smb: client: reject short READ responses in CIFSSMBRead()
In the Linux kernel, the following vulnerability has been resolved:
smb: client: reject short READ responses in CIFSSMBRead()
CIFSSMBRead() reads DataLengthHigh, DataLength and DataOffset out of
the READ_RSP returned by the server without first checking that a
whole READ_RSP was actually received. The length of the response is
recorded in rsp_iov.iov_len, but nothing constrains it to be at least
read_rsp_size before those fields are dereferenced.
A malicious or compromised SMB1 server can return a response shorter
than the READ_RSP header, so that parsing the header itself reads past
the end of the receive buffer. SMB1 is not negotiated by
In the Linux kernel, the following vulnerability has been resolved:
smb: client: reject userspace cifs.idmap descriptions
cifs.idmap key descriptions carry authority-bearing fields (owner and
group SIDs and uid/gid values in "os:"/"gs:"/"oi:"/"gi:" form) that the
cifs.idmap upcall helper treats as kernel-originating inputs. Unlike
its sibling cifs.spnego, the cifs.idmap key type has no vet_description
hook, so userspace can create keys of this type through
request_key(2)/add_key(2) and supply those fields without CIFS origin.
A request_key(2) call with a non-NULL callout then drives a root
usermodehelper upcall (/sbin/request-key -> cifs.i
smb: client: reject out-of-bounds DataOffset in CIFSSMBRead()
In the Linux kernel, the following vulnerability has been resolved:
smb: client: reject out-of-bounds DataOffset in CIFSSMBRead()
The SMB1 synchronous read helper CIFSSMBRead() validates the server's
DataLength against CIFSMaxBufSize and the caller's count, but never
validates DataOffset. The copy source is formed as
&pSMBr->hdr.Protocol + le16_to_cpu(pSMBr->DataOffset)
and memcpy()'d for DataLength bytes with no check that the
[DataOffset, DataOffset + DataLength) range lies within the response
actually received from the server.
A malicious or compromised SMB1 server can return a response carrying
an in-range DataLength and a large Dat
smb: client: pin DFS superblock in iterator callback
In the Linux kernel, the following vulnerability has been resolved:
smb: client: pin DFS superblock in iterator callback
tcon_super_cb() stores a raw superblock pointer, but __cifs_get_super()
takes its active reference only after iterate_supers_type() has dropped
s_umount and its passive reference. Concurrent DFS automount expiry can
therefore free the superblock before cifs_sb_active() uses it.
A deterministic KASAN test reproduces the race as:
BUG: KASAN: slab-use-after-free in cifs_sb_active+0x77/0x80
The same test passes with this change applied.
Take the active reference in the callback while iterate_supers_type()
still holds s_
smb: client: honor forceuid/forcegid when mapping SIDs to uid/gid
In the Linux kernel, the following vulnerability has been resolved:
smb: client: honor forceuid/forcegid when mapping SIDs to uid/gid
When the administrator mounts with forceuid or forcegid (uid=/gid=
mount options), they expect all files to appear owned by the specified
user/group. However, several code paths unconditionally called
sid_to_id() to overwrite cf_uid/cf_gid with server-provided values,
ignoring the administrator's explicit override:
- smb311_posix_info_to_fattr() (stat via POSIX extensions)
- cifs_posix_to_fattr() (readdir via POSIX extensions)
- parse_sec_desc() (CIFS ACL ownership mapping)
This allowed an untrusted
smb: client: fix one-byte OOB read in smb2_parse_native_symlink()
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix one-byte OOB read in smb2_parse_native_symlink()
When parsing a share-root relative native symlink, memcpy copies
smb_target+1 (skipping the leading separator) but uses
strlen(smb_target)+1 as the length, reading one byte past the
allocated buffer.
