
 822
 823	key = key_ref_to_ptr(key_ref);
 824
 825	ret = key_read_state(key);
 826	if (ret < 0)
 827		goto error2; /* Negatively instantiated */
 828
 829	/* see if we can read it directly */
 830	ret = key_permission(key_ref, KEY_NEED_READ);
 831	if (ret == 0)
 832		goto can_read_key;
 833	if (ret != -EACCES)
 834		goto error2;
 835
 836	/* we can't; see if it's searchable from this process's keyrings
 837	 * - we automatically take account of the fact that it may be
 838	 *   dangling off an instantiation key
 839	 */
 840	if (!is_key_possessed(key_ref)) {
 841		ret = -EACCES;
 842		goto error2;
 843	}
 844
 845	/* the key is probably readable - now try to read it */
 846can_read_key:
 847	ret = -EOPNOTSUPP;
 848	if (key->type->read) {
 849		/* Read the data with the semaphore held (since we might sleep)
 850		 * to protect against the key being updated or revoked.
 851		 */
 852		down_read(&key->sem);
 853		ret = key_validate(key);
 854		if (ret == 0)
 855			ret = key->type->read(key, buffer, buflen);
 856		up_read(&key->sem);
 
 857	}
 858
 859error2:
 860	key_put(key);
 861error:
 862	return ret;
 863}
 864
 865/*
 866 * Change the ownership of a key
 867 *
 868 * The key must grant the caller Setattr permission for this to work, though
 869 * the key need not be fully instantiated yet.  For the UID to be changed, or
 870 * for the GID to be changed to a group the caller is not a member of, the
 871 * caller must have sysadmin capability.  If either uid or gid is -1 then that
 872 * attribute is not changed.
 873 *
 874 * If the UID is to be changed, the new user must have sufficient quota to
 875 * accept the key.  The quota deduction will be removed from the old user to
 876 * the new user should the attribute be changed.
 877 *
 878 * If successful, 0 will be returned.
 879 */
 880long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
 881{
 882	struct key_user *newowner, *zapowner = NULL;
 883	struct key *key;
 884	key_ref_t key_ref;
 885	long ret;
 886	kuid_t uid;
 887	kgid_t gid;
 888
 889	uid = make_kuid(current_user_ns(), user);
 890	gid = make_kgid(current_user_ns(), group);
 891	ret = -EINVAL;
 892	if ((user != (uid_t) -1) && !uid_valid(uid))
 893		goto error;
 894	if ((group != (gid_t) -1) && !gid_valid(gid))
 895		goto error;
 896
 897	ret = 0;
 898	if (user == (uid_t) -1 && group == (gid_t) -1)
 899		goto error;
 900
 901	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
 902				  KEY_NEED_SETATTR);
 903	if (IS_ERR(key_ref)) {
 904		ret = PTR_ERR(key_ref);
 905		goto error;
 906	}
 907
 908	key = key_ref_to_ptr(key_ref);
 909
 910	/* make the changes with the locks held to prevent chown/chown races */
 911	ret = -EACCES;
 912	down_write(&key->sem);
 913
 914	if (!capable(CAP_SYS_ADMIN)) {
 915		/* only the sysadmin can chown a key to some other UID */
 916		if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
 917			goto error_put;
 918
 919		/* only the sysadmin can set the key's GID to a group other
 920		 * than one of those that the current process subscribes to */
 921		if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
 922			goto error_put;
 923	}
 924
 925	/* change the UID */
 926	if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
 927		ret = -ENOMEM;
 928		newowner = key_user_lookup(uid);
 929		if (!newowner)
 930			goto error_put;
 931
 932		/* transfer the quota burden to the new user */
 933		if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
 934			unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
 935				key_quota_root_maxkeys : key_quota_maxkeys;
 936			unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
 937				key_quota_root_maxbytes : key_quota_maxbytes;
 938
 939			spin_lock(&newowner->lock);
 940			if (newowner->qnkeys + 1 >= maxkeys ||
 941			    newowner->qnbytes + key->quotalen >= maxbytes ||
 942			    newowner->qnbytes + key->quotalen <
 943			    newowner->qnbytes)
 944				goto quota_overrun;
 945
 946			newowner->qnkeys++;
 947			newowner->qnbytes += key->quotalen;
