[FFmpeg-cvslog] tiffdec: use bytestream2 to simplify overread/overwrite protection
Justin Ruggles
git at videolan.org
Mon Apr 21 17:23:39 CEST 2014
ffmpeg | branch: release/1.1 | Justin Ruggles <justin.ruggles at gmail.com> | Sun Sep 29 19:47:55 2013 -0400| [85b8b169175a55fc862e01ecc96f649374bc14d2] | committer: Sean McGovern
tiffdec: use bytestream2 to simplify overread/overwrite protection
Based on a patch by Paul B Mahol <onemda at gmail.com>
CC:libav-stable at libav.org
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=85b8b169175a55fc862e01ecc96f649374bc14d2
---
libavcodec/tiff.c | 249 ++++++++++++++++++++++++-----------------------------
1 file changed, 113 insertions(+), 136 deletions(-)
diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
index 264e985..309f1a9 100644
--- a/libavcodec/tiff.c
+++ b/libavcodec/tiff.c
@@ -26,6 +26,7 @@
*/
#include "avcodec.h"
+#include "bytestream.h"
#include "config.h"
#if CONFIG_ZLIB
#include <zlib.h>
@@ -42,6 +43,7 @@
typedef struct TiffContext {
AVCodecContext *avctx;
AVFrame picture;
+ GetByteContext gb;
int width, height;
unsigned int bpp, bppcount;
@@ -56,33 +58,27 @@ typedef struct TiffContext {
int strips, rps, sstype;
int sot;
- const uint8_t *stripdata;
- const uint8_t *stripsizes;
- int stripsize, stripoff;
+ int stripsizesoff, stripsize, stripoff, strippos;
LZWState *lzw;
} TiffContext;
-static unsigned tget_short(const uint8_t **p, int le)
+static unsigned tget_short(GetByteContext *gb, int le)
{
- unsigned v = le ? AV_RL16(*p) : AV_RB16(*p);
- *p += 2;
- return v;
+ return le ? bytestream2_get_le16(gb) : bytestream2_get_be16(gb);
}
-static unsigned tget_long(const uint8_t **p, int le)
+static unsigned tget_long(GetByteContext *gb, int le)
{
- unsigned v = le ? AV_RL32(*p) : AV_RB32(*p);
- *p += 4;
- return v;
+ return le ? bytestream2_get_le32(gb) : bytestream2_get_be32(gb);
}
-static unsigned tget(const uint8_t **p, int type, int le)
+static unsigned tget(GetByteContext *gb, int type, int le)
{
switch (type) {
- case TIFF_BYTE : return *(*p)++;
- case TIFF_SHORT: return tget_short(p, le);
- case TIFF_LONG : return tget_long(p, le);
- default : return UINT_MAX;
+ case TIFF_BYTE: return bytestream2_get_byte(gb);
+ case TIFF_SHORT: return tget_short(gb, le);
+ case TIFF_LONG: return tget_long(gb, le);
+ default: return UINT_MAX;
}
}
@@ -112,8 +108,8 @@ static int tiff_uncompress(uint8_t *dst, unsigned long *len, const uint8_t *src,
static int tiff_unpack_strip(TiffContext *s, uint8_t *dst, int stride,
const uint8_t *src, int size, int lines)
{
+ PutByteContext pb;
int c, line, pixels, code;
- const uint8_t *ssrc = src;
int width = ((s->width * s->bpp) + 7) >> 3;
if (size <= 0)
@@ -151,6 +147,16 @@ static int tiff_unpack_strip(TiffContext *s, uint8_t *dst, int stride,
av_log(s->avctx, AV_LOG_ERROR, "Error initializing LZW decoder\n");
return -1;
}
+ for (line = 0; line < lines; line++) {
+ pixels = ff_lzw_decode(s->lzw, dst, width);
+ if (pixels < width) {
+ av_log(s->avctx, AV_LOG_ERROR, "Decoded only %i bytes of %i\n",
+ pixels, width);
+ return AVERROR_INVALIDDATA;
+ }
+ dst += stride;
+ }
+ return 0;
}
if (s->compr == TIFF_CCITT_RLE || s->compr == TIFF_G3
|| s->compr == TIFF_G4) {
@@ -187,63 +193,40 @@ static int tiff_unpack_strip(TiffContext *s, uint8_t *dst, int stride,
av_free(src2);
return ret;
}
+
+ bytestream2_init(&s->gb, src, size);
