Narrow the scope of local variables in tls_construct_client_key_exchange()

This is in preparation for splitting up this over long function.

Reviewed-by: Richard Levitte <levitte@openssl.org>

1 files changed, 58 insertions, 52 deletions

diff --git a/ssl/statem/statem_clnt.c b/ssl/statem/statem_clnt.c
index bcbb0fd2ba..e52bbe3b1b 100644
--- a/ssl/statem/statem_clnt.c
+++ b/ssl/statem/statem_clnt.c
@@ -2020,20 +2020,7 @@ int tls_construct_client_key_exchange(SSL *s)
     size_t pskhdrlen = 0;
 #endif
     unsigned long alg_k;
-#ifndef OPENSSL_NO_RSA
-    unsigned char *q;
-    EVP_PKEY *pkey = NULL;
-    EVP_PKEY_CTX *pctx = NULL;
-#endif
-#if !defined(OPENSSL_NO_EC) || !defined(OPENSSL_NO_DH)
-    EVP_PKEY *ckey = NULL, *skey = NULL;
-#endif
-#ifndef OPENSSL_NO_EC
-    unsigned char *encodedPoint = NULL;
-    int encoded_pt_len = 0;
-#endif
-    unsigned char *pms = NULL;
-    size_t pmslen = 0;
+
     alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
 
     p = ssl_handshake_start(s);
@@ -2050,6 +2037,8 @@ int tls_construct_client_key_exchange(SSL *s)
         char identity[PSK_MAX_IDENTITY_LEN + 1];
         size_t identitylen;
         unsigned char psk[PSK_MAX_PSK_LEN];
+        unsigned char *tmppsk;
+        char *tmpidentity;
         size_t psklen;
 
         if (s->psk_client_callback == NULL) {
@@ -2073,35 +2062,36 @@ int tls_construct_client_key_exchange(SSL *s)
                    SSL_R_PSK_IDENTITY_NOT_FOUND);
             goto psk_err;
         }
-        OPENSSL_free(s->s3->tmp.psk);
-        s->s3->tmp.psk = OPENSSL_memdup(psk, psklen);
-        OPENSSL_cleanse(psk, psklen);
-
-        if (s->s3->tmp.psk == NULL) {
-            OPENSSL_cleanse(identity, sizeof(identity));
-            goto memerr;
-        }
 
-        s->s3->tmp.psklen = psklen;
         identitylen = strlen(identity);
         if (identitylen > PSK_MAX_IDENTITY_LEN) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE,
                    ERR_R_INTERNAL_ERROR);
             goto psk_err;
         }
-        OPENSSL_free(s->session->psk_identity);
-        s->session->psk_identity = OPENSSL_strdup(identity);
-        if (s->session->psk_identity == NULL) {
+
+        tmppsk = OPENSSL_memdup(psk, psklen);
+        tmpidentity = OPENSSL_strdup(identity);
+        if (tmppsk == NULL || tmpidentity == NULL) {
             OPENSSL_cleanse(identity, sizeof(identity));
+            OPENSSL_cleanse(psk, psklen);
+            OPENSSL_clear_free(tmppsk, psklen);
+            OPENSSL_clear_free(tmpidentity, identitylen);
             goto memerr;
         }
 
+        OPENSSL_free(s->s3->tmp.psk);
+        s->s3->tmp.psk = tmppsk;
+        s->s3->tmp.psklen = psklen;
+        OPENSSL_free(s->session->psk_identity);
+        s->session->psk_identity = tmpidentity;
         s2n(identitylen, p);
         memcpy(p, identity, identitylen);
         pskhdrlen = 2 + identitylen;
         p += identitylen;
         psk_err = 0;
 psk_err:
+        OPENSSL_cleanse(psk, psklen);
         OPENSSL_cleanse(identity, sizeof(identity));
         if (psk_err != 0) {
             ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
@@ -2118,11 +2108,12 @@ psk_err:
     }
 #ifndef OPENSSL_NO_RSA
     else if (alg_k & (SSL_kRSA | SSL_kRSAPSK)) {
+        unsigned char *q;
+        EVP_PKEY *pkey = NULL;
+        EVP_PKEY_CTX *pctx = NULL;
         size_t enclen;
-        pmslen = SSL_MAX_MASTER_KEY_LENGTH;
-        pms = OPENSSL_malloc(pmslen);
-        if (pms == NULL)
-            goto memerr;
+        unsigned char *pms = NULL;
+        size_t pmslen = 0;
 
         if (s->session->peer == NULL) {
             /*
@@ -2140,10 +2131,17 @@ psk_err:
             goto err;
         }
 