This fixes the following KASAN splat when accessing an SMB symlink
with a target of '\a\b':
BUG: KASAN: slab-out-of-bounds in smb2_parse_native_symlink+0x4f5/0xca0
Read of size 5 at addr ffff88800878fe21 by task netfsfuzz-execu/1
CPU: 1 UID: 0 PID: 1 Comm: netfsfuzz-execu Tainted: G N
7.2.0-11943-g2709d
smb: client: fail DACL rewrite when the new DACL exceeds 64K
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fail DACL rewrite when the new DACL exceeds 64K
replace_sids_and_copy_aces() and set_chmod_dacl() accumulate the size of
the DACL they build in a u16. That accumulator can wrap.
validate_dacl() caps num_aces at (dacl_size - sizeof(struct smb_acl)) /
20, i.e. 3276 for a maximally sized DACL, while each rewritten ACE can
grow to sizeof(struct smb_ace) (76 bytes) once its SID is replaced with
one carrying SID_MAX_SUB_AUTHORITIES sub-authorities. The worst case is
therefore sizeof(struct smb_acl) + 3276 * 76 = 248984 bytes, far beyond
what a u16 can hold. A wrapar
smb: client: fix cifsFileInfo reference leak in deferred close
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix cifsFileInfo reference leak in deferred close
When cifs_close() defers a close, it hands the cifsFileInfo reference
of the closing struct file to the queued work. Each execution of
smb2_deferred_work_close() drops one such reference.
deferred_close_scheduled can be false while the work is pending: the
workqueue clears PENDING when the callback starts to run, before the
callback clears the flag under deferred_lock. A close in that
interval requeues the running work, and the callback then clears the
flag, leaving the requeued work pending with the flag down.
smb: client: avoid leaking refcount in cifs_queue_oplock_break()
In the Linux kernel, the following vulnerability has been resolved:
smb: client: avoid leaking refcount in cifs_queue_oplock_break()
cifs_queue_oplock_break() unconditionally takes a reference on the
target file before queueing cifs_oplock_break(). Only that work item
decreases the reference counter again.
If another oplock break arrives while that work is still queued,
queue_work() will return false and not queue this second work item. As a
result, we will never reach the point to drop the file reference again
and are leaking this reference. This can be triggered when interacting
with a slow-responding server.
As a result, later unmount
smb: client: avoid leaking refcount when cifs_sb_tlink() fails
In the Linux kernel, the following vulnerability has been resolved:
smb: client: avoid leaking refcount when cifs_sb_tlink() fails
cifs_oplock_break() takes over the reference that
cifs_queue_oplock_break() acquired when it queued the work, and drops it
with _cifsFileInfo_put() once the break has been processed.
Only in setups with "-o multiuser", cifs_sb_tlink() may fail, at which
point cifs_oplock_break() returns without putting the file reference,
mirroring the reference leak we already fixed in the companion patch to
cifs_queue_oplock_break().
This would trigger a crash due to busy inodes on the next unmount:
BUG: Dentry ... still
smb: client: fix heap overflow in DACL owner/group rewrite
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix heap overflow in DACL owner/group rewrite
When id_mode_to_cifs_acl rewrites an existing DACL, it allocates a
buffer sized according to the on-disk DACL length reported by
dacl_ptr->size. However, replace_sids_and_copy_aces may rewrite each
ACE with a new owner/group SID obtained from the cifs.idmap upcall.
Those SIDs can have up to SID_MAX_SUB_AUTHORITIES (15) sub-authorities,
making each ACE up to 76 bytes (sizeof(struct smb_ace)).
If the original DACL contains short SIDs (e.g., 1 sub-authority) while
the replacement SIDs are long, the rewritten ACEs over
smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr()
In the Linux kernel, the following vulnerability has been resolved:
smb: client: avoid using uninitialized SIDs in cifs_posix_to_fattr()
cifs_posix_to_fattr() ignores the return value of posix_info_parse().
When a malformed POSIX directory entry is encountered (e.g. invalid
SID lengths from an untrusted server), posix_info_parse() returns -1
without populating the 'parsed' struct. The uninitialized stack
memory in parsed.owner and parsed.group is then passed to
sid_to_id(), which processes the garbage bytes and passes them to
request_key() to construct a SID string, potentially leaking kernel
stack contents to the userspace idmap daemon.
In the Linux kernel, the following vulnerability has been resolved:
xfs: initialise error in xfs_defer_finish_one()
xfs_defer_finish_one() declares error without an initialiser and only
assigns it inside the loop over dfp->dfp_work. When that list is empty
the loop body never runs, control falls through to the "Done with the
dfp, free it" path, and the function returns an indeterminate value.
