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avcodec/dolby_e: fix potentially undefined pointer arithmetic

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Avoid undefined behavior in skip_input() by checking that enough data is
available before incrementing input pointer.

Check return values of parse_key() and skip_input() and exit early with
error if there is not enough data.
This commit is contained in:
foo86 2017-07-22 17:19:25 +03:00
parent 0689cc2475
commit 5e715b583d
1 changed files with 28 additions and 17 deletions
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45
libavcodec/dolby_e.c
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@ -28,21 +28,28 @@
#include "dolby_e.h"
#include "fft.h"
static void skip_input(DBEContext *s, int nb_words)
static int skip_input(DBEContext *s, int nb_words)
{
if (nb_words > s->input_size) {
av_log(s->avctx, AV_LOG_ERROR, "Packet too short\n");
return AVERROR_INVALIDDATA;
}
s->input += nb_words * s->word_bytes;
s->input_size -= nb_words;
return 0;
}
static int parse_key(DBEContext *s)
{
int key = 0;
if (s->key_present && s->input_size > 0)
key = AV_RB24(s->input) >> 24 - s->word_bits;
skip_input(s, s->key_present);
return key;
if (s->key_present) {
uint8_t *key = s->input;
int ret = skip_input(s, 1);
if (ret < 0)
return ret;
return AV_RB24(key) >> 24 - s->word_bits;
}
return 0;
}
static int convert_input(DBEContext *s, int nb_words, int key)
@ -83,8 +90,10 @@ static int convert_input(DBEContext *s, int nb_words, int key)
static int parse_metadata(DBEContext *s)
{
int i, ret, key = parse_key(s), mtd_size;
int i, ret, key, mtd_size;
if ((key = parse_key(s)) < 0)
return key;
if ((ret = convert_input(s, 1, key)) < 0)
return ret;
@ -135,14 +144,13 @@ static int parse_metadata(DBEContext *s)
return AVERROR_INVALIDDATA;
}
skip_input(s, mtd_size + 1);
return 0;
return skip_input(s, mtd_size + 1);
}
static int parse_metadata_ext(DBEContext *s)
{
if (s->mtd_ext_size)
skip_input(s, s->key_present + s->mtd_ext_size + 1);
return skip_input(s, s->key_present + s->mtd_ext_size + 1);
return 0;
}
@ -455,7 +463,10 @@ static int parse_channel(DBEContext *s, int ch, int seg_id)
static int parse_audio(DBEContext *s, int start, int end, int seg_id)
{
int ch, ret, key = parse_key(s);
int ch, ret, key;
if ((key = parse_key(s)) < 0)
return key;
for (ch = start; ch < end; ch++) {
if (!s->ch_size[ch]) {
@ -469,17 +480,17 @@ static int parse_audio(DBEContext *s, int start, int end, int seg_id)
return ret;
s->channels[seg_id][ch].nb_groups = 0;
}
skip_input(s, s->ch_size[ch]);
if ((ret = skip_input(s, s->ch_size[ch])) < 0)
return ret;
}
skip_input(s, 1);
return 0;
return skip_input(s, 1);
}
static int parse_meter(DBEContext *s)
{
if (s->meter_size)
skip_input(s, s->key_present + s->meter_size + 1);
return skip_input(s, s->key_present + s->meter_size + 1);
return 0;
}