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Check length of written metadata block in stream encoder framing

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This commit is contained in:
Martijn van Beurden 2022-11-15 11:01:56 +01:00
parent 7ab61a7b29
commit 36bba3befb
1 changed files with 20 additions and 7 deletions
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27
src/libFLAC/stream_encoder_framing.c
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@ -46,8 +46,11 @@ static FLAC__bool add_residual_partitioned_rice_(FLAC__BitWriter *bw, const FLAC
FLAC__bool FLAC__add_metadata_block(const FLAC__StreamMetadata *metadata, FLAC__BitWriter *bw)
{
uint32_t i, j;
uint32_t i, j, metadata_length;
const uint32_t vendor_string_length = (uint32_t)strlen(FLAC__VENDOR_STRING);
const uint32_t start_bits = FLAC__bitwriter_get_input_bits_unconsumed(bw);
FLAC__ASSERT(FLAC__bitwriter_is_byte_aligned(bw));
if(!FLAC__bitwriter_write_raw_uint32(bw, metadata->is_last, FLAC__STREAM_METADATA_IS_LAST_LEN))
return false;
@ -58,17 +61,17 @@ FLAC__bool FLAC__add_metadata_block(const FLAC__StreamMetadata *metadata, FLAC__
/*
* First, for VORBIS_COMMENTs, adjust the length to reflect our vendor string
*/
i = metadata->length;
metadata_length = metadata->length;
if(metadata->type == FLAC__METADATA_TYPE_VORBIS_COMMENT) {
FLAC__ASSERT(metadata->data.vorbis_comment.vendor_string.length == 0 || 0 != metadata->data.vorbis_comment.vendor_string.entry);
i -= metadata->data.vorbis_comment.vendor_string.length;
i += vendor_string_length;
metadata_length -= metadata->data.vorbis_comment.vendor_string.length;
metadata_length += vendor_string_length;
}
FLAC__ASSERT(i < (1u << FLAC__STREAM_METADATA_LENGTH_LEN));
FLAC__ASSERT(metadata_length < (1u << FLAC__STREAM_METADATA_LENGTH_LEN));
/* double protection */
if(i >= (1u << FLAC__STREAM_METADATA_LENGTH_LEN))
if(metadata_length >= (1u << FLAC__STREAM_METADATA_LENGTH_LEN))
return false;
if(!FLAC__bitwriter_write_raw_uint32(bw, i, FLAC__STREAM_METADATA_LENGTH_LEN))
if(!FLAC__bitwriter_write_raw_uint32(bw, metadata_length, FLAC__STREAM_METADATA_LENGTH_LEN))
return false;
switch(metadata->type) {
@ -217,6 +220,16 @@ FLAC__bool FLAC__add_metadata_block(const FLAC__StreamMetadata *metadata, FLAC__
break;
}
/* Now check whether metadata block length was correct */
{
uint32_t length_in_bits = FLAC__bitwriter_get_input_bits_unconsumed(bw);
if(length_in_bits < start_bits)
return false;
length_in_bits -= start_bits;
if(length_in_bits % 8 != 0 || length_in_bits != (metadata_length*8+32))
return false;
}
FLAC__ASSERT(FLAC__bitwriter_is_byte_aligned(bw));
return true;
}