[FFmpeg-cvslog] avcodec/tiff: assert that raw tiff dng blit does not write over the end of a line

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Feb 15 17:12:38 2020 +0100| [e444e5bb1ad9434ab79790a5aececcd6b783360b] | committer: Michael Niedermayer

avcodec/tiff: assert that raw tiff dng blit does not write over the end of a line

Found-by: 黄宁 <tsukimurarin at 163.com>
Reviewed-by: Nick Renieris <velocityra at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e444e5bb1ad9434ab79790a5aececcd6b783360b
---

 libavcodec/tiff.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
index 176bfc274b..45cb225d0a 100644
--- a/libavcodec/tiff.c
+++ b/libavcodec/tiff.c
@@ -704,18 +704,20 @@ static int tiff_unpack_strip(TiffContext *s, AVFrame *p, uint8_t *dst, int strid
 
             /* Color processing for DNG images with uncompressed strips (non-tiled) */
             if (is_dng) {
-                int is_u16, pixel_size_bytes, pixel_size_bits;
+                int is_u16, pixel_size_bytes, pixel_size_bits, elements;
 
                 is_u16 = (s->bpp > 8);
                 pixel_size_bits = (is_u16 ? 16 : 8);
                 pixel_size_bytes = (is_u16 ? sizeof(uint16_t) : sizeof(uint8_t));
 
+                elements = width / pixel_size_bytes * pixel_size_bits / s->bpp * s->bppcount; // need to account for [1, 16] bpp
+                av_assert0 (elements * pixel_size_bytes <= FFABS(stride));
                 dng_blit(s,
                          dst,
                          0, // no stride, only 1 line
                          dst,
                          0, // no stride, only 1 line
-                         width / pixel_size_bytes * pixel_size_bits / s->bpp * s->bppcount, // need to account for [1, 16] bpp
+                         elements,
                          1,
                          0, // single-component variation is only preset in JPEG-encoded DNGs
                          is_u16);