An issue was discovered in the Linux kernel through 5.10.1, as used with Xen through 4.14.x. The Linux kernel PV block backend expects the kernel thread handler to reset ring->xenblkd to NULL when stopped. However, the handler may not have time to run if the frontend quickly toggles between the states connect and disconnect. As a consequence, the block backend may re-use a pointer after it was freed. A misbehaving guest can trigger a dom0 crash by continuously connecting / disconnecting a block frontend. Privilege escalation and information leaks cannot be ruled out. This only affects systems with a Linux blkback.
Platform | Package | Release Date | Advisory |
---|---|---|---|
Amazon Linux 1 | kernel | 2021-01-26 00:11 | ALAS-2021-1477 |
Amazon Linux 2 - Core | kernel | 2021-01-25 23:09 | ALAS2-2021-1588 |
Amazon Linux 2 - Kernel-5.4 Extra | kernel | 2022-01-20 19:53 | ALAS2KERNEL-5.4-2022-019 |
Score Type | Score | Vector | |
---|---|---|---|
Amazon Linux | CVSSv2 | 7.2 | AV:L/AC:L/Au:N/C:C/I:C/A:C |
Amazon Linux | CVSSv3 | 8.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
NVD | CVSSv2 | 7.2 | AV:L/AC:L/Au:N/C:C/I:C/A:C |
NVD | CVSSv3 | 8.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |