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	       (IS_ENABLED(CONFIG_KEY_NOTIFICATIONS)	? KEYCTL_CAPS1_NOTIFICATIONS : 0)
  42	       ),
  43};
  44
  45static int key_get_type_from_user(char *type,
  46				  const char __user *_type,
  47				  unsigned len)
  48{
  49	int ret;
  50
  51	ret = strncpy_from_user(type, _type, len);
  52	if (ret < 0)
  53		return ret;
  54	if (ret == 0 || ret >= len)
  55		return -EINVAL;
  56	if (type[0] == '.')
  57		return -EPERM;
  58	type[len - 1] = '\0';
  59	return 0;
  60}
  61
  62/*
  63 * Extract the description of a new key from userspace and either add it as a
  64 * new key to the specified keyring or update a matching key in that keyring.
  65 *
  66 * If the description is NULL or an empty string, the key type is asked to
  67 * generate one from the payload.
  68 *
  69 * The keyring must be writable so that we can attach the key to it.
  70 *
  71 * If successful, the new key's serial number is returned, otherwise an error
  72 * code is returned.
  73 */
  74SYSCALL_DEFINE5(add_key, const char __user *, _type,
  75		const char __user *, _description,
  76		const void __user *, _payload,
  77		size_t, plen,
  78		key_serial_t, ringid)
  79{
  80	key_ref_t keyring_ref, key_ref;
  81	char type[32], *description;
  82	void *payload;
  83	long ret;
  84
  85	ret = -EINVAL;
  86	if (plen > 1024 * 1024 - 1)
  87		goto error;
  88
  89	/* draw all the data into kernel space */
  90	ret = key_get_type_from_user(type, _type, sizeof(type));
  91	if (ret < 0)
  92		goto error;
  93
  94	description = NULL;
  95	if (_description) {
  96		description = strndup_user(_description, KEY_MAX_DESC_SIZE);
  97		if (IS_ERR(description)) {
  98			ret = PTR_ERR(description);
  99			goto error;
 100		}
 101		if (!*description) {
 102			kfree(description);
 103			description = NULL;
 104		} else if ((description[0] == '.') &&
 105			   (strncmp(type, "keyring", 7) == 0)) {
 106			ret = -EPERM;
 107			goto error2;
 108		}
 109	}
 110
 111	/* pull the payload in if one was supplied */
 112	payload = NULL;
 113
 114	if (plen) {
 115		ret = -ENOMEM;
 116		payload = kvmalloc(plen, GFP_KERNEL);
 117		if (!payload)
 118			goto error2;
 119
 120		ret = -EFAULT;
 121		if (copy_from_user(payload, _payload, plen) != 0)
 122			goto error3;
 123	}
 124
 125	/* find the target keyring (which must be writable) */
 126	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
 127	if (IS_ERR(keyring_ref)) {
 128		ret = PTR_ERR(keyring_ref);
 129		goto error3;
 130	}
 131
 132	/* create or update the requested key and add it to the target
 133	 * keyring */
 134	key_ref = key_create_or_update(keyring_ref, type, description,
 135				       payload, plen, KEY_PERM_UNDEF,
 136				       KEY_ALLOC_IN_QUOTA);
 137	if (!IS_ERR(key_ref)) {
 138		ret = key_ref_to_ptr(key_ref)->serial;
 139		key_ref_put(key_ref);
 140	}
 141	else {
 142		ret = PTR_ERR(key_ref);
 143	}
 144
 145	key_ref_put(keyring_ref);
 146 error3:
 147	kvfree_sensitive(payload, plen);
 
 
 
 148 error2:
 149	kfree(description);
 150 error:
 151	return ret;
 152}
 153
 154/*
 155 * Search the process keyrings and keyring trees linked from those for a
 156 * matching key.  Keyrings must have appropriate Search permission to be
 157 * searched.
 158 *
 159 * If a key is found, it will be attached to the destination keyring if there's
 160 * one specified and the serial number of the key will be returned.
 161 *
 162 * If no key is found, /sbin/request-key will be invoked if _callout_info is
 163 * non-NULL in an attempt to create a key.  The _callout_info string will be
 164 * passed to /sbin/request-key to aid with completing the request.  If the
 165 * _callout_info string is "" then it will be changed to "-".
 166 */
 167SYSCALL_DEFINE4(request_key, const char __user *, _type,
 168		const char __user *, _description,
 169		const char __user *, _callout_info,
 170		key_serial_t, destringid)
 171{
 172	struct key_type *ktype;
 173	struct key *key;
 174	key_ref_t dest_ref;
 175	size_t callout_len;
 176	char type[32], *description, *callout_info;
 177	long ret;
 178
 179	/* pull the type into kernel space */
 180	ret = key_get_type_from_user(type, _type, sizeof(type));
 181	if (ret < 0)
 182		goto error;
 183
 184	/* pull the description into kernel space */
 185	description = strndup_user(_description, KEY_MAX_DESC_SIZE);
 186	if (IS_ERR(description)) {
 187		ret = PTR_ERR(description);
 188		goto error;
 189	}
 190
 191	/* pull the callout info into kernel space */
 192	callout_info = NULL;
 193	callout_len = 0;
 194	if (_callout_info) {
 195		callout_info = strndup_user(_callout_info, PAGE_SIZE);
 196		if (IS_ERR(callout_info)) {
 197			ret = PTR_ERR(callout_info);
 198			goto error2;
 199		}
 200		callout_len = strlen(callout_info);
 201	}
 202
 203	/* get the destination keyring if specified */
 204	dest_ref = NULL;
 205	if (destringid) {
 206		dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
 207					   KEY_NEED_WRITE);
 208		if (IS_ERR(dest_ref)) {
 209			ret = PTR_ERR(dest_ref);
 210			goto error3;
 211		}
 212	}
 213
 214	/* find the key type */
 215	ktype = key_type_lookup(type);
 216	if (IS_ERR(ktype)) {
 217		ret = PTR_ERR(ktype);
 218		goto error4;
 219	}
 220
 221	/* do the search */
 222	key = request_key_and_link(ktype, description, NULL, callout_info,
 223				   callout_len, NULL, key_ref_to_ptr(dest_ref),
 224				   KEY_ALLOC_IN_QUOTA);
 225	if (IS_ERR(key)) {
 226		ret = PTR_ERR(key);
 227		goto error5;
 228	}
 229
 230	/* wait for the key to finish being constructed */
 231	ret = wait_for_key_construction(key, 1);
 232	if (ret < 0)
 233		goto error6;
 234
 235	ret = key->serial;
 236
 237error6:
 238 	key_put(key);
 239error5:
 240	key_type_put(ktype);
 241error4:
 242	key_ref_put(dest_ref);
 243error3:
 244	kfree(callout_info);
 245error2:
 246	kfree(description);
 247error:
 248	return ret;
 249}
 250
 251/*
 252 * Get the ID of the specified process keyring.
