user/sven/linux.git/security, branch v4.14.178

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

selinux: ensure we cleanup the internal AVC counters on error in avc_update()

2020-02-28T15:36:09Z

[ Upstream commit 030b995ad9ece9fa2d218af4429c1c78c2342096 ] In AVC update we don't call avc_node_kill() when avc_xperms_populate() fails, resulting in the avc->avc_cache.active_nodes counter having a false value. In last patch this changes was missed , so correcting it. Fixes: fa1aa143ac4a ("selinux: extended permissions for ioctls") Signed-off-by: Jaihind Yadav Signed-off-by: Ravi Kumar Siddojigari [PM: merge fuzz, minor description cleanup] Signed-off-by: Paul Moore Signed-off-by: Sasha Levin

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

apparmor: don't try to replace stale label in ptrace access check

2020-01-27T13:46:04Z

[ Upstream commit 1f8266ff58840d698a1e96d2274189de1bdf7969 ] As a comment above begin_current_label_crit_section() explains, begin_current_label_crit_section() must run in sleepable context because when label_is_stale() is true, aa_replace_current_label() runs, which uses prepare_creds(), which can sleep. Until now, the ptrace access check (which runs with a task lock held) violated this rule. Also add a might_sleep() assertion to begin_current_label_crit_section(), because asserts are less likely to be ignored than comments. Fixes: b2d09ae449ced ("apparmor: move ptrace checks to using labels") Signed-off-by: Jann Horn Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: fix unsigned len comparison with less than zero

2020-01-04T12:59:51Z

[ Upstream commit 00e0590dbaec6f1bcaa36a85467d7e3497ced522 ] The sanity check in macro update_for_len checks to see if len is less than zero, however, len is a size_t so it can never be less than zero, so this sanity check is a no-op. Fix this by making len a ssize_t so the comparison will work and add ulen that is a size_t copy of len so that the min() macro won't throw warnings about comparing different types. Addresses-Coverity: ("Macro compares unsigned to 0") Fixes: f1bd904175e8 ("apparmor: add the base fns() for domain labels") Signed-off-by: Colin Ian King Signed-off-by: John Johansen Signed-off-by: Sasha Levin

apparmor: delete the dentry in aafs_remove() to avoid a leak

2019-12-05T14:38:01Z

[ Upstream commit 201218e4d3dfa1346e30997f48725acce3f26d01 ] Although the apparmorfs dentries are always dropped from the dentry cache when the usage count drops to zero, there is no guarantee that this will happen in aafs_remove(), as another thread might still be using it. In this scenario, this means that the dentry will temporarily continue to appear in the results of lookups, even after the call to aafs_remove(). In the case of removal of a profile - it also causes simple_rmdir() on the profile directory to fail, as the directory won't be empty until the usage counts of all child dentries have decreased to zero. This results in the dentry for the profile directory leaking and appearing empty in the file system tree forever. Signed-off-by: Chris Coulson Signed-off-by: John Johansen Signed-off-by: Sasha Levin

ima: always return negative code for error

2019-10-11T16:18:37Z

[ Upstream commit f5e1040196dbfe14c77ce3dfe3b7b08d2d961e88 ] integrity_kernel_read() returns the number of bytes read. If this is a short read then this positive value is returned from ima_calc_file_hash_atfm(). Currently this is only indirectly called from ima_calc_file_hash() and this function only tests for the return value being zero or nonzero and also doesn't forward the return value. Nevertheless there's no point in returning a positive value as an error, so translate a short read into -EINVAL. Signed-off-by: Sascha Hauer Signed-off-by: Mimi Zohar Signed-off-by: Sasha Levin