From 646257d1f4004855d486024527a4784bf57c4c4d Mon Sep 17 00:00:00 2001
From: Heiko Schocher <hs@denx.de>
Date: Mon, 3 Mar 2014 12:19:26 +0100
Subject: [PATCH] rsa: add sha256-rsa2048 algorithm

based on patch from andreas@oetken.name:

http://patchwork.ozlabs.org/patch/294318/
commit message:
I currently need support for rsa-sha256 signatures in u-boot and found out that
the code for signatures is not very generic. Thus adding of different
hash-algorithms for rsa-signatures is not easy to do without copy-pasting the
rsa-code. I attached a patch for how I think it could be better and included
support for rsa-sha256. This is a fast first shot.

aditionally work:
- removed checkpatch warnings
- removed compiler warnings
- rebased against current head

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: andreas@oetken.name
Cc: Simon Glass <sjg@chromium.org>
---
 common/image-sig.c                                 | 38 +++++++++
 doc/uImage.FIT/signature.txt                       | 14 +++-
 include/image.h                                    | 21 +++++
 include/rsa-checksum.h                             | 23 +++++
 include/rsa.h                                      | 14 ++++
 lib/rsa/Makefile                                   |  2 +-
 lib/rsa/rsa-checksum.c                             | 98 ++++++++++++++++++++++
 lib/rsa/rsa-sign.c                                 | 10 ++-
 lib/rsa/rsa-verify.c                               | 83 ++++++------------
 .../{sign-configs.its => sign-configs-sha1.its}    |  0
 test/vboot/sign-configs-sha256.its                 | 45 ++++++++++
 .../{sign-images.its => sign-images-sha1.its}      |  0
 test/vboot/sign-images-sha256.its                  | 42 ++++++++++
 test/vboot/vboot_test.sh                           | 66 ++++++++-------
 14 files changed, 363 insertions(+), 93 deletions(-)
 create mode 100644 include/rsa-checksum.h
 create mode 100644 lib/rsa/rsa-checksum.c
 rename test/vboot/{sign-configs.its => sign-configs-sha1.its} (100%)
 create mode 100644 test/vboot/sign-configs-sha256.its
 rename test/vboot/{sign-images.its => sign-images-sha1.its} (100%)
 create mode 100644 test/vboot/sign-images-sha256.its

diff --git a/common/image-sig.c b/common/image-sig.c
index 973b06d..8b6f49b 100644
--- a/common/image-sig.c
+++ b/common/image-sig.c
@@ -14,15 +14,53 @@ DECLARE_GLOBAL_DATA_PTR;
 #endif /* !USE_HOSTCC*/
 #include <image.h>
 #include <rsa.h>
+#include <rsa-checksum.h>
 
 #define IMAGE_MAX_HASHED_NODES		100
 
+#ifdef USE_HOSTCC
+__attribute__((weak)) void *get_blob(void)
+{
+	return NULL;
+}
+#endif
+
+struct checksum_algo checksum_algos[] = {
+	{
+		"sha1",
+		SHA1_SUM_LEN,
+#if IMAGE_ENABLE_SIGN
+		EVP_sha1,
+#else
+		sha1_calculate,
+		padding_sha1_rsa2048,
+#endif
+	},
+	{
+		"sha256",
+		SHA256_SUM_LEN,
+#if IMAGE_ENABLE_SIGN
+		EVP_sha256,
+#else
+		sha256_calculate,
+		padding_sha256_rsa2048,
+#endif
+	}
+};
 struct image_sig_algo image_sig_algos[] = {
 	{
 		"sha1,rsa2048",
 		rsa_sign,
 		rsa_add_verify_data,
 		rsa_verify,
+		&checksum_algos[0],
+	},
+	{
+		"sha256,rsa2048",
+		rsa_sign,
+		rsa_add_verify_data,
+		rsa_verify,
+		&checksum_algos[1],
 	}
 };
 
diff --git a/doc/uImage.FIT/signature.txt b/doc/uImage.FIT/signature.txt
index bc9f3fa..71f8b6c 100644
--- a/doc/uImage.FIT/signature.txt
+++ b/doc/uImage.FIT/signature.txt
@@ -346,7 +346,9 @@ Simple Verified Boot Test
 
