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/keyctl.h>
  18#include <linux/fs.h>
  19#include <linux/capability.h>
 
  20#include <linux/string.h>
  21#include <linux/err.h>
  22#include <linux/vmalloc.h>
  23#include <linux/security.h>
  24#include <asm/uaccess.h>
 
 
  25#include "internal.h"
  26
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  27static int key_get_type_from_user(char *type,
  28				  const char __user *_type,
  29				  unsigned len)
  30{
  31	int ret;
  32
  33	ret = strncpy_from_user(type, _type, len);
  34	if (ret < 0)
  35		return ret;
  36	if (ret == 0 || ret >= len)
  37		return -EINVAL;
  38	if (type[0] == '.')
  39		return -EPERM;
  40	type[len - 1] = '\0';
  41	return 0;
  42}
  43
  44/*
  45 * Extract the description of a new key from userspace and either add it as a
  46 * new key to the specified keyring or update a matching key in that keyring.
  47 *
 
 
 
  48 * The keyring must be writable so that we can attach the key to it.
  49 *
  50 * If successful, the new key's serial number is returned, otherwise an error
  51 * code is returned.
  52 */
  53SYSCALL_DEFINE5(add_key, const char __user *, _type,
  54		const char __user *, _description,
  55		const void __user *, _payload,
  56		size_t, plen,
  57		key_serial_t, ringid)
  58{
  59	key_ref_t keyring_ref, key_ref;
  60	char type[32], *description;
  61	void *payload;
  62	long ret;
  63	bool vm;
  64
  65	ret = -EINVAL;
  66	if (plen > 1024 * 1024 - 1)
  67		goto error;
  68
  69	/* draw all the data into kernel space */
  70	ret = key_get_type_from_user(type, _type, sizeof(type));
  71	if (ret < 0)
  72		goto error;
  73
  74	description = strndup_user(_description, PAGE_SIZE);
  75	if (IS_ERR(description)) {
  76		ret = PTR_ERR(description);
  77		goto error;
 
 
 
 
 
 
 
 
 
 
 
  78	}
  79
  80	/* pull the payload in if one was supplied */
  81	payload = NULL;
  82
  83	vm = false;
  84	if (_payload) {
  85		ret = -ENOMEM;
  86		payload = kmalloc(plen, GFP_KERNEL);
  87		if (!payload) {
  88			if (plen <= PAGE_SIZE)
  89				goto error2;
  90			vm = true;
  91			payload = vmalloc(plen);
  92			if (!payload)
  93				goto error2;
  94		}
  95
  96		ret = -EFAULT;
  97		if (copy_from_user(payload, _payload, plen) != 0)
  98			goto error3;
  99	}
 100
 101	/* find the target keyring (which must be writable) */
 102	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
 103	if (IS_ERR(keyring_ref)) {
 104		ret = PTR_ERR(keyring_ref);
 105		goto error3;
 106	}
 107
 108	/* create or update the requested key and add it to the target
 109	 * keyring */
 110	key_ref = key_create_or_update(keyring_ref, type, description,
 111				       payload, plen, KEY_PERM_UNDEF,
 112				       KEY_ALLOC_IN_QUOTA);
 113	if (!IS_ERR(key_ref)) {
 114		ret = key_ref_to_ptr(key_ref)->serial;
 115		key_ref_put(key_ref);
 116	}
 117	else {
 118		ret = PTR_ERR(key_ref);
 119	}
 120
 121	key_ref_put(keyring_ref);
 122 error3:
 123	if (!vm)
 124		kfree(payload);
 125	else
 126		vfree(payload);
 127 error2:
 128	kfree(description);
 129 error:
 130	return ret;
 131}
 132
 133/*
 134 * Search the process keyrings and keyring trees linked from those for a
 135 * matching key.  Keyrings must have appropriate Search permission to be
 136 * searched.
 137 *
 138 * If a key is found, it will be attached to the destination keyring if there's
 139 * one specified and the serial number of the key will be returned.
 140 *
 141 * If no key is found, /sbin/request-key will be invoked if _callout_info is
 142 * non-NULL in an attempt to create a key.  The _callout_info string will be
 143 * passed to /sbin/request-key to aid with completing the request.  If the
 144 * _callout_info string is "" then it will be changed to "-".
 145 */
 146SYSCALL_DEFINE4(request_key, const char __user *, _type,
 147		const char __user *, _description,
 148		const char __user *, _callout_info,
 149		key_serial_t, destringid)
 150{
 151	struct key_type *ktype;
 152	struct key *key;
 153	key_ref_t dest_ref;
 154	size_t callout_len;
 155	char type[32], *description, *callout_info;
 156	long ret;
 157
 158	/* pull the type into kernel space */
 159	ret = key_get_type_from_user(type, _type, sizeof(type));
 160	if (ret < 0)
 161		goto error;
 162
 163	/* pull the description into kernel space */
 164	description = strndup_user(_description, PAGE_SIZE);
 165	if (IS_ERR(description)) {
 166		ret = PTR_ERR(description);
 167		goto error;
 168	}
 169
 170	/* pull the callout info into kernel space */
 171	callout_info = NULL;
 172	callout_len = 0;
 173	if (_callout_info) {
 174		callout_info = strndup_user(_callout_info, PAGE_SIZE);
 175		if (IS_ERR(callout_info)) {
 176			ret = PTR_ERR(callout_info);
 177			goto error2;
 178		}
 179		callout_len = strlen(callout_info);
 180	}
 181
 182	/* get the destination keyring if specified */
 183	dest_ref = NULL;
 184	if (destringid) {
 185		dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
 186					   KEY_WRITE);
 187		if (IS_ERR(dest_ref)) {
 188			ret = PTR_ERR(dest_ref);
 189			goto error3;
 190		}
 191	}
 192
 193	/* find the key type */
 194	ktype = key_type_lookup(type);
 195	if (IS_ERR(ktype)) {
 196		ret = PTR_ERR(ktype);
 197		goto error4;
 198	}
 199
 200	/* do the search */
 201	key = request_key_and_link(ktype, description, callout_info,
 202				   callout_len, NULL, key_ref_to_ptr(dest_ref),
 203				   KEY_ALLOC_IN_QUOTA);
 204	if (IS_ERR(key)) {
 205		ret = PTR_ERR(key);
 206		goto error5;
 207	}
 208
 209	/* wait for the key to finish being constructed */
 210	ret = wait_for_key_construction(key, 1);
 211	if (ret < 0)
 212		goto error6;
 213
 214	ret = key->serial;
 215
 216error6:
 217 	key_put(key);
 218error5:
 219	key_type_put(ktype);
 220error4:
 221	key_ref_put(dest_ref);
 222error3:
 223	kfree(callout_info);
 224error2:
 225	kfree(description);
 226error:
 227	return ret;
 228}
 229
 230/*
 231 * Get the ID of the specified process keyring.
 232 *
 233 * The requested keyring must have search permission to be found.
 234 *
 235 * If successful, the ID of the requested keyring will be returned.
 236 */
 237long keyctl_get_keyring_ID(key_serial_t id, int create)
 238{
 239	key_ref_t key_ref;
 240	unsigned long lflags;
 241	long ret;
 242
 243	lflags = create ? KEY_LOOKUP_CREATE : 0;
 244	key_ref = lookup_user_key(id, lflags, KEY_SEARCH);
 245	if (IS_ERR(key_ref)) {
 246		ret = PTR_ERR(key_ref);
 247		goto error;
 248	}
 249
 250	ret = key_ref_to_ptr(key_ref)->serial;
 251	key_ref_put(key_ref);
 252error:
 253	return ret;
 254}
 255
 256/*
 257 * Join a (named) session keyring.
 258 *
 259 * Create and join an anonymous session keyring or join a named session
 260 * keyring, creating it if necessary.  A named session keyring must have Search
 261 * permission for it to be joined.  Session keyrings without this permit will
 262 * be skipped over.
 
