rsa: add a structure for the padding

The rsa signature use a padding algorithm. By default, we use the
padding pkcs-1.5. In order to add some new padding algorithm, we
add a padding framework to manage several padding algorithm.
The choice of the padding is done in the file .its.

Signed-off-by: Philippe Reynes <philippe.reynes@softathome.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

7 files changed, 116 insertions, 23 deletions

diff --git a/common/image-fit.c b/common/image-fit.c
index 8d39a243f8..ac901e131c 100644
--- a/common/image-fit.c
+++ b/common/image-fit.c
@@ -165,6 +165,7 @@ static void fit_image_print_data(const void *fit, int noffset, const char *p,
 	uint8_t *value;
 	int value_len;
 	char *algo;
+	const char *padding;
 	int required;
 	int ret, i;
 
@@ -184,6 +185,10 @@ static void fit_image_print_data(const void *fit, int noffset, const char *p,
 		printf(" (required)");
 	printf("\n");
 
+	padding = fdt_getprop(fit, noffset, "padding", NULL);
+	if (padding)
+		printf("%s  %s padding: %s\n", p, type, padding);
+
 	ret = fit_image_hash_get_value(fit, noffset, &value,
 				       &value_len);
 	printf("%s  %s value:   ", p, type);
diff --git a/common/image-sig.c b/common/image-sig.c
index 5d860e1266..3d8281f2fa 100644
--- a/common/image-sig.c
+++ b/common/image-sig.c
@@ -71,6 +71,13 @@ struct crypto_algo crypto_algos[] = {
 
 };
 
+struct padding_algo padding_algos[] = {
+	{
+		.name = "pkcs-1.5",
+		.verify = padding_pkcs_15_verify,
+	},
+};
+
 struct checksum_algo *image_get_checksum_algo(const char *full_name)
 {
 	int i;
@@ -106,6 +113,21 @@ struct crypto_algo *image_get_crypto_algo(const char *full_name)
 	return NULL;
 }
 
+struct padding_algo *image_get_padding_algo(const char *name)
+{
+	int i;
+
+	if (!name)
+		return NULL;
+
+	for (i = 0; i < ARRAY_SIZE(padding_algos); i++) {
+		if (!strcmp(padding_algos[i].name, name))
+			return &padding_algos[i];
+	}
+
+	return NULL;
+}
+
 /**
  * fit_region_make_list() - Make a list of image regions
  *
@@ -155,6 +177,7 @@ static int fit_image_setup_verify(struct image_sign_info *info,
 		char **err_msgp)
 {
 	char *algo_name;
+	const char *padding_name;
 
 	if (fdt_totalsize(fit) > CONFIG_FIT_SIGNATURE_MAX_SIZE) {
 		*err_msgp = "Total size too large";
@@ -165,6 +188,11 @@ static int fit_image_setup_verify(struct image_sign_info *info,
 		*err_msgp = "Can't get hash algo property";
 		return -1;
 	}
+
+	padding_name = fdt_getprop(fit, noffset, "padding", NULL);
+	if (!padding_name)
+		padding_name = RSA_DEFAULT_PADDING_NAME;
+
 	memset(info, '\0', sizeof(*info));
 	info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
 	info->fit = (void *)fit;
@@ -172,6 +200,7 @@ static int fit_image_setup_verify(struct image_sign_info *info,
 	info->name = algo_name;
 	info->checksum = image_get_checksum_algo(algo_name);
 	info->crypto = image_get_crypto_algo(algo_name);
+	info->padding = image_get_padding_algo(padding_name);
 	info->fdt_blob = gd_fdt_blob();
 	info->required_keynode = required_keynode;
 	printf("%s:%s", algo_name, info->keyname);
diff --git a/include/image.h b/include/image.h
index f67502e333..e75d1763b5 100644
--- a/include/image.h
+++ b/include/image.h
@@ -1101,6 +1101,7 @@ struct image_sign_info {
 	int node_offset;		/* Offset of signature node */
 	const char *name;		/* Algorithm name */
 	struct checksum_algo *checksum;	/* Checksum algorithm information */
+	struct padding_algo *padding;	/* Padding algorithm information */
 	struct crypto_algo *crypto;	/* Crypto algorithm information */
 	const void *fdt_blob;		/* FDT containing public keys */
 	int required_keynode;		/* Node offset of key to use: -1=any */
@@ -1186,6 +1187,13 @@ struct crypto_algo {
 		      uint8_t *sig, uint sig_len);
 };
 
