An issue was discovered in the Linux kernel 5.5 through 5.7.9, as used in Xen through 4.13.x for x86 PV guests. An attacker may be granted the I/O port permissions of an unrelated task. This occurs because tss_invalidate_io_bitmap mishandling causes a loss of synchronization between the I/O bitmaps of TSS and Xen, aka CID-cadfad870154.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15852
Reference (s):
- https://security.netapp.com/advisory/ntap-20200810-0001/
- http://xenbits.xen.org/xsa/advisory-329.html
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=cadfad870154e14f745ec845708bc17d166065f2
- https://github.com/torvalds/linux/commit/cadfad870154e14f745ec845708bc17d166065f2
- MLIST:[oss-security] 20200721 Xen Security Advisory 329 v3 (CVE-2020-15852) – Linux ioperm bitmap context switching issues