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avio: redesign ffio_rewind_with_probe_data() 

This prevents a double free

Fixes CID718285
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2012-10-13 02:08:59 +02:00
parent 54b2d317ed
commit 120b38b966
3 changed files with 11 additions and 7 deletions
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2
libavformat/avio_internal.h
View File

@ -64,7 +64,7 @@ static av_always_inline void ffio_wfourcc(AVIOContext *pb, const uint8_t *s)
* @return 0 in case of success, a negative value corresponding to an
* AVERROR code in case of failure
*/
int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char *buf, int buf_size);
int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char **buf, int buf_size);
uint64_t ffio_read_varlen(AVIOContext *bc);

13
libavformat/aviobuf.c
View File

@ -726,27 +726,32 @@ static int url_resetbuf(AVIOContext *s, int flags)
return 0;
}
int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char *buf, int buf_size)
int ffio_rewind_with_probe_data(AVIOContext *s, unsigned char **bufp, int buf_size)
{
int64_t buffer_start;
int buffer_size;
int overlap, new_size, alloc_size;
uint8_t *buf = *bufp;
if (s->write_flag)
if (s->write_flag) {
av_freep(bufp);
return AVERROR(EINVAL);
}
buffer_size = s->buf_end - s->buffer;
/* the buffers must touch or overlap */
if ((buffer_start = s->pos - buffer_size) > buf_size)
if ((buffer_start = s->pos - buffer_size) > buf_size) {
av_freep(bufp);
return AVERROR(EINVAL);
}
overlap = buf_size - buffer_start;
new_size = buf_size + buffer_size - overlap;
alloc_size = FFMAX(s->buffer_size, new_size);
if (alloc_size > buf_size)
if (!(buf = av_realloc_f(buf, 1, alloc_size)))
if (!(buf = (*bufp) = av_realloc_f(buf, 1, alloc_size)))
return AVERROR(ENOMEM);
if (new_size > buf_size) {

3
libavformat/utils.c
View File

@ -470,8 +470,7 @@ int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
}
/* rewind. reuse probe buffer to avoid seeking */
if ((ret = ffio_rewind_with_probe_data(pb, buf, pd.buf_size)) < 0)
av_free(buf);
ret = ffio_rewind_with_probe_data(pb, &buf, pd.buf_size);
return ret;
}