gstreamer1-plugins-bad-free/SOURCES/0001-mxfdemux-Fix-integer-overflow-causing-out-of-bounds-.patch

From 27959a895db3949dee1c93cc05cb73465e2a1fbe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Thu, 10 Aug 2023 15:45:01 +0300
Subject: [PATCH 1/4] mxfdemux: Fix integer overflow causing out of bounds
 writes when handling invalid uncompressed video

Check ahead of time when parsing the track information whether
width, height and bpp are valid and usable without overflows.

Fixes ZDI-CAN-21660, CVE-2023-40474

Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/2896

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5362>
---
 subprojects/gst-plugins-bad/gst/mxf/mxfup.c | 51 +++++++++++++++++----
 1 file changed, 43 insertions(+), 8 deletions(-)

diff --git a/subprojects/gst-plugins-bad/gst/mxf/mxfup.c b/subprojects/gst-plugins-bad/gst/mxf/mxfup.c
index d8b6664dab..ba86255f20 100644
--- a/subprojects/gst-plugins-bad/gst/mxf/mxfup.c
+++ b/subprojects/gst-plugins-bad/gst/mxf/mxfup.c
@@ -134,6 +134,8 @@ mxf_up_handle_essence_element (const MXFUL * key, GstBuffer * buffer,
     gpointer mapping_data, GstBuffer ** outbuf)
 {
   MXFUPMappingData *data = mapping_data;
+  gsize expected_in_stride = 0, out_stride = 0;
+  gsize expected_in_size = 0, out_size = 0;
 
   /* SMPTE 384M 7.1 */
   if (key->u[12] != 0x15 || (key->u[14] != 0x01 && key->u[14] != 0x02
@@ -162,22 +164,25 @@ mxf_up_handle_essence_element (const MXFUL * key, GstBuffer * buffer,
     }
   }
 
-  if (gst_buffer_get_size (buffer) != data->bpp * data->width * data->height) {
+  // Checked for overflows when parsing the descriptor
+  expected_in_stride = data->bpp * data->width;
+  out_stride = GST_ROUND_UP_4 (expected_in_stride);
+  expected_in_size = expected_in_stride * data->height;
+  out_size = out_stride * data->height;
+
+  if (gst_buffer_get_size (buffer) != expected_in_size) {
     GST_ERROR ("Invalid buffer size");
     gst_buffer_unref (buffer);
     return GST_FLOW_ERROR;
   }
 
-  if (data->bpp != 4
-      || GST_ROUND_UP_4 (data->width * data->bpp) != data->width * data->bpp) {
+  if (data->bpp != 4 || out_stride != expected_in_stride) {
     guint y;
     GstBuffer *ret;
     GstMapInfo inmap, outmap;
     guint8 *indata, *outdata;
 
-    ret =
-        gst_buffer_new_and_alloc (GST_ROUND_UP_4 (data->width * data->bpp) *
-        data->height);
+    ret = gst_buffer_new_and_alloc (out_size);
     gst_buffer_map (buffer, &inmap, GST_MAP_READ);
     gst_buffer_map (ret, &outmap, GST_MAP_WRITE);
     indata = inmap.data;
@@ -185,8 +190,8 @@ mxf_up_handle_essence_element (const MXFUL * key, GstBuffer * buffer,
 
     for (y = 0; y < data->height; y++) {
       memcpy (outdata, indata, data->width * data->bpp);
-      outdata += GST_ROUND_UP_4 (data->width * data->bpp);
-      indata += data->width * data->bpp;
+      outdata += out_stride;
+      indata += expected_in_stride;
     }
 
     gst_buffer_unmap (buffer, &inmap);
@@ -394,6 +399,36 @@ mxf_up_create_caps (MXFMetadataTimelineTrack * track, GstTagList ** tags,
     return NULL;
   }
 
+  if (caps) {
+    MXFUPMappingData *data = *mapping_data;
+    gsize expected_in_stride = 0, out_stride = 0;
+    gsize expected_in_size = 0, out_size = 0;
+
+    // Do some checking of the parameters to see if they're valid and
+    // we can actually work with them.
+    if (data->image_start_offset > data->image_end_offset) {
+      GST_WARNING ("Invalid image start/end offset");
+      g_free (data);
+      *mapping_data = NULL;
+      gst_clear_caps (&caps);
+
+      return NULL;
+    }
+
+    if (!g_size_checked_mul (&expected_in_stride, data->bpp, data->width) ||
+        (out_stride = GST_ROUND_UP_4 (expected_in_stride)) < expected_in_stride
+        || !g_size_checked_mul (&expected_in_size, expected_in_stride,
+            data->height)
+        || !g_size_checked_mul (&out_size, out_stride, data->height)) {
+      GST_ERROR ("Invalid resolution or bit depth");
+      g_free (data);
+      *mapping_data = NULL;
+      gst_clear_caps (&caps);
+
+      return NULL;
+    }
+  }
+
   return caps;
 }
 
-- 
2.43.0