[U-Boot] [PATCH 4/7] rsa: add sha256-rsa2048 algorithm

25 Jan 2014

based on patch from andreas@oetken.name:
http://patchwork.ozlabs.org/patch/294318/
- removed checkpatch warnings
- removed compiler warnings
- rebased against current head
Signed-off-by: Heiko Schocher hs@denx.de
Cc: Simon Glass sjg@chromium.org
Cc: andreas@oetken.name
---
 common/image-sig.c     | 33 +++++++++++++++++
 include/image.h        | 21 +++++++++++
 include/rsa-checksum.h | 25 +++++++++++++
 include/rsa.h          | 25 +++++++++++++
 lib/rsa/Makefile       |  2 +-
 lib/rsa/rsa-checksum.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++
 lib/rsa/rsa-sign.c     | 10 +++---
 lib/rsa/rsa-verify.c   | 83 +++++++++++++-----------------------------
 8 files changed, 233 insertions(+), 64 deletions(-)
 create mode 100644 include/rsa-checksum.h
 create mode 100644 lib/rsa/rsa-checksum.c

diff --git a/common/image-sig.c b/common/image-sig.c
index 973b06d..8b212a7 100644
--- a/common/image-sig.c
+++ b/common/image-sig.c
@@ -14,15 +14,47 @@ DECLARE_GLOBAL_DATA_PTR;
 #endif /* !USE_HOSTCC*/
 #include <image.h>
 #include <rsa.h>
+#include <rsa-checksum.h>
#define IMAGE_MAX_HASHED_NODES		100
+#if defined(CONFIG_FIT_SIGNATURE)
+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],
    }
 };
@@ -407,3 +439,4 @@ int fit_config_verify(const void *fit, int conf_noffset)
    return !fit_config_verify_required_sigs(fit, conf_noffset,
    					gd_fdt_blob());
 }
+#endif
diff --git a/include/image.h b/include/image.h
index f001a5f..eb3429f 100644
--- a/include/image.h
+++ b/include/image.h
@@ -832,6 +832,7 @@ 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
@@ -871,6 +872,23 @@ 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 */
@@ -921,6 +939,9 @@ 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..12494a6
--- /dev/null
+++ b/include/rsa-checksum.h
@@ -0,0 +1,25 @@
+/*
+ * 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>
+
+#if IMAGE_ENABLE_VERIFY
+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
+
+#endif
diff --git a/include/rsa.h b/include/rsa.h
index add4c78..adf809b 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;        /* 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 */
+};
+
 #if IMAGE_ENABLE_SIGN
 /**
  * sign() - calculate and return signature for given input data
@@ -80,6 +94,10 @@ static inline int rsa_add_verify_data(struct image_sign_info *info,
 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_256(struct image_sign_info *info,
+	       const struct image_region region[], int region_count,
+	       uint8_t *sig, uint sig_len);
 #else
 static inline int rsa_verify(struct image_sign_info *info,
    	const struct image_region region[], int region_count,
@@ -87,6 +105,13 @@ static inline int rsa_verify(struct image_sign_info *info,
 {
    return -ENXIO;
 }
+
+static inline int rsa_verify_256(struct image_sign_info *info,
+		const struct image_region region[], int region_count,
+		uint8_t *sig, uint sig_len)
+{
+	return -ENXIO;
+}
 #endif
#endif
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) {
-- 
1.8.3.1


    