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FFmpeg
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png: split header state and data state in two separate variables. 

Fixes a reported (but false) race condition in tsan for fate-apng:

WARNING: ThreadSanitizer: data race (pid=6274)
  Read of size 4 at 0x7d680001ec78 by main thread (mutexes: write M1338):
    #0 update_thread_context src/libavcodec/pngdec.c:1456 (ffmpeg+0x000000dacf0c)
[..]
  Previous write of size 4 at 0x7d680001ec78 by thread T1 (mutexes: write M1335):
    #0 decode_idat_chunk src/libavcodec/pngdec.c:737 (ffmpeg+0x000000dae951)
tags/n3.4
Ronald S. Bultje 9 years ago
parent
1f50baa2b2
commit
478f1c3d5e
2 changed files with 39 additions and 31 deletions
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  1. +0
    -5
      libavcodec/png.h
  2. +39
    -26
      libavcodec/pngdec.c

+ 0
- 5
libavcodec/png.h View File

@@ -42,11 +42,6 @@
#define PNG_FILTER_VALUE_PAETH 4
#define PNG_FILTER_VALUE_MIXED 5

#define PNG_IHDR 0x0001
#define PNG_IDAT 0x0002
#define PNG_ALLIMAGE 0x0004
#define PNG_PLTE 0x0008

#define NB_PASSES 7

#define PNGSIG 0x89504e470d0a1a0a


+ 39
- 26
libavcodec/pngdec.c View File

@@ -36,6 +36,16 @@

#include <zlib.h>

enum PNGHeaderState {
PNG_IHDR = 1 << 0,
PNG_PLTE = 1 << 1,
};

enum PNGImageState {
PNG_IDAT = 1 << 0,
PNG_ALLIMAGE = 1 << 1,
};

typedef struct PNGDecContext {
PNGDSPContext dsp;
AVCodecContext *avctx;
@@ -45,7 +55,8 @@ typedef struct PNGDecContext {
ThreadFrame last_picture;
ThreadFrame picture;

int state;
enum PNGHeaderState hdr_state;
enum PNGImageState pic_state;
int width, height;
int cur_w, cur_h;
int last_w, last_h;
@@ -334,7 +345,7 @@ static void png_handle_row(PNGDecContext *s)
}
s->y++;
if (s->y == s->cur_h) {
s->state |= PNG_ALLIMAGE;
s->pic_state |= PNG_ALLIMAGE;
if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
if (s->bit_depth == 16) {
deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
@@ -369,7 +380,7 @@ static void png_handle_row(PNGDecContext *s)
memset(s->last_row, 0, s->row_size);
for (;;) {
if (s->pass == NB_PASSES - 1) {
s->state |= PNG_ALLIMAGE;
s->pic_state |= PNG_ALLIMAGE;
goto the_end;
} else {
s->pass++;
@@ -404,7 +415,7 @@ static int png_decode_idat(PNGDecContext *s, int length)
return AVERROR_EXTERNAL;
}
if (s->zstream.avail_out == 0) {
if (!(s->state & PNG_ALLIMAGE)) {
if (!(s->pic_state & PNG_ALLIMAGE)) {
png_handle_row(s);
}
s->zstream.avail_out = s->crow_size;
@@ -541,12 +552,12 @@ static int decode_ihdr_chunk(AVCodecContext *avctx, PNGDecContext *s,
if (length != 13)
return AVERROR_INVALIDDATA;

if (s->state & PNG_IDAT) {
if (s->pic_state & PNG_IDAT) {
av_log(avctx, AV_LOG_ERROR, "IHDR after IDAT\n");
return AVERROR_INVALIDDATA;
}

if (s->state & PNG_IHDR) {
if (s->hdr_state & PNG_IHDR) {
av_log(avctx, AV_LOG_ERROR, "Multiple IHDR\n");
return AVERROR_INVALIDDATA;
}
@@ -569,7 +580,7 @@ static int decode_ihdr_chunk(AVCodecContext *avctx, PNGDecContext *s,
s->filter_type = bytestream2_get_byte(&s->gb);
s->interlace_type = bytestream2_get_byte(&s->gb);
bytestream2_skip(&s->gb, 4); /* crc */
s->state |= PNG_IHDR;
s->hdr_state |= PNG_IHDR;
if (avctx->debug & FF_DEBUG_PICT_INFO)
av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d "
"compression_type=%d filter_type=%d interlace_type=%d\n",
@@ -585,7 +596,7 @@ error:

static int decode_phys_chunk(AVCodecContext *avctx, PNGDecContext *s)
{
if (s->state & PNG_IDAT) {
if (s->pic_state & PNG_IDAT) {
av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
return AVERROR_INVALIDDATA;
}
@@ -605,11 +616,11 @@ static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s,
int ret;
size_t byte_depth = s->bit_depth > 8 ? 2 : 1;

if (!(s->state & PNG_IHDR)) {
if (!(s->hdr_state & PNG_IHDR)) {
av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
return AVERROR_INVALIDDATA;
}
if (!(s->state & PNG_IDAT)) {
if (!(s->pic_state & PNG_IDAT)) {
/* init image info */
avctx->width = s->width;
avctx->height = s->height;
@@ -734,7 +745,7 @@ static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s,
s->zstream.next_out = s->crow_buf;
}

s->state |= PNG_IDAT;
s->pic_state |= PNG_IDAT;

