VBoot Reference: Fix many memory leaks.

src/platform/vboot_reference/utils/signature_digest.c

 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "signature_digest.h"
 #define OPENSSL_NO_SHA
 #include <openssl/engine.h>
 #include <openssl/pem.h>
 #include <openssl/rsa.h>
@@ skipping 34 matching lines @@
                       int algorithm) {
   FILE* key_fp = NULL;
   RSA* key = NULL;
   uint8_t* signature = NULL;
   uint8_t* signature_digest = SignatureDigest(buf, len, algorithm);
   int signature_digest_len = (hash_size_map[algorithm] +
                               digestinfo_size_map[algorithm]);
   key_fp  = fopen(key_file, "r");
   if (!key_fp) {
     fprintf(stderr, "SignatureBuf(): Couldn't open key file: %s\n", key_file);
+    Free(signature_digest);
     return NULL;
   }
   if ((key = PEM_read_RSAPrivateKey(key_fp, NULL, NULL, NULL)))
     signature = (uint8_t*) Malloc(siglen_map[algorithm]);
   else
     fprintf(stderr, "SignatureBuf(): Couldn't read private key from file: %s\n",
             key_file);
   if (signature) {
     if (-1 == RSA_private_encrypt(signature_digest_len,  /* Input length. */
                                   signature_digest,  /* Input data. */
                                   signature,  /* Output signature. */
                                   key,  /* Key to use. */
                                   RSA_PKCS1_PADDING))  /* Padding to use. */
       fprintf(stderr, "SignatureBuf(): RSA_private_encrypt() failed.\n");
   }
+  fclose(key_fp);
   if (key)
     RSA_free(key);
   Free(signature_digest);
   return signature;
 }