File gstreamer-flxdec-write-bounds-checking.patch of Package gstreamer-0_10-plugins-good
From ec66c7c584f0b41c98e93758d9b53bd6dd582df2 Mon Sep 17 00:00:00 2001
From: Matthew Waters <matthew@centricular.com>
Date: Tue, 22 Nov 2016 19:05:00 +1100
Subject: [PATCH] flxdec: add some write bounds checking
Without checking the bounds of the frame we are writing into, we can
write off the end of the destination buffer.
https://scarybeastsecurity.blogspot.dk/2016/11/0day-exploit-advancing-exploitation.html
https://bugzilla.gnome.org/show_bug.cgi?id=774834
Rebased by Mike Gorse <mgorse@suse.com>
---
diff -urp gst-plugins-good-0.10.31.orig/gst/flx/gstflxdec.c gst-plugins-good-0.10.31/gst/flx/gstflxdec.c
--- gst-plugins-good-0.10.31.orig/gst/flx/gstflxdec.c 2011-12-30 08:59:09.000000000 -0500
+++ gst-plugins-good-0.10.31/gst/flx/gstflxdec.c 2016-12-19 15:57:23.561699521 -0500
@@ -70,9 +70,9 @@ static gboolean gst_flxdec_src_event_han
static gboolean gst_flxdec_sink_event_handler (GstPad * pad, GstEvent * event);
static void flx_decode_color (GstFlxDec *, guchar *, guchar *, gint);
-static void flx_decode_brun (GstFlxDec *, guchar *, guchar *);
-static void flx_decode_delta_fli (GstFlxDec *, guchar *, guchar *);
-static void flx_decode_delta_flc (GstFlxDec *, guchar *, guchar *);
+static gboolean flx_decode_brun (GstFlxDec *, guchar *, guchar *);
+static gboolean flx_decode_delta_fli (GstFlxDec *, guchar *, guchar *);
+static gboolean flx_decode_delta_flc (GstFlxDec *, guchar *, guchar *);
#define rndalign(off) ((off) + ((off) & 1))
@@ -225,13 +225,14 @@ gst_flxdec_sink_event_handler (GstPad *
return ret;
}
-static void
+static gboolean
flx_decode_chunks (GstFlxDec * flxdec, gulong count, guchar * data,
guchar * dest)
{
FlxFrameChunk *hdr;
+ gboolean ret = TRUE;
- g_return_if_fail (data != NULL);
+ g_return_val_if_fail (data != NULL, FALSE);
while (count--) {
hdr = (FlxFrameChunk *) data;
@@ -250,17 +251,17 @@ flx_decode_chunks (GstFlxDec * flxdec, g
break;
case FLX_BRUN:
- flx_decode_brun (flxdec, data, dest);
+ ret = flx_decode_brun (flxdec, data, dest);
data += rndalign (hdr->size) - FlxFrameChunkSize;
break;
case FLX_LC:
- flx_decode_delta_fli (flxdec, data, dest);
+ ret = flx_decode_delta_fli (flxdec, data, dest);
data += rndalign (hdr->size) - FlxFrameChunkSize;
break;
case FLX_SS2:
- flx_decode_delta_flc (flxdec, data, dest);
+ ret = flx_decode_delta_flc (flxdec, data, dest);
data += rndalign (hdr->size) - FlxFrameChunkSize;
break;
@@ -278,7 +279,12 @@ flx_decode_chunks (GstFlxDec * flxdec, g
data += rndalign (hdr->size) - FlxFrameChunkSize;
break;
}
+
+ if (!ret)
+ break;
}
+
+ return ret;
}
@@ -311,13 +317,13 @@ flx_decode_color (GstFlxDec * flxdec, gu
}
}
-static void
+static gboolean
flx_decode_brun (GstFlxDec * flxdec, guchar * data, guchar * dest)
{
gulong count, lines, row;
guchar x;
- g_return_if_fail (flxdec != NULL);
+ g_return_val_if_fail (flxdec != NULL, FALSE);
lines = flxdec->hdr.height;
while (lines--) {
@@ -335,12 +341,21 @@ flx_decode_brun (GstFlxDec * flxdec, guc
if (count > 0x7f) {
/* literal run */
count = 0x100 - count;
+ if ((glong) row - count < 0) {
+ GST_ERROR_OBJECT (flxdec, "Invalid BRUN packet detected.");
+ return FALSE;
+ }
row -= count;
while (count--)
*dest++ = *data++;
} else {
+ if ((glong) row - count < 0) {
+ GST_ERROR_OBJECT (flxdec, "Invalid BRUN packet detected.");
+ return FALSE;
+ }
+
/* replicate run */
row -= count;
x = *data++;
@@ -350,16 +365,18 @@ flx_decode_brun (GstFlxDec * flxdec, guc
}
}
}
+
+ return TRUE;
}
-static void
+static gboolean
flx_decode_delta_fli (GstFlxDec * flxdec, guchar * data, guchar * dest)
{
gulong count, packets, lines, start_line;
guchar *start_p, x;
- g_return_if_fail (flxdec != NULL);
- g_return_if_fail (flxdec->delta != NULL);
+ g_return_val_if_fail (flxdec != NULL, FALSE);
+ g_return_val_if_fail (flxdec->delta != NULL, FALSE);
/* use last frame for delta */