+struct padding_algo {
+	const char *name;
+	int (*verify)(struct image_sign_info *info,
+		      uint8_t *pad, int pad_len,
+		      const uint8_t *hash, int hash_len);
+};
+
 /**
  * image_get_checksum_algo() - Look up a checksum algorithm
  *
@@ -1203,6 +1211,14 @@ struct checksum_algo *image_get_checksum_algo(const char *full_name);
 struct crypto_algo *image_get_crypto_algo(const char *full_name);
 
 /**
+ * image_get_padding_algo() - Look up a padding algorithm
+ *
+ * @param name		Name of padding algorithm
+ * @return pointer to algorithm information, or NULL if not found
+ */
+struct padding_algo *image_get_padding_algo(const char *name);
+
+/**
  * fit_image_verify_required_sigs() - Verify signatures marked as 'required'
  *
  * @fit:		FIT to check
diff --git a/include/u-boot/rsa.h b/include/u-boot/rsa.h
index 68bcb14c74..16b4c4caee 100644
--- a/include/u-boot/rsa.h
+++ b/include/u-boot/rsa.h
@@ -97,6 +97,10 @@ 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 padding_pkcs_15_verify(struct image_sign_info *info,
+			   uint8_t *msg, int msg_len,
+			   const uint8_t *hash, int hash_len);
 #else
 static inline int rsa_verify(struct image_sign_info *info,
 		const struct image_region region[], int region_count,
@@ -104,8 +108,17 @@ static inline int rsa_verify(struct image_sign_info *info,
 {
 	return -ENXIO;
 }
+
+static inline int padding_pkcs_15_verify(struct image_sign_info *info,
+					 uint8_t *msg, int msg_len,
+					 const uint8_t *hash, int hash_len)
+{
+	return -ENXIO;
+}
 #endif
 
+#define RSA_DEFAULT_PADDING_NAME		"pkcs-1.5"
+
 #define RSA2048_BYTES	(2048 / 8)
 #define RSA4096_BYTES	(4096 / 8)
 
diff --git a/lib/rsa/rsa-sign.c b/lib/rsa/rsa-sign.c
index 78e348eeea..6aa0e2ab5d 100644
--- a/lib/rsa/rsa-sign.c
+++ b/lib/rsa/rsa-sign.c
@@ -387,11 +387,13 @@ static void rsa_engine_remove(ENGINE *e)
 	}
 }
 
-static int rsa_sign_with_key(RSA *rsa, struct checksum_algo *checksum_algo,
+static int rsa_sign_with_key(RSA *rsa, struct padding_algo *padding_algo,
+			     struct checksum_algo *checksum_algo,
 		const struct image_region region[], int region_count,
 		uint8_t **sigp, uint *sig_size)
 {
 	EVP_PKEY *key;
+	EVP_PKEY_CTX *ckey;
 	EVP_MD_CTX *context;
 	int ret = 0;
 	size_t size;
@@ -422,7 +424,14 @@ static int rsa_sign_with_key(RSA *rsa, struct checksum_algo *checksum_algo,
 		goto err_create;
 	}
 	EVP_MD_CTX_init(context);
-	if (EVP_DigestSignInit(context, NULL,
+
+	ckey = EVP_PKEY_CTX_new(key, NULL);
+	if (!ckey) {
+		ret = rsa_err("EVP key context creation failed");
+		goto err_create;
+	}
+
+	if (EVP_DigestSignInit(context, &ckey,
 			       checksum_algo->calculate_sign(),
 			       NULL, key) <= 0) {
 		ret = rsa_err("Signer setup failed");
@@ -488,7 +497,7 @@ int rsa_sign(struct image_sign_info *info,
 	ret = rsa_get_priv_key(info->keydir, info->keyname, e, &rsa);
 	if (ret)
 		goto err_priv;
-	ret = rsa_sign_with_key(rsa, info->checksum, region,
+	ret = rsa_sign_with_key(rsa, info->padding, info->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 bc83354378..279a9ba456 100644
--- a/lib/rsa/rsa-verify.c
+++ b/lib/rsa/rsa-verify.c
@@ -57,31 +57,57 @@ static int rsa_verify_padding(const uint8_t *msg, const int pad_len,
 	return ret;
 }
 
