CVE-2019-25044

The block subsystem in the Linux kernel before 5.2 has a use-after-free that can lead to arbitrary code execution in the kernel context and privilege escalation, aka CID-c3e2219216c9. This is related to blk_mq_free_rqs and blk_cleanup_queue.

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 Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.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://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.2
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c3e2219216c92919a6bd1711f340f5faa98695e6
• https://security.netapp.com/advisory/ntap-20210629-0006/
• https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-blk_mq_free_rqs
• https://syzkaller.appspot.com/bug?id=36fe241584203cf394d44560a42e3430434f1213
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.2
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c3e2219216c92919a6bd1711f340f5faa98695e6
• https://security.netapp.com/advisory/ntap-20210629-0006/
• https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-blk_mq_free_rqs
• https://syzkaller.appspot.com/bug?id=36fe241584203cf394d44560a42e3430434f1213