bootloader_sha256_handle_t bootloader_sha256_start()
{
mbedtls_sha256_context *ctx = (mbedtls_sha256_context *)malloc(sizeof(mbedtls_sha256_context));
if (!ctx) {
return NULL;
}
mbedtls_sha256_init(ctx);
mbedtls_sha256_starts(ctx, false);
return ctx;
}
/*
* Compute SHA256 over the image.
*/
static int
bootutil_img_hash(struct image_header *hdr, const struct flash_area *fap,
uint8_t *tmp_buf, uint32_t tmp_buf_sz,
uint8_t *hash_result, uint8_t *seed, int seed_len)
{
mbedtls_sha256_context sha256_ctx;
uint32_t blk_sz;
uint32_t size;
uint32_t off;
int rc;
mbedtls_sha256_init(&sha256_ctx);
mbedtls_sha256_starts(&sha256_ctx, 0);
/* in some cases (split image) the hash is seeded with data from
* the loader image */
if(seed && (seed_len > 0)) {
mbedtls_sha256_update(&sha256_ctx, seed, seed_len);
}
size = hdr->ih_img_size + hdr->ih_hdr_size;
/*
* Hash is computed over image header and image itself. No TLV is
* included ATM.
*/
size = hdr->ih_img_size + hdr->ih_hdr_size;
for (off = 0; off < size; off += blk_sz) {
/* Pet the watchdog, in case it is still enabled after a soft reset. */
hal_watchdog_tickle();
blk_sz = size - off;
if (blk_sz > tmp_buf_sz) {
blk_sz = tmp_buf_sz;
}
rc = flash_area_read(fap, off, tmp_buf, blk_sz);
if (rc) {
return rc;
}
mbedtls_sha256_update(&sha256_ctx, tmp_buf, blk_sz);
}
mbedtls_sha256_finish(&sha256_ctx, hash_result);
return 0;
}
static void
boot_test_util_write_hash(const struct image_header *hdr, int slot)
{
uint8_t tmpdata[1024];
uint8_t hash[32];
int rc;
uint32_t off;
uint32_t blk_sz;
uint32_t sz;
mbedtls_sha256_context ctx;
uint8_t flash_id;
uint32_t addr;
struct image_tlv tlv;
mbedtls_sha256_init(&ctx);
mbedtls_sha256_starts(&ctx, 0);
flash_id = boot_test_img_addrs[slot].flash_id;
addr = boot_test_img_addrs[slot].address;
sz = hdr->ih_hdr_size + hdr->ih_img_size;
for (off = 0; off < sz; off += blk_sz) {
blk_sz = sz - off;
if (blk_sz > sizeof(tmpdata)) {
blk_sz = sizeof(tmpdata);
}
rc = hal_flash_read(flash_id, addr + off, tmpdata, blk_sz);
TEST_ASSERT(rc == 0);
mbedtls_sha256_update(&ctx, tmpdata, blk_sz);
}
mbedtls_sha256_finish(&ctx, hash);
tlv.it_type = IMAGE_TLV_SHA256;
tlv._pad = 0;
tlv.it_len = sizeof(hash);
rc = hal_flash_write(flash_id, addr + off, &tlv, sizeof(tlv));
TEST_ASSERT(rc == 0);
off += sizeof(tlv);
rc = hal_flash_write(flash_id, addr + off, hash, sizeof(hash));
TEST_ASSERT(rc == 0);
}
/**
* fast_sha256_vector - SHA256 hash for data vector
* @num_elem: Number of elements in the data vector
* @addr: Pointers to the data areas
* @len: Lengths of the data blocks
* @mac: Buffer for the hash
* Returns: 0 on success, -1 of failure
*/
int
fast_sha256_vector(size_t num_elem, const uint8_t *addr[], const size_t *len,
uint8_t *mac)
{
mbedtls_sha256_context ctx;
mbedtls_sha256_init(&ctx);
mbedtls_sha256_starts(&ctx, 0);
for(size_t index = 0; index < num_elem; index++) {
mbedtls_sha256_update(&ctx, addr[index], len[index]);
}
mbedtls_sha256_finish(&ctx, mac);
mbedtls_sha256_free(&ctx);
return 0;
}
void mbedtls_entropy_init( mbedtls_entropy_context *ctx )
{
memset( ctx, 0, sizeof(mbedtls_entropy_context) );
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_init( &ctx->mutex );
#endif
#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
mbedtls_sha512_starts( &ctx->accumulator, 0 );
#else
mbedtls_sha256_starts( &ctx->accumulator, 0 );
#endif
#if defined(MBEDTLS_HAVEGE_C)
mbedtls_havege_init( &ctx->havege_data );
#endif
