Description

In the Linux kernel, the following vulnerability has been resolved: ping: Fix potentail NULL deref for /proc/net/icmp. After commit dbca1596bbb0 ("ping: convert to RCU lookups, get rid of rwlock"), we use RCU for ping sockets, but we should use spinlock for /proc/net/icmp to avoid a potential NULL deref mentioned in the previous patch. Let's go back to using spinlock there. Note we can convert ping sockets to use hlist instead of hlist_nulls because we do not use SLAB_TYPESAFE_BY_RCU for ping sockets.

References 3

• git.kernel.org https://git.kernel.org/stable/c/176cbb6da28f36506cc60a4bec4ab8df0c16713a
• git.kernel.org https://git.kernel.org/stable/c/5a08a32e624908890aa0a2eb442bb6a7669891a8
• git.kernel.org https://git.kernel.org/stable/c/ab5fb73ffa01072b4d8031cc05801fa1cb653bee

Remediation