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avcodec/avpacket: Improve overflow checks when packing dictionary 

Also avoid reallocations.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This commit is contained in:
Andreas Rheinhardt 2021-03-17 18:32:36 +01:00
parent e318438f2f
commit 04d001ca9b
1 changed files with 20 additions and 20 deletions
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40
libavcodec/avpacket.c
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@ -509,37 +509,37 @@ int av_packet_split_side_data(AVPacket *pkt){
uint8_t *av_packet_pack_dictionary(AVDictionary *dict, int *size)
{
AVDictionaryEntry *t = NULL;
uint8_t *data = NULL;
*size = 0;
if (!dict)
return NULL;
while ((t = av_dict_get(dict, "", t, AV_DICT_IGNORE_SUFFIX))) {
const size_t keylen = strlen(t->key);
const size_t valuelen = strlen(t->value);
const size_t new_size = *size + keylen + 1 + valuelen + 1;
uint8_t *const new_data = av_realloc(data, new_size);
for (int pass = 0; pass < 2; pass++) {
const AVDictionaryEntry *t = NULL;
size_t total_length = 0;
if (!new_data)
goto fail;
data = new_data;
if (new_size > INT_MAX)
goto fail;
while ((t = av_dict_get(dict, "", t, AV_DICT_IGNORE_SUFFIX))) {
for (int i = 0; i < 2; i++) {
const char *str = i ? t->value : t->key;
const size_t len = strlen(str) + 1;
memcpy(data + *size, t->key, keylen + 1);
memcpy(data + *size + keylen + 1, t->value, valuelen + 1);
*size = new_size;
if (pass)
memcpy(data + total_length, str, len);
else if (len > INT_MAX - total_length)
return NULL;
total_length += len;
}
}
if (pass)
break;
data = av_malloc(total_length);
if (!data)
return NULL;
*size = total_length;
}
return data;
fail:
av_freep(&data);
*size = 0;
return NULL;
}
int av_packet_unpack_dictionary(const uint8_t *data, int size, AVDictionary **dict)