CVE-2024-57982

Severity CVSS v4.0:
Pending analysis
Type:
CWE-125 Out-of-bounds Read
Publication date:
27/02/2025
Last modified:
07/03/2025

Description

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> xfrm: state: fix out-of-bounds read during lookup<br /> <br /> lookup and resize can run in parallel.<br /> <br /> The xfrm_state_hash_generation seqlock ensures a retry, but the hash<br /> functions can observe a hmask value that is too large for the new hlist<br /> array.<br /> <br /> rehash does:<br /> rcu_assign_pointer(net-&gt;xfrm.state_bydst, ndst) [..]<br /> net-&gt;xfrm.state_hmask = nhashmask;<br /> <br /> While state lookup does:<br /> h = xfrm_dst_hash(net, daddr, saddr, tmpl-&gt;reqid, encap_family);<br /> hlist_for_each_entry_rcu(x, net-&gt;xfrm.state_bydst + h, bydst) {<br /> <br /> This is only safe in case the update to state_bydst is larger than<br /> net-&gt;xfrm.xfrm_state_hmask (or if the lookup function gets<br /> serialized via state spinlock again).<br /> <br /> Fix this by prefetching state_hmask and the associated pointers.<br /> The xfrm_state_hash_generation seqlock retry will ensure that the pointer<br /> and the hmask will be consistent.<br /> <br /> The existing helpers, like xfrm_dst_hash(), are now unsafe for RCU side,<br /> add lockdep assertions to document that they are only safe for insert<br /> side.<br /> <br /> xfrm_state_lookup_byaddr() uses the spinlock rather than RCU.<br /> AFAICS this is an oversight from back when state lookup was converted to<br /> RCU, this lock should be replaced with RCU in a future patch.

Vulnerable products and versions

CPE From Up to
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* 4.9 (including) 6.12.13 (excluding)
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* 6.13 (including) 6.13.2 (excluding)