In the Linux kernel, the following vulnerability has been resolved: nfsd: fix heap overflow in NFSv4.0 LOCK replay cache The NFSv4.0 replay cache uses a fixed 112-byte inline buffer (rp_ibuf[NFSD4_REPLAY_ISIZE]) to store encoded operation responses. This size was calculated based on OPEN responses and does not account for LOCK denied responses, which include the conflicting lock owner as a variable-length field up to 1024 bytes (NFS4_OPAQUE_LIMIT). When a LOCK operation is denied due to a conflict with an existing lock that has a large owner, nfsd4_encode_operation() copies the full encoded response into the undersized replay buffer via read_bytes_from_xdr_buf() with no bounds check. This results in a slab-out-of-bounds write of up to 944 bytes past the end of the buffer, corrupting adjacent heap memory. This can be triggered remotely by an unauthenticated attacker with two cooperating NFSv4.0 clients: one sets a lock with a large owner string, then the other requests a conflicting lock to provoke the denial. We could fix this by increasing NFSD4_REPLAY_ISIZE to allow for a full opaque, but that would increase the size of every stateowner, when most lockowners are not that large. Instead, fix this by checking the encoded response length against NFSD4_REPLAY_ISIZE before copying into the replay buffer. If the response is too large, set rp_buflen to 0 to skip caching the replay payload. The status is still cached, and the client already received the correct response on the original request.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
| Attack Vector | NETWORK |
|---|---|
| Attack Complexity | LOW |
| Privileges Required | NONE |
| User Interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality Impact | HIGH |
| Integrity Impact | HIGH |
| Availability Impact | HIGH |
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Type: Secondary
Exploitability Score: 3.9
Impact Score: 5.9
| Source | Type | Description |
|---|---|---|
| [email protected] | Primary |
en
CWE-787
|
| 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary |
en
CWE-787
|
| Vendor | Product | Version | Update | Type |
|---|---|---|---|---|
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bdd7d7500> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bdd7d5bc0> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bde282080> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bdd7d4880> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bdd7d5180> | Operating System |
| linux | linux_kernel | * | <built-in method update of dict object at 0x702bdd7d4f40> | Operating System |
| linux | linux_kernel | 2.6.12 | <built-in method update of dict object at 0x702ba6ed96c0> | Operating System |
| linux | linux_kernel | 2.6.12 | <built-in method update of dict object at 0x702b83f2cf80> | Operating System |
| linux | linux_kernel | 2.6.12 | <built-in method update of dict object at 0x702bdd7d6440> | Operating System |
| linux | linux_kernel | 2.6.12 | <built-in method update of dict object at 0x702bdd7d51c0> | Operating System |
| linux | linux_kernel | 2.6.12 | <built-in method update of dict object at 0x702ba6ed9d40> | Operating System |
| linux | linux_kernel | 7.0 | <built-in method update of dict object at 0x702bdd7d6340> | Operating System |
| linux | linux_kernel | 7.0 | <built-in method update of dict object at 0x702bdd7d7100> | Operating System |
| linux | linux_kernel | 7.0 | <built-in method update of dict object at 0x702bdd7d6800> | Operating System |
| linux | linux_kernel | 7.0 | <built-in method update of dict object at 0x702bdd7d63c0> | Operating System |
| Vulnerable | CPE |
|---|---|
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* |
| Yes | cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* |