kernel/linux.git/fs/locks.c, branch v6.1.168

lockd: fix vfs_test_lock() calls

2026-01-11T14:19:22+00:00

[ Upstream commit a49a2a1baa0c553c3548a1c414b6a3c005a8deba ] Usage of vfs_test_lock() is somewhat confused. Documentation suggests it is given a "lock" but this is not the case. It is given a struct file_lock which contains some details of the sort of lock it should be looking for. In particular passing a "file_lock" containing fl_lmops or fl_ops is meaningless and possibly confusing. This is particularly problematic in lockd. nlmsvc_testlock() receives an initialised "file_lock" from xdr-decode, including manager ops and an owner. It then mistakenly passes this to vfs_test_lock() which might replace the owner and the ops. This can lead to confusion when freeing the lock. The primary role of the 'struct file_lock' passed to vfs_test_lock() is to report a conflicting lock that was found, so it makes more sense for nlmsvc_testlock() to pass "conflock", which it uses for returning the conflicting lock. With this change, freeing of the lock is not confused and code in __nlm4svc_proc_test() and __nlmsvc_proc_test() can be simplified. Documentation for vfs_test_lock() is improved to reflect its real purpose, and a WARN_ON_ONCE() is added to avoid a similar problem in the future. Reported-by: Olga Kornievskaia Closes: https://lore.kernel.org/all/20251021130506.45065-1-okorniev@redhat.com Signed-off-by: NeilBrown Fixes: 20fa19027286 ("nfs: add export operations") Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever [ adapted c.flc_* field accesses to direct fl_* fields ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

filelock: Fix fcntl/close race recovery compat path

2024-07-27T09:32:19+00:00

commit f8138f2ad2f745b9a1c696a05b749eabe44337ea upstream. When I wrote commit 3cad1bc01041 ("filelock: Remove locks reliably when fcntl/close race is detected"), I missed that there are two copies of the code I was patching: The normal version, and the version for 64-bit offsets on 32-bit kernels. Thanks to Greg KH for stumbling over this while doing the stable backport... Apply exactly the same fix to the compat path for 32-bit kernels. Fixes: c293621bbf67 ("[PATCH] stale POSIX lock handling") Cc: stable@kernel.org Link: https://bugs.chromium.org/p/project-zero/issues/detail?id=2563 Signed-off-by: Jann Horn Link: https://lore.kernel.org/r/20240723-fs-lock-recover-compatfix-v1-1-148096719529@google.com Signed-off-by: Christian Brauner Signed-off-by: Greg Kroah-Hartman

filelock: Remove locks reliably when fcntl/close race is detected

2024-07-25T07:49:07+00:00

commit 3cad1bc010416c6dd780643476bc59ed742436b9 upstream. When fcntl_setlk() races with close(), it removes the created lock with do_lock_file_wait(). However, LSMs can allow the first do_lock_file_wait() that created the lock while denying the second do_lock_file_wait() that tries to remove the lock. In theory (but AFAIK not in practice), posix_lock_file() could also fail to remove a lock due to GFP_KERNEL allocation failure (when splitting a range in the middle). After the bug has been triggered, use-after-free reads will occur in lock_get_status() when userspace reads /proc/locks. This can likely be used to read arbitrary kernel memory, but can't corrupt kernel memory. This only affects systems with SELinux / Smack / AppArmor / BPF-LSM in enforcing mode and only works from some security contexts. Fix it by calling locks_remove_posix() instead, which is designed to reliably get rid of POSIX locks associated with the given file and files_struct and is also used by filp_flush(). Fixes: c293621bbf67 ("[PATCH] stale POSIX lock handling") Cc: stable@kernel.org Link: https://bugs.chromium.org/p/project-zero/issues/detail?id=2563 Signed-off-by: Jann Horn Link: https://lore.kernel.org/r/20240702-fs-lock-recover-2-v1-1-edd456f63789@google.com Reviewed-by: Jeff Layton Signed-off-by: Christian Brauner [stable fixup: ->c.flc_type was ->fl_type in older kernels] Signed-off-by: Jann Horn Signed-off-by: Greg Kroah-Hartman