 253 *
 254 * The requested keyring must have search permission to be found.
 255 *
 256 * If successful, the ID of the requested keyring will be returned.
 257 */
 258long keyctl_get_keyring_ID(key_serial_t id, int create)
 259{
 260	key_ref_t key_ref;
 261	unsigned long lflags;
 262	long ret;
 263
 264	lflags = create ? KEY_LOOKUP_CREATE : 0;
 265	key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
 266	if (IS_ERR(key_ref)) {
 267		ret = PTR_ERR(key_ref);
 268		goto error;
 269	}
 270
 271	ret = key_ref_to_ptr(key_ref)->serial;
 272	key_ref_put(key_ref);
 273error:
 274	return ret;
 275}
 276
 277/*
 278 * Join a (named) session keyring.
 279 *
 280 * Create and join an anonymous session keyring or join a named session
 281 * keyring, creating it if necessary.  A named session keyring must have Search
 282 * permission for it to be joined.  Session keyrings without this permit will
 283 * be skipped over.  It is not permitted for userspace to create or join
 284 * keyrings whose name begin with a dot.
 285 *
 286 * If successful, the ID of the joined session keyring will be returned.
 287 */
 288long keyctl_join_session_keyring(const char __user *_name)
 289{
 290	char *name;
 291	long ret;
 292
 293	/* fetch the name from userspace */
 294	name = NULL;
 295	if (_name) {
 296		name = strndup_user(_name, KEY_MAX_DESC_SIZE);
 297		if (IS_ERR(name)) {
 298			ret = PTR_ERR(name);
 299			goto error;
 300		}
 301
 302		ret = -EPERM;
 303		if (name[0] == '.')
 304			goto error_name;
 305	}
 306
 307	/* join the session */
 308	ret = join_session_keyring(name);
 309error_name:
 310	kfree(name);
 311error:
 312	return ret;
 313}
 314
 315/*
 316 * Update a key's data payload from the given data.
 317 *
 318 * The key must grant the caller Write permission and the key type must support
 319 * updating for this to work.  A negative key can be positively instantiated
 320 * with this call.
 321 *
 322 * If successful, 0 will be returned.  If the key type does not support
 323 * updating, then -EOPNOTSUPP will be returned.
 324 */
 325long keyctl_update_key(key_serial_t id,
 326		       const void __user *_payload,
 327		       size_t plen)
 328{
 329	key_ref_t key_ref;
 330	void *payload;
 331	long ret;
 332
 333	ret = -EINVAL;
 334	if (plen > PAGE_SIZE)
 335		goto error;
 336
 337	/* pull the payload in if one was supplied */
 338	payload = NULL;
 339	if (plen) {
 340		ret = -ENOMEM;
 341		payload = kvmalloc(plen, GFP_KERNEL);
 342		if (!payload)
 343			goto error;
 344
 345		ret = -EFAULT;
 346		if (copy_from_user(payload, _payload, plen) != 0)
 347			goto error2;
 348	}
 349
 350	/* find the target key (which must be writable) */
 351	key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
 352	if (IS_ERR(key_ref)) {
 353		ret = PTR_ERR(key_ref);
 354		goto error2;
 355	}
 356
 357	/* update the key */
 358	ret = key_update(key_ref, payload, plen);
 359
 360	key_ref_put(key_ref);
 361error2:
 362	kvfree_sensitive(payload, plen);
 363error:
 364	return ret;
 365}
 366
 367/*
 368 * Revoke a key.
 369 *
 370 * The key must be grant the caller Write or Setattr permission for this to
 371 * work.  The key type should give up its quota claim when revoked.  The key
 372 * and any links to the key will be automatically garbage collected after a
 373 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
 374 *
 375 * Keys with KEY_FLAG_KEEP set should not be revoked.
 376 *
 377 * If successful, 0 is returned.
 378 */
 379long keyctl_revoke_key(key_serial_t id)
 380{
 381	key_ref_t key_ref;
 382	struct key *key;
 383	long ret;
 384
 385	key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
 386	if (IS_ERR(key_ref)) {
 387		ret = PTR_ERR(key_ref);
 388		if (ret != -EACCES)
 389			goto error;
 390		key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
 391		if (IS_ERR(key_ref)) {
 392			ret = PTR_ERR(key_ref);
 393			goto error;
 394		}
 395	}
 396
 397	key = key_ref_to_ptr(key_ref);
 398	ret = 0;
 399	if (test_bit(KEY_FLAG_KEEP, &key->flags))
 400		ret = -EPERM;
 401	else
 402		key_revoke(key);
 403
 404	key_ref_put(key_ref);
 405error:
 406	return ret;
 407}
 408
 409/*
 410 * Invalidate a key.
 411 *
 412 * The key must be grant the caller Invalidate permission for this to work.
 413 * The key and any links to the key will be automatically garbage collected
 414 * immediately.
 415 *
 416 * Keys with KEY_FLAG_KEEP set should not be invalidated.
 417 *
 418 * If successful, 0 is returned.
 419 */
 420long keyctl_invalidate_key(key_serial_t id)
 421{
 422	key_ref_t key_ref;
 423	struct key *key;
 424	long ret;
 425
 426	kenter("%d", id);
 427
 428	key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
 429	if (IS_ERR(key_ref)) {
 430		ret = PTR_ERR(key_ref);
 431
 432		/* Root is permitted to invalidate certain special keys */
 433		if (capable(CAP_SYS_ADMIN)) {
 434			key_ref = lookup_user_key(id, 0, KEY_SYSADMIN_OVERRIDE);
 435			if (IS_ERR(key_ref))
 436				goto error;
 437			if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
 438				     &key_ref_to_ptr(key_ref)->flags))
 439				goto invalidate;
 440			goto error_put;
 441		}
 442
 443		goto error;
 444	}
 445
 446invalidate:
 447	key = key_ref_to_ptr(key_ref);
 448	ret = 0;
 449	if (test_bit(KEY_FLAG_KEEP, &key->flags))
 450		ret = -EPERM;
 451	else
 452		key_invalidate(key);
 453error_put:
 454	key_ref_put(key_ref);
 455error:
 456	kleave(" = %ld", ret);
 457	return ret;
 458}
 459
 460/*
 461 * Clear the specified keyring, creating an empty process keyring if one of the
 462 * special keyring IDs is used.
 463 *
 464 * The keyring must grant the caller Write permission and not have
 465 * KEY_FLAG_KEEP set for this to work.  If successful, 0 will be returned.
