Description
In the Linux kernel, the following vulnerability has been resolved: netlink: Fix wraparounds of sk->sk_rmem_alloc. Netlink has this pattern in some places if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) atomic_add(skb->truesize, &sk->sk_rmem_alloc); , which has the same problem fixed by commit 5a465a0da13e ("udp: Fix multiple wraparounds of sk->sk_rmem_alloc."). For example, if we set INT_MAX to SO_RCVBUFFORCE, the condition is always false as the two operands are of int. Then, a single socket can eat as many skb as possible until OOM happens, and we can see multiple wraparounds of sk->sk_rmem_alloc. Let's fix it by using atomic_add_return() and comparing the two variables as unsigned int. Before: [root@fedora ~]# ss -f netlink Recv-Q Send-Q Local Address:Port Peer Address:Port -1668710080 0 rtnl:nl_wraparound/293 * After: [root@fedora ~]# ss -f netlink Recv-Q Send-Q Local Address:Port Peer Address:Port 2147483072 0 rtnl:nl_wraparound/290 * ^ `--- INT_MAX - 576
Product status
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 9da025150b7c14a8390fc06aea314c0a4011e82c
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before c4ceaac5c5ba0b992ee1dc88e2a02421549e5c98
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before fd69af06101090eaa60b3d216ae715f9c0a58e5b
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 76602d8e13864524382b0687dc32cd8f19164d5a
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 55baecb9eb90238f60a8350660d6762046ebd3bd
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before 4b8e18af7bea92f8b7fb92d40aeae729209db250
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before cd7ff61bfffd7000143c42bbffb85eeb792466d6
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (git) before ae8f160e7eb24240a2a79fc4c815c6a0d4ee16cc
2.6.12
Any version before 2.6.12
5.4.296 (semver)
5.10.240 (semver)
5.15.189 (semver)
6.1.146 (semver)
6.6.99 (semver)
6.12.39 (semver)
6.15.7 (semver)
6.16 (original_commit_for_fix)
References
lists.debian.org/debian-lts-announce/2025/10/msg00008.html
lists.debian.org/debian-lts-announce/2025/10/msg00007.html
git.kernel.org/...c/9da025150b7c14a8390fc06aea314c0a4011e82c
git.kernel.org/...c/c4ceaac5c5ba0b992ee1dc88e2a02421549e5c98
git.kernel.org/...c/fd69af06101090eaa60b3d216ae715f9c0a58e5b
git.kernel.org/...c/76602d8e13864524382b0687dc32cd8f19164d5a
git.kernel.org/...c/55baecb9eb90238f60a8350660d6762046ebd3bd
git.kernel.org/...c/4b8e18af7bea92f8b7fb92d40aeae729209db250
git.kernel.org/...c/cd7ff61bfffd7000143c42bbffb85eeb792466d6
git.kernel.org/...c/ae8f160e7eb24240a2a79fc4c815c6a0d4ee16cc