From aedb60a67c10a0861af179725d060765262ba0fb Mon Sep 17 00:00:00 2001 From: Serge Hallyn Date: Fri, 29 Feb 2008 15:14:57 +0000 Subject: file capabilities: remove cap_task_kill() The original justification for cap_task_kill() was as follows: check_kill_permission() does appropriate uid equivalence checks. However with file capabilities it becomes possible for an unprivileged user to execute a file with file capabilities resulting in a more privileged task with the same uid. However now that cap_task_kill() always returns 0 (permission granted) when p->uid==current->uid, the whole hook is worthless, and only likely to create more subtle problems in the corner cases where it might still be called but return -EPERM. Those cases are basically when uids are different but euid/suid is equivalent as per the check in check_kill_permission(). One example of a still-broken application is 'at' for non-root users. This patch removes cap_task_kill(). Signed-off-by: Serge Hallyn Acked-by: Andrew G. Morgan Earlier-version-tested-by: Luiz Fernando N. Capitulino Acked-by: Casey Schaufler Signed-off-by: Linus Torvalds --- security/capability.c | 1 - 1 file changed, 1 deletion(-) (limited to 'security/capability.c') diff --git a/security/capability.c b/security/capability.c index 9e99f36a8b5..2c6e06d18fa 100644 --- a/security/capability.c +++ b/security/capability.c @@ -40,7 +40,6 @@ static struct security_operations capability_ops = { .inode_need_killpriv = cap_inode_need_killpriv, .inode_killpriv = cap_inode_killpriv, - .task_kill = cap_task_kill, .task_setscheduler = cap_task_setscheduler, .task_setioprio = cap_task_setioprio, .task_setnice = cap_task_setnice, -- cgit v1.2.3