lib: rsa: function to verify a signature against a hash
From: Heiko Stuebner <heiko.stuebner@...> Date: Fri, 22 May 2020 11:17:20 +0200
Commit-Message
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@...>
Patch-Comment
Patch depends on at least lib: rsa: take spl/non-spl into account when building rsa_verify_with_pkey() include/u-boot/rsa.h | 21 +++++++++++++++++ lib/rsa/rsa-verify.c | 56 +++++++++++++++++++++++++------------------- 2 files changed, 53 insertions(+), 24 deletions(-)
Statistics
- 53 lines added
- 24 lines removed
Changes
----------------------------- include/u-boot/rsa.h -----------------------------
index 2d3024d8b7..a0bae495f0 100644
@@ -82,6 +82,20 @@ static inline int rsa_add_verify_data(struct image_sign_info *info,
#endif
#if IMAGE_ENABLE_VERIFY
+/**
+ * rsa_verify_hash() - Verify a signature against a hash
+ *
+ * Verify a RSA PKCS1.5 signature against an expected hash.
+ *
+ * @info: Specifies key and FIT information
+ * @hash: Hash according to algorithm specified in @info
+ * @sig: Signature
+ * @sig_len: Number of bytes in signature
+ * @return 0 if verified, -ve on error
+ */
+int rsa_verify_hash(struct image_sign_info *info,
+ const uint8_t *hash, uint8_t *sig, uint sig_len);
+
/**
* rsa_verify() - Verify a signature against some data
*
@@ -108,6 +122,13 @@ int padding_pss_verify(struct image_sign_info *info,
const uint8_t *hash, int hash_len);
#endif /* CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT */
#else
+static inline int rsa_verify_hash(struct image_sign_info *info,
+ const uint8_t *hash,
+ uint8_t *sig, uint sig_len)
+{
+ return -ENXIO;
+}
+
static inline int rsa_verify(struct image_sign_info *info,
const struct image_region region[], int region_count,
uint8_t *sig, uint sig_len)
----------------------------- lib/rsa/rsa-verify.c -----------------------------
index 61d98e6e2d..6c4bbc4625 100644
@@ -478,33 +478,11 @@ static int rsa_verify_with_keynode(struct image_sign_info *info,
}
#endif
+int rsa_verify_hash(struct image_sign_info *info,
+ const uint8_t *hash, uint8_t *sig, uint sig_len)
{
int ret = -EACCES;
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 @@ int rsa_verify(struct image_sign_info *info,
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);
+}