It should be possible to trace init if securelevel is at 0, single-user mode,

without having to peg the system at securelevel -1.

1 files changed, 16 insertions, 1 deletions

diff --git a/sys/miscfs/procfs/procfs_ctl.c b/sys/miscfs/procfs/procfs_ctl.c
index d10fe26313f..1ebe5546fe3 100644
--- a/sys/miscfs/procfs/procfs_ctl.c
+++ b/sys/miscfs/procfs/procfs_ctl.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: procfs_ctl.c,v 1.2 1996/02/27 08:03:35 niklas Exp $	*/
+/*	$OpenBSD: procfs_ctl.c,v 1.3 1996/09/26 18:06:34 bitblt Exp $	*/
 /*	$NetBSD: procfs_ctl.c,v 1.14 1996/02/09 22:40:48 christos Exp $	*/
 
 /*
@@ -124,6 +124,21 @@ procfs_control(curp, p, op)
 			return (EINVAL);
 
 		/*
+		 * it's not owned by you, or the last exec gave us
+		 * setuid/setgid privs (unless you're root),
+		 */
+		if ((t->p_cred->p_ruid != p->p_cred->p_ruid ||
+			ISSET(t->p_flag, P_SUGID)) &&
+		    (error = suser(p->p_ucred, &p->p_acflag)) != 0)
+			return (error);
+
+		/*
+		 * ...it's init, which controls the security level
+		 */
+		if (t->p_pid == 1 && securelevel > 0)
+			return (EPERM);
+
+		/*
 		 * Go ahead and set the trace flag.
 		 * Save the old parent (it's reset in
 		 *   _DETACH, and also in kern_exit.c:wait4()