An item-less pending item reaches this through xfs_defer_add_barrier(),
which xfs_reap_ag_blocks() uses on any CONFIG_XFS_ONLINE_REPAIR kernel.
xfs_defer_finish_noroll() treats any non-EAGAIN return as fatal, so a
non-zero stack value turns a success
xfs: initialise args->total for parent pointer updates
In the Linux kernel, the following vulnerability has been resolved:
xfs: initialise args->total for parent pointer updates
xfs_parent_da_args_init() builds an xfs_da_args from a zeroed
xfs_parent_args (kmem_cache_zalloc), leaving args->total == 0.
xfs_da_grow_inode_int() treats that field as a running block reservation
and subtracts from it; because it is an xfs_extlen_t (uint32_t), the
first attr-fork growth wraps it to ~0U. That defeats the free-space
check in xfs_alloc_space_available(), and when it coincides with an AG
that has exactly zero available blocks the allocation is clamped to
maxlen 0 and returns -ENOSPC, which xfs_defer_fini
xfs: fix under-reservation of blocks when repairing sf directories
In the Linux kernel, the following vulnerability has been resolved:
xfs: fix under-reservation of blocks when repairing sf directories
Whilst running QA on XFS for-next as of 7.3-rc2 with MKFS_OPTIONS="-n
size=8192", I observed the following (trimmed) dmesg splat:
XFS: Assertion failed: args->total >= dp->i_nblocks - nblks, file: fs/xfs/libxfs/xfs_da_btree.c, line: 2387
WARNING: fs/xfs/xfs_message.c:104 at assfail+0x46/0x4a [xfs], CPU#0: xfs_scrub/1426511
CPU: 0 UID: 0 PID: 1426511 Comm: xfs_scrub Tainted: G W 7.3.0-rc2-djwx #rc2 PREEMPT(lazy) 6e418570b606a39783b0e7e7b30dc407b965f9e8
Tainted: [W]=WARN
RIP: 0010:assfa
xfs: fix exchange-range reflink flag clearing issue with INO1_WRITTEN
In the Linux kernel, the following vulnerability has been resolved:
xfs: fix exchange-range reflink flag clearing issue with INO1_WRITTEN
When exchanging two full-file ranges, xmi_can_exchange_reflink_flags()
can move the reflink inode flag from the file that currently has it to
the other file, as long as exactly one side is marked. This assumes
that the file contents, and therefore all shared extents, are exchanged.
That assumption is not true when XFS_EXCHMAPS_INO1_WRITTEN is set.
xfs_exchmaps_can_skip_mapping() can skip hole and unwritten mappings
from file1, so an exchange can complete without moving every mapping
that the earlier fla
xfs: don't spin forever on zero-length dirents when salvaging them
In the Linux kernel, the following vulnerability has been resolved:
xfs: don't spin forever on zero-length dirents when salvaging them
LOLLM noticed that xrep_dir_recover_data can spin forever if it
encounters an unused dirent that claims to have length zero. Fix that,
and prevent the same thing from happening with a zero-length entry.
xfs: don't leak new_bp if xfs_btree_bload_drop_buf fails
In the Linux kernel, the following vulnerability has been resolved:
xfs: don't leak new_bp if xfs_btree_bload_drop_buf fails
LOLLM observes that in xfs_btree_bload_prep_block,
xfs_btree_bload_drop_buf can hit an IO error if writing the delwri
buffer list to disk fails. In this case, we fail to release new_bp,
which means we lose a locked buffer. Fix that.
xfs: don't leak dqacct if rhashtable insertion fails
In the Linux kernel, the following vulnerability has been resolved:
xfs: don't leak dqacct if rhashtable insertion fails
LOLLM observes that xqcheck_mod_live_ino_dqtrx doesn't free the newly
allocated dqa object if rhashtable insertion fails. Fix this leak.
xfs: destroy seen inode bitmap when we fail to add a dirpath
In the Linux kernel, the following vulnerability has been resolved:
xfs: destroy seen inode bitmap when we fail to add a dirpath
LOLLM observes a memory leak in xchk_dirtree_create_path if we create
the directory path object but appending the name to the path fails.
When this happens, we don't tear down the (empty) seen inode bitmap.
This is a pretty trivial error, but let's not leave logic bombs.
Do the same for a similar bug in xrep_dirtree_create_adoption_path.