 948			spin_unlock(&newowner->lock);
 949
 950			spin_lock(&key->user->lock);
 951			key->user->qnkeys--;
 952			key->user->qnbytes -= key->quotalen;
 953			spin_unlock(&key->user->lock);
 954		}
 955
 956		atomic_dec(&key->user->nkeys);
 957		atomic_inc(&newowner->nkeys);
 958
 959		if (key->state != KEY_IS_UNINSTANTIATED) {
 960			atomic_dec(&key->user->nikeys);
 961			atomic_inc(&newowner->nikeys);
 962		}
 963
 964		zapowner = key->user;
 965		key->user = newowner;
 966		key->uid = uid;
 967	}
 968
 969	/* change the GID */
 970	if (group != (gid_t) -1)
 971		key->gid = gid;
 972
 973	ret = 0;
 974
 975error_put:
 976	up_write(&key->sem);
 977	key_put(key);
 978	if (zapowner)
 979		key_user_put(zapowner);
 980error:
 981	return ret;
 982
 983quota_overrun:
 984	spin_unlock(&newowner->lock);
 985	zapowner = newowner;
 986	ret = -EDQUOT;
 987	goto error_put;
 988}
 989
 990/*
 991 * Change the permission mask on a key.
 992 *
 993 * The key must grant the caller Setattr permission for this to work, though
 994 * the key need not be fully instantiated yet.  If the caller does not have
 995 * sysadmin capability, it may only change the permission on keys that it owns.
 996 */
 997long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
 998{
 999	struct key *key;
1000	key_ref_t key_ref;
1001	long ret;
1002
1003	ret = -EINVAL;
1004	if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
1005		goto error;
1006
1007	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1008				  KEY_NEED_SETATTR);
1009	if (IS_ERR(key_ref)) {
1010		ret = PTR_ERR(key_ref);
1011		goto error;
1012	}
1013
1014	key = key_ref_to_ptr(key_ref);
1015
1016	/* make the changes with the locks held to prevent chown/chmod races */
1017	ret = -EACCES;
1018	down_write(&key->sem);
1019
1020	/* if we're not the sysadmin, we can only change a key that we own */
1021	if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) {
1022		key->perm = perm;
1023		ret = 0;
1024	}
1025
1026	up_write(&key->sem);
1027	key_put(key);
1028error:
1029	return ret;
1030}
1031
1032/*
1033 * Get the destination keyring for instantiation and check that the caller has
1034 * Write permission on it.
1035 */
1036static long get_instantiation_keyring(key_serial_t ringid,
1037				      struct request_key_auth *rka,
1038				      struct key **_dest_keyring)
1039{
1040	key_ref_t dkref;
1041
1042	*_dest_keyring = NULL;
1043
1044	/* just return a NULL pointer if we weren't asked to make a link */
1045	if (ringid == 0)
1046		return 0;
1047
1048	/* if a specific keyring is nominated by ID, then use that */
1049	if (ringid > 0) {
1050		dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
1051		if (IS_ERR(dkref))
1052			return PTR_ERR(dkref);
1053		*_dest_keyring = key_ref_to_ptr(dkref);
1054		return 0;
1055	}
1056
1057	if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
1058		return -EINVAL;
1059
1060	/* otherwise specify the destination keyring recorded in the
1061	 * authorisation key (any KEY_SPEC_*_KEYRING) */
1062	if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1063		*_dest_keyring = key_get(rka->dest_keyring);
1064		return 0;
1065	}
1066
1067	return -ENOKEY;
1068}
1069
1070/*
1071 * Change the request_key authorisation key on the current process.
1072 */
1073static int keyctl_change_reqkey_auth(struct key *key)
1074{
1075	struct cred *new;
1076
1077	new = prepare_creds();
1078	if (!new)
1079		return -ENOMEM;
1080
1081	key_put(new->request_key_auth);
1082	new->request_key_auth = key_get(key);
1083
1084	return commit_creds(new);
1085}
1086
1087/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1088 * Instantiate a key with the specified payload and link the key into the
1089 * destination keyring if one is given.
1090 *
1091 * The caller must have the appropriate instantiation permit set for this to
1092 * work (see keyctl_assume_authority).  No other permissions are required.
1093 *
1094 * If successful, 0 will be returned.
1095 */
1096long keyctl_instantiate_key_common(key_serial_t id,
1097				   struct iov_iter *from,
 
