Correctly calculate the key block length when used with export ciphers.

While here, use meaningful variable names and simplify the calculation.

1 files changed, 24 insertions, 17 deletions

diff --git a/src/lib/libssl/src/ssl/s3_enc.c b/src/lib/libssl/src/ssl/s3_enc.c
index d21d9e1216..8e004fbe46 100644
--- a/src/lib/libssl/src/ssl/s3_enc.c
+++ b/src/lib/libssl/src/ssl/s3_enc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: s3_enc.c,v 1.46 2014/06/13 15:28:49 jsing Exp $ */
+/* $OpenBSD: s3_enc.c,v 1.47 2014/06/13 16:04:13 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -386,10 +386,10 @@ err2:
 int
 ssl3_setup_key_block(SSL *s)
 {
-        unsigned char *p;
-        const EVP_CIPHER *c;
-        const EVP_MD *hash;
-        int num;
+        int key_block_len, mac_len, key_len, iv_len;
+        unsigned char *key_block;
+        const EVP_CIPHER *cipher;
+        const EVP_MD *mac;
         int ret = 0;
         SSL_COMP *comp;
 
@@ -402,35 +402,42 @@ ssl3_setup_key_block(SSL *s)
                 return (0);
         }
 
-        if (!ssl_cipher_get_evp(s->session, &c, &hash, NULL, NULL)) {
+        if (!ssl_cipher_get_evp(s->session, &cipher, &mac, NULL, NULL)) {
                 SSLerr(SSL_F_SSL3_SETUP_KEY_BLOCK,
                     SSL_R_CIPHER_OR_HASH_UNAVAILABLE);
                 return (0);
         }
 
-        s->s3->tmp.new_sym_enc = c;
-        s->s3->tmp.new_hash = hash;
+        s->s3->tmp.new_sym_enc = cipher;
+        s->s3->tmp.new_hash = mac;
         s->s3->tmp.new_compression = comp;
 
-        num = EVP_MD_size(hash);
-        if (num < 0)
+        mac_len = EVP_MD_size(mac);
+        key_len = EVP_CIPHER_key_length(cipher);
+        iv_len = EVP_CIPHER_iv_length(cipher);
+
+        if (mac_len < 0)
                 return 0;
 
-        num = EVP_CIPHER_key_length(c) + num + EVP_CIPHER_iv_length(c);
-        num *= 2;
+        if (SSL_C_IS_EXPORT(s->session->cipher) &&
+            key_len > SSL_C_EXPORT_KEYLENGTH(s->session->cipher))
+                key_len = SSL_C_EXPORT_KEYLENGTH(s->session->cipher);
+
+        key_block_len = (mac_len + key_len + iv_len) * 2;
 
         ssl3_cleanup_key_block(s);
 
-        if ((p = malloc(num)) == NULL)
+        if ((key_block = malloc(key_block_len)) == NULL)
                 goto err;
 
-        s->s3->tmp.key_block_length = num;
-        s->s3->tmp.key_block = p;
+        s->s3->tmp.key_block_length = key_block_len;
+        s->s3->tmp.key_block = key_block;
 
-        ret = ssl3_generate_key_block(s, p, num);
+        ret = ssl3_generate_key_block(s, key_block, key_block_len);
 
         if (!(s->options & SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS)) {
-                /* enable vulnerability countermeasure for CBC ciphers with
+                /*
+                 * Enable vulnerability countermeasure for CBC ciphers with
                  * known-IV problem (http://www.openssl.org/~bodo/tls-cbc.txt)
                  */
                 s->s3->need_empty_fragments = 1;