 263 *
 264 * If successful, the ID of the joined session keyring will be returned.
 265 */
 266long keyctl_join_session_keyring(const char __user *_name)
 267{
 268	char *name;
 269	long ret;
 270
 271	/* fetch the name from userspace */
 272	name = NULL;
 273	if (_name) {
 274		name = strndup_user(_name, PAGE_SIZE);
 275		if (IS_ERR(name)) {
 276			ret = PTR_ERR(name);
 277			goto error;
 278		}
 
 
 
 
 279	}
 280
 281	/* join the session */
 282	ret = join_session_keyring(name);
 
 283	kfree(name);
 284
 285error:
 286	return ret;
 287}
 288
 289/*
 290 * Update a key's data payload from the given data.
 291 *
 292 * The key must grant the caller Write permission and the key type must support
 293 * updating for this to work.  A negative key can be positively instantiated
 294 * with this call.
 295 *
 296 * If successful, 0 will be returned.  If the key type does not support
 297 * updating, then -EOPNOTSUPP will be returned.
 298 */
 299long keyctl_update_key(key_serial_t id,
 300		       const void __user *_payload,
 301		       size_t plen)
 302{
 303	key_ref_t key_ref;
 304	void *payload;
 305	long ret;
 306
 307	ret = -EINVAL;
 308	if (plen > PAGE_SIZE)
 309		goto error;
 310
 311	/* pull the payload in if one was supplied */
 312	payload = NULL;
 313	if (_payload) {
 314		ret = -ENOMEM;
 315		payload = kmalloc(plen, GFP_KERNEL);
 316		if (!payload)
 317			goto error;
 318
 319		ret = -EFAULT;
 320		if (copy_from_user(payload, _payload, plen) != 0)
 321			goto error2;
 322	}
 323
 324	/* find the target key (which must be writable) */
 325	key_ref = lookup_user_key(id, 0, KEY_WRITE);
 326	if (IS_ERR(key_ref)) {
 327		ret = PTR_ERR(key_ref);
 328		goto error2;
 329	}
 330
 331	/* update the key */
 332	ret = key_update(key_ref, payload, plen);
 333
 334	key_ref_put(key_ref);
 335error2:
 336	kfree(payload);
 337error:
 338	return ret;
 339}
 340
 341/*
 342 * Revoke a key.
 343 *
 344 * The key must be grant the caller Write or Setattr permission for this to
 345 * work.  The key type should give up its quota claim when revoked.  The key
 346 * and any links to the key will be automatically garbage collected after a
 347 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
 348 *
 
 
 349 * If successful, 0 is returned.
 350 */
 351long keyctl_revoke_key(key_serial_t id)
 352{
 353	key_ref_t key_ref;
 
 354	long ret;
 355
 356	key_ref = lookup_user_key(id, 0, KEY_WRITE);
 357	if (IS_ERR(key_ref)) {
 358		ret = PTR_ERR(key_ref);
 359		if (ret != -EACCES)
 360			goto error;
 361		key_ref = lookup_user_key(id, 0, KEY_SETATTR);
 362		if (IS_ERR(key_ref)) {
 363			ret = PTR_ERR(key_ref);
 364			goto error;
 365		}
 366	}
 367
 368	key_revoke(key_ref_to_ptr(key_ref));
 369	ret = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 370
 
 
 
 
 
 
 
 
 371	key_ref_put(key_ref);
 372error:
 
 373	return ret;
 374}
 375
 376/*
 377 * Clear the specified keyring, creating an empty process keyring if one of the
 378 * special keyring IDs is used.
 379 *
 380 * The keyring must grant the caller Write permission for this to work.  If
 381 * successful, 0 will be returned.
 382 */
 383long keyctl_keyring_clear(key_serial_t ringid)
 384{
 385	key_ref_t keyring_ref;
 
 386	long ret;
 387
 388	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
 389	if (IS_ERR(keyring_ref)) {
 390		ret = PTR_ERR(keyring_ref);
 
 
 
 
 
 
 
 
 
 
 
 
 391		goto error;
 392	}
 393
 394	ret = keyring_clear(key_ref_to_ptr(keyring_ref));
 395
 
 
 
 
 
 396	key_ref_put(keyring_ref);
 397error:
 398	return ret;
 399}
 400
 401/*
 402 * Create a link from a keyring to a key if there's no matching key in the
 403 * keyring, otherwise replace the link to the matching key with a link to the
 404 * new key.
 405 *
 406 * The key must grant the caller Link permission and the the keyring must grant
 407 * the caller Write permission.  Furthermore, if an additional link is created,
 408 * the keyring's quota will be extended.
 409 *
 410 * If successful, 0 will be returned.
 411 */
 412long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
 413{
 414	key_ref_t keyring_ref, key_ref;
 415	long ret;
 416
 417	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
 418	if (IS_ERR(keyring_ref)) {
 419		ret = PTR_ERR(keyring_ref);
 420		goto error;
 421	}
 422
 423	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK);
 424	if (IS_ERR(key_ref)) {
 425		ret = PTR_ERR(key_ref);
 426		goto error2;
 427	}
 428
 429	ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
 430
 431	key_ref_put(key_ref);
 432error2:
 433	key_ref_put(keyring_ref);
 434error:
 435	return ret;
 436}
 437
 438/*
 439 * Unlink a key from a keyring.
 440 *
 441 * The keyring must grant the caller Write permission for this to work; the key
 442 * itself need not grant the caller anything.  If the last link to a key is
 443 * removed then that key will be scheduled for destruction.
 444 *
 
