666897 - Wireshark: Array index error in ENTTEC dissector

commit 66966b531c0aff764644989a5bcda2b6ce46b51f

Author: gerald <gerald@f5534014-38df-0310-8fa8-9805f1628bb7>

Date:   Fri Dec 31 22:24:06 2010 +0000

    From FRAsse via bug 5539:

    There's a buffer overflow in ENTTEC DMX Data RLE, leading to crashes and

    potential code execution.

    From me: ep_allocate our buffers.

    git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@35318 f5534014-38df-0310-8fa8-9805f1628bb7

diff --git a/epan/dissectors/packet-enttec.c b/epan/dissectors/packet-enttec.c

index 6e6cccc..66d3e18 100644

--- a/epan/dissectors/packet-enttec.c

+++ b/epan/dissectors/packet-enttec.c

@@ -193,8 +193,8 @@ dissect_enttec_dmx_data(tvbuff_t *tvb, guint offset, proto_tree *tree)

 		"%3u: %s"

 	};

-	static guint8 dmx_data[512];

-	static guint16 dmx_data_offset[513]; /* 1 extra for last offset */

+	guint8 *dmx_data = ep_alloc(512 * sizeof(guint8));

+	guint16 *dmx_data_offset = ep_alloc(513 * sizeof(guint16)); /* 1 extra for last offset */

 	emem_strbuf_t *dmx_epstr;

 	proto_tree *hi,*si;

@@ -225,10 +225,10 @@ dissect_enttec_dmx_data(tvbuff_t *tvb, guint offset, proto_tree *tree)

 		length = 512;

 	if (type == ENTTEC_DATA_TYPE_RLE) {

-		/* uncompres the DMX data */

+		/* uncompress the DMX data */

 		ui = 0;

 		ci = 0;

-		while (ci < length) {

+		while (ci < length && ui < 512) {

 			v = tvb_get_guint8(tvb, offset+ci);

 			if (v == 0xFE) {

 				ci++;

@@ -236,7 +236,7 @@ dissect_enttec_dmx_data(tvbuff_t *tvb, guint offset, proto_tree *tree)

 				ci++;

 				v = tvb_get_guint8(tvb, offset+ci);

 				ci++;

-				for (i=0;i < count;i++) {

+				for (i=0;i < count && ui < 512;i++) {

 					dmx_data[ui] = v;

 					dmx_data_offset[ui] = ci-3;

 					ui++;