Description
In the Linux kernel, the following vulnerability has been resolved: KEYS: Fix add_key() race with keyring restriction __key_create_or_update() snapshots keyring->restrict_link before taking the destination keyring's semaphore. keyring_restrict() installs a restriction while holding that semaphore. This allows a writer to observe no restriction, wait for the keyring owner to install a reject-all restriction and return successfully, and then link a key using the stale NULL snapshot. The writer only needs write permission on the destination keyring. Move the restrict_link read after __key_link_lock() and __key_link_begin(). The read and the subsequent restriction check are then serialized with restriction installation by keyring->sem. The race was reproduced on v7.2.8 in 19 executions where restriction installation returned before the link completed. All 19 linked the key despite the reject-all restriction. With this change, 312 executions reached the same ordering and every add_key() call failed with -EPERM. The issue was found by manual concurrency analysis assisted by AI-based analysis and independently verified with a QEMU reproducer and kernel instrumentation.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c to < 24806fc9bca28fa1433bf938d1424dcb45d80e50affected5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c to < 9a5c2700336878465a630804a2d21864f22eca9caffected5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c to < b3e404550dc2b7f3d4bb64b1da8005a1fa9a798daffected5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c to < 305f1828b871dd46bf41addeb6f11d2c162dcb25affected5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c to < f99399b48e3edd6851fac34cd329bab9f1f33bafaffected5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c to < 11516a0c402a6c1fa52254aa70d8d65fb921e59eaffected5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c to < da0b595d8e6e2dd798f6e34e09dc51a13b888514affected5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c to < dd3ea3fcba7c75493760cdbccd35f029597e8d5eaffected
Linux Linux
Default version status: affected
4.7affected0 to < 4.7unaffected5.10.273 to ≤ 5.10.*unaffected5.15.224 to ≤ 5.15.*unaffected6.1.191 to ≤ 6.1.*unaffected6.6.160 to ≤ 6.6.*unaffected6.12.113 to ≤ 6.12.*unaffected6.18.57 to ≤ 6.18.*unaffected7.2.11 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/24806fc9bca28fa1433bf938d1424dcb45d80e50 ↗
- https://git.kernel.org/stable/c/9a5c2700336878465a630804a2d21864f22eca9c ↗
- https://git.kernel.org/stable/c/b3e404550dc2b7f3d4bb64b1da8005a1fa9a798d ↗
- https://git.kernel.org/stable/c/305f1828b871dd46bf41addeb6f11d2c162dcb25 ↗
- https://git.kernel.org/stable/c/f99399b48e3edd6851fac34cd329bab9f1f33baf ↗
- https://git.kernel.org/stable/c/11516a0c402a6c1fa52254aa70d8d65fb921e59e ↗
- https://git.kernel.org/stable/c/da0b595d8e6e2dd798f6e34e09dc51a13b888514 ↗
- https://git.kernel.org/stable/c/dd3ea3fcba7c75493760cdbccd35f029597e8d5e ↗