 
1098				   key_serial_t ringid)
1099{
1100	const struct cred *cred = current_cred();
1101	struct request_key_auth *rka;
1102	struct key *instkey, *dest_keyring;
1103	size_t plen = from ? iov_iter_count(from) : 0;
1104	void *payload;
1105	long ret;
 
1106
1107	kenter("%d,,%zu,%d", id, plen, ringid);
1108
1109	if (!plen)
1110		from = NULL;
1111
1112	ret = -EINVAL;
1113	if (plen > 1024 * 1024 - 1)
1114		goto error;
1115
1116	/* the appropriate instantiation authorisation key must have been
1117	 * assumed before calling this */
1118	ret = -EPERM;
1119	instkey = cred->request_key_auth;
1120	if (!instkey)
1121		goto error;
1122
1123	rka = instkey->payload.data[0];
1124	if (rka->target_key->serial != id)
1125		goto error;
1126
1127	/* pull the payload in if one was supplied */
1128	payload = NULL;
1129
1130	if (from) {
1131		ret = -ENOMEM;
1132		payload = kvmalloc(plen, GFP_KERNEL);
1133		if (!payload)
1134			goto error;
 
 
 
 
 
 
1135
1136		ret = -EFAULT;
1137		if (!copy_from_iter_full(payload, plen, from))
1138			goto error2;
1139	}
1140
1141	/* find the destination keyring amongst those belonging to the
1142	 * requesting task */
1143	ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1144	if (ret < 0)
1145		goto error2;
1146
1147	/* instantiate the key and link it into a keyring */
1148	ret = key_instantiate_and_link(rka->target_key, payload, plen,
1149				       dest_keyring, instkey);
1150
1151	key_put(dest_keyring);
1152
1153	/* discard the assumed authority if it's just been disabled by
1154	 * instantiation of the key */
1155	if (ret == 0)
1156		keyctl_change_reqkey_auth(NULL);
1157
1158error2:
1159	if (payload) {
1160		memzero_explicit(payload, plen);
1161		kvfree(payload);
1162	}
1163error:
1164	return ret;
1165}
1166
1167/*
1168 * Instantiate a key with the specified payload and link the key into the
1169 * destination keyring if one is given.
1170 *
1171 * The caller must have the appropriate instantiation permit set for this to
1172 * work (see keyctl_assume_authority).  No other permissions are required.
1173 *
1174 * If successful, 0 will be returned.
1175 */
1176long keyctl_instantiate_key(key_serial_t id,
1177			    const void __user *_payload,
1178			    size_t plen,
1179			    key_serial_t ringid)
1180{
1181	if (_payload && plen) {
1182		struct iovec iov;
1183		struct iov_iter from;
1184		int ret;
 
1185
1186		ret = import_single_range(WRITE, (void __user *)_payload, plen,
1187					  &iov, &from);
1188		if (unlikely(ret))
1189			return ret;
1190
1191		return keyctl_instantiate_key_common(id, &from, ringid);
1192	}
1193
1194	return keyctl_instantiate_key_common(id, NULL, ringid);
1195}
1196
1197/*
1198 * Instantiate a key with the specified multipart payload and link the key into
1199 * the destination keyring if one is given.
1200 *
1201 * The caller must have the appropriate instantiation permit set for this to
1202 * work (see keyctl_assume_authority).  No other permissions are required.
1203 *
1204 * If successful, 0 will be returned.
1205 */
1206long keyctl_instantiate_key_iov(key_serial_t id,
1207				const struct iovec __user *_payload_iov,
1208				unsigned ioc,
1209				key_serial_t ringid)
1210{
1211	struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1212	struct iov_iter from;
1213	long ret;
1214
1215	if (!_payload_iov)
1216		ioc = 0;
1217
1218	ret = import_iovec(WRITE, _payload_iov, ioc,
1219				    ARRAY_SIZE(iovstack), &iov, &from);
1220	if (ret < 0)
1221		return ret;
1222	ret = keyctl_instantiate_key_common(id, &from, ringid);
1223	kfree(iov);
 
 
 
 
 
1224	return ret;
 
 
 
 
 
