PRF and handshake hash revision.

Change handshake hash array into a single digest context simplifying the
handhake hash code. Use EVP_md5_sha1() if needed for handshake hashes in
TLS 1.1 and earlier.

Simplify PRF code to also use a single digest and treat EVP_md5_sha1()
as a special case.

Modify algorithm2 field of ciphers to use a single index value for handshake
hash and PRF instead of a bitmap.

Reviewed-by: Matt Caswell <matt@openssl.org>

6 files changed, 138 insertions, 231 deletions

diff --git a/ssl/s3_enc.c b/ssl/s3_enc.c
index b801d0541b..bb900e9ca8 100644
--- a/ssl/s3_enc.c
+++ b/ssl/s3_enc.c
@@ -140,26 +140,6 @@
 #include <openssl/evp.h>
 #include <openssl/md5.h>
 
-static const unsigned char ssl3_pad_1[48] = {
-    0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
-    0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
-    0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
-    0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
-    0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36,
-    0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36
-};
-
-static const unsigned char ssl3_pad_2[48] = {
-    0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
-    0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
-    0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
-    0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
-    0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c,
-    0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c
-};
-
-static int ssl3_handshake_mac(SSL *s, int md_nid,
-                              const char *sender, int len, unsigned char *p);
 static int ssl3_generate_key_block(SSL *s, unsigned char *km, int num)
 {
     EVP_MD_CTX m5;
@@ -488,69 +468,48 @@ void ssl3_init_finished_mac(SSL *s)
 
 void ssl3_free_digest_list(SSL *s)
 {
-    int i;
     BIO_free(s->s3->handshake_buffer);
     s->s3->handshake_buffer = NULL;
-    if (!s->s3->handshake_dgst)
-        return;
-    for (i = 0; i < SSL_MAX_DIGEST; i++) {
-        if (s->s3->handshake_dgst[i])
-            EVP_MD_CTX_destroy(s->s3->handshake_dgst[i]);
-    }
-    OPENSSL_free(s->s3->handshake_dgst);
+    EVP_MD_CTX_destroy(s->s3->handshake_dgst);
     s->s3->handshake_dgst = NULL;
 }
 
 void ssl3_finish_mac(SSL *s, const unsigned char *buf, int len)
 {
-    if (s->s3->handshake_dgst == NULL) {
+    if (s->s3->handshake_dgst == NULL)
         BIO_write(s->s3->handshake_buffer, (void *)buf, len);
-    } else {
-        int i;
-        for (i = 0; i < SSL_MAX_DIGEST; i++) {
-            if (s->s3->handshake_dgst[i] != NULL)
-                EVP_DigestUpdate(s->s3->handshake_dgst[i], buf, len);
-        }
-    }
+    else
+        EVP_DigestUpdate(s->s3->handshake_dgst, buf, len);
 }
 
 int ssl3_digest_cached_records(SSL *s, int keep)
 {
-    int i;
-    long mask;
     const EVP_MD *md;
     long hdatalen;
     void *hdata;
 
     if (s->s3->handshake_dgst == NULL) {
-        /* Allocate handshake_dgst array */
-        s->s3->handshake_dgst =
-            OPENSSL_malloc(sizeof(*s->s3->handshake_dgst) * SSL_MAX_DIGEST);
-        if (s->s3->handshake_dgst == NULL) {
-            SSLerr(SSL_F_SSL3_DIGEST_CACHED_RECORDS, ERR_R_MALLOC_FAILURE);
-            return 0;
-        }
         hdatalen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
         if (hdatalen <= 0) {
             SSLerr(SSL_F_SSL3_DIGEST_CACHED_RECORDS, SSL_R_BAD_HANDSHAKE_LENGTH);
             return 0;
         }
 
-        /* Loop through bits of algorithm2 field and create MD_CTX-es */
-        for (i = 0; ssl_get_handshake_digest(i, &mask, &md); i++) {
-            if ((mask & ssl_get_algorithm2(s)) && md) {
-                s->s3->handshake_dgst[i] = EVP_MD_CTX_create();
-                if (EVP_MD_nid(md) == NID_md5) {
-                    EVP_MD_CTX_set_flags(s->s3->handshake_dgst[i],
-                                         EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
-                }
-                EVP_DigestInit_ex(s->s3->handshake_dgst[i], md, NULL);
-                EVP_DigestUpdate(s->s3->handshake_dgst[i], hdata, hdatalen);
-            } else {
-                s->s3->handshake_dgst[i] = NULL;
-            }
+        s->s3->handshake_dgst = EVP_MD_CTX_create();
+        if (s->s3->handshake_dgst == NULL) {
+            SSLerr(SSL_F_SSL3_DIGEST_CACHED_RECORDS, ERR_R_MALLOC_FAILURE);
+            return 0;
         }
 