 
 445 * If successful, 0 will be returned.
 446 */
 447long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
 448{
 449	key_ref_t keyring_ref, key_ref;
 
 450	long ret;
 451
 452	keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE);
 453	if (IS_ERR(keyring_ref)) {
 454		ret = PTR_ERR(keyring_ref);
 455		goto error;
 456	}
 457
 458	key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0);
 459	if (IS_ERR(key_ref)) {
 460		ret = PTR_ERR(key_ref);
 461		goto error2;
 462	}
 463
 464	ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
 
 
 
 
 
 
 465
 466	key_ref_put(key_ref);
 467error2:
 468	key_ref_put(keyring_ref);
 469error:
 470	return ret;
 471}
 472
 473/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 474 * Return a description of a key to userspace.
 475 *
 476 * The key must grant the caller View permission for this to work.
 477 *
 478 * If there's a buffer, we place up to buflen bytes of data into it formatted
 479 * in the following way:
 480 *
 481 *	type;uid;gid;perm;description<NUL>
 482 *
 483 * If successful, we return the amount of description available, irrespective
 484 * of how much we may have copied into the buffer.
 485 */
 486long keyctl_describe_key(key_serial_t keyid,
 487			 char __user *buffer,
 488			 size_t buflen)
 489{
 490	struct key *key, *instkey;
 491	key_ref_t key_ref;
 492	char *tmpbuf;
 493	long ret;
 
 494
 495	key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
 496	if (IS_ERR(key_ref)) {
 497		/* viewing a key under construction is permitted if we have the
 498		 * authorisation token handy */
 499		if (PTR_ERR(key_ref) == -EACCES) {
 500			instkey = key_get_instantiation_authkey(keyid);
 501			if (!IS_ERR(instkey)) {
 502				key_put(instkey);
 503				key_ref = lookup_user_key(keyid,
 504							  KEY_LOOKUP_PARTIAL,
 505							  0);
 506				if (!IS_ERR(key_ref))
 507					goto okay;
 508			}
 509		}
 510
 511		ret = PTR_ERR(key_ref);
 512		goto error;
 513	}
 514
 515okay:
 516	/* calculate how much description we're going to return */
 517	ret = -ENOMEM;
 518	tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 519	if (!tmpbuf)
 520		goto error2;
 521
 522	key = key_ref_to_ptr(key_ref);
 
 523
 524	ret = snprintf(tmpbuf, PAGE_SIZE - 1,
 525		       "%s;%d;%d;%08x;%s",
 526		       key->type->name,
 527		       key->uid,
 528		       key->gid,
 529		       key->perm,
 530		       key->description ?: "");
 531
 532	/* include a NUL char at the end of the data */
 533	if (ret > PAGE_SIZE - 1)
 534		ret = PAGE_SIZE - 1;
 535	tmpbuf[ret] = 0;
 536	ret++;
 537
 538	/* consider returning the data */
 539	if (buffer && buflen > 0) {
 540		if (buflen > ret)
 541			buflen = ret;
 542
 543		if (copy_to_user(buffer, tmpbuf, buflen) != 0)
 544			ret = -EFAULT;
 545	}
 546
 547	kfree(tmpbuf);
 548error2:
 549	key_ref_put(key_ref);
 550error:
 551	return ret;
 552}
 553
 554/*
 555 * Search the specified keyring and any keyrings it links to for a matching
 556 * key.  Only keyrings that grant the caller Search permission will be searched
 557 * (this includes the starting keyring).  Only keys with Search permission can
 558 * be found.
 559 *
 560 * If successful, the found key will be linked to the destination keyring if
 561 * supplied and the key has Link permission, and the found key ID will be
 562 * returned.
 563 */
 564long keyctl_keyring_search(key_serial_t ringid,
 565			   const char __user *_type,
 566			   const char __user *_description,
 567			   key_serial_t destringid)
 568{
 569	struct key_type *ktype;
 570	key_ref_t keyring_ref, key_ref, dest_ref;
 571	char type[32], *description;
 572	long ret;
 573
 574	/* pull the type and description into kernel space */
 575	ret = key_get_type_from_user(type, _type, sizeof(type));
 576	if (ret < 0)
 577		goto error;
 578
 579	description = strndup_user(_description, PAGE_SIZE);
 580	if (IS_ERR(description)) {
 581		ret = PTR_ERR(description);
 582		goto error;
 583	}
 584
 585	/* get the keyring at which to begin the search */
 586	keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH);
 587	if (IS_ERR(keyring_ref)) {
 588		ret = PTR_ERR(keyring_ref);
 589		goto error2;
 590	}
 591
 592	/* get the destination keyring if specified */
 593	dest_ref = NULL;
 594	if (destringid) {
 595		dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
 596					   KEY_WRITE);
 597		if (IS_ERR(dest_ref)) {
 598			ret = PTR_ERR(dest_ref);
 599			goto error3;
 600		}
 601	}
 602
 603	/* find the key type */
 604	ktype = key_type_lookup(type);
 605	if (IS_ERR(ktype)) {
 606		ret = PTR_ERR(ktype);
 607		goto error4;
 608	}
 609
 610	/* do the search */
 611	key_ref = keyring_search(keyring_ref, ktype, description);
 612	if (IS_ERR(key_ref)) {
 613		ret = PTR_ERR(key_ref);
 614
 615		/* treat lack or presence of a negative key the same */
 616		if (ret == -EAGAIN)
 617			ret = -ENOKEY;
 618		goto error5;
 619	}
 620
 621	/* link the resulting key to the destination keyring if we can */
 622	if (dest_ref) {
 623		ret = key_permission(key_ref, KEY_LINK);
 624		if (ret < 0)
 625			goto error6;
 626
 627		ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
 628		if (ret < 0)
 629			goto error6;
 630	}
 631
 632	ret = key_ref_to_ptr(key_ref)->serial;
 633
 634error6:
 635	key_ref_put(key_ref);
 636error5:
 637	key_type_put(ktype);
 638error4:
 639	key_ref_put(dest_ref);
 640error3:
 641	key_ref_put(keyring_ref);
 642error2:
 643	kfree(description);
 644error:
 645	return ret;
 646}
 647
 648/*
 649 * Read a key's payload.
 650 *
 651 * The key must either grant the caller Read permission, or it must grant the
 652 * caller Search permission when searched for from the process keyrings.
 653 *
 654 * If successful, we place up to buflen bytes of data into the buffer, if one
 655 * is provided, and return the amount of data that is available in the key,
 656 * irrespective of how much we copied into the buffer.
 657 */
 658long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
 659{
 660	struct key *key;
 661	key_ref_t key_ref;
 662	long ret;
 663
 664	/* find the key first */
 665	key_ref = lookup_user_key(keyid, 0, 0);
 666	if (IS_ERR(key_ref)) {
 667		ret = -ENOKEY;
 668		goto error;
 669	}
 670
 671	key = key_ref_to_ptr(key_ref);
 672
 
