CVE-2019-19813

In the Linux kernel 5.0.21, mounting a crafted btrfs filesystem image, performing some operations, and then making a syncfs system call can lead to a use-after-free in __mutex_lock in kernel/locking/mutex.c. This is related to mutex_can_spin_on_owner in kernel/locking/mutex.c, __btrfs_qgroup_free_meta in fs/btrfs/qgroup.c, and btrfs_insert_delayed_items in fs/btrfs/delayed-inode.c.

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 Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.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://github.com/bobfuzzer/CVE/tree/master/CVE-2019-19813
• https://lists.debian.org/debian-lts-announce/2020/09/msg00025.html
• https://lists.debian.org/debian-lts-announce/2021/03/msg00010.html
• https://security.netapp.com/advisory/ntap-20200103-0001/
• https://usn.ubuntu.com/4414-1/
• https://github.com/bobfuzzer/CVE/tree/master/CVE-2019-19813
• https://lists.debian.org/debian-lts-announce/2020/09/msg00025.html
• https://lists.debian.org/debian-lts-announce/2021/03/msg00010.html
• https://security.netapp.com/advisory/ntap-20200103-0001/
• https://usn.ubuntu.com/4414-1/