+        md = ssl_handshake_md(s);
+        if (md == NULL) {
+            SSLerr(SSL_F_SSL3_DIGEST_CACHED_RECORDS, ERR_R_INTERNAL_ERROR);
+            return 0;
+        }
+
+        EVP_DigestInit_ex(s->s3->handshake_dgst, md, NULL);
+        EVP_DigestUpdate(s->s3->handshake_dgst, hdata, hdatalen);
+
     }
     if (keep == 0) {
         BIO_free(s->s3->handshake_buffer);
@@ -560,77 +519,40 @@ int ssl3_digest_cached_records(SSL *s, int keep)
     return 1;
 }
 
-int ssl3_final_finish_mac(SSL *s,
-                          const char *sender, int len, unsigned char *p)
+int ssl3_final_finish_mac(SSL *s, const char *sender, int len, unsigned char *p)
 {
-    int ret, sha1len;
-    ret = ssl3_handshake_mac(s, NID_md5, sender, len, p);
-    if (ret == 0)
-        return 0;
-
-    p += ret;
-
-    sha1len = ssl3_handshake_mac(s, NID_sha1, sender, len, p);
-    if (sha1len == 0)
-        return 0;
-
-    ret += sha1len;
-    return (ret);
-}
-
-static int ssl3_handshake_mac(SSL *s, int md_nid,
-                              const char *sender, int len, unsigned char *p)
-{
-    unsigned int ret;
-    int npad, n;
-    unsigned int i;
-    unsigned char md_buf[EVP_MAX_MD_SIZE];
-    EVP_MD_CTX ctx, *d = NULL;
+    int ret;
+    EVP_MD_CTX ctx;
 
     if (!ssl3_digest_cached_records(s, 0))
         return 0;
 
-    /*
-     * Search for digest of specified type in the handshake_dgst array
-     */
-    for (i = 0; i < SSL_MAX_DIGEST; i++) {
-        if (s->s3->handshake_dgst[i]
-            && EVP_MD_CTX_type(s->s3->handshake_dgst[i]) == md_nid) {
-            d = s->s3->handshake_dgst[i];
-            break;
-        }
-    }
-    if (!d) {
+    if (EVP_MD_CTX_type(s->s3->handshake_dgst) != NID_md5_sha1) {
         SSLerr(SSL_F_SSL3_HANDSHAKE_MAC, SSL_R_NO_REQUIRED_DIGEST);
         return 0;
     }
+
     EVP_MD_CTX_init(&ctx);
-    EVP_MD_CTX_set_flags(&ctx, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
-    EVP_MD_CTX_copy_ex(&ctx, d);
-    n = EVP_MD_CTX_size(&ctx);
-    if (n < 0)
+    EVP_MD_CTX_copy_ex(&ctx, s->s3->handshake_dgst);
+
+    ret = EVP_MD_CTX_size(&ctx);
+    if (ret < 0) {
+        EVP_MD_CTX_cleanup(&ctx);
         return 0;
+    }
 
-    npad = (48 / n) * n;
     if ((sender != NULL && EVP_DigestUpdate(&ctx, sender, len) <= 0)
-            || EVP_DigestUpdate(&ctx, s->session->master_key,
-                                s->session->master_key_length) <= 0
-            || EVP_DigestUpdate(&ctx, ssl3_pad_1, npad) <= 0
-            || EVP_DigestFinal_ex(&ctx, md_buf, &i) <= 0
-
-            || EVP_DigestInit_ex(&ctx, EVP_MD_CTX_md(&ctx), NULL) <= 0
-            || EVP_DigestUpdate(&ctx, s->session->master_key,
-                                s->session->master_key_length) <= 0
-            || EVP_DigestUpdate(&ctx, ssl3_pad_2, npad) <= 0
-            || EVP_DigestUpdate(&ctx, md_buf, i) <= 0
-            || EVP_DigestFinal_ex(&ctx, p, &ret) <= 0) {
+            || EVP_MD_CTX_ctrl(&ctx, EVP_CTRL_SSL3_MASTER_SECRET,
+                               s->session->master_key_length,
+                               s->session->master_key) <= 0
+            || EVP_DigestFinal_ex(&ctx, p, NULL) <= 0) {
         SSLerr(SSL_F_SSL3_HANDSHAKE_MAC, ERR_R_INTERNAL_ERROR);
         ret = 0;
     }
 