 Please see doc/uImage.FIT/verified-boot.txt for more information
 
+/home/hs/ids/u-boot/sandbox/tools/mkimage -D -I dts -O dtb -p 2000
 Build keys
+do sha1 test
 Build FIT with signed images
 Test Verified Boot Run: unsigned signatures:: OK
 Sign images
@@ -355,10 +357,20 @@ Build FIT with signed configuration
 Test Verified Boot Run: unsigned config: OK
 Sign images
 Test Verified Boot Run: signed config: OK
+Test Verified Boot Run: signed config with bad hash: OK
+do sha256 test
+Build FIT with signed images
+Test Verified Boot Run: unsigned signatures:: OK
+Sign images
+Test Verified Boot Run: signed images: OK
+Build FIT with signed configuration
+Test Verified Boot Run: unsigned config: OK
+Sign images
+Test Verified Boot Run: signed config: OK
+Test Verified Boot Run: signed config with bad hash: OK
 
 Test passed
 
-
 Future Work
 -----------
 - Roll-back protection using a TPM is done using the tpm command. This can
diff --git a/include/image.h b/include/image.h
index 52969aa..44b2b46 100644
--- a/include/image.h
+++ b/include/image.h
@@ -833,6 +833,7 @@ int calculate_hash(const void *data, int data_len, const char *algo,
 # ifdef USE_HOSTCC
 #  define IMAGE_ENABLE_SIGN	1
 #  define IMAGE_ENABLE_VERIFY	0
+# include  <openssl/evp.h>
 #else
 #  define IMAGE_ENABLE_SIGN	0
 #  define IMAGE_ENABLE_VERIFY	1
@@ -872,6 +873,23 @@ struct image_region {
 	int size;
 };
 
+#if IMAGE_ENABLE_VERIFY
+# include <rsa-checksum.h>
+#endif
+struct checksum_algo {
+	const char *name;
+	const int checksum_len;
+#if IMAGE_ENABLE_SIGN
+	const EVP_MD *(*calculate)(void);
+#else
+#if IMAGE_ENABLE_VERIFY
+	void (*calculate)(const struct image_region region[],
+			  int region_count, uint8_t *checksum);
+	const uint8_t *rsa_padding;
+#endif
+#endif
+};
+
 struct image_sig_algo {
 	const char *name;		/* Name of algorithm */
 
@@ -922,6 +940,9 @@ struct image_sig_algo {
 	int (*verify)(struct image_sign_info *info,
 		      const struct image_region region[], int region_count,
 		      uint8_t *sig, uint sig_len);
+
+	/* pointer to checksum algorithm */
+	struct checksum_algo *checksum;
 };
 
 /**
diff --git a/include/rsa-checksum.h b/include/rsa-checksum.h
new file mode 100644
index 0000000..850b253
--- /dev/null
+++ b/include/rsa-checksum.h
@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2013, Andreas Oetken.
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+*/
+
+#ifndef _RSA_CHECKSUM_H
+#define _RSA_CHECKSUM_H
+
+#include <errno.h>
+#include <image.h>
+#include <sha1.h>
+#include <sha256.h>
+
+extern const uint8_t padding_sha256_rsa2048[];
+extern const uint8_t padding_sha1_rsa2048[];
+
+void sha256_calculate(const struct image_region region[], int region_count,
+		      uint8_t *checksum);
+void sha1_calculate(const struct image_region region[], int region_count,
+		    uint8_t *checksum);
+
+#endif
diff --git a/include/rsa.h b/include/rsa.h
index add4c78..e9ae870 100644
--- a/include/rsa.h
+++ b/include/rsa.h
@@ -15,6 +15,20 @@
 #include <errno.h>
 #include <image.h>
 
