CVE-2024-42318 — landlock: Don't lose track of restrictions on cred_transfer
In the Linux kernel, the following vulnerability has been resolved: landlock: Don't lose track of restrictions on cred_transfer When a process' cred struct is replaced, this _…
Published: 2024-08-17 · CVSS: 8.8 · CVSS 3.1
In the Linux kernel, the following vulnerability has been resolved: landlock: Don't lose track of restrictions on cred_transfer When a process' cred struct is replaced, this _almost_ always invokes the cred_prepare LSM hook; but in one special case (when KEYCTL_SESSION_TO_PARENT updates the parent's credentials), the cred_transfer LSM hook is used instead. Landlock only implements the cred_prepare hook, not cred_transfer, so KEYCTL_SESSION_TO_PARENT causes all information on Landlock restrictions to be lost. This basically means that a process with the ability to use the fork() and keyctl() syscalls can get rid of all Landlock restrictions on itself. Fix it by adding a cred_transfer hook that does the same thing as the existing cred_prepare hook. (Implemented by having hook_cred_prepare() call hook_cred_transfer() so that the two functions are less likely to accidentally diverge in the future.)
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7