filelock: fix potential use-after-free in posix_lock_inode

2024-07-18T11:18:32+00:00

[ Upstream commit 1b3ec4f7c03d4b07bad70697d7e2f4088d2cfe92 ] Light Hsieh reported a KASAN UAF warning in trace_posix_lock_inode(). The request pointer had been changed earlier to point to a lock entry that was added to the inode's list. However, before the tracepoint could fire, another task raced in and freed that lock. Fix this by moving the tracepoint inside the spinlock, which should ensure that this doesn't happen. Fixes: 74f6f5912693 ("locks: fix KASAN: use-after-free in trace_event_raw_event_filelock_lock") Link: https://lore.kernel.org/linux-fsdevel/724ffb0a2962e912ea62bb0515deadf39c325112.camel@kernel.org/ Reported-by: Light Hsieh (謝明燈) Signed-off-by: Jeff Layton Link: https://lore.kernel.org/r/20240702-filelock-6-10-v1-1-96e766aadc98@kernel.org Reviewed-by: Alexander Aring Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

filelock: add a new locks_inode_context accessor function

2024-03-06T14:45:16+00:00

[ Upstream commit 401a8b8fd5acd51582b15238d72a8d0edd580e9f ] There are a number of places in the kernel that are accessing the inode->i_flctx field without smp_load_acquire. This is required to ensure that the caller doesn't see a partially-initialized structure. Add a new accessor function for it to make this clear and convert all of the relevant accesses in locks.c to use it. Also, convert locks_free_lock_context to use the helper as well instead of just doing a "bare" assignment. Reviewed-by: Christoph Hellwig Signed-off-by: Jeff Layton Stable-dep-of: 77c67530e1f9 ("nfsd: use locks_inode_context helper") Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman

locks: fix KASAN: use-after-free in trace_event_raw_event_filelock_lock

2023-09-23T09:11:00+00:00

[ Upstream commit 74f6f5912693ce454384eaeec48705646a21c74f ] As following backtrace, the struct file_lock request , in posix_lock_inode is free before ftrace function using. Replace the ftrace function ahead free flow could fix the use-after-free issue. [name:report&]=============================================== BUG:KASAN: use-after-free in trace_event_raw_event_filelock_lock+0x80/0x12c [name:report&]Read at addr f6ffff8025622620 by task NativeThread/16753 [name:report_hw_tags&]Pointer tag: [f6], memory tag: [fe] [name:report&] BT: Hardware name: MT6897 (DT) Call trace: dump_backtrace+0xf8/0x148 show_stack+0x18/0x24 dump_stack_lvl+0x60/0x7c print_report+0x2c8/0xa08 kasan_report+0xb0/0x120 __do_kernel_fault+0xc8/0x248 do_bad_area+0x30/0xdc do_tag_check_fault+0x1c/0x30 do_mem_abort+0x58/0xbc el1_abort+0x3c/0x5c el1h_64_sync_handler+0x54/0x90 el1h_64_sync+0x68/0x6c trace_event_raw_event_filelock_lock+0x80/0x12c posix_lock_inode+0xd0c/0xd60 do_lock_file_wait+0xb8/0x190 fcntl_setlk+0x2d8/0x440 ... [name:report&] [name:report&]Allocated by task 16752: ... slab_post_alloc_hook+0x74/0x340 kmem_cache_alloc+0x1b0/0x2f0 posix_lock_inode+0xb0/0xd60 ... [name:report&] [name:report&]Freed by task 16752: ... kmem_cache_free+0x274/0x5b0 locks_dispose_list+0x3c/0x148 posix_lock_inode+0xc40/0xd60 do_lock_file_wait+0xb8/0x190 fcntl_setlk+0x2d8/0x440 do_fcntl+0x150/0xc18 ... Signed-off-by: Will Shiu Signed-off-by: Jeff Layton Signed-off-by: Sasha Levin