 
 
 
 673	/* see if we can read it directly */
 674	ret = key_permission(key_ref, KEY_READ);
 675	if (ret == 0)
 676		goto can_read_key;
 677	if (ret != -EACCES)
 678		goto error;
 679
 680	/* we can't; see if it's searchable from this process's keyrings
 681	 * - we automatically take account of the fact that it may be
 682	 *   dangling off an instantiation key
 683	 */
 684	if (!is_key_possessed(key_ref)) {
 685		ret = -EACCES;
 686		goto error2;
 687	}
 688
 689	/* the key is probably readable - now try to read it */
 690can_read_key:
 691	ret = key_validate(key);
 692	if (ret == 0) {
 693		ret = -EOPNOTSUPP;
 694		if (key->type->read) {
 695			/* read the data with the semaphore held (since we
 696			 * might sleep) */
 697			down_read(&key->sem);
 
 698			ret = key->type->read(key, buffer, buflen);
 699			up_read(&key->sem);
 700		}
 701	}
 702
 703error2:
 704	key_put(key);
 705error:
 706	return ret;
 707}
 708
 709/*
 710 * Change the ownership of a key
 711 *
 712 * The key must grant the caller Setattr permission for this to work, though
 713 * the key need not be fully instantiated yet.  For the UID to be changed, or
 714 * for the GID to be changed to a group the caller is not a member of, the
 715 * caller must have sysadmin capability.  If either uid or gid is -1 then that
 716 * attribute is not changed.
 717 *
 718 * If the UID is to be changed, the new user must have sufficient quota to
 719 * accept the key.  The quota deduction will be removed from the old user to
 720 * the new user should the attribute be changed.
 721 *
 722 * If successful, 0 will be returned.
 723 */
 724long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
 725{
 726	struct key_user *newowner, *zapowner = NULL;
 727	struct key *key;
 728	key_ref_t key_ref;
 729	long ret;
 
 
 
 
 
 
 
 
 
