Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: libceph: fix two unsafe bare decodes in decode_lockers() decode_lockers() in cls_lock_client.c contains two bare decode operations that allow a malicious or compromised OSD to trigger slab-out-of-bounds reads: 1. ceph_decode_32(p) at the num_lockers field has no preceding bounds check. ceph_start_decoding() accepts struct_len=0 as valid -- the internal ceph_decode_need(p, end, 0, bad) always passes -- so when an OSD sends struct_len=0, ceph_start_decoding() returns success with p == end. The immediately following bare ceph_decode_32(p) then reads 4 bytes past the validated buffer boundary. The garbage value is passed directly to kzalloc_objs() as the locker count. The sibling function decode_watchers() in osd_client.c already uses ceph_decode_32_safe() after its own ceph_start_decoding() call. decode_lockers() was the only site using the bare variant. 2. ceph_decode_8(p) after the decode_locker() loop has no preceding bounds check. If an OSD crafts num_lockers such that the loop advances p exactly to end, the subsequent bare ceph_decode_8(p) reads one byte past the validated buffer boundary. The result is passed directly into *type, which is used as a lock type discriminator by callers, giving an OSD-controlled one-byte OOB read with direct influence over the lock type field. Fix both by replacing bare operations with their safe variants: ceph_decode_32(p) -> ceph_decode_32_safe(p, end, *num_lockers, err_inval) ceph_decode_8(p) -> ceph_decode_8_safe(p, end, *type, err_free_lockers) The goto targets differ intentionally: err_inval: is a new label returning -EINVAL directly. It is used for the pre-allocation failure path where *lockers is not yet allocated and must not be passed to ceph_free_lockers(). err_free_lockers: is the existing label. It is used for the post-allocation failure path where *lockers is allocated and must be freed. ret is set to -EINVAL before ceph_decode_8_safe() so that err_free_lockers returns the correct error code on bounds violation. Without this, err_free_lockers would return a stale ret value (0 from the successful decode_locker() loop), silently swallowing the error. -EINVAL is correct for both failure paths. The data received from the OSD is structurally malformed. -ENOMEM would misrepresent the failure class to callers and to stable@ backporters triaging error paths. Attacker model: a malicious or compromised OSD in a multi-tenant Ceph deployment can trigger this against any kernel client that issues the lock.get_info class method (e.g. during RBD exclusive lock acquisition). [ idryomov: trim changelog, formatting ]
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected d4ed4a530562881cc5225050e42d96034f405aae before c8ade01170a27d8ede0d761c255268af81e417f8; affected d4ed4a530562881cc5225050e42d96034f405aae before 001835c599899ef1bd3506a815110a6374451554; affected d4ed4a530562881cc5225050e42d96034f405aae before 7c422364acd93d7da1dfc27d6b54635a269653a1; affected d4ed4a530562881cc5225050e42d96034f405aae before 02430f6f729b297e803d0605871f0a670b4eafd6; affected d4ed4a530562881cc5225050e42d96034f405aae before 57ba829804fe6d34bbac3b826c4b15c1caa54862; affected d4ed4a530562881cc5225050e42d96034f405aae before 89df5d71f83f8e2781286798fd8ae5e42cf5f1a7; affected d4ed4a530562881cc5225050e42d96034f405aae before a54be593d0b749161b08a1e56189b2cb9114267a; affected d4ed4a530562881cc5225050e42d96034f405aae before a109a556115271ca7896dcda7b4b7e45e156c227 |
| Linux / Linux | affected 4.9; unaffected 0 before 4.9; unaffected 5.10.266 through 5.10.*; unaffected 5.15.217 through 5.15.*; unaffected 6.1.184 through 6.1.*; unaffected 6.6.153 through 6.6.*; unaffected 6.12.105 through 6.12.*; unaffected 6.18.46 through 6.18.*; unaffected 7.1.6 through 7.1.*; unaffected 7.2 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/c8ade01170a27d8ede0d761c255268af81e417f8
- https://git.kernel.org/stable/c/001835c599899ef1bd3506a815110a6374451554
- https://git.kernel.org/stable/c/7c422364acd93d7da1dfc27d6b54635a269653a1
- https://git.kernel.org/stable/c/02430f6f729b297e803d0605871f0a670b4eafd6
- https://git.kernel.org/stable/c/57ba829804fe6d34bbac3b826c4b15c1caa54862
- https://git.kernel.org/stable/c/89df5d71f83f8e2781286798fd8ae5e42cf5f1a7
- https://git.kernel.org/stable/c/a54be593d0b749161b08a1e56189b2cb9114267a
- https://git.kernel.org/stable/c/a109a556115271ca7896dcda7b4b7e45e156c227
ADP enrichment
No English description supplied.
No references supplied.