CVE-2023-0240

There is a logic error in io_urings implementation which can be used to trigger a use-after-free vulnerability leading to privilege escalation.

In the io_prep_async_work function the assumption that the last io_grab_identity call cannot return false is not true, and in this case the function will use the init_cred or the previous linked requests identity to do operations instead of using the current identity. This can lead to reference counting issues causing use-after-free. We recommend upgrading past version 5.10.161.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/io_uring?h=linux-5.10.y\u0026id=788d0824269bef539fe31a785b1517882eafed93
• https://github.com/gregkh/linux/commit/1e6fa5216a0e59ef02e8b6b40d553238a3b81d49
• https://kernel.dance/#788d0824269bef539fe31a785b1517882eafed93
• https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/io_uring?h=linux-5.10.y\u0026id=788d0824269bef539fe31a785b1517882eafed93
• https://github.com/gregkh/linux/commit/1e6fa5216a0e59ef02e8b6b40d553238a3b81d49
• https://kernel.dance/#788d0824269bef539fe31a785b1517882eafed93
• https://security.netapp.com/advisory/ntap-20230316-0001/