usb, signal, security: only pass the cred, not the secid, to kill_pid_info_as_cred and security_task_kill

commit d178bc3a708f39cbfefc3fab37032d3f2511b4ec ("user namespace: usb:
 make usb urbs user namespace aware (v2)") changed kill_pid_info_as_uid
to kill_pid_info_as_cred, saving and passing a cred structure instead of
uids.  Since the secid can be obtained from the cred, drop the secid fields
from the usb_dev_state and async structures, and drop the secid argument to
kill_pid_info_as_cred.  Replace the secid argument to security_task_kill
with the cred.  Update SELinux, Smack, and AppArmor to use the cred, which
avoids the need for Smack and AppArmor to use a secid at all in this hook.
Further changes to Smack might still be required to take full advantage of
this change, since it should now be possible to perform capability
checking based on the supplied cred.  The changes to Smack and AppArmor
have only been compile-tested.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.morris@microsoft.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index c6e4c83dc090..b033292f4beb 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -770,7 +770,7 @@ static int check_kill_permission(int sig, struct siginfo *info,
 		}
 	}
 
-	return security_task_kill(t, info, sig, 0);
+	return security_task_kill(t, info, sig, NULL);
 }
 
 /**
@@ -1361,7 +1361,7 @@ static int kill_as_cred_perm(const struct cred *cred,
 
 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
 int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
-			 const struct cred *cred, u32 secid)
+			 const struct cred *cred)
 {
 	int ret = -EINVAL;
 	struct task_struct *p;
@@ -1380,7 +1380,7 @@ int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
 		ret = -EPERM;
 		goto out_unlock;
 	}
-	ret = security_task_kill(p, info, sig, secid);
+	ret = security_task_kill(p, info, sig, cred);
 	if (ret)
 		goto out_unlock;