tcpdump: add security fix patch

From 0f95d441e4b5d7512cc5c326c8668a120e048eda Mon Sep 17 00:00:00 2001

From: Guy Harris <guy@alum.mit.edu>

Date: Wed, 22 Oct 2014 12:31:21 -0700

Subject: [PATCH] Do bounds checking when unescaping PPP.

Clean up a const issue while we're at it.

Upstream commit 0f95d441e4b5d.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>

---

 print-ppp.c | 16 ++++++++--------

 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/print-ppp.c b/print-ppp.c

index 8e098f05a953..9a983e6179cd 100644

--- a/print-ppp.c

+++ b/print-ppp.c

@@ -1351,14 +1351,15 @@ static void

 ppp_hdlc(netdissect_options *ndo,

          const u_char *p, int length)

 {

-	u_char *b, *s, *t, c;

+	u_char *b, *t, c;

+	const u_char *s;

 	int i, proto;

 	const void *se;

         if (length <= 0)

                 return;

-	b = (uint8_t *)malloc(length);

+	b = (u_char *)malloc(length);

 	if (b == NULL)

 		return;

@@ -1367,14 +1368,13 @@ ppp_hdlc(netdissect_options *ndo,

 	 * Do this so that we dont overwrite the original packet

 	 * contents.

 	 */

-	for (s = (u_char *)p, t = b, i = length; i > 0; i--) {

+	for (s = p, t = b, i = length; i > 0 && ND_TTEST(*s); i--) {

 		c = *s++;

 		if (c == 0x7d) {

-			if (i > 1) {

-				i--;

-				c = *s++ ^ 0x20;

-			} else

-				continue;

+			if (i <= 1 || !ND_TTEST(*s))

+				break;

+			i--;

+			c = *s++ ^ 0x20;

 		}

 		*t++ = c;

 	}

-- 

2.1.3