Vulnerability CVE-2021-47259
Published: 2024-05-21

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

NFS: Fix use-after-free in nfs4_init_client()

KASAN reports a use-after-free when attempting to mount two different
exports through two different NICs that belong to the same server.

Olga was able to hit this with kernels starting somewhere between 5.7
and 5.10, but I traced the patch that introduced the clear_bit() call to
4.13. So something must have changed in the refcounting of the clp
pointer to make this call to nfs_put_client() the very last one.

 References:
https://git.kernel.org/stable/c/c7eab9e2d7b4e983ce280276fb920af649955897
https://git.kernel.org/stable/c/42c10b0db064e45f5c5ae7019bbf2168ffab766c
https://git.kernel.org/stable/c/3e3c7ebbfac152d08be75c92802a64a1f6471a15
https://git.kernel.org/stable/c/c3b6cf64dfe4ef96e7341508d50d6998da7062c7
https://git.kernel.org/stable/c/72651c6579a25317a90536181d311c663d0329ab
https://git.kernel.org/stable/c/476bdb04c501fc64bf3b8464ffddefc8dbe01577
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