Chiebot-Mirror
/
FFmpeg
mirror of https://github.com/FFmpeg/FFmpeg.git
8
0
Fork 0
Code Issues Projects Releases Wiki Activity

Check for out of bound reads in the flic decoder.

Browse Source 
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
pull/2/head
Laurent Aimar 13 years ago committed by Michael Niedermayer
parent 23c1db9b83
commit 1f024b8820
1 changed files with 29 additions and 15 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 44
      libavcodec/flicvideo.c

44
libavcodec/flicvideo.c
Unescape View File

@ -131,7 +131,6 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
FlicDecodeContext *s = avctx->priv_data;
int stream_ptr = 0;
int stream_ptr_after_color_chunk;
int pixel_ptr;
int palette_ptr;
unsigned char palette_idx1;
@ -171,7 +170,11 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
pixels = s->frame.data[0];
pixel_limit = s->avctx->height * s->frame.linesize[0];
if (buf_size < 16 || buf_size > INT_MAX - (3 * 256 + FF_INPUT_BUFFER_PADDING_SIZE))
return AVERROR_INVALIDDATA;
frame_size = AV_RL32(&buf[stream_ptr]);
if (frame_size > buf_size)
frame_size = buf_size;
stream_ptr += 6; /* skip the magic number */
num_chunks = AV_RL16(&buf[stream_ptr]);
stream_ptr += 10; /* skip padding */
@ -179,13 +182,16 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
frame_size -= 16;
/* iterate through the chunks */
while ((frame_size > 0) && (num_chunks > 0)) {
while ((frame_size >= 6) && (num_chunks > 0)) {
int stream_ptr_after_chunk;
chunk_size = AV_RL32(&buf[stream_ptr]);
if (chunk_size > frame_size) {
av_log(avctx, AV_LOG_WARNING,
"Invalid chunk_size = %u > frame_size = %u\n", chunk_size, frame_size);
chunk_size = frame_size;
}
stream_ptr_after_chunk = stream_ptr + chunk_size;
stream_ptr += 4;
chunk_type = AV_RL16(&buf[stream_ptr]);
stream_ptr += 2;
@ -193,8 +199,6 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
switch (chunk_type) {
case FLI_256_COLOR:
case FLI_COLOR:
stream_ptr_after_color_chunk = stream_ptr + chunk_size - 6;
/* check special case: If this file is from the Magic Carpet
* game and uses 6-bit colors even though it reports 256-color
* chunks in a 0xAF12-type file (fli_type is set to 0xAF13 during
@ -218,6 +222,9 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
if (color_changes == 0)
color_changes = 256;
if (stream_ptr + color_changes * 3 > stream_ptr_after_chunk)
break;
for (j = 0; j < color_changes; j++) {
unsigned int entry;
@ -234,13 +241,6 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
s->palette[palette_ptr++] = entry;
}
}
/* color chunks sometimes have weird 16-bit alignment issues;
* therefore, take the hardline approach and set the stream_ptr
* to the value calculated w.r.t. the size specified by the color
* chunk header */
stream_ptr = stream_ptr_after_color_chunk;
break;
case FLI_DELTA:
@ -248,6 +248,8 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
compressed_lines = AV_RL16(&buf[stream_ptr]);
stream_ptr += 2;
while (compressed_lines > 0) {
if (stream_ptr + 2 > stream_ptr_after_chunk)
break;
line_packets = AV_RL16(&buf[stream_ptr]);
stream_ptr += 2;
if ((line_packets & 0xC000) == 0xC000) {
@ -267,6 +269,8 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
CHECK_PIXEL_PTR(0);
pixel_countdown = s->avctx->width;
for (i = 0; i < line_packets; i++) {
if (stream_ptr + 2 > stream_ptr_after_chunk)
break;
/* account for the skip bytes */
pixel_skip = buf[stream_ptr++];
pixel_ptr += pixel_skip;
@ -283,6 +287,8 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
}
} else {
CHECK_PIXEL_PTR(byte_run * 2);
if (stream_ptr + byte_run * 2 > stream_ptr_after_chunk)
break;
for (j = 0; j < byte_run * 2; j++, pixel_countdown--) {
palette_idx1 = buf[stream_ptr++];
pixels[pixel_ptr++] = palette_idx1;
@ -309,6 +315,8 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
CHECK_PIXEL_PTR(0);
pixel_countdown = s->avctx->width;
line_packets = buf[stream_ptr++];
if (stream_ptr + 2 * line_packets > stream_ptr_after_chunk)
break;
if (line_packets > 0) {
for (i = 0; i < line_packets; i++) {
/* account for the skip bytes */
@ -318,6 +326,8 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
byte_run = (signed char)(buf[stream_ptr++]);
if (byte_run > 0) {
CHECK_PIXEL_PTR(byte_run);
if (stream_ptr + byte_run > stream_ptr_after_chunk)
break;
for (j = 0; j < byte_run; j++, pixel_countdown--) {
palette_idx1 = buf[stream_ptr++];
pixels[pixel_ptr++] = palette_idx1;
@ -355,6 +365,8 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
stream_ptr++;
pixel_countdown = s->avctx->width;
while (pixel_countdown > 0) {
if (stream_ptr + 1 > stream_ptr_after_chunk)
break;
byte_run = (signed char)(buf[stream_ptr++]);
if (byte_run > 0) {
palette_idx1 = buf[stream_ptr++];
@ -369,6 +381,8 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
} else { /* copy bytes if byte_run < 0 */
byte_run = -byte_run;
CHECK_PIXEL_PTR(byte_run);
if (stream_ptr + byte_run > stream_ptr_after_chunk)
break;
for (j = 0; j < byte_run; j++) {
palette_idx1 = buf[stream_ptr++];
pixels[pixel_ptr++] = palette_idx1;
@ -386,10 +400,9 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
case FLI_COPY:
/* copy the chunk (uncompressed frame) */
if (chunk_size - 6 > s->avctx->width * s->avctx->height) {
if (chunk_size - 6 != s->avctx->width * s->avctx->height) {
av_log(avctx, AV_LOG_ERROR, "In chunk FLI_COPY : source data (%d bytes) " \
"bigger than image, skipping chunk\n", chunk_size - 6);
stream_ptr += chunk_size - 6;
"has incorrect size, skipping chunk\n", chunk_size - 6);
} else {
for (y_ptr = 0; y_ptr < s->frame.linesize[0] * s->avctx->height;
y_ptr += s->frame.linesize[0]) {
@ -402,7 +415,6 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
case FLI_MINI:
/* some sort of a thumbnail? disregard this chunk... */
stream_ptr += chunk_size - 6;
break;
default:
@ -410,6 +422,8 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
break;
}
stream_ptr = stream_ptr_after_chunk;
frame_size -= chunk_size;
num_chunks--;
}

Write Preview
Loading…
Cancel
Save