+/**
+ * struct rsa_public_key - holder for a public key
+ *
+ * An RSA public key consists of a modulus (typically called N), the inverse
+ * and R^2, where R is 2^(# key bits).
+ */
+
+struct rsa_public_key {
+	uint len;		/* len of modulus[] in number of uint32_t */
+	uint32_t n0inv;		/* -1 / modulus[0] mod 2^32 */
+	uint32_t *modulus;	/* modulus as little endian array */
+	uint32_t *rr;		/* R^2 as little endian array */
+};
+
 #if IMAGE_ENABLE_SIGN
 /**
  * sign() - calculate and return signature for given input data
diff --git a/lib/rsa/Makefile b/lib/rsa/Makefile
index 164ab39..a5a96cb6 100644
--- a/lib/rsa/Makefile
+++ b/lib/rsa/Makefile
@@ -7,4 +7,4 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-obj-$(CONFIG_FIT_SIGNATURE) += rsa-verify.o
+obj-$(CONFIG_FIT_SIGNATURE) += rsa-verify.o rsa-checksum.o
diff --git a/lib/rsa/rsa-checksum.c b/lib/rsa/rsa-checksum.c
new file mode 100644
index 0000000..e520e1c
--- /dev/null
+++ b/lib/rsa/rsa-checksum.c
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2013, Andreas Oetken.
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+
+#include <common.h>
+#include <fdtdec.h>
+#include <rsa.h>
+#include <sha1.h>
+#include <sha256.h>
+#include <asm/byteorder.h>
+#include <asm/errno.h>
+#include <asm/unaligned.h>
+
+#define RSA2048_BYTES 256
+
+/* PKCS 1.5 paddings as described in the RSA PKCS#1 v2.1 standard. */
+
+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
+};
+
+const uint8_t padding_sha1_rsa2048[RSA2048_BYTES - SHA1_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, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+	0xff, 0xff, 0xff, 0xff, 0x00, 0x30, 0x21, 0x30,
+	0x09, 0x06, 0x05, 0x2b, 0x0e, 0x03, 0x02, 0x1a,
+	0x05, 0x00, 0x04, 0x14
+};
+
+void sha1_calculate(const struct image_region region[], int region_count,
+		    uint8_t *checksum)
+{
+	sha1_context ctx;
+	uint32_t i;
+	i = 0;
+
+	sha1_starts(&ctx);
+	for (i = 0; i < region_count; i++)
+		sha1_update(&ctx, region[i].data, region[i].size);
+	sha1_finish(&ctx, checksum);
+}
+
+void sha256_calculate(const struct image_region region[], int region_count,
+		      uint8_t *checksum)
+{
+	sha256_context ctx;
+	uint32_t i;
+	i = 0;
+
+	sha256_starts(&ctx);
+	for (i = 0; i < region_count; i++)
+		sha256_update(&ctx, region[i].data, region[i].size);
+	sha256_finish(&ctx, checksum);
+}
diff --git a/lib/rsa/rsa-sign.c b/lib/rsa/rsa-sign.c
index 549130e..0fe6e9f 100644
--- a/lib/rsa/rsa-sign.c
+++ b/lib/rsa/rsa-sign.c
@@ -159,8 +159,9 @@ static void rsa_remove(void)
 	EVP_cleanup();
 }
 
-static int rsa_sign_with_key(RSA *rsa, const struct image_region region[],
-		int region_count, uint8_t **sigp, uint *sig_size)
+static int rsa_sign_with_key(RSA *rsa, struct checksum_algo *checksum_algo,
+		const struct image_region region[], int region_count,
+		uint8_t **sigp, uint *sig_size)
 {
 	EVP_PKEY *key;
 	EVP_MD_CTX *context;
@@ -192,7 +193,7 @@ static int rsa_sign_with_key(RSA *rsa, const struct image_region region[],
 		goto err_create;
 	}
 	EVP_MD_CTX_init(context);
-	if (!EVP_SignInit(context, EVP_sha1())) {
+	if (!EVP_SignInit(context, checksum_algo->calculate())) {
 		ret = rsa_err("Signer setup failed");
 		goto err_sign;
 	}
@@ -242,7 +243,8 @@ int rsa_sign(struct image_sign_info *info,
 	ret = rsa_get_priv_key(info->keydir, info->keyname, &rsa);
 	if (ret)
 		goto err_priv;
-	ret = rsa_sign_with_key(rsa, region, region_count, sigp, sig_len);
+	ret = rsa_sign_with_key(rsa, info->algo->checksum, region,
+				region_count, sigp, sig_len);
 	if (ret)
 		goto err_sign;
 
diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
index 02cc4e3..b3573a8 100644
--- a/lib/rsa/rsa-verify.c
+++ b/lib/rsa/rsa-verify.c
@@ -8,23 +8,11 @@
 #include <fdtdec.h>
 #include <rsa.h>
 #include <sha1.h>
+#include <sha256.h>
 #include <asm/byteorder.h>
 #include <asm/errno.h>
 #include <asm/unaligned.h>
 
