user/sven/linux.git/security/keys, branch v4.14.334

security: keys: perform capable check only on privileged operations

2023-09-23T08:46:53Z

[ Upstream commit 2d7f105edbb3b2be5ffa4d833abbf9b6965e9ce7 ] If the current task fails the check for the queried capability via `capable(CAP_SYS_ADMIN)` LSMs like SELinux generate a denial message. Issuing such denial messages unnecessarily can lead to a policy author granting more privileges to a subject than needed to silence them. Reorder CAP_SYS_ADMIN checks after the check whether the operation is actually privileged. Signed-off-by: Christian Göttsche Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen Signed-off-by: Sasha Levin

KEYS: trusted: Fix migratable=1 failing

2021-03-03T17:22:52Z

commit 8da7520c80468c48f981f0b81fc1be6599e3b0ad upstream. Consider the following transcript: $ keyctl add trusted kmk "new 32 blobauth=helloworld keyhandle=80000000 migratable=1" @u add_key: Invalid argument The documentation has the following description: migratable= 0|1 indicating permission to reseal to new PCR values, default 1 (resealing allowed) The consequence is that "migratable=1" should succeed. Fix this by allowing this condition to pass instead of return -EINVAL. [*] Documentation/security/keys/trusted-encrypted.rst Cc: stable@vger.kernel.org Cc: "James E.J. Bottomley" Cc: Mimi Zohar Cc: David Howells Fixes: d00a1c72f7f4 ("keys: add new trusted key-type") Signed-off-by: Jarkko Sakkinen Signed-off-by: Greg Kroah-Hartman

certs: Fix blacklist flag type confusion

2021-03-03T17:22:46Z

[ Upstream commit 4993e1f9479a4161fd7d93e2b8b30b438f00cb0f ] KEY_FLAG_KEEP is not meant to be passed to keyring_alloc() or key_alloc(), as these only take KEY_ALLOC_* flags. KEY_FLAG_KEEP has the same value as KEY_ALLOC_BYPASS_RESTRICTION, but fortunately only key_create_or_update() uses it. LSMs using the key_alloc hook don't check that flag. KEY_FLAG_KEEP is then ignored but fortunately (again) the root user cannot write to the blacklist keyring, so it is not possible to remove a key/hash from it. Fix this by adding a KEY_ALLOC_SET_KEEP flag that tells key_alloc() to set KEY_FLAG_KEEP on the new key. blacklist_init() can then, correctly, pass this to keyring_alloc(). We can also use this in ima_mok_init() rather than setting the flag manually. Note that this doesn't fix an observable bug with the current implementation but it is required to allow addition of new hashes to the blacklist in the future without making it possible for them to be removed. Fixes: 734114f8782f ("KEYS: Add a system blacklist keyring") Reported-by: Mickaël Salaün Signed-off-by: David Howells cc: Mickaël Salaün cc: Mimi Zohar Cc: David Woodhouse Signed-off-by: Sasha Levin

mm: add kvfree_sensitive() for freeing sensitive data objects

2020-06-20T08:24:59Z

[ Upstream commit d4eaa2837851db2bfed572898bfc17f9a9f9151e ] For kvmalloc'ed data object that contains sensitive information like cryptographic keys, we need to make sure that the buffer is always cleared before freeing it. Using memset() alone for buffer clearing may not provide certainty as the compiler may compile it away. To be sure, the special memzero_explicit() has to be used. This patch introduces a new kvfree_sensitive() for freeing those sensitive data objects allocated by kvmalloc(). The relevant places where kvfree_sensitive() can be used are modified to use it. Fixes: 4f0882491a14 ("KEYS: Avoid false positive ENOMEM error on key read") Suggested-by: Linus Torvalds Signed-off-by: Waiman Long Signed-off-by: Andrew Morton Reviewed-by: Eric Biggers Acked-by: David Howells Cc: Jarkko Sakkinen Cc: James Morris Cc: "Serge E. Hallyn" Cc: Joe Perches Cc: Matthew Wilcox Cc: David Rientjes Cc: Uladzislau Rezki Link: http://lkml.kernel.org/r/20200407200318.11711-1-longman@redhat.com Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