 466 */
 467long keyctl_keyring_clear(key_serial_t ringid)
 468{
 469	key_ref_t keyring_ref;
 470	struct key *keyring;
 471	long ret;
 472
 473	keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
 474	if (IS_ERR(keyring_ref)) {
 475		ret = PTR_ERR(keyring_ref);
 476
 477		/* Root is permitted to invalidate certain special keyrings */
 478		if (capable(CAP_SYS_ADMIN)) {
 479			keyring_ref = lookup_user_key(ringid, 0,
 480						      KEY_SYSADMIN_OVERRIDE);
 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 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_PARTIAL, KEY_NEED_UNLINK);
 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							  KEY_AUTHTOKEN_OVERRIDE);
 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 * Call the read method
 802 */
 803static long __keyctl_read_key(struct key *key, char *buffer, size_t buflen)
 804{
 805	long ret;
 806
 807	down_read(&key->sem);
 808	ret = key_validate(key);
 809	if (ret == 0)
 810		ret = key->type->read(key, buffer, buflen);
 811	up_read(&key->sem);
 812	return ret;
 813}
 814
 815/*
 816 * Read a key's payload.
 817 *
 818 * The key must either grant the caller Read permission, or it must grant the
 819 * caller Search permission when searched for from the process keyrings.
 820 *
 821 * If successful, we place up to buflen bytes of data into the buffer, if one
 822 * is provided, and return the amount of data that is available in the key,
 823 * irrespective of how much we copied into the buffer.
 824 */
 825long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
 826{
 827	struct key *key;
 828	key_ref_t key_ref;
 829	long ret;
 830	char *key_data = NULL;
 831	size_t key_data_len;
 832
 833	/* find the key first */
 834	key_ref = lookup_user_key(keyid, 0, KEY_DEFER_PERM_CHECK);
 835	if (IS_ERR(key_ref)) {
 836		ret = -ENOKEY;
 837		goto out;
 838	}
 839
 840	key = key_ref_to_ptr(key_ref);
 841
 842	ret = key_read_state(key);
 843	if (ret < 0)
 844		goto key_put_out; /* Negatively instantiated */
 845
 846	/* see if we can read it directly */
 847	ret = key_permission(key_ref, KEY_NEED_READ);
 848	if (ret == 0)
 849		goto can_read_key;
 850	if (ret != -EACCES)
 851		goto key_put_out;
 852
 853	/* we can't; see if it's searchable from this process's keyrings
 854	 * - we automatically take account of the fact that it may be
 855	 *   dangling off an instantiation key
 856	 */
 857	if (!is_key_possessed(key_ref)) {
 858		ret = -EACCES;
 859		goto key_put_out;
 860	}
 861
 862	/* the key is probably readable - now try to read it */
 863can_read_key:
 864	if (!key->type->read) {
 865		ret = -EOPNOTSUPP;
 866		goto key_put_out;
 867	}
 868
 869	if (!buffer || !buflen) {
 870		/* Get the key length from the read method */
 871		ret = __keyctl_read_key(key, NULL, 0);
 872		goto key_put_out;
 873	}
 874
 875	/*
 876	 * Read the data with the semaphore held (since we might sleep)
 877	 * to protect against the key being updated or revoked.
 878	 *
 879	 * Allocating a temporary buffer to hold the keys before
 880	 * transferring them to user buffer to avoid potential
 881	 * deadlock involving page fault and mmap_lock.
 882	 *
 883	 * key_data_len = (buflen <= PAGE_SIZE)
 884	 *		? buflen : actual length of key data
 885	 *
 886	 * This prevents allocating arbitrary large buffer which can
 887	 * be much larger than the actual key length. In the latter case,
 888	 * at least 2 passes of this loop is required.
 889	 */
 890	key_data_len = (buflen <= PAGE_SIZE) ? buflen : 0;
 891	for (;;) {
 892		if (key_data_len) {
 893			key_data = kvmalloc(key_data_len, GFP_KERNEL);
 894			if (!key_data) {
 895				ret = -ENOMEM;
 896				goto key_put_out;
 897			}
 898		}
 899
 900		ret = __keyctl_read_key(key, key_data, key_data_len);
 901
 902		/*
 903		 * Read methods will just return the required length without
 904		 * any copying if the provided length isn't large enough.
 905		 */
 906		if (ret <= 0 || ret > buflen)
 907			break;
 908
 909		/*
 910		 * The key may change (unlikely) in between 2 consecutive
 911		 * __keyctl_read_key() calls. In this case, we reallocate
 912		 * a larger buffer and redo the key read when
 913		 * key_data_len < ret <= buflen.
 914		 */
 915		if (ret > key_data_len) {
 916			if (unlikely(key_data))
 917				kvfree_sensitive(key_data, key_data_len);
 918			key_data_len = ret;
 919			continue;	/* Allocate buffer */
 920		}
 921
 922		if (copy_to_user(buffer, key_data, ret))
 923			ret = -EFAULT;
 924		break;
 925	}
 926	kvfree_sensitive(key_data, key_data_len);
 927
 928key_put_out:
 929	key_put(key);
 930out:
 931	return ret;
 932}
 933
 934/*
 935 * Change the ownership of a key
 936 *
 937 * The key must grant the caller Setattr permission for this to work, though
 938 * the key need not be fully instantiated yet.  For the UID to be changed, or
 939 * for the GID to be changed to a group the caller is not a member of, the
 940 * caller must have sysadmin capability.  If either uid or gid is -1 then that
 941 * attribute is not changed.
 942 *
 943 * If the UID is to be changed, the new user must have sufficient quota to
 944 * accept the key.  The quota deduction will be removed from the old user to
 945 * the new user should the attribute be changed.
 946 *
 947 * If successful, 0 will be returned.
