Description
In the Linux kernel, the following vulnerability has been resolved: hwrng: virtio - Fix race on data_avail and actual data The virtio rng device kicks off a new entropy request whenever the data available reaches zero. When a new request occurs at the end of a read operation, that is, when the result of that request is only needed by the next reader, then there is a race between the writing of the new data and the next reader. This is because there is no synchronisation whatsoever between the writer and the reader. Fix this by writing data_avail with smp_store_release and reading it with smp_load_acquire when we first enter read. The subsequent reads are safe because they're either protected by the first load acquire, or by the completion mechanism. Also remove the redundant zeroing of data_idx in random_recv_done (data_idx must already be zero at this point) and data_avail in request_entropy (ditto).
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
f7f510ec195781c857ab76366a3e1c59e1caae42 to < 241ef15776a7c8505008db689175b320d345ecd3affectedf7f510ec195781c857ab76366a3e1c59e1caae42 to < a43bcb0b661cbbf3ad797d2aee6b6fd06b8fc69daffectedf7f510ec195781c857ab76366a3e1c59e1caae42 to < 77471e4912d3960dafe141e268c44be8024fe4dcaffectedf7f510ec195781c857ab76366a3e1c59e1caae42 to < c76d991b6f01a5d931e7053a73bc9524975a5215affectedf7f510ec195781c857ab76366a3e1c59e1caae42 to < 22c30022cde6e2c88612b3a499223cfa912f1bc7affectedf7f510ec195781c857ab76366a3e1c59e1caae42 to < 318657b4c2077289659f1cd9e2a34f6a3b208e3eaffectedf7f510ec195781c857ab76366a3e1c59e1caae42 to < 2fc91f156b3f3446a1bce80cf4adedcbf41271c2affectedf7f510ec195781c857ab76366a3e1c59e1caae42 to < ac52578d6e8d300dd50f790f29a24169b1edd26caffected
Linux Linux
Default version status: affected
2.6.26affected0 to < 2.6.26unaffected4.19.291 to ≤ 4.19.*unaffected5.4.251 to ≤ 5.4.*unaffected5.10.188 to ≤ 5.10.*unaffected5.15.121 to ≤ 5.15.*unaffected6.1.39 to ≤ 6.1.*unaffected6.3.13 to ≤ 6.3.*unaffected6.4.4 to ≤ 6.4.*unaffected6.5 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/241ef15776a7c8505008db689175b320d345ecd3 ↗
- https://git.kernel.org/stable/c/a43bcb0b661cbbf3ad797d2aee6b6fd06b8fc69d ↗
- https://git.kernel.org/stable/c/77471e4912d3960dafe141e268c44be8024fe4dc ↗
- https://git.kernel.org/stable/c/c76d991b6f01a5d931e7053a73bc9524975a5215 ↗
- https://git.kernel.org/stable/c/22c30022cde6e2c88612b3a499223cfa912f1bc7 ↗
- https://git.kernel.org/stable/c/318657b4c2077289659f1cd9e2a34f6a3b208e3e ↗
- https://git.kernel.org/stable/c/2fc91f156b3f3446a1bce80cf4adedcbf41271c2 ↗
- https://git.kernel.org/stable/c/ac52578d6e8d300dd50f790f29a24169b1edd26c ↗