kernel/linux.git/fs/smb/client, branch v6.12.102

smb: client: validate DFS referral PathConsumed

2026-08-03T09:17:09+00:00

[ Upstream commit f6f5ee2aa33b350c671721b965251c42cebb962e ] parse_dfs_referrals() validates that the response contains the fixed referral entry array and, on for-next, the per-referral string offsets. However, the response also contains a PathConsumed value that is later used for DFS path parsing. If a malformed response provides a PathConsumed value larger than the search name, later DFS parsing can advance beyond the end of the path. Validate PathConsumed against the search name length before storing it in the parsed referral. Fixes: 4ecce920e13a ("CIFS: move DFS response parsing out of SMB1 code") Reviewed-by: Paulo Alcantara (Red Hat) Signed-off-by: Yichong Chen Signed-off-by: Steve French Signed-off-by: Sasha Levin

smb: move some duplicate definitions to common/cifsglob.h

2026-08-03T09:17:05+00:00

[ Upstream commit d877470b59910b5c50383d634dda3782386bba51 ] In order to maintain the code more easily, move duplicate definitions to new common header file. Co-developed-by: ChenXiaoSong Signed-off-by: ChenXiaoSong Signed-off-by: ZhangGuoDong Signed-off-by: Steve French Stable-dep-of: aa5d8f3f96aa ("ksmbd: pin conn during async oplock break notification") Signed-off-by: Sasha Levin

smb/client: handle overlapping allocated ranges in fallocate

2026-08-03T09:17:05+00:00

[ Upstream commit b09ae45d85dc816987a71db9eebc54b0ae288e94 ] smb3_simple_fallocate_range() can skip holes when an allocated range returned by the server starts before the current fallocate offset. The skipped hole is not zero-filled, but fallocate still returns success. A later write to that hole may therefore fail with ENOSPC. The function queries allocated ranges so that it can preserve existing contents and write zeroes only into holes. However, the server may return a range that starts before the current fallocate offset. For example, assume the fallocate request is [100, 400) and the only allocated range returned by the server is [0, 200): Request: [100, 400) Server range: [ 0, 200) allocated Correct: [100, 200) allocated data, skip [200, 400) hole, zero-fill Current: [100, 300) skipped [300, 400) zero-filled afterwards The current code adds the full server range length, 200, to the current offset 100 and moves to 300. As a result, the hole in [200, 300) is skipped without being zero-filled. Fix this by advancing only over the part of the allocated range that overlaps the current fallocate offset. Ignore ranges that end before the current offset and reject ranges whose end offset overflows. This also prevents a malformed range length from causing an out-of-bounds zero-buffer read. Fixes: 966a3cb7c7db ("cifs: improve fallocate emulation") Signed-off-by: Huiwen He Reviewed-by: ChenXiaoSong Signed-off-by: Steve French Signed-off-by: Sasha Levin

smb: client: resolve SWN tcon from live registrations

2026-07-24T14:11:50+00:00

[ Upstream commit ec457f9afe5ae9538bdcd58fd4cb442b9787e183 ] cifs_swn_notify() looks up a witness registration by id under cifs_swnreg_idr_mutex, drops the mutex, and then uses the registration's cached tcon pointer. That pointer is not a lifetime reference, and it is not a stable representative once cifs_get_swn_reg() lets multiple tcons for the same net/share name share one registration id. A same-share second mount can keep the cifs_swn_reg alive after the first tcon unregisters and is freed. The registration then still points at the freed first tcon, so taking tc_lock or incrementing tc_count through swnreg->tcon only moves the use-after-free earlier. Taking tc_lock while holding cifs_swnreg_idr_mutex also violates the documented CIFS lock order. Fix this by making the registration store only the stable witness identity: id, net name, share name, and notify flags. When a notify arrives, copy that identity under cifs_swnreg_idr_mutex, drop the mutex, then find and pin a live witness tcon that currently matches the net/share pair under the normal cifs_tcp_ses_lock -> tc_lock order. The notification path uses that pinned tcon directly and drops the reference when done. Registration and unregister messages now use the live tcon passed by the caller instead of a cached tcon in the registration. The final unregister send is folded into cifs_swn_unregister() while the registration is still protected by cifs_swnreg_idr_mutex. This removes the previous find/drop/reacquire raw-pointer window. The release path only removes the idr entry and frees the stable identity strings. This preserves the intended one-registration/many-tcon behavior: a registration id represents a net/share pair, and notify handling acts on a live representative selected at use time. It also preserves CLIENT_MOVE ordering for the representative tcon because the old-IP unregister is sent before cifs_swn_register() sends the new-IP register. Fixes: fed979a7e082 ("cifs: Set witness notification handler for messages from userspace daemon") Cc: stable@vger.kernel.org Signed-off-by: Michael Bommarito Assisted-by: Claude:claude-opus-4-7 Signed-off-by: Steve French Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

smb: client: Improve unlocking of a mutex in cifs_get_swn_reg()