 948 */
 949long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
 950{
 951	struct key_user *newowner, *zapowner = NULL;
 952	struct key *key;
 953	key_ref_t key_ref;
 954	long ret;
 955	kuid_t uid;
 956	kgid_t gid;
 957
 958	uid = make_kuid(current_user_ns(), user);
 959	gid = make_kgid(current_user_ns(), group);
 960	ret = -EINVAL;
 961	if ((user != (uid_t) -1) && !uid_valid(uid))
 962		goto error;
 963	if ((group != (gid_t) -1) && !gid_valid(gid))
 964		goto error;
 965
 966	ret = 0;
 967	if (user == (uid_t) -1 && group == (gid_t) -1)
 968		goto error;
 969
 970	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
 971				  KEY_NEED_SETATTR);
 972	if (IS_ERR(key_ref)) {
 973		ret = PTR_ERR(key_ref);
 974		goto error;
 975	}
 976
 977	key = key_ref_to_ptr(key_ref);
 978
 979	/* make the changes with the locks held to prevent chown/chown races */
 980	ret = -EACCES;
 981	down_write(&key->sem);
 982
 983	{
 984		bool is_privileged_op = false;
 985
 986		/* only the sysadmin can chown a key to some other UID */
 987		if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
 988			is_privileged_op = true;
 989
 990		/* only the sysadmin can set the key's GID to a group other
 991		 * than one of those that the current process subscribes to */
 992		if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
 993			is_privileged_op = true;
 994
 995		if (is_privileged_op && !capable(CAP_SYS_ADMIN))
 996			goto error_put;
 997	}
 998
 999	/* change the UID */
1000	if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
1001		ret = -ENOMEM;
1002		newowner = key_user_lookup(uid);
1003		if (!newowner)
1004			goto error_put;
1005
1006		/* transfer the quota burden to the new user */
1007		if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
1008			unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
1009				key_quota_root_maxkeys : key_quota_maxkeys;
1010			unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
1011				key_quota_root_maxbytes : key_quota_maxbytes;
1012
1013			spin_lock(&newowner->lock);
1014			if (newowner->qnkeys + 1 > maxkeys ||
1015			    newowner->qnbytes + key->quotalen > maxbytes ||
1016			    newowner->qnbytes + key->quotalen <
1017			    newowner->qnbytes)
1018				goto quota_overrun;
1019
1020			newowner->qnkeys++;
1021			newowner->qnbytes += key->quotalen;
1022			spin_unlock(&newowner->lock);
1023
1024			spin_lock(&key->user->lock);
1025			key->user->qnkeys--;
1026			key->user->qnbytes -= key->quotalen;
1027			spin_unlock(&key->user->lock);
1028		}
1029
1030		atomic_dec(&key->user->nkeys);
1031		atomic_inc(&newowner->nkeys);
1032
1033		if (key->state != KEY_IS_UNINSTANTIATED) {
1034			atomic_dec(&key->user->nikeys);
1035			atomic_inc(&newowner->nikeys);
1036		}
1037
1038		zapowner = key->user;
1039		key->user = newowner;
1040		key->uid = uid;
1041	}
1042
1043	/* change the GID */
1044	if (group != (gid_t) -1)
1045		key->gid = gid;
1046
1047	notify_key(key, NOTIFY_KEY_SETATTR, 0);
1048	ret = 0;
1049
1050error_put:
1051	up_write(&key->sem);
1052	key_put(key);
1053	if (zapowner)
1054		key_user_put(zapowner);
1055error:
1056	return ret;
1057
1058quota_overrun:
1059	spin_unlock(&newowner->lock);
1060	zapowner = newowner;
1061	ret = -EDQUOT;
1062	goto error_put;
1063}
1064
1065/*
1066 * Change the permission mask on a key.
1067 *
1068 * The key must grant the caller Setattr permission for this to work, though
1069 * the key need not be fully instantiated yet.  If the caller does not have
1070 * sysadmin capability, it may only change the permission on keys that it owns.
1071 */
1072long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
1073{
1074	struct key *key;
1075	key_ref_t key_ref;
1076	long ret;
1077
1078	ret = -EINVAL;
1079	if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
1080		goto error;
1081
1082	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1083				  KEY_NEED_SETATTR);
1084	if (IS_ERR(key_ref)) {
1085		ret = PTR_ERR(key_ref);
1086		goto error;
1087	}
1088
1089	key = key_ref_to_ptr(key_ref);
1090
1091	/* make the changes with the locks held to prevent chown/chmod races */
1092	ret = -EACCES;
1093	down_write(&key->sem);
1094
1095	/* if we're not the sysadmin, we can only change a key that we own */
1096	if (uid_eq(key->uid, current_fsuid()) || capable(CAP_SYS_ADMIN)) {
1097		key->perm = perm;
1098		notify_key(key, NOTIFY_KEY_SETATTR, 0);
1099		ret = 0;
1100	}
1101
1102	up_write(&key->sem);
1103	key_put(key);
1104error:
1105	return ret;
1106}
1107
1108/*
1109 * Get the destination keyring for instantiation and check that the caller has
1110 * Write permission on it.
1111 */
1112static long get_instantiation_keyring(key_serial_t ringid,
1113				      struct request_key_auth *rka,
1114				      struct key **_dest_keyring)
1115{
1116	key_ref_t dkref;
1117
1118	*_dest_keyring = NULL;
1119
1120	/* just return a NULL pointer if we weren't asked to make a link */
1121	if (ringid == 0)
1122		return 0;
1123
1124	/* if a specific keyring is nominated by ID, then use that */
1125	if (ringid > 0) {
1126		dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
1127		if (IS_ERR(dkref))
1128			return PTR_ERR(dkref);
1129		*_dest_keyring = key_ref_to_ptr(dkref);
1130		return 0;
1131	}
1132
1133	if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
1134		return -EINVAL;
1135
1136	/* otherwise specify the destination keyring recorded in the
1137	 * authorisation key (any KEY_SPEC_*_KEYRING) */
1138	if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1139		*_dest_keyring = key_get(rka->dest_keyring);
1140		return 0;
1141	}
1142
1143	return -ENOKEY;
1144}
1145
1146/*
1147 * Change the request_key authorisation key on the current process.
1148 */
1149static int keyctl_change_reqkey_auth(struct key *key)
1150{
1151	struct cred *new;
1152
1153	new = prepare_creds();
1154	if (!new)
1155		return -ENOMEM;
1156
1157	key_put(new->request_key_auth);
1158	new->request_key_auth = key_get(key);
1159
1160	return commit_creds(new);
1161}
1162
1163/*
1164 * Instantiate a key with the specified payload and link the key into the
1165 * destination keyring if one is given.
1166 *
1167 * The caller must have the appropriate instantiation permit set for this to
1168 * work (see keyctl_assume_authority).  No other permissions are required.
1169 *
1170 * If successful, 0 will be returned.
1171 */
1172static long keyctl_instantiate_key_common(key_serial_t id,
1173				   struct iov_iter *from,
1174				   key_serial_t ringid)
1175{
1176	const struct cred *cred = current_cred();
1177	struct request_key_auth *rka;
1178	struct key *instkey, *dest_keyring;
1179	size_t plen = from ? iov_iter_count(from) : 0;
1180	void *payload;
1181	long ret;
1182
1183	kenter("%d,,%zu,%d", id, plen, ringid);
1184
1185	if (!plen)
1186		from = NULL;
1187
1188	ret = -EINVAL;
1189	if (plen > 1024 * 1024 - 1)
1190		goto error;
1191
1192	/* the appropriate instantiation authorisation key must have been
1193	 * assumed before calling this */
1194	ret = -EPERM;
1195	instkey = cred->request_key_auth;
1196	if (!instkey)
1197		goto error;
1198
1199	rka = instkey->payload.data[0];
1200	if (rka->target_key->serial != id)
1201		goto error;
1202
1203	/* pull the payload in if one was supplied */
1204	payload = NULL;
1205
1206	if (from) {
1207		ret = -ENOMEM;
1208		payload = kvmalloc(plen, GFP_KERNEL);
1209		if (!payload)
1210			goto error;
1211
1212		ret = -EFAULT;
1213		if (!copy_from_iter_full(payload, plen, from))
1214			goto error2;
1215	}
1216
1217	/* find the destination keyring amongst those belonging to the
1218	 * requesting task */
1219	ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1220	if (ret < 0)
1221		goto error2;
1222
1223	/* instantiate the key and link it into a keyring */
1224	ret = key_instantiate_and_link(rka->target_key, payload, plen,
1225				       dest_keyring, instkey);
1226
1227	key_put(dest_keyring);
1228
1229	/* discard the assumed authority if it's just been disabled by
1230	 * instantiation of the key */
1231	if (ret == 0)
1232		keyctl_change_reqkey_auth(NULL);
1233
1234error2:
1235	kvfree_sensitive(payload, plen);
 
 
 
1236error:
1237	return ret;
1238}
1239
1240/*
1241 * Instantiate a key with the specified payload and link the key into the
1242 * destination keyring if one is given.
