Use CRYPTO_memcmp when comparing authenticators

Pointed out by Victor Vasiliev (vasilvv@mit.edu) via Adam Langley
(Google).
Reviewed-by: NRich Salz <rsalz@openssl.org>

crypto/evp/e_aes.c

@@ -50,6 +50,7 @@
 
 #include <openssl/opensslconf.h>
 #ifndef OPENSSL_NO_AES
+#include <openssl/crypto.h>
 # include <openssl/evp.h>
 # include <openssl/err.h>
 # include <string.h>
@@ -1555,7 +1556,7 @@ static int aes_gcm_tls_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
         /* Retrieve tag */
         CRYPTO_gcm128_tag(&gctx->gcm, ctx->buf, EVP_GCM_TLS_TAG_LEN);
         /* If tag mismatch wipe buffer */
-        if (memcmp(ctx->buf, in + len, EVP_GCM_TLS_TAG_LEN)) {
+        if (CRYPTO_memcmp(ctx->buf, in + len, EVP_GCM_TLS_TAG_LEN)) {
             OPENSSL_cleanse(out, len);
             goto err;
         }
@@ -1990,7 +1991,7 @@ static int aes_ccm_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
             !CRYPTO_ccm128_decrypt(ccm, in, out, len)) {
             unsigned char tag[16];
             if (CRYPTO_ccm128_tag(ccm, tag, cctx->M)) {
-                if (!memcmp(tag, ctx->buf, cctx->M))
+                if (!CRYPTO_memcmp(tag, ctx->buf, cctx->M))
                     rv = len;
             }
         }

crypto/evp/e_rc4_hmac_md5.c

@@ -54,6 +54,7 @@
 
 #if !defined(OPENSSL_NO_RC4) && !defined(OPENSSL_NO_MD5)
 
+# include <openssl/crypto.h>
 # include <openssl/evp.h>
 # include <openssl/objects.h>
 # include <openssl/rc4.h>
@@ -209,7 +210,7 @@ static int rc4_hmac_md5_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out,
             MD5_Update(&key->md, mac, MD5_DIGEST_LENGTH);
             MD5_Final(mac, &key->md);
 
-            if (memcmp(out + plen, mac, MD5_DIGEST_LENGTH))
+            if (CRYPTO_memcmp(out + plen, mac, MD5_DIGEST_LENGTH))
                 return 0;
         } else {
             MD5_Update(&key->md, out + md5_off, len - md5_off);

crypto/modes/gcm128.c

@@ -1685,7 +1685,7 @@ int CRYPTO_gcm128_finish(GCM128_CONTEXT *ctx, const unsigned char *tag,
     ctx->Xi.u[1] ^= ctx->EK0.u[1];
 
     if (tag && len <= sizeof(ctx->Xi))
-        return memcmp(ctx->Xi.c, tag, len);
+        return CRYPTO_memcmp(ctx->Xi.c, tag, len);
     else
         return -1;
 }

crypto/pkcs12/p12_mutl.c

@@ -59,6 +59,7 @@
 
 # include <stdio.h>
 # include "internal/cryptlib.h"
+#include <openssl/crypto.h>
 # include <openssl/hmac.h>
 # include <openssl/rand.h>
 # include <openssl/pkcs12.h>
@@ -123,7 +124,7 @@ int PKCS12_verify_mac(PKCS12 *p12, const char *pass, int passlen)
         return 0;
     }
     if ((maclen != (unsigned int)p12->mac->dinfo->digest->length)
-        || memcmp(mac, p12->mac->dinfo->digest->data, maclen))
+        || CRYPTO_memcmp(mac, p12->mac->dinfo->digest->data, maclen))
         return 0;
     return 1;
 }