ffmpeg: fix CVE-2023-51796

Buffer Overflow vulnerability in Ffmpeg v.N113007-g8d24a28d06 allows a local
attacker to execute arbitrary code via the libavfilter/f_reverse.c:269:26
in areverse_request_frame.

(From OE-Core rev: ec7301d63376197ed3e89282545109f046d63888)

Signed-off-by: Archana Polampalli <archana.polampalli@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

meta/recipes-multimedia/ffmpeg/ffmpeg/CVE-2023-51796.patch

@@ -0,0 +1,39 @@
+From 61e73851a33f0b4cb7662f8578a4695e77bd3c19 Mon Sep 17 00:00:00 2001
+From: Michael Niedermayer <michael@niedermayer.cc>
+Date: Sat, 23 Dec 2023 18:04:32 +0100
+Subject: [PATCH 3/4] avfilter/f_reverse: Apply PTS compensation only when pts
+ is  available
+
+Fixes: out of array access
+Fixes: tickets/10753/poc16ffmpeg
+
+Regression since: 45dc668aea0edac34969b5a1ff76cf9ad3a09be1
+Found-by: Zeng Yunxiang
+Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
+
+CVE: CVE-2023-51796
+
+Upstream-Status: Backport [https://github.com/ffmpeg/FFmpeg/commit/61e73851a33f0b4cb7662f8578a4695e77bd3c19]
+
+Signed-off-by: Archana Polampalli <archana.polampalli@windriver.com>
+---
+ libavfilter/f_reverse.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/libavfilter/f_reverse.c b/libavfilter/f_reverse.c
+index f7a7e71..7b919d6 100644
+--- a/libavfilter/f_reverse.c
++++ b/libavfilter/f_reverse.c
+@@ -251,7 +251,9 @@ static int areverse_request_frame(AVFilterLink *outlink)
+     if (ret == AVERROR_EOF && s->nb_frames > 0) {
+         AVFrame *out = s->frames[s->nb_frames - 1];
+         out->pts     = s->pts[s->flush_idx++] - s->nb_samples;
+-        s->nb_samples += s->pts[s->flush_idx] - s->pts[s->flush_idx - 1] - out->nb_samples;
++        if (s->nb_frames > 1)
++            s->nb_samples += s->pts[s->flush_idx] - s->pts[s->flush_idx - 1] - out->nb_samples;
++
+
+         if (av_sample_fmt_is_planar(out->format))
+             reverse_samples_planar(out);
+--
+2.40.0

meta/recipes-multimedia/ffmpeg/ffmpeg_5.0.1.bb

@@ -38,6 +38,7 @@ SRC_URI = "https://www.ffmpeg.org/releases/${BP}.tar.xz \
            file://CVE-2023-51798.patch \
            file://CVE-2023-47342.patch \
            file://CVE-2023-50007.patch \
+           file://CVE-2023-51796.patch \
           "
 
 SRC_URI[sha256sum] = "ef2efae259ce80a240de48ec85ecb062cecca26e4352ffb3fda562c21a93007b"