generic-library/ffmpeg
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

rm: prevent infinite loops for index parsing.

Browse Source 
Specifically, prevent jumping back in the file for the next index, since
this can lead to infinite loops where we jump between indexes referring
to each other, and don't read indexes that don't fit in the file.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
(cherry picked from commit aac07a7a4c2c7a4a29cf6dbc88c1b9fdd191b99d)

Signed-off-by: Reinhard Tartler <siretart@tauware.de>
This commit is contained in:
Ronald S. Bultje 2012-02-22 11:33:24 -08:00 committed by Reinhard Tartler
parent 0d30e2c6f2
commit abe3572878
1 changed files with 17 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
libavformat/rmdec.c
View File

@ -370,8 +370,19 @@ static int rm_read_index(AVFormatContext *s)
st = s->streams[n];
break;
}
if (n == s->nb_streams)
if (n == s->nb_streams) {
av_log(s, AV_LOG_ERROR,
"Invalid stream index %d for index at pos %"PRId64"\n",
str_id, avio_tell(pb));
goto skip;
} else if ((avio_size(pb) - avio_tell(pb)) / 14 < n_pkts) {
av_log(s, AV_LOG_ERROR,
"Nr. of packets in packet index for stream index %d "
"exceeds filesize (%"PRId64" at %"PRId64" = %d)\n",
str_id, avio_size(pb), avio_tell(pb),
(avio_size(pb) - avio_tell(pb)) / 14);
goto skip;
}
for (n = 0; n < n_pkts; n++) {
avio_skip(pb, 2);
@ -383,9 +394,12 @@ static int rm_read_index(AVFormatContext *s)
}
skip:
if (next_off && avio_tell(pb) != next_off &&
avio_seek(pb, next_off, SEEK_SET) < 0)
if (next_off && avio_tell(pb) < next_off &&
avio_seek(pb, next_off, SEEK_SET) < 0) {
av_log(s, AV_LOG_ERROR,
"Non-linear index detected, not supported\n");
return -1;
}
} while (next_off);
return 0;