1243 *
1244 * The caller must have the appropriate instantiation permit set for this to
1245 * work (see keyctl_assume_authority).  No other permissions are required.
1246 *
1247 * If successful, 0 will be returned.
1248 */
1249long keyctl_instantiate_key(key_serial_t id,
1250			    const void __user *_payload,
1251			    size_t plen,
1252			    key_serial_t ringid)
1253{
1254	if (_payload && plen) {
 
1255		struct iov_iter from;
1256		int ret;
1257
1258		ret = import_ubuf(ITER_SOURCE, (void __user *)_payload, plen,
1259				  &from);
1260		if (unlikely(ret))
1261			return ret;
1262
1263		return keyctl_instantiate_key_common(id, &from, ringid);
1264	}
1265
1266	return keyctl_instantiate_key_common(id, NULL, ringid);
1267}
1268
1269/*
1270 * Instantiate a key with the specified multipart payload and link the key into
1271 * the destination keyring if one is given.
1272 *
1273 * The caller must have the appropriate instantiation permit set for this to
1274 * work (see keyctl_assume_authority).  No other permissions are required.
1275 *
1276 * If successful, 0 will be returned.
1277 */
1278long keyctl_instantiate_key_iov(key_serial_t id,
1279				const struct iovec __user *_payload_iov,
1280				unsigned ioc,
1281				key_serial_t ringid)
1282{
1283	struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1284	struct iov_iter from;
1285	long ret;
1286
1287	if (!_payload_iov)
1288		ioc = 0;
1289
1290	ret = import_iovec(ITER_SOURCE, _payload_iov, ioc,
1291				    ARRAY_SIZE(iovstack), &iov, &from);
1292	if (ret < 0)
1293		return ret;
1294	ret = keyctl_instantiate_key_common(id, &from, ringid);
1295	kfree(iov);
1296	return ret;
1297}
1298
1299/*
1300 * Negatively instantiate the key with the given timeout (in seconds) and link
1301 * the key into the destination keyring if one is given.
1302 *
1303 * The caller must have the appropriate instantiation permit set for this to
1304 * work (see keyctl_assume_authority).  No other permissions are required.
1305 *
1306 * The key and any links to the key will be automatically garbage collected
1307 * after the timeout expires.
1308 *
1309 * Negative keys are used to rate limit repeated request_key() calls by causing
1310 * them to return -ENOKEY until the negative key expires.
1311 *
1312 * If successful, 0 will be returned.
1313 */
1314long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1315{
1316	return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1317}
1318
1319/*
1320 * Negatively instantiate the key with the given timeout (in seconds) and error
1321 * code and link the key into the destination keyring if one is given.
1322 *
1323 * The caller must have the appropriate instantiation permit set for this to
1324 * work (see keyctl_assume_authority).  No other permissions are required.
1325 *
1326 * The key and any links to the key will be automatically garbage collected
1327 * after the timeout expires.
1328 *
1329 * Negative keys are used to rate limit repeated request_key() calls by causing
1330 * them to return the specified error code until the negative key expires.
1331 *
1332 * If successful, 0 will be returned.
1333 */
1334long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1335		       key_serial_t ringid)
1336{
1337	const struct cred *cred = current_cred();
1338	struct request_key_auth *rka;
1339	struct key *instkey, *dest_keyring;
1340	long ret;
1341
1342	kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1343
1344	/* must be a valid error code and mustn't be a kernel special */
1345	if (error <= 0 ||
1346	    error >= MAX_ERRNO ||
1347	    error == ERESTARTSYS ||
1348	    error == ERESTARTNOINTR ||
1349	    error == ERESTARTNOHAND ||
1350	    error == ERESTART_RESTARTBLOCK)
1351		return -EINVAL;
1352
1353	/* the appropriate instantiation authorisation key must have been
1354	 * assumed before calling this */
1355	ret = -EPERM;
1356	instkey = cred->request_key_auth;
1357	if (!instkey)
1358		goto error;
1359
1360	rka = instkey->payload.data[0];
1361	if (rka->target_key->serial != id)
1362		goto error;
1363
1364	/* find the destination keyring if present (which must also be
1365	 * writable) */
1366	ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1367	if (ret < 0)
1368		goto error;
1369
1370	/* instantiate the key and link it into a keyring */
1371	ret = key_reject_and_link(rka->target_key, timeout, error,
1372				  dest_keyring, instkey);
1373
1374	key_put(dest_keyring);
1375
1376	/* discard the assumed authority if it's just been disabled by
1377	 * instantiation of the key */
1378	if (ret == 0)
1379		keyctl_change_reqkey_auth(NULL);
1380
1381error:
1382	return ret;
1383}
1384
1385/*
1386 * Read or set the default keyring in which request_key() will cache keys and
1387 * return the old setting.
1388 *
1389 * If a thread or process keyring is specified then it will be created if it
1390 * doesn't yet exist.  The old setting will be returned if successful.
1391 */
1392long keyctl_set_reqkey_keyring(int reqkey_defl)
1393{
1394	struct cred *new;
1395	int ret, old_setting;
1396
1397	old_setting = current_cred_xxx(jit_keyring);
1398
1399	if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1400		return old_setting;
1401
1402	new = prepare_creds();
1403	if (!new)
1404		return -ENOMEM;
1405
1406	switch (reqkey_defl) {
1407	case KEY_REQKEY_DEFL_THREAD_KEYRING:
1408		ret = install_thread_keyring_to_cred(new);
1409		if (ret < 0)
1410			goto error;
1411		goto set;
1412
1413	case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1414		ret = install_process_keyring_to_cred(new);
1415		if (ret < 0)
1416			goto error;
1417		goto set;
1418
1419	case KEY_REQKEY_DEFL_DEFAULT:
1420	case KEY_REQKEY_DEFL_SESSION_KEYRING:
1421	case KEY_REQKEY_DEFL_USER_KEYRING:
1422	case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1423	case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1424		goto set;
1425
1426	case KEY_REQKEY_DEFL_NO_CHANGE:
1427	case KEY_REQKEY_DEFL_GROUP_KEYRING:
1428	default:
1429		ret = -EINVAL;
1430		goto error;
1431	}
1432
1433set:
1434	new->jit_keyring = reqkey_defl;
1435	commit_creds(new);
1436	return old_setting;
1437error:
1438	abort_creds(new);
1439	return ret;
1440}
1441
1442/*
1443 * Set or clear the timeout on a key.