#if !defined(MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES)
#if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
mbedtls_entropy_add_source( ctx, mbedtls_platform_entropy_poll, NULL,
MBEDTLS_ENTROPY_MIN_PLATFORM,
MBEDTLS_ENTROPY_SOURCE_STRONG );
#endif
#if defined(MBEDTLS_TIMING_C)
mbedtls_entropy_add_source( ctx, mbedtls_hardclock_poll, NULL,
MBEDTLS_ENTROPY_MIN_HARDCLOCK,
MBEDTLS_ENTROPY_SOURCE_WEAK );
#endif
#if defined(MBEDTLS_HAVEGE_C)
mbedtls_entropy_add_source( ctx, mbedtls_havege_poll, &ctx->havege_data,
MBEDTLS_ENTROPY_MIN_HAVEGE,
MBEDTLS_ENTROPY_SOURCE_STRONG );
#endif
#if defined(MBEDTLS_ENTROPY_HARDWARE_ALT)
mbedtls_entropy_add_source( ctx, mbedtls_hardware_poll, NULL,
MBEDTLS_ENTROPY_MIN_HARDWARE,
MBEDTLS_ENTROPY_SOURCE_STRONG );
#endif
#endif /* MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES */
}
static void sha256_starts_wrap( void *ctx )
{
mbedtls_sha256_starts( (mbedtls_sha256_context *) ctx, 0 );
}
int mbedtls_entropy_func( void *data, unsigned char *output, size_t len )
{
int ret, count = 0, i, done;
mbedtls_entropy_context *ctx = (mbedtls_entropy_context *) data;
unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
if( len > MBEDTLS_ENTROPY_BLOCK_SIZE )
return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
#if defined(MBEDTLS_THREADING_C)
if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
return( ret );
#endif
/*
* Always gather extra entropy before a call
*/
do
{
if( count++ > ENTROPY_MAX_LOOP )
{
ret = MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
goto exit;
}
if( ( ret = entropy_gather_internal( ctx ) ) != 0 )
goto exit;
done = 1;
for( i = 0; i < ctx->source_count; i++ )
if( ctx->source[i].size < ctx->source[i].threshold )
done = 0;
}
while( ! done );
memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
mbedtls_sha512_finish( &ctx->accumulator, buf );
/*
* Reset accumulator and counters and recycle existing entropy
*/
memset( &ctx->accumulator, 0, sizeof( mbedtls_sha512_context ) );
mbedtls_sha512_starts( &ctx->accumulator, 0 );
mbedtls_sha512_update( &ctx->accumulator, buf, MBEDTLS_ENTROPY_BLOCK_SIZE );
/*
* Perform second SHA-512 on entropy
*/
mbedtls_sha512( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, buf, 0 );
#else /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */
mbedtls_sha256_finish( &ctx->accumulator, buf );
/*
* Reset accumulator and counters and recycle existing entropy
*/
memset( &ctx->accumulator, 0, sizeof( mbedtls_sha256_context ) );
mbedtls_sha256_starts( &ctx->accumulator, 0 );
mbedtls_sha256_update( &ctx->accumulator, buf, MBEDTLS_ENTROPY_BLOCK_SIZE );
/*
* Perform second SHA-256 on entropy
*/
mbedtls_sha256( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, buf, 0 );
#endif /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */
for( i = 0; i < ctx->source_count; i++ )
ctx->source[i].size = 0;
memcpy( output, buf, len );
ret = 0;
exit:
#if defined(MBEDTLS_THREADING_C)
if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
#endif
return( ret );
}
int example(void)
{
printf( "\r\n\r\n" );
/*
* Method 1: use all-in-one function of a specific SHA-xxx module
*/
unsigned char output1[32]; /* SHA-256 outputs 32 bytes */
/* 0 here means use the full SHA-256, not the SHA-224 variant */
mbedtls_sha256(hello_buffer, hello_len, output1, 0);
print_hex("Method 1", output1, sizeof output1);
/*
* Method 2: use the streaming interface of a specific SHA-xxx module
* This is useful if we get our input piecewise.