+        pmslen = SSL_MAX_MASTER_KEY_LENGTH;
+        pms = OPENSSL_malloc(pmslen);
+        if (pms == NULL)
+            goto memerr;
+
         pms[0] = s->client_version >> 8;
         pms[1] = s->client_version & 0xff;
-        if (RAND_bytes(pms + 2, pmslen - 2) <= 0)
+        if (RAND_bytes(pms + 2, pmslen - 2) <= 0) {
+            OPENSSL_clear_free(pms, pmslen);
             goto err;
+        }
 
         q = p;
         /* Fix buf for TLS and beyond */
@@ -2152,11 +2150,15 @@ psk_err:
         pctx = EVP_PKEY_CTX_new(pkey, NULL);
         if (pctx == NULL || EVP_PKEY_encrypt_init(pctx) <= 0
             || EVP_PKEY_encrypt(pctx, NULL, &enclen, pms, pmslen) <= 0) {
+            OPENSSL_clear_free(pms, pmslen);
+            EVP_PKEY_CTX_free(pctx);
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE,
                    ERR_R_EVP_LIB);
             goto err;
         }
         if (EVP_PKEY_encrypt(pctx, p, &enclen, pms, pmslen) <= 0) {
+            OPENSSL_clear_free(pms, pmslen);
+            EVP_PKEY_CTX_free(pctx);
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE,
                    SSL_R_BAD_RSA_ENCRYPT);
             goto err;
@@ -2176,12 +2178,17 @@ psk_err:
             s2n(n, q);
             n += 2;
         }
+
+        s->s3->tmp.pms = pms;
+        s->s3->tmp.pmslen = pmslen;
     }
 #endif
 #ifndef OPENSSL_NO_DH
     else if (alg_k & (SSL_kDHE | SSL_kDHEPSK)) {
         DH *dh_clnt = NULL;
         const BIGNUM *pub_key;
+        EVP_PKEY *ckey = NULL, *skey = NULL;
+
         skey = s->s3->peer_tmp;
         if (skey == NULL) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE,
@@ -2194,6 +2201,7 @@ psk_err:
         if (dh_clnt == NULL || ssl_derive(s, ckey, skey) == 0) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE,
                    ERR_R_INTERNAL_ERROR);
+            EVP_PKEY_free(ckey);
             goto err;
         }
 
@@ -2211,6 +2219,9 @@ psk_err:
 
 #ifndef OPENSSL_NO_EC
     else if (alg_k & (SSL_kECDHE | SSL_kECDHEPSK)) {
+        unsigned char *encodedPoint = NULL;
+        int encoded_pt_len = 0;
+        EVP_PKEY *ckey = NULL, *skey = NULL;
 
         skey = s->s3->peer_tmp;
         if ((skey == NULL) || EVP_PKEY_get0_EC_KEY(skey) == NULL) {
@@ -2223,6 +2234,7 @@ psk_err:
 
         if (ssl_derive(s, ckey, skey) == 0) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE, ERR_R_EVP_LIB);
+            EVP_PKEY_free(ckey);
             goto err;
         }
 
@@ -2233,6 +2245,7 @@ psk_err:
 
         if (encoded_pt_len == 0) {
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE, ERR_R_EC_LIB);
+            EVP_PKEY_free(ckey);
             goto err;
         }
 
@@ -2263,15 +2276,13 @@ psk_err:
         unsigned char shared_ukm[32], tmp[256];
         EVP_MD_CTX *ukm_hash;
         int dgst_nid = NID_id_GostR3411_94;
+        unsigned char *pms = NULL;
+        size_t pmslen = 0;
+
         if ((s->s3->tmp.new_cipher->algorithm_auth & SSL_aGOST12) != 0)
             dgst_nid = NID_id_GostR3411_2012_256;
 