1444 *
1445 * Either the key must grant the caller Setattr permission or else the caller
1446 * must hold an instantiation authorisation token for the key.
1447 *
1448 * The timeout is either 0 to clear the timeout, or a number of seconds from
1449 * the current time.  The key and any links to the key will be automatically
1450 * garbage collected after the timeout expires.
1451 *
1452 * Keys with KEY_FLAG_KEEP set should not be timed out.
1453 *
1454 * If successful, 0 is returned.
1455 */
1456long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1457{
1458	struct key *key, *instkey;
1459	key_ref_t key_ref;
1460	long ret;
1461
1462	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1463				  KEY_NEED_SETATTR);
1464	if (IS_ERR(key_ref)) {
1465		/* setting the timeout on a key under construction is permitted
1466		 * if we have the authorisation token handy */
1467		if (PTR_ERR(key_ref) == -EACCES) {
1468			instkey = key_get_instantiation_authkey(id);
1469			if (!IS_ERR(instkey)) {
1470				key_put(instkey);
1471				key_ref = lookup_user_key(id,
1472							  KEY_LOOKUP_PARTIAL,
1473							  KEY_AUTHTOKEN_OVERRIDE);
1474				if (!IS_ERR(key_ref))
1475					goto okay;
1476			}
1477		}
1478
1479		ret = PTR_ERR(key_ref);
1480		goto error;
1481	}
1482
1483okay:
1484	key = key_ref_to_ptr(key_ref);
1485	ret = 0;
1486	if (test_bit(KEY_FLAG_KEEP, &key->flags)) {
1487		ret = -EPERM;
1488	} else {
1489		key_set_timeout(key, timeout);
1490		notify_key(key, NOTIFY_KEY_SETATTR, 0);
1491	}
1492	key_put(key);
1493
1494error:
1495	return ret;
1496}
1497
1498/*
1499 * Assume (or clear) the authority to instantiate the specified key.
1500 *
1501 * This sets the authoritative token currently in force for key instantiation.
1502 * This must be done for a key to be instantiated.  It has the effect of making
1503 * available all the keys from the caller of the request_key() that created a
1504 * key to request_key() calls made by the caller of this function.
1505 *
1506 * The caller must have the instantiation key in their process keyrings with a
1507 * Search permission grant available to the caller.
1508 *
1509 * If the ID given is 0, then the setting will be cleared and 0 returned.
1510 *
1511 * If the ID given has a matching an authorisation key, then that key will be
1512 * set and its ID will be returned.  The authorisation key can be read to get
1513 * the callout information passed to request_key().
1514 */
1515long keyctl_assume_authority(key_serial_t id)
1516{
1517	struct key *authkey;
1518	long ret;
1519
1520	/* special key IDs aren't permitted */
1521	ret = -EINVAL;
1522	if (id < 0)
1523		goto error;
1524
1525	/* we divest ourselves of authority if given an ID of 0 */
1526	if (id == 0) {
1527		ret = keyctl_change_reqkey_auth(NULL);
1528		goto error;
1529	}
1530
1531	/* attempt to assume the authority temporarily granted to us whilst we
1532	 * instantiate the specified key
1533	 * - the authorisation key must be in the current task's keyrings
1534	 *   somewhere
1535	 */
1536	authkey = key_get_instantiation_authkey(id);
1537	if (IS_ERR(authkey)) {
1538		ret = PTR_ERR(authkey);
1539		goto error;
1540	}
1541
1542	ret = keyctl_change_reqkey_auth(authkey);
1543	if (ret == 0)
1544		ret = authkey->serial;
1545	key_put(authkey);
1546error:
1547	return ret;
1548}
1549
1550/*
1551 * Get a key's the LSM security label.
1552 *
1553 * The key must grant the caller View permission for this to work.
1554 *
1555 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1556 *
1557 * If successful, the amount of information available will be returned,
1558 * irrespective of how much was copied (including the terminal NUL).
1559 */
1560long keyctl_get_security(key_serial_t keyid,
1561			 char __user *buffer,
1562			 size_t buflen)
1563{
1564	struct key *key, *instkey;
1565	key_ref_t key_ref;
1566	char *context;
1567	long ret;
1568
1569	key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1570	if (IS_ERR(key_ref)) {
1571		if (PTR_ERR(key_ref) != -EACCES)
1572			return PTR_ERR(key_ref);
1573
1574		/* viewing a key under construction is also permitted if we
1575		 * have the authorisation token handy */
1576		instkey = key_get_instantiation_authkey(keyid);
1577		if (IS_ERR(instkey))
1578			return PTR_ERR(instkey);
1579		key_put(instkey);
1580
1581		key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL,
1582					  KEY_AUTHTOKEN_OVERRIDE);
1583		if (IS_ERR(key_ref))
1584			return PTR_ERR(key_ref);
1585	}
1586
1587	key = key_ref_to_ptr(key_ref);
1588	ret = security_key_getsecurity(key, &context);
1589	if (ret == 0) {
1590		/* if no information was returned, give userspace an empty
1591		 * string */
1592		ret = 1;
1593		if (buffer && buflen > 0 &&
1594		    copy_to_user(buffer, "", 1) != 0)
1595			ret = -EFAULT;
1596	} else if (ret > 0) {
1597		/* return as much data as there's room for */
1598		if (buffer && buflen > 0) {
1599			if (buflen > ret)
1600				buflen = ret;
1601
1602			if (copy_to_user(buffer, context, buflen) != 0)
1603				ret = -EFAULT;
1604		}
1605
1606		kfree(context);
1607	}
1608
1609	key_ref_put(key_ref);
1610	return ret;
1611}
1612
1613/*
1614 * Attempt to install the calling process's session keyring on the process's
1615 * parent process.
1616 *
1617 * The keyring must exist and must grant the caller LINK permission, and the
1618 * parent process must be single-threaded and must have the same effective
1619 * ownership as this process and mustn't be SUID/SGID.
1620 *
1621 * The keyring will be emplaced on the parent when it next resumes userspace.
1622 *
1623 * If successful, 0 will be returned.