KEYS: Avoid false positive ENOMEM error on key read

2020-05-02T15:24:18Z

[ Upstream commit 4f0882491a148059a52480e753b7f07fc550e188 ] By allocating a kernel buffer with a user-supplied buffer length, it is possible that a false positive ENOMEM error may be returned because the user-supplied length is just too large even if the system do have enough memory to hold the actual key data. Moreover, if the buffer length is larger than the maximum amount of memory that can be returned by kmalloc() (2^(MAX_ORDER-1) number of pages), a warning message will also be printed. To reduce this possibility, we set a threshold (PAGE_SIZE) over which we do check the actual key length first before allocating a buffer of the right size to hold it. The threshold is arbitrary, it is just used to trigger a buffer length check. It does not limit the actual key length as long as there is enough memory to satisfy the memory request. To further avoid large buffer allocation failure due to page fragmentation, kvmalloc() is used to allocate the buffer so that vmapped pages can be used when there is not a large enough contiguous set of pages available for allocation. In the extremely unlikely scenario that the key keeps on being changed and made longer (still <= buflen) in between 2 __keyctl_read_key() calls, the __keyctl_read_key() calling loop in keyctl_read_key() may have to be iterated a large number of times, but definitely not infinite. Signed-off-by: Waiman Long Signed-off-by: David Howells Signed-off-by: Sasha Levin