 
-        pmslen = 32;
-        pms = OPENSSL_malloc(pmslen);
-        if (pms == NULL)
-            goto memerr;
-
         /*
          * Get server sertificate PKEY and create ctx from it
          */
@@ -2295,12 +2306,17 @@ psk_err:
          */
 
         /* Otherwise, generate ephemeral key pair */
+        pmslen = 32;
+        pms = OPENSSL_malloc(pmslen);
+        if (pms == NULL)
+            goto memerr;
 
         if (pkey_ctx == NULL
                 || EVP_PKEY_encrypt_init(pkey_ctx) <= 0
                 /* Generate session key */
                 || RAND_bytes(pms, pmslen) <= 0) {
             EVP_PKEY_CTX_free(pkey_ctx);
+            OPENSSL_clear_free(pms, pmslen);
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE,
                    ERR_R_INTERNAL_ERROR);
             goto err;
@@ -2331,6 +2347,7 @@ psk_err:
                                     SSL3_RANDOM_SIZE) <= 0
                 || EVP_DigestFinal_ex(ukm_hash, shared_ukm, &md_len) <= 0) {
             EVP_MD_CTX_free(ukm_hash);
+            OPENSSL_clear_free(pms, pmslen);
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE,
                    ERR_R_INTERNAL_ERROR);
             goto err;
@@ -2339,6 +2356,7 @@ psk_err:
         if (EVP_PKEY_CTX_ctrl
             (pkey_ctx, -1, EVP_PKEY_OP_ENCRYPT, EVP_PKEY_CTRL_SET_IV, 8,
              shared_ukm) < 0) {
+            OPENSSL_clear_free(pms, pmslen);
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE,
                    SSL_R_LIBRARY_BUG);
             goto err;
@@ -2350,6 +2368,7 @@ psk_err:
         *(p++) = V_ASN1_SEQUENCE | V_ASN1_CONSTRUCTED;
         msglen = 255;
         if (EVP_PKEY_encrypt(pkey_ctx, tmp, &msglen, pms, pmslen) <= 0) {
+            OPENSSL_clear_free(pms, pmslen);
             SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE,
                    SSL_R_LIBRARY_BUG);
             goto err;
@@ -2370,7 +2389,8 @@ psk_err:
             s->s3->flags |= TLS1_FLAGS_SKIP_CERT_VERIFY;
         }
         EVP_PKEY_CTX_free(pkey_ctx);
-
+        s->s3->tmp.pms = pms;
+        s->s3->tmp.pmslen = pmslen;
     }
 #endif
 #ifndef OPENSSL_NO_SRP
@@ -2411,27 +2431,13 @@ psk_err:
         goto err;
     }
 
-    if (pms != NULL) {
-        s->s3->tmp.pms = pms;
-        s->s3->tmp.pmslen = pmslen;
-    }
-
     return 1;
  memerr:
     ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_INTERNAL_ERROR);
     SSLerr(SSL_F_TLS_CONSTRUCT_CLIENT_KEY_EXCHANGE, ERR_R_MALLOC_FAILURE);
  err:
-    OPENSSL_clear_free(pms, pmslen);
+    OPENSSL_clear_free(s->s3->tmp.pms, s->s3->tmp.pmslen);
     s->s3->tmp.pms = NULL;
-#ifndef OPENSSL_NO_RSA
-    EVP_PKEY_CTX_free(pctx);
-#endif
-#ifndef OPENSSL_NO_EC
-    OPENSSL_free(encodedPoint);
-#endif
-#if !defined(OPENSSL_NO_EC) || !defined(OPENSSL_NO_DH)
-    EVP_PKEY_free(ckey);
-#endif
 #ifndef OPENSSL_NO_PSK
     OPENSSL_clear_free(s->s3->tmp.psk, s->s3->tmp.psklen);
     s->s3->tmp.psk = NULL;