1624 */
1625long keyctl_session_to_parent(void)
1626{
1627	struct task_struct *me, *parent;
1628	const struct cred *mycred, *pcred;
1629	struct callback_head *newwork, *oldwork;
1630	key_ref_t keyring_r;
1631	struct cred *cred;
1632	int ret;
1633
1634	keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1635	if (IS_ERR(keyring_r))
1636		return PTR_ERR(keyring_r);
1637
1638	ret = -ENOMEM;
1639
1640	/* our parent is going to need a new cred struct, a new tgcred struct
1641	 * and new security data, so we allocate them here to prevent ENOMEM in
1642	 * our parent */
1643	cred = cred_alloc_blank();
1644	if (!cred)
1645		goto error_keyring;
1646	newwork = &cred->rcu;
1647
1648	cred->session_keyring = key_ref_to_ptr(keyring_r);
1649	keyring_r = NULL;
1650	init_task_work(newwork, key_change_session_keyring);
1651
1652	me = current;
1653	rcu_read_lock();
1654	write_lock_irq(&tasklist_lock);
1655
1656	ret = -EPERM;
1657	oldwork = NULL;
1658	parent = rcu_dereference_protected(me->real_parent,
1659					   lockdep_is_held(&tasklist_lock));
1660
1661	/* the parent mustn't be init and mustn't be a kernel thread */
1662	if (parent->pid <= 1 || !parent->mm)
1663		goto unlock;
1664
1665	/* the parent must be single threaded */
1666	if (!thread_group_empty(parent))
1667		goto unlock;
1668
1669	/* the parent and the child must have different session keyrings or
1670	 * there's no point */
1671	mycred = current_cred();
1672	pcred = __task_cred(parent);
1673	if (mycred == pcred ||
1674	    mycred->session_keyring == pcred->session_keyring) {
1675		ret = 0;
1676		goto unlock;
1677	}
1678
1679	/* the parent must have the same effective ownership and mustn't be
1680	 * SUID/SGID */
1681	if (!uid_eq(pcred->uid,	 mycred->euid) ||
1682	    !uid_eq(pcred->euid, mycred->euid) ||
1683	    !uid_eq(pcred->suid, mycred->euid) ||
1684	    !gid_eq(pcred->gid,	 mycred->egid) ||
1685	    !gid_eq(pcred->egid, mycred->egid) ||
1686	    !gid_eq(pcred->sgid, mycred->egid))
1687		goto unlock;
1688
1689	/* the keyrings must have the same UID */
1690	if ((pcred->session_keyring &&
1691	     !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1692	    !uid_eq(mycred->session_keyring->uid, mycred->euid))
1693		goto unlock;
1694
1695	/* cancel an already pending keyring replacement */
1696	oldwork = task_work_cancel(parent, key_change_session_keyring);
1697
1698	/* the replacement session keyring is applied just prior to userspace
1699	 * restarting */
1700	ret = task_work_add(parent, newwork, TWA_RESUME);
1701	if (!ret)
1702		newwork = NULL;
1703unlock:
1704	write_unlock_irq(&tasklist_lock);
1705	rcu_read_unlock();
1706	if (oldwork)
1707		put_cred(container_of(oldwork, struct cred, rcu));
1708	if (newwork)
1709		put_cred(cred);
1710	return ret;
1711
1712error_keyring:
1713	key_ref_put(keyring_r);
1714	return ret;
1715}
1716
1717/*
1718 * Apply a restriction to a given keyring.
1719 *
1720 * The caller must have Setattr permission to change keyring restrictions.
1721 *
1722 * The requested type name may be a NULL pointer to reject all attempts
1723 * to link to the keyring.  In this case, _restriction must also be NULL.
1724 * Otherwise, both _type and _restriction must be non-NULL.
1725 *
1726 * Returns 0 if successful.
1727 */
1728long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1729			     const char __user *_restriction)
1730{
1731	key_ref_t key_ref;
1732	char type[32];
1733	char *restriction = NULL;
1734	long ret;
1735
1736	key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1737	if (IS_ERR(key_ref))
1738		return PTR_ERR(key_ref);
1739
1740	ret = -EINVAL;
1741	if (_type) {
1742		if (!_restriction)
1743			goto error;
1744
1745		ret = key_get_type_from_user(type, _type, sizeof(type));
1746		if (ret < 0)
1747			goto error;
1748
1749		restriction = strndup_user(_restriction, PAGE_SIZE);
1750		if (IS_ERR(restriction)) {
1751			ret = PTR_ERR(restriction);
1752			goto error;
1753		}
1754	} else {
1755		if (_restriction)
1756			goto error;
1757	}
1758
1759	ret = keyring_restrict(key_ref, _type ? type : NULL, restriction);
1760	kfree(restriction);
1761error:
1762	key_ref_put(key_ref);
1763	return ret;
1764}
1765
1766#ifdef CONFIG_KEY_NOTIFICATIONS
1767/*
1768 * Watch for changes to a key.
1769 *
1770 * The caller must have View permission to watch a key or keyring.
1771 */
1772long keyctl_watch_key(key_serial_t id, int watch_queue_fd, int watch_id)
1773{
1774	struct watch_queue *wqueue;
1775	struct watch_list *wlist = NULL;
1776	struct watch *watch = NULL;
1777	struct key *key;
1778	key_ref_t key_ref;
1779	long ret;
1780
1781	if (watch_id < -1 || watch_id > 0xff)
1782		return -EINVAL;
1783
1784	key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_VIEW);
1785	if (IS_ERR(key_ref))
1786		return PTR_ERR(key_ref);
1787	key = key_ref_to_ptr(key_ref);
1788
1789	wqueue = get_watch_queue(watch_queue_fd);
1790	if (IS_ERR(wqueue)) {
1791		ret = PTR_ERR(wqueue);
1792		goto err_key;
1793	}
1794
1795	if (watch_id >= 0) {
1796		ret = -ENOMEM;
1797		if (!key->watchers) {
1798			wlist = kzalloc(sizeof(*wlist), GFP_KERNEL);
1799			if (!wlist)
1800				goto err_wqueue;
1801			init_watch_list(wlist, NULL);
1802		}
1803
1804		watch = kzalloc(sizeof(*watch), GFP_KERNEL);
1805		if (!watch)
1806			goto err_wlist;
1807
1808		init_watch(watch, wqueue);
1809		watch->id	= key->serial;
1810		watch->info_id	= (u32)watch_id << WATCH_INFO_ID__SHIFT;
1811
1812		ret = security_watch_key(key);
1813		if (ret < 0)
1814			goto err_watch;
1815
1816		down_write(&key->sem);
1817		if (!key->watchers) {
1818			key->watchers = wlist;
1819			wlist = NULL;
1820		}
1821
1822		ret = add_watch_to_object(watch, key->watchers);
1823		up_write(&key->sem);
1824
1825		if (ret == 0)
1826			watch = NULL;
1827	} else {
1828		ret = -EBADSLT;
1829		if (key->watchers) {
1830			down_write(&key->sem);
1831			ret = remove_watch_from_object(key->watchers,
1832						       wqueue, key_serial(key),
1833						       false);
1834			up_write(&key->sem);
1835		}
1836	}
1837
1838err_watch:
1839	kfree(watch);
1840err_wlist:
1841	kfree(wlist);
1842err_wqueue:
1843	put_watch_queue(wqueue);
1844err_key:
1845	key_put(key);
1846	return ret;
1847}
1848#endif /* CONFIG_KEY_NOTIFICATIONS */
1849
1850/*
1851 * Get keyrings subsystem capabilities.