-/**
- * struct rsa_public_key - holder for a public key
- *
- * An RSA public key consists of a modulus (typically called N), the inverse
- * and R^2, where R is 2^(# key bits).
- */
-struct rsa_public_key {
-	uint len;		/* Length of modulus[] in number of uint32_t */
-	uint32_t n0inv;		/* -1 / modulus[0] mod 2^32 */
-	uint32_t *modulus;	/* modulus as little endian array */
-	uint32_t *rr;		/* R^2 as little endian array */
-};
-
 #define UINT64_MULT32(v, multby)  (((uint64_t)(v)) * ((uint32_t)(multby)))
 
 #define RSA2048_BYTES	(2048 / 8)
@@ -36,39 +24,6 @@ struct rsa_public_key {
 /* This is the maximum signature length that we support, in bits */
 #define RSA_MAX_SIG_BITS	2048
 
-static const uint8_t padding_sha1_rsa2048[RSA2048_BYTES - SHA1_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, 0xff, 0xff, 0xff, 0xff,
-	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x30, 0x21, 0x30,
-	0x09, 0x06, 0x05, 0x2b, 0x0e, 0x03, 0x02, 0x1a,
-	0x05, 0x00, 0x04, 0x14
-};
-
 /**
  * subtract_modulus() - subtract modulus from the given value
  *
@@ -209,13 +164,14 @@ static int pow_mod(const struct rsa_public_key *key, uint32_t *inout)
 }
 
 static int rsa_verify_key(const struct rsa_public_key *key, const uint8_t *sig,
-		const uint32_t sig_len, const uint8_t *hash)
+			  const uint32_t sig_len, const uint8_t *hash,
+			  struct checksum_algo *algo)
 {
 	const uint8_t *padding;
 	int pad_len;
 	int ret;
 
-	if (!key || !sig || !hash)
+	if (!key || !sig || !hash || !algo)
 		return -EIO;
 
 	if (sig_len != (key->len * sizeof(uint32_t))) {
@@ -223,6 +179,8 @@ static int rsa_verify_key(const struct rsa_public_key *key, const uint8_t *sig,
 		return -EINVAL;
 	}
 
+	debug("Checksum algorithm: %s", algo->name);
+
 	/* Sanity check for stack size */
 	if (sig_len > RSA_MAX_SIG_BITS / 8) {
 		debug("Signature length %u exceeds maximum %d\n", sig_len,
@@ -238,9 +196,8 @@ static int rsa_verify_key(const struct rsa_public_key *key, const uint8_t *sig,
 	if (ret)
 		return ret;
 
-	/* Determine padding to use depending on the signature type. */
-	padding = padding_sha1_rsa2048;
-	pad_len = RSA2048_BYTES - SHA1_SUM_LEN;
+	padding = algo->rsa_padding;
+	pad_len = RSA2048_BYTES - algo->checksum_len;
 
 	/* Check pkcs1.5 padding bytes. */
 	if (memcmp(buf, padding, pad_len)) {
@@ -309,7 +266,7 @@ static int rsa_verify_with_keynode(struct image_sign_info *info,
 	}
 
 	debug("key length %d\n", key.len);
-	ret = rsa_verify_key(&key, sig, sig_len, hash);
+	ret = rsa_verify_key(&key, sig, sig_len, hash, info->algo->checksum);
 	if (ret) {
 		printf("%s: RSA failed to verify: %d\n", __func__, ret);
 		return ret;
@@ -323,12 +280,22 @@ int rsa_verify(struct image_sign_info *info,
 	       uint8_t *sig, uint sig_len)
 {
 	const void *blob = info->fdt_blob;
-	uint8_t hash[SHA1_SUM_LEN];
+	/* Reserve memory for maximum checksum-length */
+	uint8_t hash[RSA2048_BYTES];
 	int ndepth, noffset;
 	int sig_node, node;
 	char name[100];
-	sha1_context ctx;
-	int ret, i;
+	int ret;
+
+	/*
+	 * Verify that the checksum-length does not exceed the
+	 * rsa-signature-length
+	 */
+	if (info->algo->checksum->checksum_len > RSA2048_BYTES) {
+		debug("%s: invlaid checksum-algorithm %s for RSA2048\n",
+		      __func__, info->algo->checksum->name);
+		return -EINVAL;
+	}
 
 	sig_node = fdt_subnode_offset(blob, 0, FIT_SIG_NODENAME);
 	if (sig_node < 0) {
@@ -336,10 +303,8 @@ int rsa_verify(struct image_sign_info *info,
 		return -ENOENT;
 	}
 
