CVE - CVE-2024-54680

CVE-ID
CVE-2024-54680	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix TCP timers deadlock after rmmod Commit ef7134c7fc48 ("smb: client: Fix use-after-free of network namespace.") fixed a netns UAF by manually enabled socket refcounting (sk->sk_net_refcnt=1 and sock_inuse_add(net, 1)). The reason the patch worked for that bug was because we now hold references to the netns (get_net_track() gets a ref internally) and they're properly released (internally, on __sk_destruct()), but only because sk->sk_net_refcnt was set. Problem: (this happens regardless of CONFIG_NET_NS_REFCNT_TRACKER and regardless if init_net or other) Setting sk->sk_net_refcnt=1 manually and after socket creation is not only out of cifs scope, but also technically wrong -- it's set conditionally based on user (=1) vs kernel (=0) sockets. And net/ implementations seem to base their user vs kernel space operations on it. e.g. upon TCP socket close, the TCP timers are not cleared because sk->sk_net_refcnt=1: (cf. commit 151c9c724d05 ("tcp: properly terminate timers for kernel sockets")) net/ipv4/tcp.c: void tcp_close(struct sock *sk, long timeout) { lock_sock(sk); __tcp_close(sk, timeout); release_sock(sk); if (!sk->sk_net_refcnt) inet_csk_clear_xmit_timers_sync(sk); sock_put(sk); } Which will throw a lockdep warning and then, as expected, deadlock on tcp_write_timer(). A way to reproduce this is by running the reproducer from ef7134c7fc48 and then 'rmmod cifs'. A few seconds later, the deadlock/lockdep warning shows up. Fix: We shouldn't mess with socket internals ourselves, so do not set sk_net_refcnt manually. Also change __sock_create() to sock_create_kern() for explicitness. As for non-init_net network namespaces, we deal with it the best way we can -- hold an extra netns reference for server->ssocket and drop it when it's released. This ensures that the netns still exists whenever we need to create/destroy server->ssocket, but is not directly tied to it.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/127e907e11ccd54b59bb78fc22c43ccb76c71079 URL:https://git.kernel.org/stable/c/127e907e11ccd54b59bb78fc22c43ccb76c71079 MISC:https://git.kernel.org/stable/c/906807c734ed219dcb2e7bbfde5c4168ed72a3d0 URL:https://git.kernel.org/stable/c/906807c734ed219dcb2e7bbfde5c4168ed72a3d0 MISC:https://git.kernel.org/stable/c/e9f2517a3e18a54a3943c098d2226b245d488801 URL:https://git.kernel.org/stable/c/e9f2517a3e18a54a3943c098d2226b245d488801
Assigning CNA
kernel.org
Date Record Created
20250111	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20250111)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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