[U-Boot] [PATCH 3/3] fit: rsa: Add support for SHA256 hash

[Marek Vasut]

Add support for "sha256,rsa2048" signature. This patch utilises the previously
laid groundwork for adding other hashes.

Signed-off-by: Marek Vasut <marex at denx.de>
---
 common/image-sig.c   |  8 +++++++-
 lib/rsa/rsa-sign.c   |  5 +++++
 lib/rsa/rsa-verify.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+), 1 deletion(-)

diff --git a/common/image-sig.c b/common/image-sig.c
index 973b06d..c3d63bc 100644
--- a/common/image-sig.c
+++ b/common/image-sig.c
@@ -23,7 +23,13 @@ struct image_sig_algo image_sig_algos[] = {
 		rsa_sign,
 		rsa_add_verify_data,
 		rsa_verify,
-	}
+	},
+	{
+		"sha256,rsa2048",
+		rsa_sign,
+		rsa_add_verify_data,
+		rsa_verify,
+	},
 };
 
 struct image_sig_algo *image_get_sig_algo(const char *name)
diff --git a/lib/rsa/rsa-sign.c b/lib/rsa/rsa-sign.c
index 4e11720..f1167b1 100644
--- a/lib/rsa/rsa-sign.c
+++ b/lib/rsa/rsa-sign.c
@@ -17,6 +17,7 @@
 
 enum rsa_hash_type {
 	RSA_HASH_SHA1,
+	RSA_HASH_SHA256,
 	RSA_HASH_UNKNOWN,
 };
 
@@ -169,6 +170,8 @@ static const EVP_MD *rsa_sign_get_hash(enum rsa_hash_type hash)
 	switch (hash) {
 	case RSA_HASH_SHA1:
 		return EVP_sha1();
+	case RSA_HASH_SHA256:
+		return EVP_sha256();
 	default:	/* This must never happen. */
 		rsa_err("Invalid hash type!\n");
 		exit(1);
@@ -258,6 +261,8 @@ static enum rsa_hash_type rsa_get_sha_type(struct image_sign_info *info)
 
 	if (!strncmp(info->algo->name, "sha1", hash_str_len))
 		return RSA_HASH_SHA1;
+	else if (!strncmp(info->algo->name, "sha256", hash_str_len))
+		return RSA_HASH_SHA256;
 	else
 		return RSA_HASH_UNKNOWN;
 }
diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
index 9617f8d..67fb882 100644
--- a/lib/rsa/rsa-verify.c
+++ b/lib/rsa/rsa-verify.c
@@ -9,6 +9,7 @@
 #include <malloc.h>
 #include <rsa.h>
 #include <sha1.h>
+#include <sha256.h>
 #include <asm/byteorder.h>
 #include <asm/errno.h>
 #include <asm/unaligned.h>
@@ -70,6 +71,37 @@ static const uint8_t padding_sha1_rsa2048[RSA2048_BYTES - SHA1_SUM_LEN] = {
 	0x05, 0x00, 0x04, 0x14
 };
 
+static const uint8_t padding_sha256_rsa2048[RSA2048_BYTES - SHA256_SUM_LEN] = {
+	0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0x00, 0x30, 0x31, 0x30,
+	0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65,
+	0x03, 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20,
+};
+
 /**
  * subtract_modulus() - subtract modulus from the given value
  *
@@ -337,6 +369,28 @@ rsa_compute_hash_sha1(const struct image_region region[], int region_count,
 	return 0;
 }
 
+static int
+rsa_compute_hash_sha256(const struct image_region region[], int region_count,
+		     uint8_t **out_hash)
+{
+	sha256_context ctx;
+	int i;
+	uint8_t *hash;
+
+	hash = calloc(1, SHA256_SUM_LEN);
+	if (!hash)
+		return -ENOMEM;
+
+	sha256_starts(&ctx);
+	for (i = 0; i < region_count; i++)
+		sha256_update(&ctx, region[i].data, region[i].size);
+	sha256_finish(&ctx, hash);
+
+	*out_hash = hash;
+
+	return 0;
+}
+
 static int rsa_compute_hash(struct image_sign_info *info,
 			   const struct image_region region[], int region_count,
 			   uint8_t **out_hash, const uint8_t **padding,
@@ -349,6 +403,10 @@ static int rsa_compute_hash(struct image_sign_info *info,
 		pad = padding_sha1_rsa2048;
 		len = RSA2048_BYTES - SHA1_SUM_LEN;
 		ret = rsa_compute_hash_sha1(region, region_count, out_hash);
+	} else if (!strcmp(info->algo->name, "sha256,rsa2048")) {
+		pad = padding_sha256_rsa2048;
+		len = RSA2048_BYTES - SHA256_SUM_LEN;
+		ret = rsa_compute_hash_sha256(region, region_count, out_hash);
 	} else {
 		ret = -EINVAL;
 	}
-- 
1.8.5.3