Yama: Check for pid death before checking ancestry
commit9474f4e7cd
upstream. It's possible that a pid has died before we take the rcu lock, in which case we can't walk the ancestry list as it may be detached. Instead, check for death first before doing the walk. Reported-by: syzbot+a9ac39bf55329e206219@syzkaller.appspotmail.com Fixes:2d514487fa
("security: Yama LSM") Cc: stable@vger.kernel.org Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: James Morris <james.morris@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
f97fd2926e
commit
41c13bfcc4
|
@ -373,7 +373,9 @@ static int yama_ptrace_access_check(struct task_struct *child,
|
|||
break;
|
||||
case YAMA_SCOPE_RELATIONAL:
|
||||
rcu_read_lock();
|
||||
if (!task_is_descendant(current, child) &&
|
||||
if (!pid_alive(child))
|
||||
rc = -EPERM;
|
||||
if (!rc && !task_is_descendant(current, child) &&
|
||||
!ptracer_exception_found(current, child) &&
|
||||
!ns_capable(__task_cred(child)->user_ns, CAP_SYS_PTRACE))
|
||||
rc = -EPERM;
|
||||
|
|
Loading…
Reference in New Issue