1852 */
1853long keyctl_capabilities(unsigned char __user *_buffer, size_t buflen)
1854{
1855	size_t size = buflen;
1856
1857	if (size > 0) {
1858		if (size > sizeof(keyrings_capabilities))
1859			size = sizeof(keyrings_capabilities);
1860		if (copy_to_user(_buffer, keyrings_capabilities, size) != 0)
1861			return -EFAULT;
1862		if (size < buflen &&
1863		    clear_user(_buffer + size, buflen - size) != 0)
1864			return -EFAULT;
1865	}
1866
1867	return sizeof(keyrings_capabilities);
1868}
1869
1870/*
1871 * The key control system call
1872 */
1873SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1874		unsigned long, arg4, unsigned long, arg5)
1875{
1876	switch (option) {
1877	case KEYCTL_GET_KEYRING_ID:
1878		return keyctl_get_keyring_ID((key_serial_t) arg2,
1879					     (int) arg3);
1880
1881	case KEYCTL_JOIN_SESSION_KEYRING:
1882		return keyctl_join_session_keyring((const char __user *) arg2);
1883
1884	case KEYCTL_UPDATE:
1885		return keyctl_update_key((key_serial_t) arg2,
1886					 (const void __user *) arg3,
1887					 (size_t) arg4);
1888
1889	case KEYCTL_REVOKE:
1890		return keyctl_revoke_key((key_serial_t) arg2);
1891
1892	case KEYCTL_DESCRIBE:
1893		return keyctl_describe_key((key_serial_t) arg2,
1894					   (char __user *) arg3,
1895					   (unsigned) arg4);
1896
1897	case KEYCTL_CLEAR:
1898		return keyctl_keyring_clear((key_serial_t) arg2);
1899
1900	case KEYCTL_LINK:
1901		return keyctl_keyring_link((key_serial_t) arg2,
1902					   (key_serial_t) arg3);
1903
1904	case KEYCTL_UNLINK:
1905		return keyctl_keyring_unlink((key_serial_t) arg2,
1906					     (key_serial_t) arg3);
1907
1908	case KEYCTL_SEARCH:
1909		return keyctl_keyring_search((key_serial_t) arg2,
1910					     (const char __user *) arg3,
1911					     (const char __user *) arg4,
1912					     (key_serial_t) arg5);
1913
1914	case KEYCTL_READ:
1915		return keyctl_read_key((key_serial_t) arg2,
1916				       (char __user *) arg3,
1917				       (size_t) arg4);
1918
1919	case KEYCTL_CHOWN:
1920		return keyctl_chown_key((key_serial_t) arg2,
1921					(uid_t) arg3,
1922					(gid_t) arg4);
1923
1924	case KEYCTL_SETPERM:
1925		return keyctl_setperm_key((key_serial_t) arg2,
1926					  (key_perm_t) arg3);
1927
1928	case KEYCTL_INSTANTIATE:
1929		return keyctl_instantiate_key((key_serial_t) arg2,
1930					      (const void __user *) arg3,
1931					      (size_t) arg4,
1932					      (key_serial_t) arg5);
1933
1934	case KEYCTL_NEGATE:
1935		return keyctl_negate_key((key_serial_t) arg2,
1936					 (unsigned) arg3,
1937					 (key_serial_t) arg4);
1938
1939	case KEYCTL_SET_REQKEY_KEYRING:
1940		return keyctl_set_reqkey_keyring(arg2);
1941
1942	case KEYCTL_SET_TIMEOUT:
1943		return keyctl_set_timeout((key_serial_t) arg2,
1944					  (unsigned) arg3);
1945
1946	case KEYCTL_ASSUME_AUTHORITY:
1947		return keyctl_assume_authority((key_serial_t) arg2);
1948
1949	case KEYCTL_GET_SECURITY:
1950		return keyctl_get_security((key_serial_t) arg2,
1951					   (char __user *) arg3,
1952					   (size_t) arg4);
1953
1954	case KEYCTL_SESSION_TO_PARENT:
1955		return keyctl_session_to_parent();
1956
1957	case KEYCTL_REJECT:
1958		return keyctl_reject_key((key_serial_t) arg2,
1959					 (unsigned) arg3,
1960					 (unsigned) arg4,
1961					 (key_serial_t) arg5);
1962
1963	case KEYCTL_INSTANTIATE_IOV:
1964		return keyctl_instantiate_key_iov(
1965			(key_serial_t) arg2,
1966			(const struct iovec __user *) arg3,
1967			(unsigned) arg4,
1968			(key_serial_t) arg5);
1969
1970	case KEYCTL_INVALIDATE:
1971		return keyctl_invalidate_key((key_serial_t) arg2);
1972
1973	case KEYCTL_GET_PERSISTENT:
1974		return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1975
1976	case KEYCTL_DH_COMPUTE:
1977		return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1978					 (char __user *) arg3, (size_t) arg4,
1979					 (struct keyctl_kdf_params __user *) arg5);
1980
1981	case KEYCTL_RESTRICT_KEYRING:
1982		return keyctl_restrict_keyring((key_serial_t) arg2,
1983					       (const char __user *) arg3,
1984					       (const char __user *) arg4);
1985
1986	case KEYCTL_PKEY_QUERY:
1987		if (arg3 != 0)
1988			return -EINVAL;
1989		return keyctl_pkey_query((key_serial_t)arg2,
1990					 (const char __user *)arg4,
1991					 (struct keyctl_pkey_query __user *)arg5);
1992
1993	case KEYCTL_PKEY_ENCRYPT:
1994	case KEYCTL_PKEY_DECRYPT:
1995	case KEYCTL_PKEY_SIGN:
1996		return keyctl_pkey_e_d_s(
1997			option,
1998			(const struct keyctl_pkey_params __user *)arg2,
1999			(const char __user *)arg3,
2000			(const void __user *)arg4,
2001			(void __user *)arg5);
2002
2003	case KEYCTL_PKEY_VERIFY:
2004		return keyctl_pkey_verify(
2005			(const struct keyctl_pkey_params __user *)arg2,
2006			(const char __user *)arg3,
2007			(const void __user *)arg4,
2008			(const void __user *)arg5);
2009
2010	case KEYCTL_MOVE:
2011		return keyctl_keyring_move((key_serial_t)arg2,
2012					   (key_serial_t)arg3,
2013					   (key_serial_t)arg4,
2014					   (unsigned int)arg5);
2015
2016	case KEYCTL_CAPABILITIES:
2017		return keyctl_capabilities((unsigned char __user *)arg2, (size_t)arg3);
2018
2019	case KEYCTL_WATCH_KEY:
2020		return keyctl_watch_key((key_serial_t)arg2, (int)arg3, (int)arg4);
2021
2022	default:
2023		return -EOPNOTSUPP;
2024	}
2025}