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[prefix] Use CRC32 to verify each block prior to decompression

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Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2016-03-23 13:41:17 +00:00
parent 05027a7a12
commit c4e8c40227
3 changed files with 160 additions and 45 deletions
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52
src/util/zbin.c
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@@ -144,6 +144,7 @@ static int read_zinfo_file ( const char *filename,
static int alloc_output_file ( size_t max_len, struct output_file *output ) {
output->len = 0;
output->hdr_len = 0;
output->max_len = ( max_len );
output->buf = malloc ( max_len );
if ( ! output->buf ) {
@@ -241,19 +242,41 @@ static void bcj_filter ( void *data, size_t len ) {
};
}
#define CRCPOLY 0xedb88320
#define CRCSEED 0xffffffff
static uint32_t crc32_le ( uint32_t crc, const void *data, size_t len ) {
const uint8_t *src = data;
uint32_t mult;
unsigned int i;
while ( len-- ) {
crc ^= *(src++);
for ( i = 0 ; i < 8 ; i++ ) {
mult = ( ( crc & 1 ) ? CRCPOLY : 0 );
crc = ( ( crc >> 1 ) ^ mult );
}
}
return crc;
}
static int process_zinfo_pack ( struct input_file *input,
struct output_file *output,
union zinfo_record *zinfo ) {
struct zinfo_pack *pack = &zinfo->pack;
size_t offset = pack->offset;
size_t len = pack->len;
size_t start_len;
size_t packed_len = 0;
size_t remaining = ( output->max_len - output->len );
size_t remaining;
lzma_options_lzma options;
const lzma_filter filters[] = {
{ .id = LZMA_FILTER_LZMA1, .options = &options },
{ .id = LZMA_VLI_UNKNOWN }
};
void *packed;
uint32_t *len32;
uint32_t *crc32;
if ( ( offset + len ) > input->len ) {
fprintf ( stderr, "Input buffer overrun on pack\n" );
@@ -261,6 +284,9 @@ static int process_zinfo_pack ( struct input_file *input,
}
output->len = align ( output->len, pack->align );
start_len = output->len;
len32 = ( output->buf + output->len );
output->len += sizeof ( *len32 );
if ( output->len > output->max_len ) {
fprintf ( stderr, "Output buffer overrun on pack\n" );
return -1;
@@ -268,28 +294,34 @@ static int process_zinfo_pack ( struct input_file *input,
bcj_filter ( ( input->buf + offset ), len );
packed = ( output->buf + output->len );
remaining = ( output->max_len - output->len );
lzma_lzma_preset ( &options, LZMA_PRESET );
options.lc = LZMA_LC;
options.lp = LZMA_LP;
options.pb = LZMA_PB;
if ( lzma_raw_buffer_encode ( filters, NULL, ( input->buf + offset ),
len, ( output->buf + output->len ),
&packed_len, remaining ) != LZMA_OK ) {
len, packed, &packed_len,
remaining ) != LZMA_OK ) {
fprintf ( stderr, "Compression failure\n" );
return -1;
}
if ( DEBUG ) {
fprintf ( stderr, "PACK [%#zx,%#zx) to [%#zx,%#zx)\n",
offset, ( offset + len ), output->len,
( output->len + packed_len ) );
}
output->len += packed_len;
crc32 = ( output->buf + output->len );
output->len += sizeof ( *crc32 );
if ( output->len > output->max_len ) {
fprintf ( stderr, "Output buffer overrun on pack\n" );
return -1;
}
*len32 = ( packed_len + sizeof ( *crc32 ) );
*crc32 = crc32_le ( CRCSEED, packed, packed_len );
if ( DEBUG ) {
fprintf ( stderr, "PACK [%#zx,%#zx) to [%#zx,%#zx) crc %#08x\n",
offset, ( offset + len ), start_len, output->len,
*crc32 );
}
return 0;
}