kernel/linux.git/fs, branch v6.18.35

ksmbd: OOB read regression in smb_check_perm_dacl() ACE-walk loops

2026-06-09T10:28:42+00:00

commit 0e60dafe97eca61721f3db456f97d97a80c6c8ae upstream. Commit d07b26f39246 ("ksmbd: require minimum ACE size in smb_check_perm_dacl()") introduced a transposed bounds check: if (offsetof(struct smb_ace, sid) + aces_size < CIFS_SID_BASE_SIZE) Since offsetof(..sid) is 8 and CIFS_SID_BASE_SIZE is 8, this evaluates to `aces_size < 0`. Because `aces_size` is always non-negative, this check becomes dead code and never breaks the loop. Worse, that commit removed the old 4-byte guard, meaning the loop now reads `ace->size` (offset 2) even when `aces_size` is 0-3 bytes. This re-opens a 2-byte heap out-of-bounds (OOB) read past the pntsd allocation during subsequent SMB2_CREATE operations. Fix this by properly transposing the comparison to require at least 16 bytes (8-byte offset + 8-byte SID base), matching the correct form used in smb_inherit_dacl(). Fixes: d07b26f39246 ("ksmbd: require minimum ACE size in smb_check_perm_dacl()") Cc: stable@vger.kernel.org Signed-off-by: Ali Ganiyev Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

smb: client: fix uninitialized variable in smb2_writev_callback

2026-06-09T10:28:35+00:00

commit 9d2491197a00acf8c423512078458c2855102b66 upstream. compiling with W=2 pointed out that "written may be used uninitialized" Fixes: 20d72b00ca81 ("netfs: Fix the request's work item to not require a ref") Cc: stable@vger.kernel.org Reviewed-by: David Howells Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

hpfs: fix a crash if hpfs_map_dnode_bitmap fails

2026-06-09T10:28:34+00:00

commit 974820a59efde7c1a7e1260bcfe9bb81f833cc9f upstream. If hpfs_map_dnode_bitmap fails, the code would call hpfs_brelse4 on uninitialized quad buffer head, causing a crash. Signed-off-by: Mikulas Patocka Reported-by: Farhad Alemi Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

smb: client: validate the whole DACL before rewriting it in cifsacl

2026-06-09T10:28:32+00:00

[ Upstream commit 0a8cf165566ba55a39fd0f4de172119dd646d39a ] build_sec_desc() and id_mode_to_cifs_acl() derive a DACL pointer from a server-supplied dacloffset and then use the incoming ACL to rebuild the chmod/chown security descriptor. The original fix only checked that the struct smb_acl header fits before reading dacl_ptr->size or dacl_ptr->num_aces. That avoids the immediate header-field OOB read, but the rewrite helpers still walk ACEs based on pdacl->num_aces with no structural validation of the incoming DACL body. A malicious server can return a truncated DACL that still contains a header, claims one or more ACEs, and then drive replace_sids_and_copy_aces() or set_chmod_dacl() past the validated extent while they compare or copy attacker-controlled ACEs. Factor the DACL structural checks into validate_dacl(), extend them to validate each ACE against the DACL bounds, and use the shared validator before the chmod/chown rebuild paths. parse_dacl() reuses the same validator so the read-side parser and write-side rewrite paths agree on what constitutes a well-formed incoming DACL. Fixes: bc3e9dd9d104 ("cifs: Change SIDs in ACEs while transferring file ownership.") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-6 Assisted-by: Codex:gpt-5-4 Signed-off-by: Michael Bommarito Signed-off-by: Steve French Signed-off-by: Sasha Levin

ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE

2026-06-09T10:28:28+00:00

[ Upstream commit cc57232cae23c0df91b4a59d0f519141ce9b5b02 ] FSCTL_SET_SPARSE in fsctl_set_sparse() modifies the file's sparse attribute and saves it through xattr without any permission checks. This exposes two issues: 1) A client on a read-only share can change the sparse attribute on files it opened, even though the share is read-only. Other FSCTL write operations already check test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE), but FSCTL_SET_SPARSE does not. 2) Even on writable shares, clients without FILE_WRITE_DATA or FILE_WRITE_ATTRIBUTES access should not modify the sparse attribute. Similar handle-level checks exist in other functions but are missing here. Add both share-level writable check and per-handle access check. Use goto out on error to avoid leaking file references. Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Cc: Namjae Jeon Cc: Sergey Senozhatsky Cc: Steve French Signed-off-by: Sean Shen Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin

ksmbd: fix durable reconnect error path file lifetime

2026-06-01T15:51:08+00:00

[ Upstream commit 3515503322f4819277091839eed46b695096aca5 ] After a durable reconnect succeeds, ksmbd_reopen_durable_fd() republishes the same ksmbd_file into the session volatile-id table. If smb2_open() then takes a later error path, cleanup first calls ksmbd_fd_put(work, fp) and then unconditionally calls ksmbd_put_durable_fd(dh_info.fp). In this case fp and dh_info.fp are the same object. The first put drops the reconnect lookup reference, but the final durable put can run __ksmbd_close_fd(NULL, fp). Because the final close is not session-aware, it can free the file object without removing the volatile-id entry that was just published into the session table. Use the session-aware put for the final reconnect drop when the reconnect had already succeeded and the error path is cleaning up the republished file. Earlier reconnect failures, before fp is assigned to dh_info.fp, keep using the durable-only put path. Fixes: 1baff47b81f9 ("ksmbd: fix use-after-free in smb2_open during durable reconnect") Signed-off-by: Junyi Liu Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin

