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Check stored foreign metadata chunks

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When foreign metadata is being restored, the master chunk and the
format chunk (and similar) are skipped over. This commit adds code
checking whether the stored chunk agrees with what is written.

This will catch cases where a legacy wave format file has been
stored to FLAC with --keep-foreign-metadata, but is being restored
to WAVE_FORMAT_EXTENSIBLE, or AIFF-C to AIFF. Also, it will reveal
when a FLAC file has been changed in length, or had an invalid
format chunk
This commit is contained in:
Martijn van Beurden 2023-01-27 21:03:39 +01:00
parent 3f1f82c8fa
commit 1ef4120c93
1 changed files with 44 additions and 8 deletions

52
src/flac/foreign_metadata.c

@ -72,6 +72,31 @@ static FLAC__bool copy_data_(FILE *fin, FILE *fout, size_t size, const char **er
return true;
}
/* compare 'size' bytes from file 'fin' to 'fout', filling in *error with 'read_error' or 'write_error' as necessary */
static FLAC__bool compare_data_(FILE *fin, FILE *fout, size_t size, const char **error, const char * const read_error, const char * const write_error, const char * const compare_error)
{
FLAC__byte buffer_in[4096];
FLAC__byte buffer_out[4096]; /* sizes need to be the same */
size_t left;
for(left = size; left > 0; ) {
size_t need = min(sizeof(buffer_in), left);
if(fread(buffer_in, 1, need, fin) < need) {
if(error) *error = read_error;
return false;
}
if(fread(buffer_out, 1, need, fout) < need) {
if(error) *error = write_error;
return false;
}
if(memcmp(buffer_in, buffer_out, need)) {
if(error) *error = compare_error;
return false;
}
left -= need;
}
return true;
}
static FLAC__bool append_block_(foreign_metadata_t *fm, FLAC__off_t offset, FLAC__uint32 size, const char **error)
{
foreign_block_t *fb = safe_realloc_nofree_muladd2_(fm->blocks, sizeof(foreign_block_t), /*times (*/fm->num_blocks, /*+*/1/*)*/);
@ -666,12 +691,18 @@ static FLAC__bool read_from_flac_(foreign_metadata_t *fm, FILE *f, FLAC__Metadat
static FLAC__bool write_to_iff_(foreign_metadata_t *fm, FILE *fin, FILE *fout, FLAC__off_t offset1, FLAC__off_t offset2, FLAC__off_t offset3, const char **error)
{
size_t i;
if(fseeko(fout, offset1, SEEK_SET) < 0) {
if(error) *error = "seek failed in WAVE/AIFF file (002)";
return false;
(void)offset1, (void)offset2;
/* don't write first (RIFF/RF64/FORM) chunk, or ds64 chunk in the case of RF64, compare instead */
for(i = 0; i < (fm->is_rf64?2:1); i++) {
if(fseeko(fin, fm->blocks[i].offset, SEEK_SET) < 0) {
if(error) *error = "seek failed in FLAC file (003)";
return false;
}
if(!compare_data_(fin, fout, fm->blocks[i].size, error, "read failed in WAVE/AIFF file (004)", "write failed in FLAC file (005)", "stored foreign metadata seems invalid"))
return false;
}
/* don't write first (RIFF/RF64/FORM) chunk, or ds64 chunk in the case of RF64 */
for(i = fm->is_rf64?2:1; i < fm->format_block; i++) {
for(; i < fm->format_block; i++) {
if(fseeko(fin, fm->blocks[i].offset, SEEK_SET) < 0) {
if(error) *error = "seek failed in FLAC file (003)";
return false;
@ -679,11 +710,16 @@ static FLAC__bool write_to_iff_(foreign_metadata_t *fm, FILE *fin, FILE *fout, F
if(!copy_data_(fin, fout, fm->blocks[i].size, error, "read failed in WAVE/AIFF file (004)", "write failed in FLAC file (005)"))
return false;
}
if(fseeko(fout, offset2, SEEK_SET) < 0) {
if(error) *error = "seek failed in WAVE/AIFF file (006)";
/* compare format block */
if(fseeko(fin, fm->blocks[i].offset, SEEK_SET) < 0) {
if(error) *error = "seek failed in FLAC file (003)";
return false;
}
for(i = fm->format_block+1; i < fm->audio_block; i++) {
if(!compare_data_(fin, fout, fm->blocks[i].size, error, "read failed in WAVE/AIFF file (004)", "write failed in FLAC file (005)", "stored foreign format block differs from written block. Perhaps the file is being restored to a different format than that of the original file"))
return false;
i++;
for(; i < fm->audio_block; i++) {
if(fseeko(fin, fm->blocks[i].offset, SEEK_SET) < 0) {
if(error) *error = "seek failed in FLAC file (007)";
return false;