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From bcfe7befea53869e7836be912ee7efe875877169 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
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Date: Wed, 18 May 2022 12:00:48 +0300
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Subject: [PATCH 1/4] avidemux: Fix integer overflow resulting in heap
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 corruption in DIB buffer inversion code
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Check that width*bpp/8 doesn't overflow a guint and also that
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height*stride fits into the provided buffer without overflowing.
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Thanks to Adam Doupe for analyzing and reporting the issue.
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CVE: CVE-2022-1921
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See https://gstreamer.freedesktop.org/security/sa-2022-0001.html
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Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1224
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Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2608>
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---
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 gst/avi/gstavidemux.c | 17 ++++++++++++++---
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 1 file changed, 14 insertions(+), 3 deletions(-)
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diff --git a/gst/avi/gstavidemux.c b/gst/avi/gstavidemux.c
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index 25c97da03e..1c87c668d0 100644
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--- a/gst/avi/gstavidemux.c
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+++ b/gst/avi/gstavidemux.c
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@@ -4971,8 +4971,8 @@ swap_line (guint8 * d1, guint8 * d2, guint8 * tmp, gint bytes)
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 static GstBuffer *
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 gst_avi_demux_invert (GstAviStream * stream, GstBuffer * buf)
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 {
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-  gint y, w, h;
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-  gint bpp, stride;
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+  guint y, w, h;
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+  guint bpp, stride;
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   guint8 *tmp = NULL;
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   GstMapInfo map;
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   guint32 fourcc;
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@@ -4999,12 +4999,23 @@ gst_avi_demux_invert (GstAviStream * stream, GstBuffer * buf)
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   h = stream->strf.vids->height;
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   w = stream->strf.vids->width;
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   bpp = stream->strf.vids->bit_cnt ? stream->strf.vids->bit_cnt : 8;
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+
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+  if ((guint64) w * ((guint64) bpp / 8) > G_MAXUINT - 4) {
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+    GST_WARNING ("Width x stride overflows");
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+    return buf;
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+  }
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+
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+  if (w == 0 || h == 0) {
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+    GST_WARNING ("Zero width or height");
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+    return buf;
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+  }
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+
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   stride = GST_ROUND_UP_4 (w * (bpp / 8));
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   buf = gst_buffer_make_writable (buf);
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   gst_buffer_map (buf, &map, GST_MAP_READWRITE);
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-  if (map.size < (stride * h)) {
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+  if (map.size < ((guint64) stride * (guint64) h)) {
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     GST_WARNING ("Buffer is smaller than reported Width x Height x Depth");
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     gst_buffer_unmap (buf, &map);
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     return buf;
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-- 
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2.38.1
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