erofs: fix managed cache race for unaligned extents

2026-06-01T15:51:05+00:00

[ Upstream commit 649932fc3815eda2f24eb4de4b3a5e94886ee0b9 ] After unaligned compressed extents were introduced, the following race could occur: [Thread 1] [Thread 2] (z_erofs_fill_bio_vec) ... filemap_add_folio (1) (z_erofs_bind_cache) .. .. folio_attach_private (2) filemap_add_folio (3) again Since (1) is executed but (2) hasn't been executed yet, it's possible that another thread finds the same managed folio in z_erofs_bind_cache() for a different pcluster and calls filemap_add_folio() again since folio->private is still Z_EROFS_PREALLOCATED_FOLIO. Fix this by explicitly clearing folio->private before making the folio visible in the managed cache so that another pcluster can simply wait on the locked managed folio as what we did for other shared cases [1]. This only impacts unaligned data compression (`-E48bit` with zstd, for example). [1] Commit 9e2f9d34dd12 ("erofs: handle overlapped pclusters out of crafted images properly") was originally introduced to handle crafted overlapped extents, but it addresses unaligned extents as well. Fixes: 7361d1e3763b ("erofs: support unaligned encoded data") Reported-by: Arseniy Krasnov Closes: https://lore.kernel.org/r/4a2f3801-fac1-42fe-ae75-da315822e088@salutedevices.com Tested-by: Arseniy Krasnov Signed-off-by: Gao Xiang Signed-off-by: Sasha Levin

btrfs: fix squota accounting during enable generation

2026-06-01T15:51:02+00:00

[ Upstream commit d7c600554816b8ef70adffe078a0e360c055d82b ] The first transaction that enables squotas is special and a bit tricky. We have to set BTRFS_FS_QUOTA_ENABLED after the transaction to avoid a deadlock, so any delayed refs that run before we set the bit are not squota accounted. For data this is fine, we don't get an owner_ref, so there is no real harm, it's as if the extent predated squotas. However for metadata, the tree block will have gen == enable_gen so when we free it later, we will decrement the squota accounting, which can result in an underflow. Before it is freed, btrfs check shows errors, as we have mismatched usage between the node generations/owners and the squota values. There are two angles to this fix: 1. For extents that come in delayed_refs that run during the enable_gen transaction, we must actually set enable_gen to the *next* transaction. That is the first transaction that we can really properly account in any way. 2. For extents that come in between the end of our transaction handle and the time we set the BTRFS_FS_QUOTA_ENABLED bit, we need an additional bit, BTRFS_FS_SQUOTA_ENABLING which only affects recording squota deltas, so we do pick up those extents. Otherwise, we would miss them, even for enable_gen + 1. Fixes: bd7c1ea3a302 ("btrfs: qgroup: check generation when recording simple quota delta") Reviewed-by: Qu Wenruo Signed-off-by: Boris Burkov Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: check for subvolume before deleting squota qgroup

2026-06-01T15:51:02+00:00

[ Upstream commit 1e92637722ae4bd417f7a37e8d1485dc23b93935 ] The invariant that we want to maintain with subvolume qgroups is that the qgroup can only be deleted if there is no root. With squotas, we thought that it was sufficient to just check the usage, because we assumed that deleting a subvolume will drive it's qgroups usage to 0, and thus 0 usage implies no subvolume. However, this is false, for two reasons: - A subvol whose extents are all from before squotas was enabled. - A subvol that was created in this transaction and for which we have not yet run any delayed refs. In both cases, deleting the qgroup breaks the desired invariant and we are left with a subvolume with no qgroup but squotas are enabled. Fix this by unifying the deletion check logic between full qgroups and squotas. Squotas do all the same checks *and* the additional usage == 0 check, which is the one extra rule peculiar to squotas. Link: https://lore.kernel.org/linux-btrfs/adnBhWfJQ1n3hZC8@merlins.org/ Fixes: a8df35619948 ("btrfs: forbid deleting live subvol qgroup") Reviewed-by: Qu Wenruo Signed-off-by: Boris Burkov Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: relax squota parent qgroup deletion rule

2026-06-01T15:51:01+00:00

[ Upstream commit adb0af40fe89fd42f1ef277bf60d9cfa7c2ae472 ] Currently, with squotas, we do not allow removing a parent qgroup with no members if it still has usage accounted to it. This makes it really difficult to recover from accounting bugs, as we have no good way of getting back to 0 usage. Instead, allow deletion (it's safe at 0 members..) while still warning about the inconsistency by adding a squota parent check. Reviewed-by: Qu Wenruo Signed-off-by: Boris Burkov Signed-off-by: David Sterba Stable-dep-of: 1e92637722ae ("btrfs: check for subvolume before deleting squota qgroup") Signed-off-by: Sasha Levin