-	sha1_starts(&ctx);
-	for (i = 0; i < region_count; i++)
-		sha1_update(&ctx, region[i].data, region[i].size);
-	sha1_finish(&ctx, hash);
+	/* Calculate checksum with checksum-algorithm */
+	info->algo->checksum->calculate(region, region_count, hash);
 
 	/* See if we must use a particular key */
 	if (info->required_keynode != -1) {
diff --git a/test/vboot/sign-configs.its b/test/vboot/sign-configs-sha1.its
similarity index 100%
rename from test/vboot/sign-configs.its
rename to test/vboot/sign-configs-sha1.its
diff --git a/test/vboot/sign-configs-sha256.its b/test/vboot/sign-configs-sha256.its
new file mode 100644
index 0000000..1b3432e
--- /dev/null
+++ b/test/vboot/sign-configs-sha256.its
@@ -0,0 +1,45 @@
+/dts-v1/;
+
+/ {
+	description = "Chrome OS kernel image with one or more FDT blobs";
+	#address-cells = <1>;
+
+	images {
+		kernel@1 {
+			data = /incbin/("test-kernel.bin");
+			type = "kernel_noload";
+			arch = "sandbox";
+			os = "linux";
+			compression = "none";
+			load = <0x4>;
+			entry = <0x8>;
+			kernel-version = <1>;
+			hash@1 {
+				algo = "sha256";
+			};
+		};
+		fdt@1 {
+			description = "snow";
+			data = /incbin/("sandbox-kernel.dtb");
+			type = "flat_dt";
+			arch = "sandbox";
+			compression = "none";
+			fdt-version = <1>;
+			hash@1 {
+				algo = "sha256";
+			};
+		};
+	};
+	configurations {
+		default = "conf@1";
+		conf@1 {
+			kernel = "kernel@1";
+			fdt = "fdt@1";
+			signature@1 {
+				algo = "sha256,rsa2048";
+				key-name-hint = "dev";
+				sign-images = "fdt", "kernel";
+			};
+		};
+	};
+};
diff --git a/test/vboot/sign-images.its b/test/vboot/sign-images-sha1.its
similarity index 100%
rename from test/vboot/sign-images.its
rename to test/vboot/sign-images-sha1.its
diff --git a/test/vboot/sign-images-sha256.its b/test/vboot/sign-images-sha256.its
new file mode 100644
index 0000000..e6aa9fc
--- /dev/null
+++ b/test/vboot/sign-images-sha256.its
@@ -0,0 +1,42 @@
+/dts-v1/;
+
+/ {
+	description = "Chrome OS kernel image with one or more FDT blobs";
+	#address-cells = <1>;
+
+	images {
+		kernel@1 {
+			data = /incbin/("test-kernel.bin");
+			type = "kernel_noload";
+			arch = "sandbox";
+			os = "linux";
+			compression = "none";
+			load = <0x4>;
+			entry = <0x8>;
+			kernel-version = <1>;
+			signature@1 {
+				algo = "sha256,rsa2048";
+				key-name-hint = "dev";
+			};
+		};
+		fdt@1 {
+			description = "snow";
+			data = /incbin/("sandbox-kernel.dtb");
+			type = "flat_dt";
+			arch = "sandbox";
+			compression = "none";
+			fdt-version = <1>;
+			signature@1 {
+				algo = "sha256,rsa2048";
+				key-name-hint = "dev";
+			};
+		};
+	};
+	configurations {
+		default = "conf@1";
+		conf@1 {
+			kernel = "kernel@1";
+			fdt = "fdt@1";
+		};
+	};
+};
diff --git a/test/vboot/vboot_test.sh b/test/vboot/vboot_test.sh
index bb2c605..3e2856e 100755
--- a/test/vboot/vboot_test.sh
+++ b/test/vboot/vboot_test.sh
@@ -61,47 +61,57 @@ openssl req -batch -new -x509 -key ${keys}/dev.key -out ${keys}/dev.crt
 