+ bytestream2_init_writer(&pb, dst, stride * lines);
+
for (line = 0; line < lines; line++) {
- if (src - ssrc > size) {
- av_log(s->avctx, AV_LOG_ERROR, "Source data overread\n");
- return -1;
- }
+ if (bytestream2_get_bytes_left(&s->gb) == 0 || bytestream2_get_eof(&pb))
+ break;
+ bytestream2_seek_p(&pb, stride * line, SEEK_SET);
switch (s->compr) {
case TIFF_RAW:
- if (ssrc + size - src < width)
- return AVERROR_INVALIDDATA;
if (!s->fill_order) {
- memcpy(dst, src, width);
+ bytestream2_copy_buffer(&pb, &s->gb, width);
} else {
int i;
for (i = 0; i < width; i++)
- dst[i] = ff_reverse[src[i]];
+ bytestream2_put_byte(&pb, ff_reverse[bytestream2_get_byte(&s->gb)]);
}
- src += width;
break;
case TIFF_PACKBITS:
for (pixels = 0; pixels < width;) {
- if (ssrc + size - src < 2)
- return AVERROR_INVALIDDATA;
- code = (int8_t) * src++;
+ code = (int8_t)bytestream2_get_byte(&s->gb);
if (code >= 0) {
code++;
- if (pixels + code > width ||
- ssrc + size - src < code) {
- av_log(s->avctx, AV_LOG_ERROR,
- "Copy went out of bounds\n");
- return -1;
- }
- memcpy(dst + pixels, src, code);
- src += code;
+ bytestream2_copy_buffer(&pb, &s->gb, code);
pixels += code;
} else if (code != -128) { // -127..-1
code = (-code) + 1;
- if (pixels + code > width) {
- av_log(s->avctx, AV_LOG_ERROR,
- "Run went out of bounds\n");
- return -1;
- }
- c = *src++;
- memset(dst + pixels, c, code);
+ c = bytestream2_get_byte(&s->gb);
+ bytestream2_set_buffer(&pb, c, code);
pixels += code;
}
}
break;
- case TIFF_LZW:
- pixels = ff_lzw_decode(s->lzw, dst, width);
- if (pixels < width) {
- av_log(s->avctx, AV_LOG_ERROR, "Decoded only %i bytes of %i\n",
- pixels, width);
- return -1;
- }
- break;
}
- dst += stride;
}
return 0;
}
@@ -302,20 +285,19 @@ static int init_image(TiffContext *s)
return 0;
}
-static int tiff_decode_tag(TiffContext *s, const uint8_t *start,
- const uint8_t *buf, const uint8_t *end_buf)
+static int tiff_decode_tag(TiffContext *s)
{
unsigned tag, type, count, off, value = 0;
- int i, j;
+ int i, start;
uint32_t *pal;
- const uint8_t *rp, *gp, *bp;
- if (end_buf - buf < 12)
+ if (bytestream2_get_bytes_left(&s->gb) < 12)
return -1;
- tag = tget_short(&buf, s->le);
- type = tget_short(&buf, s->le);
- count = tget_long(&buf, s->le);
- off = tget_long(&buf, s->le);
+ tag = tget_short(&s->gb, s->le);
+ type = tget_short(&s->gb, s->le);
+ count = tget_long(&s->gb, s->le);
+ off = tget_long(&s->gb, s->le);
+ start = bytestream2_tell(&s->gb);
if (type == 0 || type >= FF_ARRAY_ELEMS(type_sizes)) {
av_log(s->avctx, AV_LOG_DEBUG, "Unknown tiff type (%u) encountered\n",
@@ -327,35 +309,26 @@ static int tiff_decode_tag(TiffContext *s, const uint8_t *start,
switch (type) {
case TIFF_BYTE:
case TIFF_SHORT:
- buf -= 4;
- value = tget(&buf, type, s->le);
- buf = NULL;
+ bytestream2_seek(&s->gb, -4, SEEK_CUR);
+ value = tget(&s->gb, type, s->le);
break;
case TIFF_LONG:
value = off;
- buf = NULL;
break;
case TIFF_STRING:
if (count <= 4) {
- buf -= 4;
+ bytestream2_seek(&s->gb, -4, SEEK_CUR);
break;
}
default:
value = UINT_MAX;
- buf = start + off;
+ bytestream2_seek(&s->gb, off, SEEK_SET);
}
} else {
- if (count <= 4 && type_sizes[type] * count <= 4) {
- buf -= 4;
- } else {
- buf = start + off;
- }
- }
-
- if (buf && (buf < start || buf > end_buf)) {
- av_log(s->avctx, AV_LOG_ERROR,
- "Tag referencing position outside the image\n");
