Further clean up of context handling in tls1_change_cipher_state().

Rather than doing a complex dance to figure out if we should reuse the
cipher context and clean it later on, just free it and allocate a new one.
This simplifies the code path, especially in the write case where special
handling is required for DTLS.

Also, calling EVP_CIPHER_CTX_init() for a newly created cipher context is
unnecessary, since EVP_CIPHER_CTX_new() already does this (not to mention
that it was already missing from the write case).

1 files changed, 17 insertions, 21 deletions

diff --git a/src/lib/libssl/t1_enc.c b/src/lib/libssl/t1_enc.c
index 497b767d57..87e241edca 100644
--- a/src/lib/libssl/t1_enc.c
+++ b/src/lib/libssl/t1_enc.c
@@ -324,7 +324,6 @@ tls1_change_cipher_state(SSL *s, int which)
         EVP_PKEY *mac_key;
         int is_export, exp_label_len;
         char is_read, use_client_keys;
-        int reuse_dd = 0;
 
         is_export = SSL_C_IS_EXPORT(s->s3->tmp.new_cipher);
         cipher = s->s3->tmp.new_sym_enc;
@@ -388,17 +387,14 @@ tls1_change_cipher_state(SSL *s, int which)
                 else
                         s->mac_flags &= ~SSL_MAC_FLAG_READ_MAC_STREAM;
 
-                if (s->enc_read_ctx != NULL)
-                        reuse_dd = 1;
-                else if ((s->enc_read_ctx = malloc(sizeof(EVP_CIPHER_CTX))) == NULL)
-                        goto err;
-                else {
-                        /* make sure it's intialized in case we exit later with an error */
-                        EVP_CIPHER_CTX_init(s->enc_read_ctx);
-                }
-                cipher_ctx = s->enc_read_ctx;
+                EVP_CIPHER_CTX_free(s->enc_read_ctx);
+                s->enc_read_ctx = NULL;
+                EVP_MD_CTX_destroy(s->read_hash);
+                s->read_hash = NULL;
 
-                ssl_clear_hash_ctx(&s->read_hash);
+                if ((cipher_ctx = EVP_CIPHER_CTX_new()) == NULL)
+                        goto err;
+                s->enc_read_ctx = cipher_ctx;
                 if ((mac_ctx = EVP_MD_CTX_create()) == NULL)
                         goto err;
                 s->read_hash = mac_ctx;
@@ -411,11 +407,6 @@ tls1_change_cipher_state(SSL *s, int which)
                         s->mac_flags |= SSL_MAC_FLAG_WRITE_MAC_STREAM;
                 else
                         s->mac_flags &= ~SSL_MAC_FLAG_WRITE_MAC_STREAM;
-                if (s->enc_write_ctx != NULL && !SSL_IS_DTLS(s))
-                        reuse_dd = 1;
-                else if ((s->enc_write_ctx = EVP_CIPHER_CTX_new()) == NULL)
-                        goto err;
-                cipher_ctx = s->enc_write_ctx;
 
                 /*
                  * DTLS fragments retain a pointer to the compression, cipher
@@ -424,8 +415,15 @@ tls1_change_cipher_state(SSL *s, int which)
                  * contexts that are used for DTLS - these are instead freed
                  * by DTLS when its frees a ChangeCipherSpec fragment.
                  */
-                if (!SSL_IS_DTLS(s))
-                        ssl_clear_hash_ctx(&s->write_hash);
+                if (!SSL_IS_DTLS(s)) {
+                        EVP_CIPHER_CTX_free(s->enc_write_ctx);
+                        s->enc_write_ctx = NULL;
+                        EVP_MD_CTX_destroy(s->write_hash);
+                        s->write_hash = NULL;
+                }
+                if ((cipher_ctx = EVP_CIPHER_CTX_new()) == NULL)
+                        goto err;
+                s->enc_write_ctx = cipher_ctx;
                 if ((mac_ctx = EVP_MD_CTX_create()) == NULL)
                         goto err;
                 s->write_hash = mac_ctx;
@@ -435,9 +433,6 @@ tls1_change_cipher_state(SSL *s, int which)
                         memset(&(s->s3->write_sequence[0]), 0, 8);
         }
 
-        if (reuse_dd)
-                EVP_CIPHER_CTX_cleanup(cipher_ctx);
-
         key_len = EVP_CIPHER_key_length(cipher);
         if (is_export) {
                 if (key_len > SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher))
@@ -499,6 +494,7 @@ tls1_change_cipher_state(SSL *s, int which)
                 EVP_DigestSignInit(mac_ctx, NULL, mac, NULL, mac_key);
                 EVP_PKEY_free(mac_key);
         }
+
         if (is_export) {
                 /* In here I set both the read and write key/iv to the
                  * same value since only the correct one will be used :-).