filelocks: use mount idmapping for setlease permission check

2023-03-17T07:50:32+00:00

commit 42d0c4bdf753063b6eec55415003184d3ca24f6e upstream. A user should be allowed to take out a lease via an idmapped mount if the fsuid matches the mapped uid of the inode. generic_setlease() is checking the unmapped inode uid, causing these operations to be denied. Fix this by comparing against the mapped inode uid instead of the unmapped uid. Fixes: 9caccd41541a ("fs: introduce MOUNT_ATTR_IDMAP") Cc: stable@vger.kernel.org Signed-off-by: Seth Forshee (DigitalOcean) Signed-off-by: Christian Brauner (Microsoft) Signed-off-by: Greg Kroah-Hartman

filelock: new helper: vfs_inode_has_locks

2023-01-12T11:02:22+00:00

[ Upstream commit ab1ddef98a715eddb65309ffa83267e4e84a571e ] Ceph has a need to know whether a particular inode has any locks set on it. It's currently tracking that by a num_locks field in its filp->private_data, but that's problematic as it tries to decrement this field when releasing locks and that can race with the file being torn down. Add a new vfs_inode_has_locks helper that just returns whether any locks are currently held on the inode. Reviewed-by: Xiubo Li Reviewed-by: Christoph Hellwig Signed-off-by: Jeff Layton Stable-dep-of: 461ab10ef7e6 ("ceph: switch to vfs_inode_has_locks() to fix file lock bug") Signed-off-by: Sasha Levin

locks: Fix dropped call to ->fl_release_private()

2022-08-17T19:08:58+00:00

Prior to commit 4149be7bda7e, sys_flock() would allocate the file_lock struct it was going to use to pass parameters, call ->flock() and then call locks_free_lock() to get rid of it - which had the side effect of calling locks_release_private() and thus ->fl_release_private(). With commit 4149be7bda7e, however, this is no longer the case: the struct is now allocated on the stack, and locks_free_lock() is no longer called - and thus any remaining private data doesn't get cleaned up either. This causes afs flock to cause oops. Kasan catches this as a UAF by the list_del_init() in afs_fl_release_private() for the file_lock record produced by afs_fl_copy_lock() as the original record didn't get delisted. It can be reproduced using the generic/504 xfstest. Fix this by reinstating the locks_release_private() call in sys_flock(). I'm not sure if this would affect any other filesystems. If not, then the release could be done in afs_flock() instead. Changes ======= ver #2) - Don't need to call ->fl_release_private() after calling the security hook, only after calling ->flock(). Fixes: 4149be7bda7e ("fs/lock: Don't allocate file_lock in flock_make_lock().") cc: Chuck Lever cc: Jeff Layton cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/166075758809.3532462.13307935588777587536.stgit@warthog.procyon.org.uk/ # v1 Acked-by: Kuniyuki Iwashima Signed-off-by: David Howells Signed-off-by: Jeff Layton

fs/lock: Rearrange ops in flock syscall.

2022-07-18T14:01:47+00:00

The previous patch added flock_translate_cmd() in flock syscall. The test and the other one for LOCK_MAND do not depend on struct fd and are cheaper, so we can put them at the top and defer fdget() after that. Also, we can remove the unlock variable and use type instead. While at it, we fix this checkpatch error. CHECK: spaces preferred around that '|' (ctx:VxV) #45: FILE: fs/locks.c:2099: + if (type != F_UNLCK && !(f.file->f_mode & (FMODE_READ|FMODE_WRITE))) ^ Finally, we can move the can_sleep part just before we use it. Signed-off-by: Kuniyuki Iwashima Signed-off-by: Jeff Layton