CVE-2020-10690

There is a use-after-free in kernel versions before 5.5 due to a race condition between the release of ptp_clock and cdev while resource deallocation. When a (high privileged) process allocates a ptp device file (like /dev/ptpX) and voluntarily goes to sleep. During this time if the underlying device is removed, it can cause an exploitable condition as the process wakes up to terminate and clean all attached files. The system crashes due to the cdev structure being invalid (as already freed) which is pointed to by the inode.

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 Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.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

• http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00022.html
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-10690
• https://lists.debian.org/debian-lts-announce/2020/06/msg00011.html
• https://lists.debian.org/debian-lts-announce/2020/06/msg00013.html
• https://security.netapp.com/advisory/ntap-20200608-0001/
• https://usn.ubuntu.com/4419-1/
• http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00022.html
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-10690
• https://lists.debian.org/debian-lts-announce/2020/06/msg00011.html
• https://lists.debian.org/debian-lts-announce/2020/06/msg00013.html
• https://security.netapp.com/advisory/ntap-20200608-0001/
• https://usn.ubuntu.com/4419-1/