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avformat/tedcaptionsdec: Fix leak of AVBPrint upon error

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The tedcaptions demuxer uses an AVBPrint whose string is not restricted
to its internal buffer; it therefore needs to be cleaned up, yet this is
not done on error, as parse_file() returned simply returned directly.
This is fixed by going to fail first in such cases.
Furthermore, there is also a second way how this string can leak: By
having more than one subtitle per subtitle block, as the new one simply
overwrites the old one in this case as the AVBPrint is initialized each
time upon encountering a subtitle line. The code has been modified to
simply append the new subtitle to the old one, so that the old one can't
leak any more.

Reviewed-by: Nicolas George <george@nsup.org>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This commit is contained in:
Andreas Rheinhardt 2020-09-20 16:16:51 +02:00
parent b0dee629da
commit 9f7e592df2
1 changed files with 36 additions and 37 deletions
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73
libavformat/tedcaptionsdec.c
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@ -94,25 +94,20 @@ static int parse_string(AVIOContext *pb, int *cur_byte, AVBPrint *bp, int full)
{
int ret;
av_bprint_init(bp, 0, full ? AV_BPRINT_SIZE_UNLIMITED : AV_BPRINT_SIZE_AUTOMATIC);
ret = expect_byte(pb, cur_byte, '"');
if (ret < 0)
goto fail;
return ret;
while (*cur_byte > 0 && *cur_byte != '"') {
if (*cur_byte == '\\') {
next_byte(pb, cur_byte);
if (*cur_byte < 0) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
if (*cur_byte < 0)
return AVERROR_INVALIDDATA;
if ((*cur_byte | 32) == 'u') {
unsigned chr = 0, i;
for (i = 0; i < 4; i++) {
next_byte(pb, cur_byte);
if (!HEX_DIGIT_TEST(*cur_byte)) {
ret = ERR_CODE(*cur_byte);
goto fail;
}
if (!HEX_DIGIT_TEST(*cur_byte))
return ERR_CODE(*cur_byte);
chr = chr * 16 + HEX_DIGIT_VAL(*cur_byte);
}
av_bprint_utf8(bp, chr);
@ -126,22 +121,18 @@ static int parse_string(AVIOContext *pb, int *cur_byte, AVBPrint *bp, int full)
}
ret = expect_byte(pb, cur_byte, '"');
if (ret < 0)
goto fail;
if (full && !av_bprint_is_complete(bp)) {
ret = AVERROR(ENOMEM);
goto fail;
}
return 0;
return ret;
if (full && !av_bprint_is_complete(bp))
return AVERROR(ENOMEM);
fail:
av_bprint_finalize(bp, NULL);
return ret;
return 0;
}
static int parse_label(AVIOContext *pb, int *cur_byte, AVBPrint *bp)
{
int ret;
av_bprint_init(bp, 0, AV_BPRINT_SIZE_AUTOMATIC);
ret = parse_string(pb, cur_byte, bp, 0);
if (ret < 0)
return ret;
@ -195,6 +186,8 @@ static int parse_file(AVIOContext *pb, FFDemuxSubtitlesQueue *subs)
int64_t pos, start, duration;
AVPacket *pkt;
av_bprint_init(&content, 0, AV_BPRINT_SIZE_UNLIMITED);
next_byte(pb, &cur_byte);
ret = expect_byte(pb, &cur_byte, '{');
if (ret < 0)
@ -206,34 +199,34 @@ static int parse_file(AVIOContext *pb, FFDemuxSubtitlesQueue *subs)
if (ret < 0)
return AVERROR_INVALIDDATA;
while (1) {
content.size = 0;
start = duration = AV_NOPTS_VALUE;
ret = expect_byte(pb, &cur_byte, '{');
if (ret < 0)
return ret;
goto fail;
pos = avio_tell(pb) - 1;
while (1) {
ret = parse_label(pb, &cur_byte, &label);
if (ret < 0)
return ret;
goto fail;
if (!strcmp(label.str, "startOfParagraph")) {
ret = parse_boolean(pb, &cur_byte, &start_of_par);
if (ret < 0)
return ret;
goto fail;
} else if (!strcmp(label.str, "content")) {
ret = parse_string(pb, &cur_byte, &content, 1);
if (ret < 0)
return ret;
goto fail;
} else if (!strcmp(label.str, "startTime")) {
ret = parse_int(pb, &cur_byte, &start);
if (ret < 0)
return ret;
goto fail;
} else if (!strcmp(label.str, "duration")) {
ret = parse_int(pb, &cur_byte, &duration);
if (ret < 0)
return ret;
goto fail;
} else {
return AVERROR_INVALIDDATA;
ret = AVERROR_INVALIDDATA;
goto fail;
}
skip_spaces(pb, &cur_byte);
if (cur_byte != ',')
@ -242,18 +235,22 @@ static int parse_file(AVIOContext *pb, FFDemuxSubtitlesQueue *subs)
}
ret = expect_byte(pb, &cur_byte, '}');
if (ret < 0)
return ret;
goto fail;
if (!content.size || start == AV_NOPTS_VALUE ||
duration == AV_NOPTS_VALUE)
return AVERROR_INVALIDDATA;
duration == AV_NOPTS_VALUE) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
pkt = ff_subtitles_queue_insert(subs, content.str, content.len, 0);
if (!pkt)
return AVERROR(ENOMEM);
if (!pkt) {
ret = AVERROR(ENOMEM);
goto fail;
}
pkt->pos = pos;
pkt->pts = start;
pkt->duration = duration;
av_bprint_finalize(&content, NULL);
av_bprint_clear(&content);
skip_spaces(pb, &cur_byte);
if (cur_byte != ',')
@ -262,14 +259,16 @@ static int parse_file(AVIOContext *pb, FFDemuxSubtitlesQueue *subs)
}
ret = expect_byte(pb, &cur_byte, ']');
if (ret < 0)
return ret;
goto fail;
ret = expect_byte(pb, &cur_byte, '}');
if (ret < 0)
return ret;
goto fail;
skip_spaces(pb, &cur_byte);
if (cur_byte != AVERROR_EOF)
return ERR_CODE(cur_byte);
return 0;
ret = ERR_CODE(cur_byte);
fail:
av_bprint_finalize(&content, NULL);
return ret;
}
static av_cold int tedcaptions_read_header(AVFormatContext *avf)