 
1225}
1226
1227/*
1228 * Negatively instantiate the key with the given timeout (in seconds) and link
1229 * the key into the destination keyring if one is given.
1230 *
1231 * The caller must have the appropriate instantiation permit set for this to
1232 * work (see keyctl_assume_authority).  No other permissions are required.
1233 *
1234 * The key and any links to the key will be automatically garbage collected
1235 * after the timeout expires.
1236 *
1237 * Negative keys are used to rate limit repeated request_key() calls by causing
1238 * them to return -ENOKEY until the negative key expires.
1239 *
1240 * If successful, 0 will be returned.
1241 */
1242long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1243{
1244	return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1245}
1246
1247/*
1248 * Negatively instantiate the key with the given timeout (in seconds) and error
1249 * code and link the key into the destination keyring if one is given.
1250 *
1251 * The caller must have the appropriate instantiation permit set for this to
1252 * work (see keyctl_assume_authority).  No other permissions are required.
1253 *
1254 * The key and any links to the key will be automatically garbage collected
1255 * after the timeout expires.
1256 *
1257 * Negative keys are used to rate limit repeated request_key() calls by causing
1258 * them to return the specified error code until the negative key expires.
1259 *
1260 * If successful, 0 will be returned.
1261 */
1262long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1263		       key_serial_t ringid)
1264{
1265	const struct cred *cred = current_cred();
1266	struct request_key_auth *rka;
1267	struct key *instkey, *dest_keyring;
1268	long ret;
1269
1270	kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1271
1272	/* must be a valid error code and mustn't be a kernel special */
1273	if (error <= 0 ||
1274	    error >= MAX_ERRNO ||
1275	    error == ERESTARTSYS ||
1276	    error == ERESTARTNOINTR ||
1277	    error == ERESTARTNOHAND ||
1278	    error == ERESTART_RESTARTBLOCK)
1279		return -EINVAL;
1280
1281	/* the appropriate instantiation authorisation key must have been
1282	 * assumed before calling this */
1283	ret = -EPERM;
1284	instkey = cred->request_key_auth;
1285	if (!instkey)
1286		goto error;
1287
1288	rka = instkey->payload.data[0];
1289	if (rka->target_key->serial != id)
1290		goto error;
1291
1292	/* find the destination keyring if present (which must also be
1293	 * writable) */
1294	ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1295	if (ret < 0)
1296		goto error;
1297
1298	/* instantiate the key and link it into a keyring */
1299	ret = key_reject_and_link(rka->target_key, timeout, error,
1300				  dest_keyring, instkey);
1301
1302	key_put(dest_keyring);
1303
1304	/* discard the assumed authority if it's just been disabled by
1305	 * instantiation of the key */
1306	if (ret == 0)
1307		keyctl_change_reqkey_auth(NULL);
1308
1309error:
1310	return ret;
1311}
1312
1313/*
1314 * Read or set the default keyring in which request_key() will cache keys and
1315 * return the old setting.
1316 *
1317 * If a thread or process keyring is specified then it will be created if it
1318 * doesn't yet exist.  The old setting will be returned if successful.
1319 */
1320long keyctl_set_reqkey_keyring(int reqkey_defl)
1321{
1322	struct cred *new;
1323	int ret, old_setting;
1324
1325	old_setting = current_cred_xxx(jit_keyring);
1326
1327	if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1328		return old_setting;
1329
1330	new = prepare_creds();
1331	if (!new)
1332		return -ENOMEM;
1333
1334	switch (reqkey_defl) {
1335	case KEY_REQKEY_DEFL_THREAD_KEYRING:
1336		ret = install_thread_keyring_to_cred(new);
1337		if (ret < 0)
1338			goto error;
1339		goto set;
1340
1341	case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1342		ret = install_process_keyring_to_cred(new);
1343		if (ret < 0)
1344			goto error;
 
 
 