*/
unsigned char output2[32];
mbedtls_sha256_context ctx2;
mbedtls_sha256_init(&ctx2);
mbedtls_sha256_starts(&ctx2, 0); /* SHA-256, not 224 */
/* Simulating multiple fragments */
mbedtls_sha256_update(&ctx2, hello_buffer, 1);
mbedtls_sha256_update(&ctx2, hello_buffer + 1, 1);
mbedtls_sha256_update(&ctx2, hello_buffer + 2, hello_len - 2);
mbedtls_sha256_finish(&ctx2, output2);
print_hex("Method 2", output2, sizeof output2);
/* Or you could re-use the context by doing mbedtls_sha256_starts() again */
mbedtls_sha256_free(&ctx2);
/*
* Method 3: use all-in-one function of the generice interface
*/
unsigned char output3[MBEDTLS_MD_MAX_SIZE]; /* Enough for any hash */
/* Can easily pick any hash you want, by identifier */
const mbedtls_md_info_t *md_info3 = mbedtls_md_info_from_type(MBEDTLS_MD_SHA256);
if (md_info3 == NULL)
{
printf("SHA256 not available\r\n");
return 1;
}
int ret3 = mbedtls_md(md_info3, hello_buffer, hello_len, output3);
if (ret3 != 0)
{
printf("md() returned -0x%04X\r\n", -ret3);
return 1;
}
print_hex("Method 3", output3, mbedtls_md_get_size(md_info3));
/*
* Method 4: streaming & generic interface
*/
unsigned char output4[MBEDTLS_MD_MAX_SIZE]; /* Enough for any hash */
const mbedtls_md_info_t *md_info4 = mbedtls_md_info_from_type(MBEDTLS_MD_SHA256);
if (md_info4 == NULL)
{
printf("SHA256 not available\r\n");
return 1;
}
mbedtls_md_context_t ctx4;
mbedtls_md_init(&ctx4);
int ret4 = mbedtls_md_init_ctx(&ctx4, md_info4);
if (ret4 != 0)
{
printf("md_init_ctx() returned -0x%04X\r\n", -ret4);
return 1;
}
mbedtls_md_starts(&ctx4);
/* Simulating multiple fragments */
mbedtls_md_update(&ctx4, hello_buffer, 1);
mbedtls_md_update(&ctx4, hello_buffer + 1, 1);
mbedtls_md_update(&ctx4, hello_buffer + 2, hello_len - 2);
mbedtls_md_finish(&ctx4, output4);
print_hex("Method 4", output4, mbedtls_md_get_size(md_info4));
/* Or you could re-use the context by doing mbedtls_md_starts() again */
mbedtls_md_free(&ctx4);
printf("\r\nDONE\r\n");
return 0;
}
/*
* Verify the integrity of the image.
* Return non-zero if image could not be validated/does not validate.
*/
int
bootutil_img_validate(struct image_header *hdr, uint8_t flash_id, uint32_t addr,
uint8_t *tmp_buf, uint32_t tmp_buf_sz)
{
uint32_t blk_sz;
uint32_t off;
uint32_t size;
mbedtls_sha256_context sha256_ctx;
struct image_tlv tlv;
uint8_t flash_hash[32];
uint8_t computed_hash[32];
int rc;
if (hdr->ih_flags & IMAGE_F_HAS_SHA256) {
/*
* After image there's a TLV containing the hash.
*/
mbedtls_sha256_init(&sha256_ctx);
mbedtls_sha256_starts(&sha256_ctx, 0);
/*
* Hash is computed over image header and image itself. No TLV is
* included ATM.
*/
size = hdr->ih_img_size + hdr->ih_hdr_size;
for (off = 0; off < size; off += blk_sz) {
blk_sz = size - off;
if (blk_sz > tmp_buf_sz) {
blk_sz = tmp_buf_sz;
}
rc = hal_flash_read(flash_id, addr + off, tmp_buf, blk_sz);
if (rc) {
return rc;
}
mbedtls_sha256_update(&sha256_ctx, tmp_buf, blk_sz);
}
mbedtls_sha256_finish(&sha256_ctx, computed_hash);
/*
* Then find the hash TLV and this should match.
*/
size += hdr->ih_tlv_size;
for (; off < size; off += sizeof(tlv) + tlv.it_len) {
rc = hal_flash_read(flash_id, addr + off, &tlv, sizeof(tlv));
if (rc) {
return rc;
}
if (tlv.it_type == IMAGE_TLV_SHA256) {
if (tlv.it_len != sizeof(flash_hash)) {
return -1;
}
rc = hal_flash_read(flash_id, addr + off + sizeof(tlv),
flash_hash, sizeof(flash_hash));
if (rc) {
return rc;
}
if (memcmp(flash_hash, computed_hash, sizeof(flash_hash))) {
return -1;
}
return 0;
}
}
/*
* Header said there should hash TLV, no TLV found.
*/
return -1;
}
return -1;
}
