جزئیات آسیب‌پذیری

In the Linux kernel, the following vulnerability has been resolved: smack: fix cred UAF in smack_file_send_sigiotask() When inspecting the credentials of another task, objective credentials (->real_cred, accessed with __task_cred()) must always be used. Accessing ->cred on a non-current task is forbidden unless that task is being created or destroyed; a task is allowed to change its own ->cred pointer with no synchronization, and changing ->cred should only affect the current syscall. smack_file_send_sigiotask() was accessing both sets of credentials: First tsk->cred, then __task_cred(tsk). Fix it, always access the objective credentials here. I have tested that this bug can lead to a KASAN-reported UAF of struct cred in smack_file_send_sigiotask(), and that this fix prevents the race.

• https://git.kernel.org/stable/c/a512366d84e134a9eefc2cc40eeb6e80e2ec162c
• https://git.kernel.org/stable/c/7c7fe043f3099d0d35002b248967f75e55345b93
• https://git.kernel.org/stable/c/f9c7b1f2b9d8f4176d2632743f51400855978ace
• https://git.kernel.org/stable/c/b5bcf3adfa27279da4401ab8f1e1a706601a92be
• https://git.kernel.org/stable/c/ed64aa505875a3b4defd504ee8e59e1949246a62
• https://git.kernel.org/stable/c/b791401bf389a1546a830d2b381ca60fe94c7870
• https://git.kernel.org/stable/c/fedc88e38ce979a720cd2de042578cb5df3dc8de