lib: rsa: function to verify a signature against a hash
rsa_verify() expects a memory region and wants to do the hashing itself,
but there may be cases where the hashing is done via other means,
like hashing a squashfs rootfs.
So add rsa_verify_hash() to allow verifiying a signature against
an existing hash. As this entails the same verification routines
we can just move the relevant code over from rsa_verify() and also
call rsa_verify_hash() from there.
Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
index 61d98e6..6c4bbc4 100644
--- a/lib/rsa/rsa-verify.c
+++ b/lib/rsa/rsa-verify.c
@@ -478,33 +478,11 @@
}
#endif
-int rsa_verify(struct image_sign_info *info,
- const struct image_region region[], int region_count,
- uint8_t *sig, uint sig_len)
+int rsa_verify_hash(struct image_sign_info *info,
+ const uint8_t *hash, uint8_t *sig, uint sig_len)
{
- /* Reserve memory for maximum checksum-length */
- uint8_t hash[info->crypto->key_len];
int ret = -EACCES;
- /*
- * Verify that the checksum-length does not exceed the
- * rsa-signature-length
- */
- if (info->checksum->checksum_len >
- info->crypto->key_len) {
- debug("%s: invlaid checksum-algorithm %s for %s\n",
- __func__, info->checksum->name, info->crypto->name);
- return -EINVAL;
- }
-
- /* Calculate checksum with checksum-algorithm */
- ret = info->checksum->calculate(info->checksum->name,
- region, region_count, hash);
- if (ret < 0) {
- debug("%s: Error in checksum calculation\n", __func__);
- return -EINVAL;
- }
-
if (CONFIG_IS_ENABLED(RSA_VERIFY_WITH_PKEY) && !info->fdt_blob) {
/* don't rely on fdt properties */
ret = rsa_verify_with_pkey(info, hash, sig, sig_len);
@@ -555,3 +533,33 @@
return ret;
}
+
+int rsa_verify(struct image_sign_info *info,
+ const struct image_region region[], int region_count,
+ uint8_t *sig, uint sig_len)
+{
+ /* Reserve memory for maximum checksum-length */
+ uint8_t hash[info->crypto->key_len];
+ int ret = -EACCES;
+
+ /*
+ * Verify that the checksum-length does not exceed the
+ * rsa-signature-length
+ */
+ if (info->checksum->checksum_len >
+ info->crypto->key_len) {
+ debug("%s: invlaid checksum-algorithm %s for %s\n",
+ __func__, info->checksum->name, info->crypto->name);
+ return -EINVAL;
+ }
+
+ /* Calculate checksum with checksum-algorithm */
+ ret = info->checksum->calculate(info->checksum->name,
+ region, region_count, hash);
+ if (ret < 0) {
+ debug("%s: Error in checksum calculation\n", __func__);
+ return -EINVAL;
+ }
+
+ return rsa_verify_hash(info, hash, sig, sig_len);
+}