KEYS: Don't write out to userspace while holding key semaphore

2020-04-24T06:01:25Z

commit d3ec10aa95819bff18a0d936b18884c7816d0914 upstream. A lockdep circular locking dependency report was seen when running a keyutils test: [12537.027242] ====================================================== [12537.059309] WARNING: possible circular locking dependency detected [12537.088148] 4.18.0-147.7.1.el8_1.x86_64+debug #1 Tainted: G OE --------- - - [12537.125253] ------------------------------------------------------ [12537.153189] keyctl/25598 is trying to acquire lock: [12537.175087] 000000007c39f96c (&mm->mmap_sem){++++}, at: __might_fault+0xc4/0x1b0 [12537.208365] [12537.208365] but task is already holding lock: [12537.234507] 000000003de5b58d (&type->lock_class){++++}, at: keyctl_read_key+0x15a/0x220 [12537.270476] [12537.270476] which lock already depends on the new lock. [12537.270476] [12537.307209] [12537.307209] the existing dependency chain (in reverse order) is: [12537.340754] [12537.340754] -> #3 (&type->lock_class){++++}: [12537.367434] down_write+0x4d/0x110 [12537.385202] __key_link_begin+0x87/0x280 [12537.405232] request_key_and_link+0x483/0xf70 [12537.427221] request_key+0x3c/0x80 [12537.444839] dns_query+0x1db/0x5a5 [dns_resolver] [12537.468445] dns_resolve_server_name_to_ip+0x1e1/0x4d0 [cifs] [12537.496731] cifs_reconnect+0xe04/0x2500 [cifs] [12537.519418] cifs_readv_from_socket+0x461/0x690 [cifs] [12537.546263] cifs_read_from_socket+0xa0/0xe0 [cifs] [12537.573551] cifs_demultiplex_thread+0x311/0x2db0 [cifs] [12537.601045] kthread+0x30c/0x3d0 [12537.617906] ret_from_fork+0x3a/0x50 [12537.636225] [12537.636225] -> #2 (root_key_user.cons_lock){+.+.}: [12537.664525] __mutex_lock+0x105/0x11f0 [12537.683734] request_key_and_link+0x35a/0xf70 [12537.705640] request_key+0x3c/0x80 [12537.723304] dns_query+0x1db/0x5a5 [dns_resolver] [12537.746773] dns_resolve_server_name_to_ip+0x1e1/0x4d0 [cifs] [12537.775607] cifs_reconnect+0xe04/0x2500 [cifs] [12537.798322] cifs_readv_from_socket+0x461/0x690 [cifs] [12537.823369] cifs_read_from_socket+0xa0/0xe0 [cifs] [12537.847262] cifs_demultiplex_thread+0x311/0x2db0 [cifs] [12537.873477] kthread+0x30c/0x3d0 [12537.890281] ret_from_fork+0x3a/0x50 [12537.908649] [12537.908649] -> #1 (&tcp_ses->srv_mutex){+.+.}: [12537.935225] __mutex_lock+0x105/0x11f0 [12537.954450] cifs_call_async+0x102/0x7f0 [cifs] [12537.977250] smb2_async_readv+0x6c3/0xc90 [cifs] [12538.000659] cifs_readpages+0x120a/0x1e50 [cifs] [12538.023920] read_pages+0xf5/0x560 [12538.041583] __do_page_cache_readahead+0x41d/0x4b0 [12538.067047] ondemand_readahead+0x44c/0xc10 [12538.092069] filemap_fault+0xec1/0x1830 [12538.111637] __do_fault+0x82/0x260 [12538.129216] do_fault+0x419/0xfb0 [12538.146390] __handle_mm_fault+0x862/0xdf0 [12538.167408] handle_mm_fault+0x154/0x550 [12538.187401] __do_page_fault+0x42f/0xa60 [12538.207395] do_page_fault+0x38/0x5e0 [12538.225777] page_fault+0x1e/0x30 [12538.243010] [12538.243010] -> #0 (&mm->mmap_sem){++++}: [12538.267875] lock_acquire+0x14c/0x420 [12538.286848] __might_fault+0x119/0x1b0 [12538.306006] keyring_read_iterator+0x7e/0x170 [12538.327936] assoc_array_subtree_iterate+0x97/0x280 [12538.352154] keyring_read+0xe9/0x110 [12538.370558] keyctl_read_key+0x1b9/0x220 [12538.391470] do_syscall_64+0xa5/0x4b0 [12538.410511] entry_SYSCALL_64_after_hwframe+0x6a/0xdf [12538.435535] [12538.435535] other info that might help us debug this: [12538.435535] [12538.472829] Chain exists of: [12538.472829] &mm->mmap_sem --> root_key_user.cons_lock --> &type->lock_class [12538.472829] [12538.524820] Possible unsafe locking scenario: [12538.524820] [12538.551431] CPU0 CPU1 [12538.572654] ---- ---- [12538.595865] lock(&type->lock_class); [12538.613737] lock(root_key_user.cons_lock); [12538.644234] lock(&type->lock_class); [12538.672410] lock(&mm->mmap_sem); [12538.687758] [12538.687758] *** DEADLOCK *** [12538.687758] [12538.714455] 1 lock held by keyctl/25598: [12538.732097] #0: 000000003de5b58d (&type->lock_class){++++}, at: keyctl_read_key+0x15a/0x220 [12538.770573] [12538.770573] stack backtrace: [12538.790136] CPU: 2 PID: 25598 Comm: keyctl Kdump: loaded Tainted: G [12538.844855] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 12/27/2015 [12538.881963] Call Trace: [12538.892897] dump_stack+0x9a/0xf0 [12538.907908] print_circular_bug.isra.25.cold.50+0x1bc/0x279 [12538.932891] ? save_trace+0xd6/0x250 [12538.948979] check_prev_add.constprop.32+0xc36/0x14f0 [12538.971643] ? keyring_compare_object+0x104/0x190 [12538.992738] ? check_usage+0x550/0x550 [12539.009845] ? sched_clock+0x5/0x10 [12539.025484] ? sched_clock_cpu+0x18/0x1e0 [12539.043555] __lock_acquire+0x1f12/0x38d0 [12539.061551] ? trace_hardirqs_on+0x10/0x10 [12539.080554] lock_acquire+0x14c/0x420 [12539.100330] ? __might_fault+0xc4/0x1b0 [12539.119079] __might_fault+0x119/0x1b0 [12539.135869] ? __might_fault+0xc4/0x1b0 [12539.153234] keyring_read_iterator+0x7e/0x170 [12539.172787] ? keyring_read+0x110/0x110 [12539.190059] assoc_array_subtree_iterate+0x97/0x280 [12539.211526] keyring_read+0xe9/0x110 [12539.227561] ? keyring_gc_check_iterator+0xc0/0xc0 [12539.249076] keyctl_read_key+0x1b9/0x220 [12539.266660] do_syscall_64+0xa5/0x4b0 [12539.283091] entry_SYSCALL_64_after_hwframe+0x6a/0xdf One way to prevent this deadlock scenario from happening is to not allow writing to userspace while holding the key semaphore. Instead, an internal buffer is allocated for getting the keys out from the read method first before copying them out to userspace without holding the lock. That requires taking out the __user modifier from all the relevant read methods as well as additional changes to not use any userspace write helpers. That is, 1) The put_user() call is replaced by a direct copy. 2) The copy_to_user() call is replaced by memcpy(). 3) All the fault handling code is removed. Compiling on a x86-64 system, the size of the rxrpc_read() function is reduced from 3795 bytes to 2384 bytes with this patch. Fixes: ^1da177e4c3f4 ("Linux-2.6.12-rc2") Reviewed-by: Jarkko Sakkinen Signed-off-by: Waiman Long Signed-off-by: David Howells Signed-off-by: Greg Kroah-Hartman

