In most cases, s->buf_ptr will be equal to s->buf_end when
fill_buffer is called, but this may not always be the case, if
we're seeking forward by reading (permitted by the short seek
threshold).
If fill_buffer is writing to s->buf_ptr instead of s->buf_end (when
they aren't equal and s->buf_ptr is ahead of s->buffer), the data
between s->buf_ptr and s->buf_end is overwritten, leading to
inconsistent buffer content. This could return incorrect data if
later seeking back into the area before the current s->buf_ptr.
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
(cherry picked from commit
e360ada2d13af36ab7afd9ebcd2bd236d23d9b96)
static void fill_buffer(AVIOContext *s)
{
- uint8_t *dst= !s->max_packet_size && s->buf_end - s->buffer < s->buffer_size ? s->buf_ptr : s->buffer;
+ uint8_t *dst= !s->max_packet_size && s->buf_end - s->buffer < s->buffer_size ? s->buf_end : s->buffer;
int len= s->buffer_size - (dst - s->buffer);
int max_buffer_size = s->max_packet_size ? s->max_packet_size : IO_BUFFER_SIZE;