[nrf fromtree] bootutil: Allow SHA512 with TinyCrypt

The commit enables SHA512 support, for image hashing, with
TinyCrypt.
Although on 32bit machines the SHA256 will be faster than
SHA512, benefit of enabling the SHA512 is that you have only
one algorithm compiled in which reduces size of code.

Signed-off-by: Dominik Ermel <dominik.ermel@nordicsemi.no>
(cherry picked from commit f72158f)

boot/bootutil/include/bootutil/crypto/sha.h

@@ -70,7 +70,11 @@
 #endif /* MCUBOOT_USE_MBED_TLS */
 
 #if defined(MCUBOOT_USE_TINYCRYPT)
+#if defined(MCUBOOT_SHA512)
+    #include <tinycrypt/sha512.h>
+#else
     #include <tinycrypt/sha256.h>
+#endif
     #include <tinycrypt/constants.h>
 #endif /* MCUBOOT_USE_TINYCRYPT */
 
@@ -193,11 +197,19 @@ static inline int bootutil_sha_finish(bootutil_sha_context *ctx,
 #endif /* MCUBOOT_USE_MBED_TLS */
 
 #if defined(MCUBOOT_USE_TINYCRYPT)
+#if defined(MCUBOOT_SHA512)
+typedef struct tc_sha512_state_struct bootutil_sha_context;
+#else
 typedef struct tc_sha256_state_struct bootutil_sha_context;
+#endif
 
 static inline int bootutil_sha_init(bootutil_sha_context *ctx)
 {
+#if defined(MCUBOOT_SHA512)
+    tc_sha512_init(ctx);
+#else
     tc_sha256_init(ctx);
+#endif
     return 0;
 }
 
@@ -211,13 +223,21 @@ static inline int bootutil_sha_update(bootutil_sha_context *ctx,
                                       const void *data,
                                       uint32_t data_len)
 {
+#if defined(MCUBOOT_SHA512)
+    return tc_sha512_update(ctx, data, data_len);
+#else
     return tc_sha256_update(ctx, data, data_len);
+#endif
 }
 
 static inline int bootutil_sha_finish(bootutil_sha_context *ctx,
                                       uint8_t *output)
 {
+#if defined(MCUBOOT_SHA512)
+    return tc_sha512_final(output, ctx);
+#else
     return tc_sha256_final(output, ctx);
+#endif
 }
 #endif /* MCUBOOT_USE_TINYCRYPT */
 

boot/bootutil/src/image_ed25519.c

@@ -21,12 +21,14 @@
 #include "bootutil/crypto/common.h"
 #include "bootutil/crypto/sha.h"
 
+#define EDDSA_SIGNATURE_LENGTH 64
+
 static const uint8_t ed25519_pubkey_oid[] = MBEDTLS_OID_ISO_IDENTIFIED_ORG "\x65\x70";
 #define NUM_ED25519_BYTES 32
 
 extern int ED25519_verify(const uint8_t *message, size_t message_len,
-                          const uint8_t signature[64],
-                          const uint8_t public_key[32]);
+                          const uint8_t signature[EDDSA_SIGNATURE_LENGTH],
+                          const uint8_t public_key[NUM_ED25519_BYTES]);
 
 /*
  * Parse the public key used for signing.
@@ -76,7 +78,8 @@ bootutil_verify_sig(uint8_t *hash, uint32_t hlen, uint8_t *sig, size_t slen,
     uint8_t *pubkey;
     uint8_t *end;
 
-    if (hlen != IMAGE_HASH_SIZE || slen != 64) {
+    if (hlen != IMAGE_HASH_SIZE ||
+        slen != EDDSA_SIGNATURE_LENGTH) {
         FIH_SET(fih_rc, FIH_FAILURE);
         goto out;
     }