 
 730
 731	ret = 0;
 732	if (uid == (uid_t) -1 && gid == (gid_t) -1)
 733		goto error;
 734
 735	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
 736				  KEY_SETATTR);
 737	if (IS_ERR(key_ref)) {
 738		ret = PTR_ERR(key_ref);
 739		goto error;
 740	}
 741
 742	key = key_ref_to_ptr(key_ref);
 743
 744	/* make the changes with the locks held to prevent chown/chown races */
 745	ret = -EACCES;
 746	down_write(&key->sem);
 747
 748	if (!capable(CAP_SYS_ADMIN)) {
 749		/* only the sysadmin can chown a key to some other UID */
 750		if (uid != (uid_t) -1 && key->uid != uid)
 751			goto error_put;
 752
 753		/* only the sysadmin can set the key's GID to a group other
 754		 * than one of those that the current process subscribes to */
 755		if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
 756			goto error_put;
 757	}
 758
 759	/* change the UID */
 760	if (uid != (uid_t) -1 && uid != key->uid) {
 761		ret = -ENOMEM;
 762		newowner = key_user_lookup(uid, current_user_ns());
 763		if (!newowner)
 764			goto error_put;
 765
 766		/* transfer the quota burden to the new user */
 767		if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
 768			unsigned maxkeys = (uid == 0) ?
 769				key_quota_root_maxkeys : key_quota_maxkeys;
 770			unsigned maxbytes = (uid == 0) ?
 771				key_quota_root_maxbytes : key_quota_maxbytes;
 772
 773			spin_lock(&newowner->lock);
 774			if (newowner->qnkeys + 1 >= maxkeys ||
 775			    newowner->qnbytes + key->quotalen >= maxbytes ||
 776			    newowner->qnbytes + key->quotalen <
 777			    newowner->qnbytes)
 778				goto quota_overrun;
 779
 780			newowner->qnkeys++;
 781			newowner->qnbytes += key->quotalen;
 782			spin_unlock(&newowner->lock);
 783
 784			spin_lock(&key->user->lock);
 785			key->user->qnkeys--;
 786			key->user->qnbytes -= key->quotalen;
 787			spin_unlock(&key->user->lock);
 788		}
 789
 790		atomic_dec(&key->user->nkeys);
 791		atomic_inc(&newowner->nkeys);
 792
 793		if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
 794			atomic_dec(&key->user->nikeys);
 795			atomic_inc(&newowner->nikeys);
 796		}
 797
 798		zapowner = key->user;
 799		key->user = newowner;
 800		key->uid = uid;
 801	}
 802
 803	/* change the GID */
 804	if (gid != (gid_t) -1)
 805		key->gid = gid;
 806
 807	ret = 0;
 808
 809error_put:
 810	up_write(&key->sem);
 811	key_put(key);
 812	if (zapowner)
 813		key_user_put(zapowner);
 814error:
 815	return ret;
 816
 817quota_overrun:
 818	spin_unlock(&newowner->lock);
 819	zapowner = newowner;
 820	ret = -EDQUOT;
 821	goto error_put;
 822}
 823
 824/*
 825 * Change the permission mask on a key.
 826 *
 827 * The key must grant the caller Setattr permission for this to work, though
 828 * the key need not be fully instantiated yet.  If the caller does not have
 829 * sysadmin capability, it may only change the permission on keys that it owns.
 830 */
 831long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
 832{
 833	struct key *key;
 834	key_ref_t key_ref;
 835	long ret;
 836
 837	ret = -EINVAL;
 838	if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
 839		goto error;
 840
 841	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
 842				  KEY_SETATTR);
 843	if (IS_ERR(key_ref)) {
 844		ret = PTR_ERR(key_ref);
 845		goto error;
 846	}
 847
 848	key = key_ref_to_ptr(key_ref);
 849
 850	/* make the changes with the locks held to prevent chown/chmod races */
 851	ret = -EACCES;
 852	down_write(&key->sem);
 853
 854	/* if we're not the sysadmin, we can only change a key that we own */
 855	if (capable(CAP_SYS_ADMIN) || key->uid == current_fsuid()) {
 856		key->perm = perm;
 857		ret = 0;
 858	}
 859
 860	up_write(&key->sem);
 861	key_put(key);
 862error:
 863	return ret;
 864}
 865
 866/*
 867 * Get the destination keyring for instantiation and check that the caller has
 868 * Write permission on it.
 869 */
 870static long get_instantiation_keyring(key_serial_t ringid,
 871				      struct request_key_auth *rka,
 872				      struct key **_dest_keyring)
 873{
 874	key_ref_t dkref;
 875
 876	*_dest_keyring = NULL;
 877
 878	/* just return a NULL pointer if we weren't asked to make a link */
 879	if (ringid == 0)
 880		return 0;
 881
 882	/* if a specific keyring is nominated by ID, then use that */
 883	if (ringid > 0) {
 884		dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE);
 885		if (IS_ERR(dkref))
 886			return PTR_ERR(dkref);
 887		*_dest_keyring = key_ref_to_ptr(dkref);
 888		return 0;
 889	}
 890
 891	if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
 892		return -EINVAL;
 893
 894	/* otherwise specify the destination keyring recorded in the
 895	 * authorisation key (any KEY_SPEC_*_KEYRING) */
 896	if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
 897		*_dest_keyring = key_get(rka->dest_keyring);
 898		return 0;
 899	}
 900
 901	return -ENOKEY;
 902}
 903
 904/*
 905 * Change the request_key authorisation key on the current process.
 906 */
 907static int keyctl_change_reqkey_auth(struct key *key)
 908{
 909	struct cred *new;
 910
 911	new = prepare_creds();
 912	if (!new)
 913		return -ENOMEM;
 914
 915	key_put(new->request_key_auth);
 916	new->request_key_auth = key_get(key);
 917
 918	return commit_creds(new);
 919}
 920
 921/*
 922 * Copy the iovec data from userspace
 923 */
 924static long copy_from_user_iovec(void *buffer, const struct iovec *iov,
 925				 unsigned ioc)
 926{
 927	for (; ioc > 0; ioc--) {
 928		if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0)
 929			return -EFAULT;
 930		buffer += iov->iov_len;
 931		iov++;
 932	}
 933	return 0;
 934}
 935
 936/*
 937 * Instantiate a key with the specified payload and link the key into the
 938 * destination keyring if one is given.
 939 *
 940 * The caller must have the appropriate instantiation permit set for this to
 941 * work (see keyctl_assume_authority).  No other permissions are required.
 942 *
 943 * If successful, 0 will be returned.
 944 */
 945long keyctl_instantiate_key_common(key_serial_t id,
 946				   const struct iovec *payload_iov,
 947				   unsigned ioc,
 948				   size_t plen,
 949				   key_serial_t ringid)
 950{
 951	const struct cred *cred = current_cred();
 952	struct request_key_auth *rka;
 953	struct key *instkey, *dest_keyring;
 
 954	void *payload;
 955	long ret;
 956	bool vm = false;
 957
 958	kenter("%d,,%zu,%d", id, plen, ringid);
 959
 
 
 
 960	ret = -EINVAL;
 961	if (plen > 1024 * 1024 - 1)
 962		goto error;
 963
 964	/* the appropriate instantiation authorisation key must have been
 965	 * assumed before calling this */
 966	ret = -EPERM;
 967	instkey = cred->request_key_auth;
 968	if (!instkey)
 969		goto error;
 970
 971	rka = instkey->payload.data;
 972	if (rka->target_key->serial != id)
 973		goto error;
 974
 975	/* pull the payload in if one was supplied */
 976	payload = NULL;
 977
 978	if (payload_iov) {
 979		ret = -ENOMEM;
 980		payload = kmalloc(plen, GFP_KERNEL);
 981		if (!payload) {
 982			if (plen <= PAGE_SIZE)
 983				goto error;
 984			vm = true;
 985			payload = vmalloc(plen);
 986			if (!payload)
 987				goto error;
 988		}
 989
 990		ret = copy_from_user_iovec(payload, payload_iov, ioc);
 991		if (ret < 0)
 992			goto error2;
 993	}
 994
 995	/* find the destination keyring amongst those belonging to the
 996	 * requesting task */
 997	ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
 998	if (ret < 0)
 999		goto error2;
1000
1001	/* instantiate the key and link it into a keyring */
1002	ret = key_instantiate_and_link(rka->target_key, payload, plen,
1003				       dest_keyring, instkey);
1004
1005	key_put(dest_keyring);
1006
1007	/* discard the assumed authority if it's just been disabled by
1008	 * instantiation of the key */
1009	if (ret == 0)
1010		keyctl_change_reqkey_auth(NULL);
1011
1012error2:
1013	if (!vm)
1014		kfree(payload);
1015	else
1016		vfree(payload);
1017error:
1018	return ret;
1019}
1020
1021/*
1022 * Instantiate a key with the specified payload and link the key into the
1023 * destination keyring if one is given.
1024 *
1025 * The caller must have the appropriate instantiation permit set for this to
1026 * work (see keyctl_assume_authority).  No other permissions are required.
1027 *
1028 * If successful, 0 will be returned.
1029 */
1030long keyctl_instantiate_key(key_serial_t id,
1031			    const void __user *_payload,
1032			    size_t plen,
1033			    key_serial_t ringid)
1034{
1035	if (_payload && plen) {
1036		struct iovec iov[1] = {
1037			[0].iov_base = (void __user *)_payload,
1038			[0].iov_len  = plen
1039		};
 
 
 
