Mishandling of file-system uid/gid with namespaces in shiftfs
CVE-2019-15793
6.5MEDIUM
What is CVE-2019-15793?
In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, several locations which shift ids translate user/group ids before performing operations in the lower filesystem were translating them into init_user_ns, whereas they should have been translated into the s_user_ns for the lower filesystem. This resulted in using ids other than the intended ones in the lower fs, which likely did not map into the shifts s_user_ns. A local attacker could use this to possibly bypass discretionary access control permissions.
Affected Version(s)
Shiftfs in the Linux kernel 5.3.0-11.12 < 5.3 kernel*
Shiftfs in the Linux kernel 5.0 kernel < 5.0.0-35.38