In the Linux kernel, the following vulnerability has been resolved:
ipc: fix to protect IPCS lookups using RCU
syzbot reported that it discovered a use-after-free vulnerability, 0
idr_for_each() is protected by rwsem, but this is not enough. If it is not protected by RCU read-critical region, when idr_for_each() calls radix_tree_node_free() through call_rcu() to free the radix_tree_node structure, the node will be freed immediately, and when reading the next node in radix_tree_for_each_slot(), the already freed memory may be read.
Therefore, we need to add code to make sure that idr_for_each() is protected within the RCU read-critical region when we call it in shm_destroy_orphaned().
| Software | From | Fixed in |
|---|---|---|
| linux / linux_kernel | 3.1 | 5.4.295 |
| linux / linux_kernel | 5.5 | 5.10.239 |
| linux / linux_kernel | 5.11 | 5.15.186 |
| linux / linux_kernel | 5.16 | 6.1.142 |
| linux / linux_kernel | 6.2 | 6.6.95 |
| linux / linux_kernel | 6.7 | 6.12.35 |
| linux / linux_kernel | 6.13 | 6.15.4 |
| debian / debian_linux | 11.0 | 11.0.x |