return 0;
}
+#ifdef CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT
+static void u32_i2osp(uint32_t val, uint8_t *buf)
+{
+ buf[0] = (uint8_t)((val >> 24) & 0xff);
+ buf[1] = (uint8_t)((val >> 16) & 0xff);
+ buf[2] = (uint8_t)((val >> 8) & 0xff);
+ buf[3] = (uint8_t)((val >> 0) & 0xff);
+}
+
+/**
+ * mask_generation_function1() - generate an octet string
+ *
+ * Generate an octet string used to check rsa signature.
+ * It use an input octet string and a hash function.
+ *
+ * @checksum: A Hash function
+ * @seed: Specifies an input variable octet string
+ * @seed_len: Size of the input octet string
+ * @output: Specifies the output octet string
+ * @output_len: Size of the output octet string
+ * @return 0 if the octet string was correctly generated, others on error
+ */
+static int mask_generation_function1(struct checksum_algo *checksum,
+ uint8_t *seed, int seed_len,
+ uint8_t *output, int output_len)
+{
+ struct image_region region[2];
+ int ret = 0, i, i_output = 0, region_count = 2;
+ uint32_t counter = 0;
+ uint8_t buf_counter[4], *tmp;
+ int hash_len = checksum->checksum_len;
+
+ memset(output, 0, output_len);
+
+ region[0].data = seed;
+ region[0].size = seed_len;
+ region[1].data = &buf_counter[0];
+ region[1].size = 4;
+
+ tmp = malloc(hash_len);
+ if (!tmp) {
+ debug("%s: can't allocate array tmp\n", __func__);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ while (i_output < output_len) {
+ u32_i2osp(counter, &buf_counter[0]);
+
+ ret = checksum->calculate(checksum->name,
+ region, region_count,
+ tmp);
+ if (ret < 0) {
+ debug("%s: Error in checksum calculation\n", __func__);
+ goto out;
+ }
+
+ i = 0;
+ while ((i_output < output_len) && (i < hash_len)) {
+ output[i_output] = tmp[i];
+ i_output++;
+ i++;
+ }
+
+ counter++;
+ }
+
+out:
+ free(tmp);
+
+ return ret;
+}
+
+static int compute_hash_prime(struct checksum_algo *checksum,
+ uint8_t *pad, int pad_len,
+ uint8_t *hash, int hash_len,
+ uint8_t *salt, int salt_len,
+ uint8_t *hprime)
+{
+ struct image_region region[3];
+ int ret, region_count = 3;
+
+ region[0].data = pad;
+ region[0].size = pad_len;
+ region[1].data = hash;
+ region[1].size = hash_len;
+ region[2].data = salt;
+ region[2].size = salt_len;
+
+ ret = checksum->calculate(checksum->name, region, region_count, hprime);
+ if (ret < 0) {
+ debug("%s: Error in checksum calculation\n", __func__);
+ goto out;
+ }
+
+out:
+ return ret;
+}
+
+int padding_pss_verify(struct image_sign_info *info,
+ uint8_t *msg, int msg_len,
+ const uint8_t *hash, int hash_len)
+{
+ uint8_t *masked_db = NULL;
+ int masked_db_len = msg_len - hash_len - 1;
+ uint8_t *h = NULL, *hprime = NULL;
+ int h_len = hash_len;
+ uint8_t *db_mask = NULL;
+ int db_mask_len = masked_db_len;
+ uint8_t *db = NULL, *salt = NULL;
+ int db_len = masked_db_len, salt_len = msg_len - hash_len - 2;
+ uint8_t pad_zero[8] = { 0 };
+ int ret, i, leftmost_bits = 1;
+ uint8_t leftmost_mask;
+ struct checksum_algo *checksum = info->checksum;
+
+ /* first, allocate everything */
+ masked_db = malloc(masked_db_len);
+ h = malloc(h_len);
+ db_mask = malloc(db_mask_len);
+ db = malloc(db_len);
+ salt = malloc(salt_len);
+ hprime = malloc(hash_len);
+ if (!masked_db || !h || !db_mask || !db || !salt || !hprime) {
+ printf("%s: can't allocate some buffer\n", __func__);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ /* step 4: check if the last byte is 0xbc */
+ if (msg[msg_len - 1] != 0xbc) {
+ printf("%s: invalid pss padding (0xbc is missing)\n", __func__);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* step 5 */
+ memcpy(masked_db, msg, masked_db_len);
+ memcpy(h, msg + masked_db_len, h_len);
+
+ /* step 6 */
+ leftmost_mask = (0xff >> (8 - leftmost_bits)) << (8 - leftmost_bits);
+ if (masked_db[0] & leftmost_mask) {
+ printf("%s: invalid pss padding ", __func__);
+ printf("(leftmost bit of maskedDB not zero)\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* step 7 */
+ mask_generation_function1(checksum, h, h_len, db_mask, db_mask_len);
+
+ /* step 8 */
+ for (i = 0; i < db_len; i++)
+ db[i] = masked_db[i] ^ db_mask[i];
+
+ /* step 9 */
+ db[0] &= 0xff >> leftmost_bits;
+
+ /* step 10 */
+ if (db[0] != 0x01) {
+ printf("%s: invalid pss padding ", __func__);
+ printf("(leftmost byte of db isn't 0x01)\n");
+ ret = EINVAL;
+ goto out;
+ }
+
+ /* step 11 */
+ memcpy(salt, &db[1], salt_len);
+
+ /* step 12 & 13 */
+ compute_hash_prime(checksum, pad_zero, 8,
+ (uint8_t *)hash, hash_len,
+ salt, salt_len, hprime);
+
+ /* step 14 */
+ ret = memcmp(h, hprime, hash_len);
+
+out:
+ free(hprime);
+ free(salt);
+ free(db);
+ free(db_mask);
+ free(h);
+ free(masked_db);
+
+ return ret;
+}
+#endif
+
/**
* rsa_verify_key() - Verify a signature against some data using RSA Key
*
projects / platform / kernel / u-boot.git / blobdiff