Bug 2424953 (CVE-2023-53987)

Summary: CVE-2023-53987 kernel: Linux kernel: Denial of Service via NULL dereference in ping socket handling
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel. A local attacker could exploit a potential NULL dereference vulnerability in the `ping` socket handling when accessing `/proc/net/icmp`. This issue arises from an incorrect use of Read-Copy Update (RCU) instead of a spinlock. Successful exploitation of this flaw could lead to a system crash, resulting in a Denial of Service (DoS).
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Description OSIDB Bzimport 2025-12-24 12:03:17 UTC
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.