+int padding_pkcs_15_verify(struct image_sign_info *info,
+			   uint8_t *msg, int msg_len,
+			   const uint8_t *hash, int hash_len)
+{
+	struct checksum_algo *checksum = info->checksum;
+	int ret, pad_len = msg_len - checksum->checksum_len;
+
+	/* Check pkcs1.5 padding bytes. */
+	ret = rsa_verify_padding(msg, pad_len, checksum);
+	if (ret) {
+		debug("In RSAVerify(): Padding check failed!\n");
+		return -EINVAL;
+	}
+
+	/* Check hash. */
+	if (memcmp((uint8_t *)msg + pad_len, hash, msg_len - pad_len)) {
+		debug("In RSAVerify(): Hash check failed!\n");
+		return -EACCES;
+	}
+
+	return 0;
+}
+
 /**
  * rsa_verify_key() - Verify a signature against some data using RSA Key
  *
  * Verify a RSA PKCS1.5 signature against an expected hash using
  * the RSA Key properties in prop structure.
  *
+ * @info:	Specifies key and FIT information
  * @prop:	Specifies key
  * @sig:	Signature
  * @sig_len:	Number of bytes in signature
  * @hash:	Pointer to the expected hash
  * @key_len:	Number of bytes in rsa key
- * @algo:	Checksum algo structure having information on DER encoding etc.
  * @return 0 if verified, -ve on error
  */
-static int rsa_verify_key(struct key_prop *prop, const uint8_t *sig,
+static int rsa_verify_key(struct image_sign_info *info,
+			  struct key_prop *prop, const uint8_t *sig,
 			  const uint32_t sig_len, const uint8_t *hash,
-			  const uint32_t key_len, struct checksum_algo *algo)
+			  const uint32_t key_len)
 {
-	int pad_len;
 	int ret;
 #if !defined(USE_HOSTCC)
 	struct udevice *mod_exp_dev;
 #endif
+	struct checksum_algo *checksum = info->checksum;
+	struct padding_algo *padding = info->padding;
+	int hash_len = checksum->checksum_len;
 
-	if (!prop || !sig || !hash || !algo)
+	if (!prop || !sig || !hash || !checksum)
 		return -EIO;
 
 	if (sig_len != (prop->num_bits / 8)) {
@@ -89,7 +115,7 @@ static int rsa_verify_key(struct key_prop *prop, const uint8_t *sig,
 		return -EINVAL;
 	}
 
-	debug("Checksum algorithm: %s", algo->name);
+	debug("Checksum algorithm: %s", checksum->name);
 
 	/* Sanity check for stack size */
 	if (sig_len > RSA_MAX_SIG_BITS / 8) {
@@ -116,19 +142,10 @@ static int rsa_verify_key(struct key_prop *prop, const uint8_t *sig,
 		return ret;
 	}
 
-	pad_len = key_len - algo->checksum_len;
-
-	/* Check pkcs1.5 padding bytes. */
-	ret = rsa_verify_padding(buf, pad_len, algo);
+	ret = padding->verify(info, buf, key_len, hash, hash_len);
 	if (ret) {
-		debug("In RSAVerify(): Padding check failed!\n");
-		return -EINVAL;
-	}
-
-	/* Check hash. */
-	if (memcmp((uint8_t *)buf + pad_len, hash, sig_len - pad_len)) {
-		debug("In RSAVerify(): Hash check failed!\n");
-		return -EACCES;
+		debug("In RSAVerify(): padding check failed!\n");
+		return ret;
 	}
 
 	return 0;
@@ -182,8 +199,8 @@ static int rsa_verify_with_keynode(struct image_sign_info *info,
 		return -EFAULT;
 	}
 
-	ret = rsa_verify_key(&prop, sig, sig_len, hash,
-			     info->crypto->key_len, info->checksum);
+	ret = rsa_verify_key(info, &prop, sig, sig_len, hash,
+			     info->crypto->key_len);
 
 	return ret;
 }
diff --git a/tools/image-host.c b/tools/image-host.c
index 09e4f47e5a..88b329502c 100644
--- a/tools/image-host.c
+++ b/tools/image-host.c
@@ -157,6 +157,7 @@ static int fit_image_setup_sig(struct image_sign_info *info,
 {
 	const char *node_name;
 	char *algo_name;
+	const char *padding_name;
 
 	node_name = fit_get_name(fit, noffset, NULL);
 	if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
@@ -165,6 +166,8 @@ static int fit_image_setup_sig(struct image_sign_info *info,
 		return -1;
 	}
 
+	padding_name = fdt_getprop(fit, noffset, "padding", NULL);
+
 	memset(info, '\0', sizeof(*info));
 	info->keydir = keydir;
 	info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
@@ -173,6 +176,7 @@ static int fit_image_setup_sig(struct image_sign_info *info,
 	info->name = strdup(algo_name);
 	info->checksum = image_get_checksum_algo(algo_name);
 	info->crypto = image_get_crypto_algo(algo_name);
+	info->padding = image_get_padding_algo(padding_name);
 	info->require_keys = require_keys;
 	info->engine_id = engine_id;
 	if (!info->checksum || !info->crypto) {