 pushd ${dir} >/dev/null
 
-# Compile our device tree files for kernel and U-Boot (CONFIG_OF_CONTROL)
-dtc -p 0x1000 sandbox-kernel.dts -O dtb -o sandbox-kernel.dtb
-dtc -p 0x1000 sandbox-u-boot.dts -O dtb -o sandbox-u-boot.dtb
+function do_test {
+	echo do $sha test
+	# Compile our device tree files for kernel and U-Boot
+	dtc -p 0x1000 sandbox-kernel.dts -O dtb -o sandbox-kernel.dtb
+	dtc -p 0x1000 sandbox-u-boot.dts -O dtb -o sandbox-u-boot.dtb
 
-# Create a number kernel image with zeroes
-head -c 5000 /dev/zero >test-kernel.bin
+	# Create a number kernel image with zeroes
+	head -c 5000 /dev/zero >test-kernel.bin
 
-# Build the FIT, but don't sign anything yet
-echo Build FIT with signed images
-${mkimage} -D "${dtc}" -f sign-images.its test.fit >${tmp}
+	# Build the FIT, but don't sign anything yet
+	echo Build FIT with signed images
+	${mkimage} -D "${dtc}" -f sign-images-$sha.its test.fit >${tmp}
 
-run_uboot "unsigned signatures:" "dev-"
+	run_uboot "unsigned signatures:" "dev-"
 
-# Sign images with our dev keys
-echo Sign images
-${mkimage} -D "${dtc}" -F -k dev-keys -K sandbox-u-boot.dtb -r test.fit >${tmp}
+	# Sign images with our dev keys
+	echo Sign images
+	${mkimage} -D "${dtc}" -F -k dev-keys -K sandbox-u-boot.dtb \
+		-r test.fit >${tmp}
 
-run_uboot "signed images" "dev+"
+	run_uboot "signed images" "dev+"
 
 
-# Create a fresh .dtb without the public keys
-dtc -p 0x1000 sandbox-u-boot.dts -O dtb -o sandbox-u-boot.dtb
+	# Create a fresh .dtb without the public keys
+	dtc -p 0x1000 sandbox-u-boot.dts -O dtb -o sandbox-u-boot.dtb
 
-echo Build FIT with signed configuration
-${mkimage} -D "${dtc}" -f sign-configs.its test.fit >${tmp}
+	echo Build FIT with signed configuration
+	${mkimage} -D "${dtc}" -f sign-configs-$sha.its test.fit >${tmp}
 
-run_uboot "unsigned config" "sha1+ OK"
+	run_uboot "unsigned config" $sha"+ OK"
 
-# Sign images with our dev keys
-echo Sign images
-${mkimage} -D "${dtc}" -F -k dev-keys -K sandbox-u-boot.dtb -r test.fit >${tmp}
+	# Sign images with our dev keys
+	echo Sign images
+	${mkimage} -D "${dtc}" -F -k dev-keys -K sandbox-u-boot.dtb \
+		-r test.fit >${tmp}
 
-run_uboot "signed config" "dev+"
+	run_uboot "signed config" "dev+"
 
-# Increment the first byte of the signature, which should cause failure
-sig=$(fdtget -t bx test.fit /configurations/conf@1/signature@1 value)
-newbyte=$(printf %x $((0x${sig:0:2} + 1)))
-sig="${newbyte} ${sig:2}"
-fdtput -t bx test.fit /configurations/conf@1/signature@1 value ${sig}
+	# Increment the first byte of the signature, which should cause failure
+	sig=$(fdtget -t bx test.fit /configurations/conf@1/signature@1 value)
+	newbyte=$(printf %x $((0x${sig:0:2} + 1)))
+	sig="${newbyte} ${sig:2}"
+	fdtput -t bx test.fit /configurations/conf@1/signature@1 value ${sig}
 
-run_uboot "signed config with bad hash" "Bad Data Hash"
+	run_uboot "signed config with bad hash" "Bad Data Hash"
+}
+
+sha=sha1
+do_test
+sha=sha256
+do_test
 
 popd >/dev/null
 
-- 
2.7.4