 
1040
1041		return keyctl_instantiate_key_common(id, iov, 1, plen, ringid);
1042	}
1043
1044	return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1045}
1046
1047/*
1048 * Instantiate a key with the specified multipart payload and link the key into
1049 * the destination keyring if one is given.
1050 *
1051 * The caller must have the appropriate instantiation permit set for this to
1052 * work (see keyctl_assume_authority).  No other permissions are required.
1053 *
1054 * If successful, 0 will be returned.
1055 */
1056long keyctl_instantiate_key_iov(key_serial_t id,
1057				const struct iovec __user *_payload_iov,
1058				unsigned ioc,
1059				key_serial_t ringid)
1060{
1061	struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
 
1062	long ret;
1063
1064	if (_payload_iov == 0 || ioc == 0)
1065		goto no_payload;
1066
1067	ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc,
1068				    ARRAY_SIZE(iovstack), iovstack, &iov);
1069	if (ret < 0)
1070		return ret;
1071	if (ret == 0)
1072		goto no_payload_free;
1073
1074	ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid);
1075
1076	if (iov != iovstack)
1077		kfree(iov);
1078	return ret;
1079
1080no_payload_free:
1081	if (iov != iovstack)
1082		kfree(iov);
1083no_payload:
1084	return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid);
1085}
1086
1087/*
1088 * Negatively instantiate the key with the given timeout (in seconds) and link
1089 * the key into the 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 * The key and any links to the key will be automatically garbage collected
1095 * after the timeout expires.
1096 *
1097 * Negative keys are used to rate limit repeated request_key() calls by causing
1098 * them to return -ENOKEY until the negative key expires.
1099 *
1100 * If successful, 0 will be returned.
1101 */
1102long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1103{
1104	return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1105}
1106
1107/*
1108 * Negatively instantiate the key with the given timeout (in seconds) and error
1109 * code and link the key into the destination keyring if one is given.
1110 *
1111 * The caller must have the appropriate instantiation permit set for this to
1112 * work (see keyctl_assume_authority).  No other permissions are required.
1113 *
1114 * The key and any links to the key will be automatically garbage collected
1115 * after the timeout expires.
1116 *
1117 * Negative keys are used to rate limit repeated request_key() calls by causing
1118 * them to return the specified error code until the negative key expires.
1119 *
1120 * If successful, 0 will be returned.
1121 */
1122long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1123		       key_serial_t ringid)
1124{
1125	const struct cred *cred = current_cred();
1126	struct request_key_auth *rka;
1127	struct key *instkey, *dest_keyring;
1128	long ret;
1129
1130	kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1131
1132	/* must be a valid error code and mustn't be a kernel special */
1133	if (error <= 0 ||
1134	    error >= MAX_ERRNO ||
1135	    error == ERESTARTSYS ||
1136	    error == ERESTARTNOINTR ||
1137	    error == ERESTARTNOHAND ||
1138	    error == ERESTART_RESTARTBLOCK)
1139		return -EINVAL;
1140
1141	/* the appropriate instantiation authorisation key must have been
1142	 * assumed before calling this */
1143	ret = -EPERM;
1144	instkey = cred->request_key_auth;
1145	if (!instkey)
1146		goto error;
1147
1148	rka = instkey->payload.data;
1149	if (rka->target_key->serial != id)
1150		goto error;
1151
1152	/* find the destination keyring if present (which must also be
1153	 * writable) */
1154	ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1155	if (ret < 0)
1156		goto error;
1157
1158	/* instantiate the key and link it into a keyring */
1159	ret = key_reject_and_link(rka->target_key, timeout, error,
1160				  dest_keyring, instkey);
1161
1162	key_put(dest_keyring);
1163
1164	/* discard the assumed authority if it's just been disabled by
1165	 * instantiation of the key */
1166	if (ret == 0)
1167		keyctl_change_reqkey_auth(NULL);
1168
1169error:
1170	return ret;
1171}
1172
1173/*
1174 * Read or set the default keyring in which request_key() will cache keys and
1175 * return the old setting.
1176 *
1177 * If a process keyring is specified then this will be created if it doesn't
1178 * yet exist.  The old setting will be returned if successful.
1179 */
1180long keyctl_set_reqkey_keyring(int reqkey_defl)
1181{
1182	struct cred *new;
1183	int ret, old_setting;
1184
1185	old_setting = current_cred_xxx(jit_keyring);
1186
1187	if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1188		return old_setting;
1189
1190	new = prepare_creds();
1191	if (!new)
1192		return -ENOMEM;
1193
1194	switch (reqkey_defl) {
1195	case KEY_REQKEY_DEFL_THREAD_KEYRING:
1196		ret = install_thread_keyring_to_cred(new);
1197		if (ret < 0)
1198			goto error;
1199		goto set;
1200
1201	case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1202		ret = install_process_keyring_to_cred(new);
1203		if (ret < 0) {
1204			if (ret != -EEXIST)
1205				goto error;
1206			ret = 0;
1207		}
1208		goto set;
1209
1210	case KEY_REQKEY_DEFL_DEFAULT:
1211	case KEY_REQKEY_DEFL_SESSION_KEYRING:
1212	case KEY_REQKEY_DEFL_USER_KEYRING:
1213	case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1214	case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1215		goto set;
1216
1217	case KEY_REQKEY_DEFL_NO_CHANGE:
1218	case KEY_REQKEY_DEFL_GROUP_KEYRING:
1219	default:
1220		ret = -EINVAL;
1221		goto error;
1222	}
1223
1224set:
1225	new->jit_keyring = reqkey_defl;
1226	commit_creds(new);
1227	return old_setting;
1228error:
1229	abort_creds(new);
1230	return ret;
1231}
1232
1233/*
1234 * Set or clear the timeout on a key.
1235 *
1236 * Either the key must grant the caller Setattr permission or else the caller
1237 * must hold an instantiation authorisation token for the key.
1238 *
1239 * The timeout is either 0 to clear the timeout, or a number of seconds from
1240 * the current time.  The key and any links to the key will be automatically
1241 * garbage collected after the timeout expires.
1242 *
 
