SECURE BOOT: separate function created for signature

The code for image hash calculation, hash calculation from
RSA signature and comparison of hashes has been mobed to a
separate function.

Signed-off-by: Saksham Jain <saksham@freescale.com>
Signed-off-by: Aneesh Bansal <aneesh.bansal@freescale.com>
Acked-by: Ruchika Gupta <ruchika.gupta@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>

diff --git a/board/freescale/common/fsl_validate.c b/board/freescale/common/fsl_validate.c
index ef7a5ae..08a2f79 100644 (file)
--- a/board/freescale/common/fsl_validate.c
+++ b/board/freescale/common/fsl_validate.c
@@ -721,6 +721,58 @@ static inline int str2longbe(const char *p, ulong *num)
 
        return *p != '\0' && *endptr == '\0';
 }
+/* Function to calculate the ESBC Image Hash
+ * and hash from Digital signature.
+ * The Two hash's are compared to yield the
+ * result of signature validation.
+ */
+static int calculate_cmp_img_sig(struct fsl_secboot_img_priv *img)
+{
+       int ret;
+       uint32_t key_len;
+       struct key_prop prop;
+#if !defined(USE_HOSTCC)
+       struct udevice *mod_exp_dev;
+#endif
+       ret = calc_esbchdr_esbc_hash(img);
+       if (ret)
+               return ret;
+
+       /* Construct encoded hash EM' wrt PKCSv1.5 */
+       construct_img_encoded_hash_second(img);
+
+       /* Fill prop structure for public key */
+       memset(&prop, 0, sizeof(struct key_prop));
+       key_len = get_key_len(img) / 2;
+       prop.modulus = img->img_key;
+       prop.public_exponent = img->img_key + key_len;
+       prop.num_bits = key_len * 8;
+       prop.exp_len = key_len;
+
+       ret = uclass_get_device(UCLASS_MOD_EXP, 0, &mod_exp_dev);
+       if (ret) {
+               printf("RSA: Can't find Modular Exp implementation\n");
+               return -EINVAL;
+       }
+
+       ret = rsa_mod_exp(mod_exp_dev, img->img_sign, img->hdr.sign_len,
+                         &prop, img->img_encoded_hash);
+       if (ret)
+               return ret;
+
+       /*
+        * compare the encoded messages EM' and EM wrt RSA PKCSv1.5
+        * memcmp returns zero on success
+        * memcmp returns non-zero on failure
+        */
+       ret = memcmp(&img->img_encoded_hash_second, &img->img_encoded_hash,
+               img->hdr.sign_len);
+
+       if (ret)
+               return ERROR_ESBC_CLIENT_HASH_COMPARE_EM;
+
+       return 0;
+}
 
 int fsl_secboot_validate(ulong haddr, char *arg_hash_str)
 {
@@ -732,11 +784,6 @@ int fsl_secboot_validate(ulong haddr, char *arg_hash_str)
        void *esbc;
        int ret, i, hash_cmd = 0;
        u32 srk_hash[8];
-       uint32_t key_len;
-       struct key_prop prop;
-#if !defined(USE_HOSTCC)
-       struct udevice *mod_exp_dev;
-#endif
 
        if (arg_hash_str != NULL) {
                const char *cp = arg_hash_str;
@@ -821,46 +868,9 @@ int fsl_secboot_validate(ulong haddr, char *arg_hash_str)
                goto exit;
        }
 
-       ret = calc_esbchdr_esbc_hash(img);
-       if (ret) {
-               fsl_secblk_handle_error(ret);
-               goto exit;
-       }
-
-       /* Construct encoded hash EM' wrt PKCSv1.5 */
-       construct_img_encoded_hash_second(img);
-
-       /* Fill prop structure for public key */
-       memset(&prop, 0, sizeof(struct key_prop));
-       key_len = get_key_len(img) / 2;
-       prop.modulus = img->img_key;
-       prop.public_exponent = img->img_key + key_len;
-       prop.num_bits = key_len * 8;
-       prop.exp_len = key_len;
-
-       ret = uclass_get_device(UCLASS_MOD_EXP, 0, &mod_exp_dev);
-       if (ret) {
-               printf("RSA: Can't find Modular Exp implementation\n");
-               return -EINVAL;
-       }
-
-       ret = rsa_mod_exp(mod_exp_dev, img->img_sign, img->hdr.sign_len,
-                         &prop, img->img_encoded_hash);
-       if (ret) {
-               fsl_secblk_handle_error(ret);
-               goto exit;
-       }
-
-       /*
-        * compare the encoded messages EM' and EM wrt RSA PKCSv1.5
-        * memcmp returns zero on success
-        * memcmp returns non-zero on failure
-        */
-       ret = memcmp(&img->img_encoded_hash_second, &img->img_encoded_hash,
-               img->hdr.sign_len);
-
+       ret = calculate_cmp_img_sig(img);
        if (ret) {
-               fsl_secboot_handle_error(ERROR_ESBC_CLIENT_HASH_COMPARE_EM);
+               fsl_secboot_handle_error(ret);
                goto exit;
        }