1345		goto set;
1346
1347	case KEY_REQKEY_DEFL_DEFAULT:
1348	case KEY_REQKEY_DEFL_SESSION_KEYRING:
1349	case KEY_REQKEY_DEFL_USER_KEYRING:
1350	case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1351	case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1352		goto set;
1353
1354	case KEY_REQKEY_DEFL_NO_CHANGE:
1355	case KEY_REQKEY_DEFL_GROUP_KEYRING:
1356	default:
1357		ret = -EINVAL;
1358		goto error;
1359	}
1360
1361set:
1362	new->jit_keyring = reqkey_defl;
1363	commit_creds(new);
1364	return old_setting;
1365error:
1366	abort_creds(new);
1367	return ret;
1368}
1369
1370/*
1371 * Set or clear the timeout on a key.
1372 *
1373 * Either the key must grant the caller Setattr permission or else the caller
1374 * must hold an instantiation authorisation token for the key.
1375 *
1376 * The timeout is either 0 to clear the timeout, or a number of seconds from
1377 * the current time.  The key and any links to the key will be automatically
1378 * garbage collected after the timeout expires.
1379 *
1380 * Keys with KEY_FLAG_KEEP set should not be timed out.
1381 *
1382 * If successful, 0 is returned.
1383 */
1384long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1385{
1386	struct key *key, *instkey;
1387	key_ref_t key_ref;
1388	long ret;
1389
1390	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1391				  KEY_NEED_SETATTR);
1392	if (IS_ERR(key_ref)) {
1393		/* setting the timeout on a key under construction is permitted
1394		 * if we have the authorisation token handy */
1395		if (PTR_ERR(key_ref) == -EACCES) {
1396			instkey = key_get_instantiation_authkey(id);
1397			if (!IS_ERR(instkey)) {
1398				key_put(instkey);
1399				key_ref = lookup_user_key(id,
1400							  KEY_LOOKUP_PARTIAL,
1401							  0);
1402				if (!IS_ERR(key_ref))
1403					goto okay;
1404			}
1405		}
1406
1407		ret = PTR_ERR(key_ref);
1408		goto error;
1409	}
1410
1411okay:
1412	key = key_ref_to_ptr(key_ref);
1413	ret = 0;
1414	if (test_bit(KEY_FLAG_KEEP, &key->flags))
1415		ret = -EPERM;
1416	else
1417		key_set_timeout(key, timeout);
1418	key_put(key);
1419
 
1420error:
1421	return ret;
1422}
1423
1424/*
1425 * Assume (or clear) the authority to instantiate the specified key.
1426 *
1427 * This sets the authoritative token currently in force for key instantiation.
1428 * This must be done for a key to be instantiated.  It has the effect of making
1429 * available all the keys from the caller of the request_key() that created a
1430 * key to request_key() calls made by the caller of this function.
1431 *
1432 * The caller must have the instantiation key in their process keyrings with a
1433 * Search permission grant available to the caller.
1434 *
1435 * If the ID given is 0, then the setting will be cleared and 0 returned.
1436 *
1437 * If the ID given has a matching an authorisation key, then that key will be
1438 * set and its ID will be returned.  The authorisation key can be read to get
1439 * the callout information passed to request_key().
1440 */
1441long keyctl_assume_authority(key_serial_t id)
1442{
1443	struct key *authkey;
1444	long ret;
1445
1446	/* special key IDs aren't permitted */
1447	ret = -EINVAL;
1448	if (id < 0)
1449		goto error;
1450
1451	/* we divest ourselves of authority if given an ID of 0 */
1452	if (id == 0) {
1453		ret = keyctl_change_reqkey_auth(NULL);
1454		goto error;
1455	}
1456
1457	/* attempt to assume the authority temporarily granted to us whilst we
1458	 * instantiate the specified key
1459	 * - the authorisation key must be in the current task's keyrings
1460	 *   somewhere
1461	 */
1462	authkey = key_get_instantiation_authkey(id);
1463	if (IS_ERR(authkey)) {
1464		ret = PTR_ERR(authkey);
1465		goto error;
1466	}
1467
1468	ret = keyctl_change_reqkey_auth(authkey);
1469	if (ret == 0)
1470		ret = authkey->serial;
1471	key_put(authkey);
 
