Improper Update of Reference Count Affecting kernel-core package, versions *
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Test your applications- Snyk ID SNYK-RHEL9-KERNELCORE-7481745
- published 17 Jul 2024
- disclosed 12 Jul 2024
How to fix?
There is no fixed version for RHEL:9 kernel-core.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-core package and not the kernel-core package as distributed by RHEL.
See How to fix? for RHEL:9 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
cachefiles: defer exposing anon_fd until after copy_to_user() succeeds
After installing the anonymous fd, we can now see it in userland and close it. However, at this point we may not have gotten the reference count of the cache, but we will put it during colse fd, so this may cause a cache UAF.
So grab the cache reference count before fd_install(). In addition, by kernel convention, fd is taken over by the user land after fd_install(), and the kernel should not call close_fd() after that, i.e., it should call fd_install() after everything is ready, thus fd_install() is called after copy_to_user() succeeds.
References
- https://access.redhat.com/security/cve/CVE-2024-40913
- https://git.kernel.org/stable/c/4b4391e77a6bf24cba2ef1590e113d9b73b11039
- https://git.kernel.org/stable/c/b9f58cdae6a364a3270fd6b6a46e0fd4f7f8ce32
- https://git.kernel.org/stable/c/d2d3eb377a5d081bf2bed177d354a4f59b74da88
- https://git.kernel.org/stable/c/eac51d9daacd61dcc93333ff6a890cf3efc8c1c0