CVE-2025-38465 Information

Jul 26, 2025 cve

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 ( p: 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

Reference

https://git.kernel.org/stable/c/4b8e18af7bea92f8b7fb92d40aeae729209db250 https://git.kernel.org/stable/c/55baecb9eb90238f60a8350660d6762046ebd3bd https://git.kernel.org/stable/c/76602d8e13864524382b0687dc32cd8f19164d5a https://git.kernel.org/stable/c/9da025150b7c14a8390fc06aea314c0a4011e82c https://git.kernel.org/stable/c/ae8f160e7eb24240a2a79fc4c815c6a0d4ee16cc https://git.kernel.org/stable/c/c4ceaac5c5ba0b992ee1dc88e2a02421549e5c98 https://git.kernel.org/stable/c/cd7ff61bfffd7000143c42bbffb85eeb792466d6 https://git.kernel.org/stable/c/fd69af06101090eaa60b3d216ae715f9c0a58e5b

CNNVD-202507-3316 (Published: 2025-07-25)

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