p_cansignal() returns an errno value; at some point, the check for

inter-process signalling ceased to preserve and return that value,
instead always returning EPERM.  This meant that it was possible
to "probe" the pid space for processes that were not otherwise
visible.  This change reverts that reversion.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs

1 files changed, 2 insertions, 2 deletions

diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 83182d9..3b01366 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1084,9 +1084,9 @@ kill(td, uap)
 		/* kill single process */
 		if ((p = pfind(uap->pid)) == NULL) {
 			error = ESRCH;
-		} else if (p_cansignal(td->td_proc, p, uap->signum)) {
+		} else if ((error = p_cansignal(td->td_proc, p, uap->signum))
+		    != 0) {
 			PROC_UNLOCK(p);
-			error = EPERM;
 		} else {
 			if (uap->signum)
 				psignal(p, uap->signum);