 
1472error:
1473	return ret;
1474}
1475
1476/*
1477 * Get a key's the LSM security label.
1478 *
1479 * The key must grant the caller View permission for this to work.
1480 *
1481 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1482 *
1483 * If successful, the amount of information available will be returned,
1484 * irrespective of how much was copied (including the terminal NUL).
1485 */
1486long keyctl_get_security(key_serial_t keyid,
1487			 char __user *buffer,
1488			 size_t buflen)
1489{
1490	struct key *key, *instkey;
1491	key_ref_t key_ref;
1492	char *context;
1493	long ret;
1494
1495	key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1496	if (IS_ERR(key_ref)) {
1497		if (PTR_ERR(key_ref) != -EACCES)
1498			return PTR_ERR(key_ref);
1499
1500		/* viewing a key under construction is also permitted if we
1501		 * have the authorisation token handy */
1502		instkey = key_get_instantiation_authkey(keyid);
1503		if (IS_ERR(instkey))
1504			return PTR_ERR(instkey);
1505		key_put(instkey);
1506
1507		key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1508		if (IS_ERR(key_ref))
1509			return PTR_ERR(key_ref);
1510	}
1511
1512	key = key_ref_to_ptr(key_ref);
1513	ret = security_key_getsecurity(key, &context);
1514	if (ret == 0) {
1515		/* if no information was returned, give userspace an empty
1516		 * string */
1517		ret = 1;
1518		if (buffer && buflen > 0 &&
1519		    copy_to_user(buffer, "", 1) != 0)
1520			ret = -EFAULT;
1521	} else if (ret > 0) {
1522		/* return as much data as there's room for */
1523		if (buffer && buflen > 0) {
1524			if (buflen > ret)
1525				buflen = ret;
1526
1527			if (copy_to_user(buffer, context, buflen) != 0)
1528				ret = -EFAULT;
1529		}
1530
1531		kfree(context);
1532	}
1533
1534	key_ref_put(key_ref);
1535	return ret;
1536}
1537
1538/*
1539 * Attempt to install the calling process's session keyring on the process's
1540 * parent process.
1541 *
1542 * The keyring must exist and must grant the caller LINK permission, and the
1543 * parent process must be single-threaded and must have the same effective
1544 * ownership as this process and mustn't be SUID/SGID.
1545 *
1546 * The keyring will be emplaced on the parent when it next resumes userspace.
1547 *
1548 * If successful, 0 will be returned.
1549 */
1550long keyctl_session_to_parent(void)
1551{
1552	struct task_struct *me, *parent;
1553	const struct cred *mycred, *pcred;
1554	struct callback_head *newwork, *oldwork;
1555	key_ref_t keyring_r;
1556	struct cred *cred;
1557	int ret;
1558
1559	keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1560	if (IS_ERR(keyring_r))
1561		return PTR_ERR(keyring_r);
1562
1563	ret = -ENOMEM;
 
 
 
1564
1565	/* our parent is going to need a new cred struct, a new tgcred struct
1566	 * and new security data, so we allocate them here to prevent ENOMEM in
1567	 * our parent */
1568	cred = cred_alloc_blank();
1569	if (!cred)
1570		goto error_keyring;
1571	newwork = &cred->rcu;
1572
1573	cred->session_keyring = key_ref_to_ptr(keyring_r);
1574	keyring_r = NULL;
1575	init_task_work(newwork, key_change_session_keyring);
1576
1577	me = current;
1578	rcu_read_lock();
1579	write_lock_irq(&tasklist_lock);
1580
1581	ret = -EPERM;
1582	oldwork = NULL;
1583	parent = rcu_dereference_protected(me->real_parent,
1584					   lockdep_is_held(&tasklist_lock));
1585
1586	/* the parent mustn't be init and mustn't be a kernel thread */
1587	if (parent->pid <= 1 || !parent->mm)
1588		goto unlock;
1589
1590	/* the parent must be single threaded */
1591	if (!thread_group_empty(parent))
1592		goto unlock;
1593
1594	/* the parent and the child must have different session keyrings or
1595	 * there's no point */
1596	mycred = current_cred();
1597	pcred = __task_cred(parent);
1598	if (mycred == pcred ||
1599	    mycred->session_keyring == pcred->session_keyring) {
1600		ret = 0;
1601		goto unlock;
1602	}
1603
1604	/* the parent must have the same effective ownership and mustn't be
1605	 * SUID/SGID */
1606	if (!uid_eq(pcred->uid,	 mycred->euid) ||
1607	    !uid_eq(pcred->euid, mycred->euid) ||
1608	    !uid_eq(pcred->suid, mycred->euid) ||
1609	    !gid_eq(pcred->gid,	 mycred->egid) ||
1610	    !gid_eq(pcred->egid, mycred->egid) ||
1611	    !gid_eq(pcred->sgid, mycred->egid))
1612		goto unlock;
1613
1614	/* the keyrings must have the same UID */
1615	if ((pcred->session_keyring &&
1616	     !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1617	    !uid_eq(mycred->session_keyring->uid, mycred->euid))
1618		goto unlock;
1619
1620	/* cancel an already pending keyring replacement */
1621	oldwork = task_work_cancel(parent, key_change_session_keyring);
1622
1623	/* the replacement session keyring is applied just prior to userspace
1624	 * restarting */
1625	ret = task_work_add(parent, newwork, true);
1626	if (!ret)
1627		newwork = NULL;
1628unlock:
1629	write_unlock_irq(&tasklist_lock);
1630	rcu_read_unlock();
1631	if (oldwork)
1632		put_cred(container_of(oldwork, struct cred, rcu));
1633	if (newwork)
1634		put_cred(cred);
 
