Description
In the Linux kernel, the following vulnerability has been resolved: ipv4: igmp: Fix potential UAF in igmp_gq_start_timer() A race condition exists between device teardown (inetdev_destroy) and incoming IGMP query processing (igmp_rcv), leading to a Use-After-Free in the IGMP timer callback. During device destruction, inetdev_destroy() drops the primary reference to in_device, which can drop its refcount to 0. The actual freeing of in_device memory is deferred via RCU (using call_rcu()). Concurrently, igmp_rcv() runs under RCU read lock and obtains the in_device pointer. Because the memory is RCU-protected, CPU-0 can safely dereference in_device even if its refcount has hit 0. However, if CPU-0 calls igmp_gq_start_timer() and re-arms the timer, it attempts to acquire a reference using in_dev_hold(). This increments the refcount from 0 to 1, triggering a "refcount_t: addition on 0" warning. Since the in_device memory is still scheduled to be freed after the RCU grace period (as the free callback does not check the refcount again), the device is freed while the timer is still armed. When the timer expires, it accesses the freed memory, causing a kernel panic. Fix this by using refcount_inc_not_zero() (via a new helper in_dev_hold_safe()) to prevent acquiring a reference if the device is already being destroyed. If the refcount is 0, we do not arm the timer. A similar issue in IPv6 MLD is fixed in a subsequent patch.
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
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 7265c747eec415ca3109a6a14a419f7ae433b780affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < d107b4c4f8274763b7ea5ab05d45cef78e4b81baaffected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 74b301f7f197517016befb5f5dfab01f7bc64be5affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 40a1e998cb266ed4cb529a0bb4fee2b0ba732702affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 165258303357e54b75fc19b341ae2a2b7c9e3910affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 75e984fe0cb9e7fbde0c8ee838c61ce8573d3ea3affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 8d4394ffa40508e0de72f464af351f6ca6a6cdc3affected1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 7b19c0f81ed1fdaec6bc522569be367199a9edf3affected
Linux Linux
Default version status: affected
2.6.12affected0 to < 2.6.12unaffected5.10.269 to ≤ 5.10.*unaffected5.15.220 to ≤ 5.15.*unaffected6.1.187 to ≤ 6.1.*unaffected6.6.145 to ≤ 6.6.*unaffected6.12.97 to ≤ 6.12.*unaffected6.18.40 to ≤ 6.18.*unaffected7.1.5 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/7265c747eec415ca3109a6a14a419f7ae433b780 ↗
- https://git.kernel.org/stable/c/d107b4c4f8274763b7ea5ab05d45cef78e4b81ba ↗
- https://git.kernel.org/stable/c/74b301f7f197517016befb5f5dfab01f7bc64be5 ↗
- https://git.kernel.org/stable/c/40a1e998cb266ed4cb529a0bb4fee2b0ba732702 ↗
- https://git.kernel.org/stable/c/165258303357e54b75fc19b341ae2a2b7c9e3910 ↗
- https://git.kernel.org/stable/c/75e984fe0cb9e7fbde0c8ee838c61ce8573d3ea3 ↗
- https://git.kernel.org/stable/c/8d4394ffa40508e0de72f464af351f6ca6a6cdc3 ↗
- https://git.kernel.org/stable/c/7b19c0f81ed1fdaec6bc522569be367199a9edf3 ↗