First pass at cleaning up the tls1_P_hash() function - remove a pointless

EVP_DigestSignInit() call and avoid the need for ctx_tmp by reordering the
code slightly.

ok inoguchi@

1 files changed, 19 insertions, 20 deletions

diff --git a/src/lib/libssl/t1_enc.c b/src/lib/libssl/t1_enc.c
index fe822a98ef..0179ac3061 100644
--- a/src/lib/libssl/t1_enc.c
+++ b/src/lib/libssl/t1_enc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: t1_enc.c,v 1.100 2017/03/10 15:03:59 jsing Exp $ */
+/* $OpenBSD: t1_enc.c,v 1.101 2017/03/10 15:08:49 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -288,33 +288,33 @@ tls1_record_sequence_increment(unsigned char *seq)
         }
 }
 
-/* seed1 through seed5 are virtually concatenated */
+/*
+ * TLS P_hash() data expansion function - see RFC 5246, section 5.
+ */
 static int
 tls1_P_hash(const EVP_MD *md, const unsigned char *sec, int sec_len,
     const void *seed1, int seed1_len, const void *seed2, int seed2_len,
     const void *seed3, int seed3_len, const void *seed4, int seed4_len,
     const void *seed5, int seed5_len, unsigned char *out, int olen)
 {
-        int chunk;
-        size_t j;
-        EVP_MD_CTX ctx, ctx_tmp;
-        EVP_PKEY *mac_key;
         unsigned char A1[EVP_MAX_MD_SIZE];
+        EVP_MD_CTX ctx;
+        EVP_PKEY *mac_key;
         size_t A1_len;
         int ret = 0;
+        int chunk;
+        size_t j;
 
         chunk = EVP_MD_size(md);
         OPENSSL_assert(chunk >= 0);
 
         EVP_MD_CTX_init(&ctx);
-        EVP_MD_CTX_init(&ctx_tmp);
+
         mac_key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, sec, sec_len);
         if (!mac_key)
                 goto err;
         if (!EVP_DigestSignInit(&ctx, NULL, md, NULL, mac_key))
                 goto err;
-        if (!EVP_DigestSignInit(&ctx_tmp, NULL, md, NULL, mac_key))
-                goto err;
         if (seed1 && !EVP_DigestSignUpdate(&ctx, seed1, seed1_len))
                 goto err;
         if (seed2 && !EVP_DigestSignUpdate(&ctx, seed2, seed2_len))
@@ -329,15 +329,10 @@ tls1_P_hash(const EVP_MD *md, const unsigned char *sec, int sec_len,
                 goto err;
 
         for (;;) {
-                /* Reinit mac contexts */
                 if (!EVP_DigestSignInit(&ctx, NULL, md, NULL, mac_key))
                         goto err;
-                if (!EVP_DigestSignInit(&ctx_tmp, NULL, md, NULL, mac_key))
-                        goto err;
                 if (!EVP_DigestSignUpdate(&ctx, A1, A1_len))
                         goto err;
-                if (!EVP_DigestSignUpdate(&ctx_tmp, A1, A1_len))
-                        goto err;
                 if (seed1 && !EVP_DigestSignUpdate(&ctx, seed1, seed1_len))
                         goto err;
                 if (seed2 && !EVP_DigestSignUpdate(&ctx, seed2, seed2_len))
@@ -354,24 +349,28 @@ tls1_P_hash(const EVP_MD *md, const unsigned char *sec, int sec_len,
                                 goto err;
                         out += j;
                         olen -= j;
-                        /* calc the next A1 value */
-                        if (!EVP_DigestSignFinal(&ctx_tmp, A1, &A1_len))
-                                goto err;
                 } else {
-                        /* last one */
                         if (!EVP_DigestSignFinal(&ctx, A1, &A1_len))
                                 goto err;
                         memcpy(out, A1, olen);
                         break;
                 }
+
+                if (!EVP_DigestSignInit(&ctx, NULL, md, NULL, mac_key))
+                        goto err;
+                if (!EVP_DigestSignUpdate(&ctx, A1, A1_len))
+                        goto err;
+                if (!EVP_DigestSignFinal(&ctx, A1, &A1_len))
+                        goto err;
         }
         ret = 1;
 
-err:
+ err:
         EVP_PKEY_free(mac_key);
         EVP_MD_CTX_cleanup(&ctx);
-        EVP_MD_CTX_cleanup(&ctx_tmp);
+
         explicit_bzero(A1, sizeof(A1));
+
         return ret;
 }