 
 
 
1635	return ret;
1636
 
 
1637error_keyring:
1638	key_ref_put(keyring_r);
1639	return ret;
1640}
1641
1642/*
1643 * Apply a restriction to a given keyring.
1644 *
1645 * The caller must have Setattr permission to change keyring restrictions.
1646 *
1647 * The requested type name may be a NULL pointer to reject all attempts
1648 * to link to the keyring.  In this case, _restriction must also be NULL.
1649 * Otherwise, both _type and _restriction must be non-NULL.
1650 *
1651 * Returns 0 if successful.
1652 */
1653long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1654			     const char __user *_restriction)
1655{
1656	key_ref_t key_ref;
1657	char type[32];
1658	char *restriction = NULL;
1659	long ret;
1660
1661	key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1662	if (IS_ERR(key_ref))
1663		return PTR_ERR(key_ref);
1664
1665	ret = -EINVAL;
1666	if (_type) {
1667		if (!_restriction)
1668			goto error;
1669
1670		ret = key_get_type_from_user(type, _type, sizeof(type));
1671		if (ret < 0)
1672			goto error;
1673
1674		restriction = strndup_user(_restriction, PAGE_SIZE);
1675		if (IS_ERR(restriction)) {
1676			ret = PTR_ERR(restriction);
1677			goto error;
1678		}
1679	} else {
1680		if (_restriction)
1681			goto error;
1682	}
1683
1684	ret = keyring_restrict(key_ref, _type ? type : NULL, restriction);
1685	kfree(restriction);
1686error:
1687	key_ref_put(key_ref);
1688	return ret;
1689}
1690
1691/*
1692 * Get keyrings subsystem capabilities.
1693 */
1694long keyctl_capabilities(unsigned char __user *_buffer, size_t buflen)
1695{
1696	size_t size = buflen;
1697
1698	if (size > 0) {
1699		if (size > sizeof(keyrings_capabilities))
1700			size = sizeof(keyrings_capabilities);
1701		if (copy_to_user(_buffer, keyrings_capabilities, size) != 0)
1702			return -EFAULT;
1703		if (size < buflen &&
1704		    clear_user(_buffer + size, buflen - size) != 0)
1705			return -EFAULT;
1706	}
1707
1708	return sizeof(keyrings_capabilities);
1709}
1710
1711/*
1712 * The key control system call
1713 */
1714SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1715		unsigned long, arg4, unsigned long, arg5)
1716{
1717	switch (option) {
1718	case KEYCTL_GET_KEYRING_ID:
1719		return keyctl_get_keyring_ID((key_serial_t) arg2,
1720					     (int) arg3);
1721
1722	case KEYCTL_JOIN_SESSION_KEYRING:
1723		return keyctl_join_session_keyring((const char __user *) arg2);
1724
1725	case KEYCTL_UPDATE:
1726		return keyctl_update_key((key_serial_t) arg2,
1727					 (const void __user *) arg3,
1728					 (size_t) arg4);
1729
1730	case KEYCTL_REVOKE:
1731		return keyctl_revoke_key((key_serial_t) arg2);
1732
1733	case KEYCTL_DESCRIBE:
1734		return keyctl_describe_key((key_serial_t) arg2,
1735					   (char __user *) arg3,
1736					   (unsigned) arg4);
1737
1738	case KEYCTL_CLEAR:
1739		return keyctl_keyring_clear((key_serial_t) arg2);
1740
1741	case KEYCTL_LINK:
1742		return keyctl_keyring_link((key_serial_t) arg2,
1743					   (key_serial_t) arg3);
1744
1745	case KEYCTL_UNLINK:
1746		return keyctl_keyring_unlink((key_serial_t) arg2,
1747					     (key_serial_t) arg3);
1748
1749	case KEYCTL_SEARCH:
1750		return keyctl_keyring_search((key_serial_t) arg2,
1751					     (const char __user *) arg3,
1752					     (const char __user *) arg4,
1753					     (key_serial_t) arg5);
1754
