refactor(security): upgrade tools to OpenSSL 3.0

Host tools cert_tool and encrypt_fw refactored to be fully
compatible with OpenSSL v3.0.

Changes were made following the OpenSSL 3.0 migration guide:
https://www.openssl.org/docs/man3.0/man7/migration_guide.html
In some cases, those changes are straightforward and only
a small modification on the types or API calls was needed
(e.g.: replacing BN_pseudo_rand() with BN_rand(). Both identical
since v1.1.0).
The use of low level APIs is now deprecated. In some cases,
the new API provides a simplified solution for our goals and
therefore the code was simplified accordingly (e.g.: generating
RSA keys through EVP_RSA_gen() without the need of handling the
exponent). However, in some cases, a more
sophisticated approach was necessary, as the use of a context
object was required (e.g.: when retrieving the digest value from
an SHA file).

Signed-off-by: Juan Pablo Conde <juanpablo.conde@arm.com>
Change-Id: I978e8578fe7ab3e71307450ebe7e7812fbcaedb6
diff --git a/tools/cert_create/src/sha.c b/tools/cert_create/src/sha.c
index 3d977fb..06ef360 100644
--- a/tools/cert_create/src/sha.c
+++ b/tools/cert_create/src/sha.c
@@ -1,26 +1,38 @@
 /*
- * Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2022, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#include <openssl/sha.h>
 #include <stdio.h>
 #include "debug.h"
 #include "key.h"
+#include <openssl/evp.h>
+#include <openssl/obj_mac.h>
 
 #define BUFFER_SIZE	256
 
+static int get_algorithm_nid(int hash_alg)
+{
+	int nids[] = {NID_sha256, NID_sha384, NID_sha512};
+	if (hash_alg < 0 || hash_alg >= sizeof(nids) / sizeof(*nids)) {
+		return NID_undef;
+	}
+	return nids[hash_alg];
+}
+
 int sha_file(int md_alg, const char *filename, unsigned char *md)
 {
 	FILE *inFile;
-	SHA256_CTX shaContext;
-	SHA512_CTX sha512Context;
+	EVP_MD_CTX *mdctx;
+	const EVP_MD *md_type;
 	int bytes;
+	int alg_nid;
+	unsigned int total_bytes;
 	unsigned char data[BUFFER_SIZE];
 
 	if ((filename == NULL) || (md == NULL)) {
-		ERROR("%s(): NULL argument\n", __FUNCTION__);
+		ERROR("%s(): NULL argument\n", __func__);
 		return 0;
 	}
 
@@ -30,26 +42,37 @@
 		return 0;
 	}
 
+	mdctx = EVP_MD_CTX_new();
+	if (mdctx == NULL) {
+		fclose(inFile);
+		ERROR("%s(): Could not create EVP MD context\n", __func__);
+		return 0;
+	}
+
-	if (md_alg == HASH_ALG_SHA384) {
-		SHA384_Init(&sha512Context);
-		while ((bytes = fread(data, 1, BUFFER_SIZE, inFile)) != 0) {
-			SHA384_Update(&sha512Context, data, bytes);
-		}
-		SHA384_Final(md, &sha512Context);
-	} else if (md_alg == HASH_ALG_SHA512) {
-		SHA512_Init(&sha512Context);
-		while ((bytes = fread(data, 1, BUFFER_SIZE, inFile)) != 0) {
-			SHA512_Update(&sha512Context, data, bytes);
-		}
-		SHA512_Final(md, &sha512Context);
-	} else {
-		SHA256_Init(&shaContext);
-		while ((bytes = fread(data, 1, BUFFER_SIZE, inFile)) != 0) {
-			SHA256_Update(&shaContext, data, bytes);
-		}
-		SHA256_Final(md, &shaContext);
+	alg_nid = get_algorithm_nid(md_alg);
+	if (alg_nid == NID_undef) {
+		ERROR("%s(): Invalid hash algorithm\n", __func__);
+		goto err;
 	}
 
+	md_type = EVP_get_digestbynid(alg_nid);
+	if (EVP_DigestInit_ex(mdctx, md_type, NULL) == 0) {
+		ERROR("%s(): Could not initialize EVP MD digest\n", __func__);
+		goto err;
+	}
+
+	while ((bytes = fread(data, 1, BUFFER_SIZE, inFile)) != 0) {
+		EVP_DigestUpdate(mdctx, data, bytes);
+	}
+	EVP_DigestFinal_ex(mdctx, md, &total_bytes);
+
 	fclose(inFile);
+	EVP_MD_CTX_free(mdctx);
 	return 1;
+
+err:
+	fclose(inFile);
+	EVP_MD_CTX_free(mdctx);
+	return 0;
 }
+