 
1243 * If successful, 0 is returned.
1244 */
1245long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1246{
1247	struct timespec now;
1248	struct key *key, *instkey;
1249	key_ref_t key_ref;
1250	time_t expiry;
1251	long ret;
1252
1253	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1254				  KEY_SETATTR);
1255	if (IS_ERR(key_ref)) {
1256		/* setting the timeout on a key under construction is permitted
1257		 * if we have the authorisation token handy */
1258		if (PTR_ERR(key_ref) == -EACCES) {
1259			instkey = key_get_instantiation_authkey(id);
1260			if (!IS_ERR(instkey)) {
1261				key_put(instkey);
1262				key_ref = lookup_user_key(id,
1263							  KEY_LOOKUP_PARTIAL,
1264							  0);
1265				if (!IS_ERR(key_ref))
1266					goto okay;
1267			}
1268		}
1269
1270		ret = PTR_ERR(key_ref);
1271		goto error;
1272	}
1273
1274okay:
1275	key = key_ref_to_ptr(key_ref);
1276
1277	/* make the changes with the locks held to prevent races */
1278	down_write(&key->sem);
1279
1280	expiry = 0;
1281	if (timeout > 0) {
1282		now = current_kernel_time();
1283		expiry = now.tv_sec + timeout;
1284	}
1285
1286	key->expiry = expiry;
1287	key_schedule_gc(key->expiry + key_gc_delay);
1288
1289	up_write(&key->sem);
1290	key_put(key);
1291
1292	ret = 0;
1293error:
1294	return ret;
1295}
1296
1297/*
1298 * Assume (or clear) the authority to instantiate the specified key.
1299 *
1300 * This sets the authoritative token currently in force for key instantiation.
1301 * This must be done for a key to be instantiated.  It has the effect of making
1302 * available all the keys from the caller of the request_key() that created a
1303 * key to request_key() calls made by the caller of this function.
1304 *
1305 * The caller must have the instantiation key in their process keyrings with a
1306 * Search permission grant available to the caller.
1307 *
1308 * If the ID given is 0, then the setting will be cleared and 0 returned.
1309 *
1310 * If the ID given has a matching an authorisation key, then that key will be
1311 * set and its ID will be returned.  The authorisation key can be read to get
1312 * the callout information passed to request_key().
1313 */
1314long keyctl_assume_authority(key_serial_t id)
1315{
1316	struct key *authkey;
1317	long ret;
1318
1319	/* special key IDs aren't permitted */
1320	ret = -EINVAL;
1321	if (id < 0)
1322		goto error;
1323
1324	/* we divest ourselves of authority if given an ID of 0 */
1325	if (id == 0) {
1326		ret = keyctl_change_reqkey_auth(NULL);
1327		goto error;
1328	}
1329
1330	/* attempt to assume the authority temporarily granted to us whilst we
1331	 * instantiate the specified key
1332	 * - the authorisation key must be in the current task's keyrings
1333	 *   somewhere
1334	 */
1335	authkey = key_get_instantiation_authkey(id);
1336	if (IS_ERR(authkey)) {
1337		ret = PTR_ERR(authkey);
1338		goto error;
1339	}
1340
1341	ret = keyctl_change_reqkey_auth(authkey);
1342	if (ret < 0)
1343		goto error;
1344	key_put(authkey);
1345
1346	ret = authkey->serial;
1347error:
1348	return ret;
1349}
1350
1351/*
1352 * Get a key's the LSM security label.
1353 *
1354 * The key must grant the caller View permission for this to work.
1355 *
1356 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1357 *
1358 * If successful, the amount of information available will be returned,
1359 * irrespective of how much was copied (including the terminal NUL).
1360 */
1361long keyctl_get_security(key_serial_t keyid,
1362			 char __user *buffer,
1363			 size_t buflen)
1364{
1365	struct key *key, *instkey;
1366	key_ref_t key_ref;
1367	char *context;
1368	long ret;
1369
1370	key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW);
1371	if (IS_ERR(key_ref)) {
1372		if (PTR_ERR(key_ref) != -EACCES)
1373			return PTR_ERR(key_ref);
1374
1375		/* viewing a key under construction is also permitted if we
1376		 * have the authorisation token handy */
1377		instkey = key_get_instantiation_authkey(keyid);
1378		if (IS_ERR(instkey))
1379			return PTR_ERR(instkey);
1380		key_put(instkey);
1381
1382		key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0);
1383		if (IS_ERR(key_ref))
1384			return PTR_ERR(key_ref);
1385	}
1386
1387	key = key_ref_to_ptr(key_ref);
1388	ret = security_key_getsecurity(key, &context);
1389	if (ret == 0) {
1390		/* if no information was returned, give userspace an empty
1391		 * string */
1392		ret = 1;
1393		if (buffer && buflen > 0 &&
1394		    copy_to_user(buffer, "", 1) != 0)
1395			ret = -EFAULT;
1396	} else if (ret > 0) {
1397		/* return as much data as there's room for */
1398		if (buffer && buflen > 0) {
1399			if (buflen > ret)
1400				buflen = ret;
1401
1402			if (copy_to_user(buffer, context, buflen) != 0)
1403				ret = -EFAULT;
1404		}
1405
1406		kfree(context);
1407	}
1408
1409	key_ref_put(key_ref);
1410	return ret;
1411}
1412
1413/*
1414 * Attempt to install the calling process's session keyring on the process's
1415 * parent process.
1416 *
1417 * The keyring must exist and must grant the caller LINK permission, and the
1418 * parent process must be single-threaded and must have the same effective
1419 * ownership as this process and mustn't be SUID/SGID.
1420 *
1421 * The keyring will be emplaced on the parent when it next resumes userspace.
1422 *
1423 * If successful, 0 will be returned.
1424 */
1425long keyctl_session_to_parent(void)
1426{
1427#ifdef TIF_NOTIFY_RESUME
1428	struct task_struct *me, *parent;
1429	const struct cred *mycred, *pcred;
1430	struct cred *cred, *oldcred;
1431	key_ref_t keyring_r;
 
1432	int ret;
1433
1434	keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK);
1435	if (IS_ERR(keyring_r))
1436		return PTR_ERR(keyring_r);
1437
 
 
1438	/* our parent is going to need a new cred struct, a new tgcred struct
1439	 * and new security data, so we allocate them here to prevent ENOMEM in
1440	 * our parent */
1441	ret = -ENOMEM;
1442	cred = cred_alloc_blank();
1443	if (!cred)
1444		goto error_keyring;
 
1445
1446	cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r);
1447	keyring_r = NULL;
 
1448
1449	me = current;
1450	rcu_read_lock();
1451	write_lock_irq(&tasklist_lock);
1452
1453	parent = me->real_parent;
1454	ret = -EPERM;
 
 
 
