Reduce the scope of some variables in tls_process_client_key_exchange()

In preparation for splitting this function up into smaller functions this
commit reduces the scope of some of the variables to only be in scope for
the algorithm specific parts. In some cases that makes the error handling
more verbose than it needs to be - but we'll clean that up in a later
commit.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

ssl/statem/statem_srvr.c

@@ -2019,14 +2019,6 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
 {
     int al;
     unsigned long alg_k;
-#ifndef OPENSSL_NO_RSA
-    RSA *rsa = NULL;
-#endif
-#if !defined(OPENSSL_NO_EC) || !defined(OPENSSL_NO_DH)
-    EVP_PKEY *ckey = NULL;
-#endif
-    PACKET enc_premaster;
-    unsigned char *rsa_decrypt = NULL;
 
     alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
 
@@ -2111,8 +2103,10 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
         int decrypt_len;
         unsigned char decrypt_good, version_good;
         size_t j, padding_len;
+        PACKET enc_premaster;
+        RSA *rsa = NULL;
+        unsigned char *rsa_decrypt = NULL;
 
-        /* FIX THIS UP EAY EAY EAY EAY */
         rsa = EVP_PKEY_get0_RSA(s->cert->pkeys[SSL_PKEY_RSA_ENC].privatekey);
         if (rsa == NULL) {
             al = SSL_AD_HANDSHAKE_FAILURE;
@@ -2151,6 +2145,7 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
         if (rsa_decrypt == NULL) {
             al = SSL_AD_INTERNAL_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
+            OPENSSL_free(rsa_decrypt);
             goto f_err;
         }
 
@@ -2164,6 +2159,7 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
 
         if (RAND_bytes(rand_premaster_secret,
                        sizeof(rand_premaster_secret)) <= 0) {
+            OPENSSL_free(rsa_decrypt);
             goto err;
         }
 
@@ -2175,6 +2171,7 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
                                           PACKET_data(&enc_premaster),
                                           rsa_decrypt, rsa, RSA_NO_PADDING);
         if (decrypt_len < 0) {
+            OPENSSL_free(rsa_decrypt);
             goto err;
         }
 
@@ -2188,6 +2185,7 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
         if (decrypt_len < 11 + SSL_MAX_MASTER_KEY_LENGTH) {
             al = SSL_AD_DECRYPT_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE, SSL_R_DECRYPTION_FAILED);
+            OPENSSL_free(rsa_decrypt);
             goto f_err;
         }
 
@@ -2256,10 +2254,10 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
                                         sizeof(rand_premaster_secret), 0)) {
             al = SSL_AD_INTERNAL_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+            OPENSSL_free(rsa_decrypt);
             goto f_err;
         }
         OPENSSL_free(rsa_decrypt);
-        rsa_decrypt = NULL;
     } else
 #endif
 #ifndef OPENSSL_NO_DH
@@ -2269,6 +2267,7 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
         unsigned int i;
         BIGNUM *pub_key;
         const unsigned char *data;
+        EVP_PKEY *ckey = NULL;
 
         if (!PACKET_get_net_2(pkt, &i)) {
             if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {
@@ -2308,6 +2307,7 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
         ckey = EVP_PKEY_new();
         if (ckey == NULL || EVP_PKEY_copy_parameters(ckey, skey) == 0) {
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE, SSL_R_BN_LIB);
+            EVP_PKEY_free(ckey);
             goto err;
         }
         cdh = EVP_PKEY_get0_DH(ckey);
@@ -2317,17 +2317,18 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
             if (pub_key != NULL)
                 BN_free(pub_key);
+            EVP_PKEY_free(ckey);
             goto err;
         }
 
         if (ssl_derive(s, skey, ckey) == 0) {
             al = SSL_AD_INTERNAL_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+            EVP_PKEY_free(ckey);
             goto f_err;
         }
 
         EVP_PKEY_free(ckey);
-        ckey = NULL;
         EVP_PKEY_free(s->s3->tmp.pkey);
         s->s3->tmp.pkey = NULL;
 
@@ -2337,6 +2338,7 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
 #ifndef OPENSSL_NO_EC
     if (alg_k & (SSL_kECDHE | SSL_kECDHEPSK)) {
         EVP_PKEY *skey = s->s3->tmp.pkey;
+        EVP_PKEY *ckey = NULL;
 
         if (PACKET_remaining(pkt) == 0L) {
             /* We don't support ECDH client auth */
@@ -2368,11 +2370,13 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
             ckey = EVP_PKEY_new();
             if (ckey == NULL || EVP_PKEY_copy_parameters(ckey, skey) <= 0) {
                 SSLerr(SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE, ERR_R_EVP_LIB);
+                EVP_PKEY_free(ckey);
                 goto err;
             }
             if (EC_KEY_oct2key(EVP_PKEY_get0_EC_KEY(ckey), data, i,
                                NULL) == 0) {
                 SSLerr(SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE, ERR_R_EC_LIB);
+                EVP_PKEY_free(ckey);
                 goto err;
             }
         }
@@ -2380,11 +2384,11 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
         if (ssl_derive(s, skey, ckey) == 0) {
             al = SSL_AD_INTERNAL_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_KEY_EXCHANGE, ERR_R_INTERNAL_ERROR);
+            EVP_PKEY_free(ckey);
             goto f_err;
         }
 
         EVP_PKEY_free(ckey);
-        ckey = NULL;
         EVP_PKEY_free(s->s3->tmp.pkey);
         s->s3->tmp.pkey = NULL;
 
@@ -2534,10 +2538,6 @@ MSG_PROCESS_RETURN tls_process_client_key_exchange(SSL *s, PACKET *pkt)
 #if !defined(OPENSSL_NO_DH) || !defined(OPENSSL_NO_RSA) || !defined(OPENSSL_NO_EC) || defined(OPENSSL_NO_SRP)
  err:
 #endif
-#if !defined(OPENSSL_NO_EC) || !defined(OPENSSL_NO_DH)
-    EVP_PKEY_free(ckey);
-#endif
-    OPENSSL_free(rsa_decrypt);
 #ifndef OPENSSL_NO_PSK
     OPENSSL_clear_free(s->s3->tmp.psk, s->s3->tmp.psklen);
     s->s3->tmp.psk = NULL;