CVE-2024-50186 Information

Description

In the Linux kernel the following vulnerability has been resolved:

net: explicitly clear the sk pointer when pf->create fails

We have recently noticed the exact same KASAN splat as in commit 6cd4a78d962b ( et: do not leave a dangling sk pointer when socket creation fails). The problem is that commit did not fully address the problem as some pf->create implementations do not use sk_common_release in their error paths.

For example we can use the same reproducer as in the above commit but changing ping to arping. arping uses AF_PACKET socket and if packet_create fails it will just sk_free the allocated sk object.

While we could chase all the pf->create implementations and make sure they NULL the freed sk object on error from the socket we can’t guarantee future protocols will not make the same mistake.

So it is easier to just explicitly NULL the sk pointer upon return from pf->create in __sock_create. We do know that pf->create always releases the allocated sk object on error so if the pointer is not NULL it is definitely dangling.

Reference

https://git.kernel.org/stable/c/daf462ff3cde6ecf22b98d9ae770232c10d28de2 https://git.kernel.org/stable/c/b7d22a79ff4e962b8af5ffe623abd1d6c179eb9f https://git.kernel.org/stable/c/563e6892e21d6ecabdf62103fc4e7b326d212334 https://git.kernel.org/stable/c/8e1b72fd74bf9da3b099d09857f4e7f114f38e12 https://git.kernel.org/stable/c/631083143315d1b192bd7d915b967b37819e88ea