1455
1456	/* the parent mustn't be init and mustn't be a kernel thread */
1457	if (parent->pid <= 1 || !parent->mm)
1458		goto not_permitted;
1459
1460	/* the parent must be single threaded */
1461	if (!thread_group_empty(parent))
1462		goto not_permitted;
1463
1464	/* the parent and the child must have different session keyrings or
1465	 * there's no point */
1466	mycred = current_cred();
1467	pcred = __task_cred(parent);
1468	if (mycred == pcred ||
1469	    mycred->tgcred->session_keyring == pcred->tgcred->session_keyring)
1470		goto already_same;
 
 
1471
1472	/* the parent must have the same effective ownership and mustn't be
1473	 * SUID/SGID */
1474	if (pcred->uid	!= mycred->euid	||
1475	    pcred->euid	!= mycred->euid	||
1476	    pcred->suid	!= mycred->euid	||
1477	    pcred->gid	!= mycred->egid	||
1478	    pcred->egid	!= mycred->egid	||
1479	    pcred->sgid	!= mycred->egid)
1480		goto not_permitted;
1481
1482	/* the keyrings must have the same UID */
1483	if ((pcred->tgcred->session_keyring &&
1484	     pcred->tgcred->session_keyring->uid != mycred->euid) ||
1485	    mycred->tgcred->session_keyring->uid != mycred->euid)
1486		goto not_permitted;
1487
1488	/* if there's an already pending keyring replacement, then we replace
1489	 * that */
1490	oldcred = parent->replacement_session_keyring;
1491
1492	/* the replacement session keyring is applied just prior to userspace
1493	 * restarting */
1494	parent->replacement_session_keyring = cred;
1495	cred = NULL;
1496	set_ti_thread_flag(task_thread_info(parent), TIF_NOTIFY_RESUME);
1497
1498	write_unlock_irq(&tasklist_lock);
1499	rcu_read_unlock();
1500	if (oldcred)
1501		put_cred(oldcred);
1502	return 0;
1503
1504already_same:
1505	ret = 0;
1506not_permitted:
1507	write_unlock_irq(&tasklist_lock);
1508	rcu_read_unlock();
1509	put_cred(cred);
1510	return ret;
1511
1512error_keyring:
1513	key_ref_put(keyring_r);
1514	return ret;
 
1515
1516#else /* !TIF_NOTIFY_RESUME */
1517	/*
1518	 * To be removed when TIF_NOTIFY_RESUME has been implemented on
1519	 * m68k/xtensa
1520	 */
1521#warning TIF_NOTIFY_RESUME not implemented
1522	return -EOPNOTSUPP;
1523#endif /* !TIF_NOTIFY_RESUME */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1524}
1525
1526/*
1527 * The key control system call
1528 */
1529SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1530		unsigned long, arg4, unsigned long, arg5)
1531{
1532	switch (option) {
1533	case KEYCTL_GET_KEYRING_ID:
1534		return keyctl_get_keyring_ID((key_serial_t) arg2,
1535					     (int) arg3);
1536
1537	case KEYCTL_JOIN_SESSION_KEYRING:
1538		return keyctl_join_session_keyring((const char __user *) arg2);
1539
1540	case KEYCTL_UPDATE:
1541		return keyctl_update_key((key_serial_t) arg2,
1542					 (const void __user *) arg3,
1543					 (size_t) arg4);
1544
1545	case KEYCTL_REVOKE:
1546		return keyctl_revoke_key((key_serial_t) arg2);
1547
1548	case KEYCTL_DESCRIBE:
1549		return keyctl_describe_key((key_serial_t) arg2,
1550					   (char __user *) arg3,
1551					   (unsigned) arg4);
1552
1553	case KEYCTL_CLEAR:
1554		return keyctl_keyring_clear((key_serial_t) arg2);
1555
1556	case KEYCTL_LINK:
1557		return keyctl_keyring_link((key_serial_t) arg2,
1558					   (key_serial_t) arg3);
1559
1560	case KEYCTL_UNLINK:
1561		return keyctl_keyring_unlink((key_serial_t) arg2,
1562					     (key_serial_t) arg3);
1563
1564	case KEYCTL_SEARCH:
1565		return keyctl_keyring_search((key_serial_t) arg2,
1566					     (const char __user *) arg3,
1567					     (const char __user *) arg4,
1568					     (key_serial_t) arg5);
1569
1570	case KEYCTL_READ:
1571		return keyctl_read_key((key_serial_t) arg2,
1572				       (char __user *) arg3,
1573				       (size_t) arg4);
1574
1575	case KEYCTL_CHOWN:
1576		return keyctl_chown_key((key_serial_t) arg2,
1577					(uid_t) arg3,
1578					(gid_t) arg4);
1579
1580	case KEYCTL_SETPERM:
1581		return keyctl_setperm_key((key_serial_t) arg2,
1582					  (key_perm_t) arg3);
1583
1584	case KEYCTL_INSTANTIATE:
1585		return keyctl_instantiate_key((key_serial_t) arg2,
1586					      (const void __user *) arg3,
1587					      (size_t) arg4,
1588					      (key_serial_t) arg5);
1589
1590	case KEYCTL_NEGATE:
1591		return keyctl_negate_key((key_serial_t) arg2,
1592					 (unsigned) arg3,
1593					 (key_serial_t) arg4);
1594
1595	case KEYCTL_SET_REQKEY_KEYRING:
1596		return keyctl_set_reqkey_keyring(arg2);
1597
1598	case KEYCTL_SET_TIMEOUT:
1599		return keyctl_set_timeout((key_serial_t) arg2,
1600					  (unsigned) arg3);
1601
1602	case KEYCTL_ASSUME_AUTHORITY:
1603		return keyctl_assume_authority((key_serial_t) arg2);
1604
1605	case KEYCTL_GET_SECURITY:
1606		return keyctl_get_security((key_serial_t) arg2,
1607					   (char __user *) arg3,
1608					   (size_t) arg4);
1609
1610	case KEYCTL_SESSION_TO_PARENT:
1611		return keyctl_session_to_parent();
1612
1613	case KEYCTL_REJECT:
1614		return keyctl_reject_key((key_serial_t) arg2,
1615					 (unsigned) arg3,
1616					 (unsigned) arg4,
1617					 (key_serial_t) arg5);
1618
1619	case KEYCTL_INSTANTIATE_IOV:
1620		return keyctl_instantiate_key_iov(
1621			(key_serial_t) arg2,
1622			(const struct iovec __user *) arg3,
1623			(unsigned) arg4,
1624			(key_serial_t) arg5);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1625
1626	default:
1627		return -EOPNOTSUPP;
1628	}
1629}