/* set image to non-transparent bpp while decompressing */
if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE)
@@ -770,7 +781,7 @@ static int decode_plte_chunk(AVCodecContext *avctx, PNGDecContext *s,
}
for (; i < 256; i++)
s->palette[i] = (0xFFU << 24);
s->state |= PNG_PLTE;
s->hdr_state |= PNG_PLTE;
bytestream2_skip(&s->gb, 4); /* crc */

return 0;
@@ -781,18 +792,18 @@ static int decode_trns_chunk(AVCodecContext *avctx, PNGDecContext *s,
{
int v, i;

if (!(s->state & PNG_IHDR)) {
if (!(s->hdr_state & PNG_IHDR)) {
av_log(avctx, AV_LOG_ERROR, "trns before IHDR\n");
return AVERROR_INVALIDDATA;
}

if (s->state & PNG_IDAT) {
if (s->pic_state & PNG_IDAT) {
av_log(avctx, AV_LOG_ERROR, "trns after IDAT\n");
return AVERROR_INVALIDDATA;
}

if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
if (length > 256 || !(s->state & PNG_PLTE))
if (length > 256 || !(s->hdr_state & PNG_PLTE))
return AVERROR_INVALIDDATA;

for (i = 0; i < length; i++) {
@@ -906,7 +917,7 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s,
if (length != 26)
return AVERROR_INVALIDDATA;

if (!(s->state & PNG_IHDR)) {
if (!(s->hdr_state & PNG_IHDR)) {
av_log(avctx, AV_LOG_ERROR, "fctl before IHDR\n");
return AVERROR_INVALIDDATA;
}
@@ -1122,13 +1133,13 @@ static int decode_frame_common(AVCodecContext *avctx, PNGDecContext *s,
}

if (CONFIG_APNG_DECODER && avctx->codec_id == AV_CODEC_ID_APNG && length == 0) {
if (!(s->state & PNG_IDAT))
if (!(s->pic_state & PNG_IDAT))
return 0;
else
goto exit_loop;
}
av_log(avctx, AV_LOG_ERROR, "%d bytes left\n", length);
if ( s->state & PNG_ALLIMAGE
if ( s->pic_state & PNG_ALLIMAGE
&& avctx->strict_std_compliance <= FF_COMPLIANCE_NORMAL)
goto exit_loop;
ret = AVERROR_INVALIDDATA;
@@ -1228,9 +1239,9 @@ static int decode_frame_common(AVCodecContext *avctx, PNGDecContext *s,
break;
}
case MKTAG('I', 'E', 'N', 'D'):
if (!(s->state & PNG_ALLIMAGE))
if (!(s->pic_state & PNG_ALLIMAGE))
av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
if (!(s->pic_state & (PNG_ALLIMAGE|PNG_IDAT))) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
@@ -1330,7 +1341,9 @@ static int decode_frame_png(AVCodecContext *avctx,
return AVERROR_INVALIDDATA;
}

s->y = s->state = s->has_trns = 0;
s->y = s->has_trns = 0;
s->hdr_state = 0;
s->pic_state = 0;

/* init the zlib */
s->zstream.zalloc = ff_png_zalloc;
@@ -1377,7 +1390,7 @@ static int decode_frame_apng(AVCodecContext *avctx,
FFSWAP(ThreadFrame, s->picture, s->last_picture);
p = s->picture.f;

if (!(s->state & PNG_IHDR)) {
if (!(s->hdr_state & PNG_IHDR)) {
if (!avctx->extradata_size)
return AVERROR_INVALIDDATA;

@@ -1397,14 +1410,14 @@ static int decode_frame_apng(AVCodecContext *avctx,
goto end;
}
s->y = 0;
s->state &= ~(PNG_IDAT | PNG_ALLIMAGE);
s->pic_state = 0;
bytestream2_init(&s->gb, avpkt->data, avpkt->size);
if ((ret = decode_frame_common(avctx, s, p, avpkt)) < 0)
goto end;

if (!(s->state & PNG_ALLIMAGE))
if (!(s->pic_state & PNG_ALLIMAGE))
av_log(avctx, AV_LOG_WARNING, "Frame did not contain a complete image\n");
if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
if (!(s->pic_state & (PNG_ALLIMAGE|PNG_IDAT))) {
ret = AVERROR_INVALIDDATA;
goto end;
}
@@ -1453,7 +1466,7 @@ static int update_thread_context(AVCodecContext *dst, const AVCodecContext *src)

memcpy(pdst->palette, psrc->palette, sizeof(pdst->palette));

pdst->state |= psrc->state & (PNG_IHDR | PNG_PLTE);
pdst->hdr_state |= psrc->hdr_state;

ff_thread_release_buffer(dst, &pdst->last_picture);
if (psrc->last_picture.f->data[0] &&


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