     EVP_MD_CTX_cleanup(&ctx);
 
-    return ((int)ret);
+    return ret;
 }
 
 int ssl3_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
diff --git a/ssl/ssl_algs.c b/ssl/ssl_algs.c
index f4827fd787..9c12e19e17 100644
--- a/ssl/ssl_algs.c
+++ b/ssl/ssl_algs.c
@@ -110,6 +110,9 @@ int SSL_library_init(void)
 #ifndef OPENSSL_NO_MD5
     EVP_add_digest(EVP_md5());
     EVP_add_digest_alias(SN_md5, "ssl3-md5");
+# ifndef OPENSSL_NO_SHA
+    EVP_add_digest(EVP_md5_sha1());
+# endif
 #endif
     EVP_add_digest(EVP_sha1()); /* RSA with sha1 */
     EVP_add_digest_alias(SN_sha1, "ssl3-sha1");
diff --git a/ssl/ssl_ciph.c b/ssl/ssl_ciph.c
index 47f5e0f130..4e3c1e505f 100644
--- a/ssl/ssl_ciph.c
+++ b/ssl/ssl_ciph.c
@@ -212,15 +212,6 @@ static const EVP_CIPHER *ssl_cipher_methods[SSL_ENC_NUM_IDX] = {
 
 static STACK_OF(SSL_COMP) *ssl_comp_methods = NULL;
 
-#define SSL_MD_MD5_IDX  0
-#define SSL_MD_SHA1_IDX 1
-#define SSL_MD_GOST94_IDX 2
-#define SSL_MD_GOST89MAC_IDX 3
-#define SSL_MD_SHA256_IDX 4
-#define SSL_MD_SHA384_IDX 5
-#define SSL_MD_GOST12_256_IDX  6
-#define SSL_MD_GOST89MAC12_IDX 7
-#define SSL_MD_GOST12_512_IDX  8
 /*
  * Constant SSL_MAX_DIGEST equal to size of digests array should be defined
  * in the ssl_locl.h
@@ -238,11 +229,12 @@ static const ssl_cipher_table ssl_cipher_table_mac[SSL_MD_NUM_IDX] = {
     {SSL_SHA384, NID_sha384},   /* SSL_MD_SHA384_IDX 5 */
     {SSL_GOST12_256, NID_id_GostR3411_2012_256},  /* SSL_MD_GOST12_256_IDX 6 */
     {SSL_GOST89MAC12, NID_gost_mac_12},           /* SSL_MD_GOST89MAC12_IDX 7 */
-    {SSL_GOST12_512, NID_id_GostR3411_2012_512}   /* SSL_MD_GOST12_512_IDX 8 */
+    {SSL_GOST12_512, NID_id_GostR3411_2012_512},  /* SSL_MD_GOST12_512_IDX 8 */
+    {0, NID_md5_sha1}           /* SSL_MD_MD5_SHA1_IDX 9 */
 };
 
 static const EVP_MD *ssl_digest_methods[SSL_MD_NUM_IDX] = {
-    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
+    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
 };
 
 /* Utility function for table lookup */
@@ -275,14 +267,7 @@ static int ssl_mac_pkey_id[SSL_MD_NUM_IDX] = {
 };
 
 static int ssl_mac_secret_size[SSL_MD_NUM_IDX] = {
-    0, 0, 0, 0, 0, 0, 0, 0, 0
-};
-
-static const int ssl_handshake_digest_flag[SSL_MD_NUM_IDX] = {
-    SSL_HANDSHAKE_MAC_MD5, SSL_HANDSHAKE_MAC_SHA,
-    SSL_HANDSHAKE_MAC_GOST94, 0, SSL_HANDSHAKE_MAC_SHA256,
-    SSL_HANDSHAKE_MAC_SHA384, SSL_HANDSHAKE_MAC_GOST12_256, 0,
-    SSL_HANDSHAKE_MAC_GOST12_512,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 };
 
