ffmpeg: fix for CVE-2022-3964

A vulnerability classified as problematic has been found in ffmpeg. This affects an unknown part of the file
libavcodec/rpzaenc.c of the component QuickTime RPZA Video Encoder. The manipulation of the argument y_size
leads to out-of-bounds read. It is possible to initiate the attack remotely. The name of the patch is
92f9b28ed84a77138105475beba16c146bdaf984. It is recommended to apply a patch to fix this issue. The associated
identifier of this vulnerability is VDB-213543.

Reference:
https://nvd.nist.gov/vuln/detail/CVE-2022-3964

Upstream Fix:
https://github.com/FFmpeg/FFmpeg/commit/92f9b28ed84a77138105475beba16c146bdaf984

Signed-off-by: Narpat Mali <narpat.mali@windriver.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

2 files changed, 92 insertions, 1 deletions

diff --git a/meta/recipes-multimedia/ffmpeg/ffmpeg/0001-avcodec-rpzaenc-stop-accessing-out-of-bounds-frame.patch b/meta/recipes-multimedia/ffmpeg/ffmpeg/0001-avcodec-rpzaenc-stop-accessing-out-of-bounds-frame.patch
new file mode 100644
index 0000000000..2775a81cc8
--- /dev/null
+++ b/meta/recipes-multimedia/ffmpeg/ffmpeg/0001-avcodec-rpzaenc-stop-accessing-out-of-bounds-frame.patch
@@ -0,0 +1,89 @@
+From 92f9b28ed84a77138105475beba16c146bdaf984 Mon Sep 17 00:00:00 2001
+From: Paul B Mahol <onemda@gmail.com>
+Date: Sat, 12 Nov 2022 16:12:00 +0100
+Subject: [PATCH] avcodec/rpzaenc: stop accessing out of bounds frame
+
+Upstream-Status: Backport [https://github.com/FFmpeg/FFmpeg/commit/92f9b28ed84a77138105475beba16c146bdaf984]
+
+Signed-off-by: <narpat.mali@windriver.com>
+
+---
+ libavcodec/rpzaenc.c | 22 +++++++++++++++-------
+ 1 file changed, 15 insertions(+), 7 deletions(-)
+
+diff --git a/libavcodec/rpzaenc.c b/libavcodec/rpzaenc.c
+index d710eb4f82..4ced9523e2 100644
+--- a/libavcodec/rpzaenc.c
++++ b/libavcodec/rpzaenc.c
+@@ -205,7 +205,7 @@ static void get_max_component_diff(const BlockInfo *bi, const uint16_t *block_pt
+ 
+     // loop thru and compare pixels
+     for (y = 0; y < bi->block_height; y++) {
+-        for (x = 0; x < bi->block_width; x++){
++        for (x = 0; x < bi->block_width; x++) {
+             // TODO:  optimize
+             min_r = FFMIN(R(block_ptr[x]), min_r);
+             min_g = FFMIN(G(block_ptr[x]), min_g);
+@@ -278,7 +278,7 @@ static int leastsquares(const uint16_t *block_ptr, const BlockInfo *bi,
+         return -1;
+ 
+     for (i = 0; i < bi->block_height; i++) {
+-        for (j = 0; j < bi->block_width; j++){
++        for (j = 0; j < bi->block_width; j++) {
+             x = GET_CHAN(block_ptr[j], xchannel);
+             y = GET_CHAN(block_ptr[j], ychannel);
+             sumx += x;
+@@ -325,7 +325,7 @@ static int calc_lsq_max_fit_error(const uint16_t *block_ptr, const BlockInfo *bi
+     int max_err = 0;
+ 
+     for (i = 0; i < bi->block_height; i++) {
+-        for (j = 0; j < bi->block_width; j++){
++        for (j = 0; j < bi->block_width; j++) {
+             int x_inc, lin_y, lin_x;
+             x = GET_CHAN(block_ptr[j], xchannel);
+             y = GET_CHAN(block_ptr[j], ychannel);
+@@ -420,7 +420,9 @@ static void update_block_in_prev_frame(const uint16_t *src_pixels,
+                                        uint16_t *dest_pixels,
+                                        const BlockInfo *bi, int block_counter)
+ {
+-    for (int y = 0; y < 4; y++) {
++    const int y_size = FFMIN(4, bi->image_height - bi->row * 4);
++
++    for (int y = 0; y < y_size; y++) {
+         memcpy(dest_pixels, src_pixels, 8);
+         dest_pixels += bi->rowstride;
+         src_pixels += bi->rowstride;
+@@ -730,14 +732,15 @@ post_skip :
+ 
+             if (err > s->sixteen_color_thresh) { // DO SIXTEEN COLOR BLOCK
+                 uint16_t *row_ptr;
+-                int rgb555;
++                int y_size, rgb555;
+ 
+                 block_offset = get_block_info(&bi, block_counter);
+ 
+                 row_ptr = &src_pixels[block_offset];
++                y_size = FFMIN(4, bi.image_height - bi.row * 4);
+ 
+-                for (int y = 0; y < 4; y++) {
+-                    for (int x = 0; x < 4; x++){
++                for (int y = 0; y < y_size; y++) {
++                    for (int x = 0; x < 4; x++) {
+                         rgb555 = row_ptr[x] & ~0x8000;
+ 
+                         put_bits(&s->pb, 16, rgb555);
+@@ -745,6 +748,11 @@ post_skip :
+                     row_ptr += bi.rowstride;
+                 }
+ 
++                for (int y = y_size; y < 4; y++) {
++                    for (int x = 0; x < 4; x++)
++                        put_bits(&s->pb, 16, 0);
++                }
++
+                 block_counter++;
+             } else { // FOUR COLOR BLOCK
+                 block_counter += encode_four_color_block(min_color, max_color,
+-- 
+2.34.1
+
diff --git a/meta/recipes-multimedia/ffmpeg/ffmpeg_5.1.2.bb b/meta/recipes-multimedia/ffmpeg/ffmpeg_5.1.2.bb
index a0c98d4ae0..43b858984b 100644
--- a/meta/recipes-multimedia/ffmpeg/ffmpeg_5.1.2.bb
+++ b/meta/recipes-multimedia/ffmpeg/ffmpeg_5.1.2.bb
@@ -22,7 +22,9 @@ LIC_FILES_CHKSUM = "file://COPYING.GPLv2;md5=b234ee4d69f5fce4486a80fdaf4a4263 \
                     file://COPYING.LGPLv2.1;md5=bd7a443320af8c812e4c18d1b79df004 \
                     file://COPYING.LGPLv3;md5=e6a600fd5e1d9cbde2d983680233ad02"
 
-SRC_URI = "https://www.ffmpeg.org/releases/${BP}.tar.xz"
+SRC_URI = "https://www.ffmpeg.org/releases/${BP}.tar.xz \
+           file://0001-avcodec-rpzaenc-stop-accessing-out-of-bounds-frame.patch"
+
 SRC_URI[sha256sum] = "619e706d662c8420859832ddc259cd4d4096a48a2ce1eefd052db9e440eef3dc"
 
 # Build fails when thumb is enabled: https://bugzilla.yoctoproject.org/show_bug.cgi?id=7717