Description
In the Linux kernel, the following vulnerability has been resolved: hwmon: (pwm-fan) Stop RPM timer before freeing tach data sample_timer() rearms the RPM timer and accesses the devm-managed ctx->tachs and ctx->pulses_per_revolution arrays. The cleanup action which stops the timer is registered before those arrays are allocated. Since devres releases entries in reverse order, driver detach can free the arrays before pwm_fan_cleanup() shuts down the timer. A timer expiry in that window accesses the freed tach data. With a KASAN kernel, a test-only kprobe delayed entry to pwm_fan_cleanup() while normal sysfs unbind ran. Each of three runs reported three four-byte reads and two four-byte writes in sample_timer() after its backing devm allocations had been freed. The helper did not invoke the timer callback, cleanup actions or free functions. With the fix, three matching unbind runs completed without KASAN, BUG, WARNING, Oops or panic. Instrumentation confirmed that timer retirement completed before the first timer backing allocation was released. Split timer retirement from the power cleanup and register its devres action after the timer backing data and IRQ actions are installed. This preserves the early power rollback action while ensuring the timer is retired before its backing data is released. Use timer_shutdown_sync() because the callback can rearm itself.
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
01695410d4529e38fea6159fa9f1260c598290b0 to < 6f890d1fe8325ac8330473428b9a9d6526de1b32affected01695410d4529e38fea6159fa9f1260c598290b0 to < 7743183d8b0f6ba88738805c824a255baae674b9affected01695410d4529e38fea6159fa9f1260c598290b0 to < d073d306e587c1f35aaf9c07c42e54a3d5895d8faffected01695410d4529e38fea6159fa9f1260c598290b0 to < 1e824fdb14a187ce56697e803b02b1e86243a755affected01695410d4529e38fea6159fa9f1260c598290b0 to < a5ce3fe5335a24d0220958c6866830a6d5fa1cc0affected01695410d4529e38fea6159fa9f1260c598290b0 to < b48339b0a577783e4590a69e4cd2f2760ce33154affected01695410d4529e38fea6159fa9f1260c598290b0 to < 26d5ff79768548efb1e604bb6e8697c101e06269affected
Linux Linux
Default version status: affected
5.12affected0 to < 5.12unaffected5.15.224 to ≤ 5.15.*unaffected6.1.191 to ≤ 6.1.*unaffected6.6.160 to ≤ 6.6.*unaffected6.12.112 to ≤ 6.12.*unaffected6.18.54 to ≤ 6.18.*unaffected7.2.8 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/6f890d1fe8325ac8330473428b9a9d6526de1b32 ↗
- https://git.kernel.org/stable/c/7743183d8b0f6ba88738805c824a255baae674b9 ↗
- https://git.kernel.org/stable/c/d073d306e587c1f35aaf9c07c42e54a3d5895d8f ↗
- https://git.kernel.org/stable/c/1e824fdb14a187ce56697e803b02b1e86243a755 ↗
- https://git.kernel.org/stable/c/a5ce3fe5335a24d0220958c6866830a6d5fa1cc0 ↗
- https://git.kernel.org/stable/c/b48339b0a577783e4590a69e4cd2f2760ce33154 ↗
- https://git.kernel.org/stable/c/26d5ff79768548efb1e604bb6e8697c101e06269 ↗