- return -1;
+ if (count <= 4 && type_sizes[type] * count <= 4)
+ bytestream2_seek(&s->gb, -4, SEEK_CUR);
+ else
+ bytestream2_seek(&s->gb, off, SEEK_SET);
}
switch (tag) {
@@ -384,8 +357,8 @@ static int tiff_decode_tag(TiffContext *s, const uint8_t *start,
case TIFF_SHORT:
case TIFF_LONG:
s->bpp = 0;
- for (i = 0; i < count && buf < end_buf; i++)
- s->bpp += tget(&buf, type, s->le);
+ for (i = 0; i < count; i++)
+ s->bpp += tget(&s->gb, type, s->le);
break;
default:
s->bpp = -1;
@@ -446,35 +419,25 @@ static int tiff_decode_tag(TiffContext *s, const uint8_t *start,
break;
case TIFF_STRIP_OFFS:
if (count == 1) {
- s->stripdata = NULL;
+ s->strippos = 0;
s->stripoff = value;
} else
- s->stripdata = start + off;
+ s->strippos = off;
s->strips = count;
if (s->strips == 1)
s->rps = s->height;
s->sot = type;
- if (s->stripdata > end_buf) {
- av_log(s->avctx, AV_LOG_ERROR,
- "Tag referencing position outside the image\n");
- return -1;
- }
break;
case TIFF_STRIP_SIZE:
if (count == 1) {
- s->stripsizes = NULL;
- s->stripsize = value;
- s->strips = 1;
+ s->stripsizesoff = 0;
+ s->stripsize = value;
+ s->strips = 1;
} else {
- s->stripsizes = start + off;
+ s->stripsizesoff = off;
}
s->strips = count;
s->sstype = type;
- if (s->stripsizes > end_buf) {
- av_log(s->avctx, AV_LOG_ERROR,
- "Tag referencing position outside the image\n");
- return -1;
- }
break;
case TIFF_PREDICTOR:
s->predictor = value;
@@ -504,23 +467,27 @@ static int tiff_decode_tag(TiffContext *s, const uint8_t *start,
}
s->fill_order = value - 1;
break;
- case TIFF_PAL:
+ case TIFF_PAL: {
+ GetByteContext pal_gb[3];
pal = (uint32_t *) s->palette;
off = type_sizes[type];
- if (count / 3 > 256 || end_buf - buf < count / 3 * off * 3)
+ if (count / 3 > 256 ||
+ bytestream2_get_bytes_left(&s->gb) < count / 3 * off * 3)
return -1;
- rp = buf;
- gp = buf + count / 3 * off;
- bp = buf + count / 3 * off * 2;
+ pal_gb[0] = pal_gb[1] = pal_gb[2] = s->gb;
+ bytestream2_skip(&pal_gb[1], count / 3 * off);
+ bytestream2_skip(&pal_gb[2], count / 3 * off * 2);
off = (type_sizes[type] - 1) << 3;
for (i = 0; i < count / 3; i++) {
- j = (tget(&rp, type, s->le) >> off) << 16;
- j |= (tget(&gp, type, s->le) >> off) << 8;
- j |= tget(&bp, type, s->le) >> off;
- pal[i] = j;
+ uint32_t p = 0xFF000000;
+ p |= (tget(&pal_gb[0], type, s->le) >> off) << 16;
+ p |= (tget(&pal_gb[1], type, s->le) >> off) << 8;
+ p |= tget(&pal_gb[2], type, s->le) >> off;
+ pal[i] = p;
}
s->palette_is_set = 1;
break;
+ }
case TIFF_PLANAR:
if (value == 2) {
av_log(s->avctx, AV_LOG_ERROR, "Planar format is not supported\n");
@@ -539,30 +506,31 @@ static int tiff_decode_tag(TiffContext *s, const uint8_t *start,
av_log(s->avctx, AV_LOG_DEBUG, "Unknown or unsupported tag %d/0X%0X\n",
tag, tag);
}
+ bytestream2_seek(&s->gb, start, SEEK_SET);
return 0;
}
static int decode_frame(AVCodecContext *avctx,
void *data, int *got_frame, AVPacket *avpkt)
{
- const uint8_t *buf = avpkt->data;
- int buf_size = avpkt->size;
TiffContext *const s = avctx->priv_data;
AVFrame *picture = data;
AVFrame *const p = &s->picture;
- const uint8_t *orig_buf = buf, *end_buf = buf + buf_size;
unsigned off;
int id, le, ret;
int i, j, entries;
int stride;
unsigned soff, ssize;
uint8_t *dst;
+ GetByteContext stripsizes;
+ GetByteContext stripdata;
+
+ bytestream2_init(&s->gb, avpkt->data, avpkt->size);
//parse image header
