Vulnerability CVE-2023-52483
Published: 2024-02-29

Description:
In the Linux kernel, the following vulnerability has been resolved:

mctp: perform route lookups under a RCU read-side lock

Our current route lookups (mctp_route_lookup and mctp_route_lookup_null)
traverse the net's route list without the RCU read lock held. This means
the route lookup is subject to preemption, resulting in an potential
grace period expiry, and so an eventual kfree() while we still have the
route pointer.

Add the proper read-side critical section locks around the route
lookups, preventing premption and a possible parallel kfree.

The remaining net->mctp.routes accesses are already under a
rcu_read_lock, or protected by the RTNL for updates.

Based on an analysis from Sili Luo <rootlab@huawei.com>, where
introducing a delay in the route lookup could cause a UAF on
simultaneous sendmsg() and route deletion.

 References:
https://git.kernel.org/stable/c/6c52b12159049046483fdb0c411a0a1869c41a67
https://git.kernel.org/stable/c/1db0724a01b558feb1ecae551782add1951a114a
https://git.kernel.org/stable/c/2405f64a95a7a094eb24cba9bcfaffd1ea264de4
https://git.kernel.org/stable/c/5093bbfc10ab6636b32728e35813cbd79feb063c
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