2026-07-24T14:11:50+00:00

[ Upstream commit e2080b70c5851a132547bec3bd7dde847e649678 ] Use two additional labels so that another bit of common code can be better reused at the end of this function implementation. Signed-off-by: Markus Elfring Signed-off-by: Steve French Stable-dep-of: ec457f9afe5a ("smb: client: resolve SWN tcon from live registrations") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

smb: client: use kvzalloc() for megabyte buffer in simple fallocate

2026-07-24T14:11:36+00:00

commit 806c00c23e3ce8eae397a40ced536ef88ae4e012 upstream. Currently in smb3_simple_fallocate_range(), a 1 MB buffer is allocated using kzalloc(). Under heavy memory fragmentation, a contiguous 1 MB block of physical memory (an order-8 allocation) may not be available, causing the allocation to fail. This failure was observed during xfstests generic/013 on a 4GB RAM test machine running fsstress: fsstress: page allocation failure: order:8, mode:0x40dc0(GFP_KERNEL|__GFP_ZERO|__GFP_COMP), nodemask=(null),cpuset=/,mems_allowed=0 Call Trace: dump_stack_lvl+0x5d/0x80 warn_alloc+0x163/0x190 __alloc_pages_slowpath.constprop.0+0x71b/0x12f0 __alloc_frozen_pages_noprof+0x2f6/0x340 alloc_pages_mpol+0xb6/0x170 ___kmalloc_large_node+0xb3/0xd0 __kmalloc_large_noprof+0x1e/0xc0 smb3_simple_falloc.isra.0+0x62b/0x960 cifs_fallocate+0xed/0x180 vfs_fallocate+0x165/0x3c0 __x64_sys_fallocate+0x48/0xa0 do_syscall_64+0xe1/0x640 entry_SYSCALL_64_after_hwframe+0x76/0x7e Node 0 Normal: 3375*4kB ... 7*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB Since this scratch buffer does not require physically contiguous memory, switch the allocation to kvzalloc(). This retains the performance benefits of kmalloc() under normal conditions, while gracefully falling back to virtually contiguous memory when physical allocation fails. Fixes: 966a3cb7c7db ("cifs: improve fallocate emulation") Cc: stable@vger.kernel.org Signed-off-by: Fredric Cover Tested-by: Fredric Cover Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

cifs: invalidate cfid on unlink/rename/rmdir

2026-07-24T14:11:31+00:00

commit f71d68d2b473e47db260c27c98212829590d8bae upstream. Today we do not invalidate the cached_dirent or the entire parent cfid when a dentry in a dir has been removed/moved. This change invalidates the parent cfid so that we don't serve directory contents from the cache. Cc: Signed-off-by: Shyam Prasad N Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: fix overflow in passthrough ioctl bounds check

2026-07-24T14:11:25+00:00

[ Upstream commit a4f27ad055392fa164f5649e89a3637b033c5fcc ] smb2_ioctl_query_info() validates the PASSTHRU_FSCTL response payload before copying it to userspace. The payload offset and length both come from 32-bit fields. The bounds check currently adds OutputOffset and qi.input_buffer_length directly, so the addition can wrap in 32-bit arithmetic before the result is compared against the response buffer length. A malicious server can use a large OutputOffset and a small OutputCount to make the wrapped sum pass the bounds check. The later copy_to_user() then reads from io_rsp + OutputOffset, outside the response buffer. Use size_add() for the offset plus length check so overflow is treated as out of bounds. Fixes: 2b1116bbe898 ("CIFS: Use common error handling code in smb2_ioctl_query_info()") Signed-off-by: Guangshuo Li Signed-off-by: Steve French Signed-off-by: Sasha Levin

cifs: validate DFS referral string offsets

2026-07-24T14:11:24+00:00

[ Upstream commit 027a84ac6b50c12ef767c15abfc58aa865820e9e ] parse_dfs_referrals() validates that the response header and referral array fit in the received buffer, but each referral also contains string offsets supplied by the server. Those offsets are used to compute the DfsPath and NetworkAddress string pointers without checking whether they still point inside the response buffer. A malformed referral can therefore make the computed pointer exceed the end of the buffer. The resulting negative max_len is then passed to cifs_strndup_from_utf16(), and the non-Unicode path forwards it to kstrndup() as a size_t, allowing strnlen() to read out of bounds. Validate each string offset before deriving the string pointer. Fixes: 4ecce920e13a ("CIFS: move DFS response parsing out of SMB1 code") Signed-off-by: Guangshuo Li Signed-off-by: Steve French Signed-off-by: Sasha Levin

cifs: Fix missing credit release on failure in cifs_issue_read()

2026-07-24T14:11:22+00:00

[ Upstream commit c16b8c4cfb4fe2244cc33e469a93c1ab8684146b ] Fix missing release of credits in the failure path in cifs_issue_read() lest retrying the subreq just overwrites the credits value. Fixes: 69c3c023af25 ("cifs: Implement netfslib hooks") Link: https://sashiko.dev/#/patchset/20260608145432.681865-1-dhowells%40redhat.com Signed-off-by: David Howells Acked-by: Paulo Alcantara (Red Hat) cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Steve French Signed-off-by: Sasha Levin