1755	case KEYCTL_READ:
1756		return keyctl_read_key((key_serial_t) arg2,
1757				       (char __user *) arg3,
1758				       (size_t) arg4);
1759
1760	case KEYCTL_CHOWN:
1761		return keyctl_chown_key((key_serial_t) arg2,
1762					(uid_t) arg3,
1763					(gid_t) arg4);
1764
1765	case KEYCTL_SETPERM:
1766		return keyctl_setperm_key((key_serial_t) arg2,
1767					  (key_perm_t) arg3);
1768
1769	case KEYCTL_INSTANTIATE:
1770		return keyctl_instantiate_key((key_serial_t) arg2,
1771					      (const void __user *) arg3,
1772					      (size_t) arg4,
1773					      (key_serial_t) arg5);
1774
1775	case KEYCTL_NEGATE:
1776		return keyctl_negate_key((key_serial_t) arg2,
1777					 (unsigned) arg3,
1778					 (key_serial_t) arg4);
1779
1780	case KEYCTL_SET_REQKEY_KEYRING:
1781		return keyctl_set_reqkey_keyring(arg2);
1782
1783	case KEYCTL_SET_TIMEOUT:
1784		return keyctl_set_timeout((key_serial_t) arg2,
1785					  (unsigned) arg3);
1786
1787	case KEYCTL_ASSUME_AUTHORITY:
1788		return keyctl_assume_authority((key_serial_t) arg2);
1789
1790	case KEYCTL_GET_SECURITY:
1791		return keyctl_get_security((key_serial_t) arg2,
1792					   (char __user *) arg3,
1793					   (size_t) arg4);
1794
1795	case KEYCTL_SESSION_TO_PARENT:
1796		return keyctl_session_to_parent();
1797
1798	case KEYCTL_REJECT:
1799		return keyctl_reject_key((key_serial_t) arg2,
1800					 (unsigned) arg3,
1801					 (unsigned) arg4,
1802					 (key_serial_t) arg5);
1803
1804	case KEYCTL_INSTANTIATE_IOV:
1805		return keyctl_instantiate_key_iov(
1806			(key_serial_t) arg2,
1807			(const struct iovec __user *) arg3,
1808			(unsigned) arg4,
1809			(key_serial_t) arg5);
1810
1811	case KEYCTL_INVALIDATE:
1812		return keyctl_invalidate_key((key_serial_t) arg2);
1813
1814	case KEYCTL_GET_PERSISTENT:
1815		return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1816
1817	case KEYCTL_DH_COMPUTE:
1818		return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1819					 (char __user *) arg3, (size_t) arg4,
1820					 (struct keyctl_kdf_params __user *) arg5);
1821
1822	case KEYCTL_RESTRICT_KEYRING:
1823		return keyctl_restrict_keyring((key_serial_t) arg2,
1824					       (const char __user *) arg3,
1825					       (const char __user *) arg4);
1826
1827	case KEYCTL_PKEY_QUERY:
1828		if (arg3 != 0)
1829			return -EINVAL;
1830		return keyctl_pkey_query((key_serial_t)arg2,
1831					 (const char __user *)arg4,
1832					 (struct keyctl_pkey_query __user *)arg5);
1833
1834	case KEYCTL_PKEY_ENCRYPT:
1835	case KEYCTL_PKEY_DECRYPT:
1836	case KEYCTL_PKEY_SIGN:
1837		return keyctl_pkey_e_d_s(
1838			option,
1839			(const struct keyctl_pkey_params __user *)arg2,
1840			(const char __user *)arg3,
1841			(const void __user *)arg4,
1842			(void __user *)arg5);
1843
1844	case KEYCTL_PKEY_VERIFY:
1845		return keyctl_pkey_verify(
1846			(const struct keyctl_pkey_params __user *)arg2,
1847			(const char __user *)arg3,
1848			(const void __user *)arg4,
1849			(const void __user *)arg5);
1850
1851	case KEYCTL_MOVE:
1852		return keyctl_keyring_move((key_serial_t)arg2,
1853					   (key_serial_t)arg3,
1854					   (key_serial_t)arg4,
1855					   (unsigned int)arg5);
1856
1857	case KEYCTL_CAPABILITIES:
1858		return keyctl_capabilities((unsigned char __user *)arg2, (size_t)arg3);
1859
1860	default:
1861		return -EOPNOTSUPP;
1862	}
1863}