- if (end_buf - buf < 8)
+ if (avpkt->size < 8)
return AVERROR_INVALIDDATA;
- id = AV_RL16(buf);
- buf += 2;
+ id = bytestream2_get_le16(&s->gb);
if (id == 0x4949)
le = 1;
else if (id == 0x4D4D)
@@ -577,27 +545,26 @@ static int decode_frame(AVCodecContext *avctx,
s->fill_order = 0;
// As TIFF 6.0 specification puts it "An arbitrary but carefully chosen number
// that further identifies the file as a TIFF file"
- if (tget_short(&buf, le) != 42) {
+ if (tget_short(&s->gb, le) != 42) {
av_log(avctx, AV_LOG_ERROR,
"The answer to life, universe and everything is not correct!\n");
return -1;
}
- // Reset these pointers so we can tell if they were set this frame
- s->stripsizes = s->stripdata = NULL;
+ // Reset these offsets so we can tell if they were set this frame
+ s->stripsizesoff = s->strippos = 0;
/* parse image file directory */
- off = tget_long(&buf, le);
- if (off >= UINT_MAX - 14 || end_buf - orig_buf < off + 14) {
+ off = tget_long(&s->gb, le);
+ if (off >= UINT_MAX - 14 || avpkt->size < off + 14) {
av_log(avctx, AV_LOG_ERROR, "IFD offset is greater than image size\n");
return AVERROR_INVALIDDATA;
}
- buf = orig_buf + off;
- entries = tget_short(&buf, le);
+ bytestream2_seek(&s->gb, off, SEEK_SET);
+ entries = tget_short(&s->gb, le);
for (i = 0; i < entries; i++) {
- if (tiff_decode_tag(s, orig_buf, buf, end_buf) < 0)
+ if (tiff_decode_tag(s) < 0)
return -1;
- buf += 12;
}
- if (!s->stripdata && !s->stripoff) {
+ if (!s->strippos && !s->stripoff) {
av_log(avctx, AV_LOG_ERROR, "Image data is missing\n");
return -1;
}
@@ -607,30 +574,40 @@ static int decode_frame(AVCodecContext *avctx,
if (s->strips == 1 && !s->stripsize) {
av_log(avctx, AV_LOG_WARNING, "Image data size missing\n");
- s->stripsize = buf_size - s->stripoff;
+ s->stripsize = avpkt->size - s->stripoff;
}
stride = p->linesize[0];
dst = p->data[0];
+
+ if (s->stripsizesoff) {
+ if (s->stripsizesoff >= avpkt->size)
+ return AVERROR_INVALIDDATA;
+ bytestream2_init(&stripsizes, avpkt->data + s->stripsizesoff,
+ avpkt->size - s->stripsizesoff);
+ }
+ if (s->strippos) {
+ if (s->strippos >= avpkt->size)
+ return AVERROR_INVALIDDATA;
+ bytestream2_init(&stripdata, avpkt->data + s->strippos,
+ avpkt->size - s->strippos);
+ }
+
for (i = 0; i < s->height; i += s->rps) {
- if (s->stripsizes) {
- if (s->stripsizes >= end_buf)
- return AVERROR_INVALIDDATA;
- ssize = tget(&s->stripsizes, s->sstype, s->le);
- } else
+ if (s->stripsizesoff)
+ ssize = tget(&stripsizes, s->sstype, le);
+ else
ssize = s->stripsize;
- if (s->stripdata) {
- if (s->stripdata >= end_buf)
- return AVERROR_INVALIDDATA;
- soff = tget(&s->stripdata, s->sot, s->le);
- } else
+ if (s->strippos)
+ soff = tget(&stripdata, s->sot, le);
+ else
soff = s->stripoff;
- if (soff > buf_size || ssize > buf_size - soff) {
+ if (soff > avpkt->size || ssize > avpkt->size - soff) {
av_log(avctx, AV_LOG_ERROR, "Invalid strip size/offset\n");
return -1;
}
- if (tiff_unpack_strip(s, dst, stride, orig_buf + soff, ssize,
+ if (tiff_unpack_strip(s, dst, stride, avpkt->data + soff, ssize,
FFMIN(s->rps, s->height - i)) < 0)
break;
dst += s->rps * stride;
@@ -660,7 +637,7 @@ static int decode_frame(AVCodecContext *avctx,
*picture = s->picture;
*got_frame = 1;
- return buf_size;
+ return avpkt->size;
}
static av_cold int tiff_init(AVCodecContext *avctx)
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