KEYS: Use individual pages in big_key for crypto buffers

2020-04-24T06:01:24Z

commit d9f4bb1a0f4db493efe6d7c58ffe696a57de7eb3 upstream. kmalloc() can't always allocate large enough buffers for big_key to use for crypto (1MB + some metadata) so we cannot use that to allocate the buffer. Further, vmalloc'd pages can't be passed to sg_init_one() and the aead crypto accessors cannot be called progressively and must be passed all the data in one go (which means we can't pass the data in one block at a time). Fix this by allocating the buffer pages individually and passing them through a multientry scatterlist to the crypto layer. This has the bonus advantage that we don't have to allocate a contiguous series of pages. We then vmap() the page list and pass that through to the VFS read/write routines. This can trigger a warning: WARNING: CPU: 0 PID: 60912 at mm/page_alloc.c:3883 __alloc_pages_nodemask+0xb7c/0x15f8 ([<00000000002acbb6>] __alloc_pages_nodemask+0x1ee/0x15f8) [<00000000002dd356>] kmalloc_order+0x46/0x90 [<00000000002dd3e0>] kmalloc_order_trace+0x40/0x1f8 [<0000000000326a10>] __kmalloc+0x430/0x4c0 [<00000000004343e4>] big_key_preparse+0x7c/0x210 [<000000000042c040>] key_create_or_update+0x128/0x420 [<000000000042e52c>] SyS_add_key+0x124/0x220 [<00000000007bba2c>] system_call+0xc4/0x2b0 from the keyctl/padd/useradd test of the keyutils testsuite on s390x. Note that it might be better to shovel data through in page-sized lumps instead as there's no particular need to use a monolithic buffer unless the kernel itself wants to access the data. Fixes: 13100a72f40f ("Security: Keys: Big keys stored encrypted") Reported-by: Paul Bunyan Signed-off-by: David Howells cc: Kirill Marinushkin Signed-off-by: Greg Kroah-Hartman

KEYS: reaching the keys quotas correctly

2020-04-24T06:00:37Z

commit 2e356101e72ab1361821b3af024d64877d9a798d upstream. Currently, when we add a new user key, the calltrace as below: add_key() key_create_or_update() key_alloc() __key_instantiate_and_link generic_key_instantiate key_payload_reserve ...... Since commit a08bf91ce28e ("KEYS: allow reaching the keys quotas exactly"), we can reach max bytes/keys in key_alloc, but we forget to remove this limit when we reserver space for payload in key_payload_reserve. So we can only reach max keys but not max bytes when having delta between plen and type->def_datalen. Remove this limit when instantiating the key, so we can keep consistent with key_alloc. Also, fix the similar problem in keyctl_chown_key(). Fixes: 0b77f5bfb45c ("keys: make the keyring quotas controllable through /proc/sys") Fixes: a08bf91ce28e ("KEYS: allow reaching the keys quotas exactly") Cc: stable@vger.kernel.org # 5.0.x Cc: Eric Biggers Signed-off-by: Yang Xu Reviewed-by: Jarkko Sakkinen Reviewed-by: Eric Biggers Signed-off-by: Jarkko Sakkinen Signed-off-by: Greg Kroah-Hartman

keys: Timestamp new keys

2020-01-27T13:46:19Z

[ Upstream commit 7c1857bdbdf1e4c541e45eab477ee23ed4333ea4 ] Set the timestamp on new keys rather than leaving it unset. Fixes: 31d5a79d7f3d ("KEYS: Do LRU discard in full keyrings") Signed-off-by: David Howells Signed-off-by: James Morris Signed-off-by: Sasha Levin

keys: Fix missing null pointer check in request_key_auth_describe()

2019-09-21T05:15:45Z

[ Upstream commit d41a3effbb53b1bcea41e328d16a4d046a508381 ] If a request_key authentication token key gets revoked, there's a window in which request_key_auth_describe() can see it with a NULL payload - but it makes no check for this and something like the following oops may occur: BUG: Kernel NULL pointer dereference at 0x00000038 Faulting instruction address: 0xc0000000004ddf30 Oops: Kernel access of bad area, sig: 11 [#1] ... NIP [...] request_key_auth_describe+0x90/0xd0 LR [...] request_key_auth_describe+0x54/0xd0 Call Trace: [...] request_key_auth_describe+0x54/0xd0 (unreliable) [...] proc_keys_show+0x308/0x4c0 [...] seq_read+0x3d0/0x540 [...] proc_reg_read+0x90/0x110 [...] __vfs_read+0x3c/0x70 [...] vfs_read+0xb4/0x1b0 [...] ksys_read+0x7c/0x130 [...] system_call+0x5c/0x70 Fix this by checking for a NULL pointer when describing such a key. Also make the read routine check for a NULL pointer to be on the safe side. [DH: Modified to not take already-held rcu lock and modified to also check in the read routine] Fixes: 04c567d9313e ("[PATCH] Keys: Fix race between two instantiators of a key") Reported-by: Sachin Sant Signed-off-by: Hillf Danton Signed-off-by: David Howells Tested-by: Sachin Sant Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin