From: Venkatesh Srinivas <me@endeavour.zapto.org>
Date: Sun, 27 Nov 2011 17:16:45 +0000 (-0800)
Subject: kernel -- ktrace: Fix possible one-word stack leak to userspace.
X-Git-Tag: v3.0.0~549
X-Git-Url: http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/59d38b6efa9c927b3bef7d1549de7a5248fbf3fd

kernel -- ktrace: Fix possible one-word stack leak to userspace.

From OpenBSD kern_ktrace.c 1.55, via Loganaden Velvindron.
---

diff --git a/sys/kern/kern_ktrace.c b/sys/kern/kern_ktrace.c
index 6ccd577..eda9d46 100644
--- a/sys/kern/kern_ktrace.c
+++ b/sys/kern/kern_ktrace.c
@@ -128,8 +128,11 @@ ktrsysret(struct lwp *lp, int code, int error, register_t retval)
 	kth = ktrgetheader(KTR_SYSRET);
 	ktp.ktr_code = code;
 	ktp.ktr_error = error;
-	ktp.ktr_retval = retval;		/* what about val2 ? */
-
+	if (error == 0)
+		ktp.ktr_retval = retval;		/* what about val2 ? */
+	else
+		ktp.ktr_retval = 0;
+ 
 	kth->ktr_buf = (caddr_t)&ktp;
 	kth->ktr_len = sizeof(struct ktr_sysret);