memcpy (dest, GST_BUFFER_DATA (flxdec->delta),
@@ -367,6 +384,10 @@ flx_decode_delta_fli (GstFlxDec * flxdec
start_line = (data[0] + (data[1] << 8));
lines = (data[2] + (data[3] << 8));
+ if (start_line + lines > flxdec->hdr.height) {
+ GST_ERROR_OBJECT (flxdec, "Invalid FLI packet detected. too many lines.");
+ return FALSE;
+ }
data += 4;
/* start position of delta */
@@ -379,7 +400,8 @@ flx_decode_delta_fli (GstFlxDec * flxdec
while (packets--) {
/* skip count */
- dest += *data++;
+ guchar skip = *data++;
+ dest += skip;
/* RLE count */
count = *data++;
@@ -387,12 +409,24 @@ flx_decode_delta_fli (GstFlxDec * flxdec
if (count > 0x7f) {
/* literal run */
count = 0x100 - count;
- x = *data++;
+ if (skip + count > flxdec->hdr.width) {
+ GST_ERROR_OBJECT (flxdec, "Invalid FLI packet detected. "
+ "line too long.");
+ return FALSE;
+ }
+
+ x = *data++;
while (count--)
*dest++ = x;
} else {
+ if (skip + count > flxdec->hdr.width) {
+ GST_ERROR_OBJECT (flxdec, "Invalid FLI packet detected. "
+ "line too long.");
+ return FALSE;
+ }
+
/* replicate run */
while (count--)
*dest++ = *data++;
@@ -401,22 +435,28 @@ flx_decode_delta_fli (GstFlxDec * flxdec
start_p += flxdec->hdr.width;
dest = start_p;
}
+
+ return TRUE;
}
-static void
+static gboolean
flx_decode_delta_flc (GstFlxDec * flxdec, guchar * data, guchar * dest)
{
gulong count, lines, start_l, opcode;
guchar *start_p;
- g_return_if_fail (flxdec != NULL);
- g_return_if_fail (flxdec->delta != NULL);
+ g_return_val_if_fail (flxdec != NULL, FALSE);
+ g_return_val_if_fail (flxdec->delta != NULL, FALSE);
/* use last frame for delta */
memcpy (dest, GST_BUFFER_DATA (flxdec->delta),
GST_BUFFER_SIZE (flxdec->delta));
lines = (data[0] + (data[1] << 8));
+ if (lines > flxdec->hdr.height) {
+ GST_ERROR_OBJECT (flxdec, "Invalid FLC packet detected. too many lines.");
+ return FALSE;
+ }
data += 2;
start_p = dest;
@@ -429,9 +469,15 @@ flx_decode_delta_flc (GstFlxDec * flxdec
while ((opcode = (data[0] + (data[1] << 8))) & 0xc000) {
data += 2;
if ((opcode & 0xc000) == 0xc000) {
- /* skip count */
- start_l += (0x10000 - opcode);
- dest += flxdec->hdr.width * (0x10000 - opcode);
+ /* line skip count */
+ gulong skip = (0x10000 - opcode);
+ if (skip > flxdec->hdr.height) {
+ GST_ERROR_OBJECT (flxdec, "Invalid FLC packet detected. "
+ "skip line count too big.");
+ return FALSE;
+ }
+ start_l += skip;
+ dest += flxdec->hdr.width * skip;
} else {
/* last pixel */
dest += flxdec->hdr.width;
@@ -443,7 +489,8 @@ flx_decode_delta_flc (GstFlxDec * flxdec
/* last opcode is the packet count */
while (opcode--) {
/* skip count */
- dest += *data++;
+ guchar skip = *data++;
+ dest += skip;
/* RLE count */
count = *data++;
@@ -451,12 +498,25 @@ flx_decode_delta_flc (GstFlxDec * flxdec
if (count > 0x7f) {
/* replicate word run */
count = 0x100 - count;
+
+ if (skip + count > flxdec->hdr.width) {
+ GST_ERROR_OBJECT (flxdec, "Invalid FLC packet detected. "
+ "line too long.");
+ return FALSE;
+ }
+
while (count--) {
*dest++ = data[0];
*dest++ = data[1];
}
data += 2;
} else {
+ if (skip + count > flxdec->hdr.width) {
+ GST_ERROR_OBJECT (flxdec, "Invalid FLC packet detected. "
+ "line too long.");
+ return FALSE;
+ }
+
/* literal word run */
while (count--) {
*dest++ = *data++;
@@ -466,6 +526,8 @@ flx_decode_delta_flc (GstFlxDec * flxdec
}
lines--;
}
+
+ return TRUE;
}
static GstFlowReturn
@@ -593,9 +655,13 @@ gst_flxdec_chain (GstPad * pad, GstBuffe
break;
/* decode chunks */
- flx_decode_chunks (flxdec,
- ((FlxFrameType *) chunk)->chunks,
- chunk + FlxFrameTypeSize, GST_BUFFER_DATA (flxdec->frame));
+ if (!flx_decode_chunks (flxdec,
+ ((FlxFrameType *) chunk)->chunks,
+ chunk + FlxFrameTypeSize, GST_BUFFER_DATA (flxdec->frame)) {
+ GST_ELEMENT_ERROR (flxdec, STREAM, DECODE,
+ ("%s", "Could not decode chunk"), NULL);
+ return GST_FLOW_ERROR;
+ }
/* save copy of the current frame for possible delta. */
memcpy (GST_BUFFER_DATA (flxdec->delta),