 #define CIPHER_ADD      1
@@ -727,17 +712,22 @@ int ssl_cipher_get_evp(const SSL_SESSION *s, const EVP_CIPHER **enc,
         return (0);
 }
 
-int ssl_get_handshake_digest(int idx, long *mask, const EVP_MD **md)
+static const EVP_MD *ssl_cipher_table_idx(int idx)
 {
-    if (idx < 0 || idx >= SSL_MD_NUM_IDX) {
-        return 0;
-    }
-    *mask = ssl_handshake_digest_flag[idx];
-    if (*mask)
-        *md = ssl_digest_methods[idx];
-    else
-        *md = NULL;
-    return 1;
+    idx &= SSL_HANDSHAKE_MAC_MASK;
+    if (idx < 0 || idx >= SSL_MD_NUM_IDX)
+        return NULL;
+    return ssl_digest_methods[idx];
+}
+
+const EVP_MD *ssl_handshake_md(SSL *s)
+{
+    return ssl_cipher_table_idx(ssl_get_algorithm2(s));
+}
+
+const EVP_MD *ssl_prf_md(SSL *s)
+{
+    return ssl_cipher_table_idx(ssl_get_algorithm2(s) >> TLS1_PRF_DGST_SHIFT);
 }
 
 #define ITEM_SEP(a) \
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index a9370dcb87..12ae35cf8c 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -3335,27 +3335,17 @@ void ssl_clear_hash_ctx(EVP_MD_CTX **hash)
 /* Retrieve handshake hashes */
 int ssl_handshake_hash(SSL *s, unsigned char *out, int outlen)
 {
-    unsigned char *p = out;
-    int idx, ret = 0;
-    long mask;
     EVP_MD_CTX ctx;
-    const EVP_MD *md;
+    EVP_MD_CTX *hdgst = s->s3->handshake_dgst;
+    int ret = EVP_MD_CTX_size(hdgst);
     EVP_MD_CTX_init(&ctx);
-    for (idx = 0; ssl_get_handshake_digest(idx, &mask, &md); idx++) {
-        if (mask & ssl_get_algorithm2(s)) {
-            int hashsize = EVP_MD_size(md);
-            EVP_MD_CTX *hdgst = s->s3->handshake_dgst[idx];
-            if (!hdgst || hashsize < 0 || hashsize > outlen)
-                goto err;
-            if (!EVP_MD_CTX_copy_ex(&ctx, hdgst))
-                goto err;
-            if (!EVP_DigestFinal_ex(&ctx, p, NULL))
-                goto err;
-            p += hashsize;
-            outlen -= hashsize;
-        }
+    if (ret < 0 || ret > outlen) {
+        ret = 0;
+        goto err;
     }
-    ret = p - out;
+    if (!EVP_MD_CTX_copy_ex(&ctx, hdgst)
+        || EVP_DigestFinal_ex(&ctx, out, NULL) <= 0)
+        ret = 0;
  err:
     EVP_MD_CTX_cleanup(&ctx);
     return ret;
diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 70689bc324..0cbb3cc57f 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -391,38 +391,50 @@
 # define SSL_TLSV1               0x00000004U
 # define SSL_TLSV1_2             0x00000008U
 
-/* Bits for algorithm2 (handshake digests and other extra flags) */
-
-# define SSL_HANDSHAKE_MAC_MD5 0x10
-# define SSL_HANDSHAKE_MAC_SHA 0x20
-# define SSL_HANDSHAKE_MAC_GOST94 0x40
-# define SSL_HANDSHAKE_MAC_SHA256 0x80
-# define SSL_HANDSHAKE_MAC_SHA384 0x100
-# define SSL_HANDSHAKE_MAC_GOST12_256 0x200
-# define SSL_HANDSHAKE_MAC_GOST12_512 0x400
-# define SSL_HANDSHAKE_MAC_DEFAULT (SSL_HANDSHAKE_MAC_MD5 | SSL_HANDSHAKE_MAC_SHA)
-
 /*
  * When adding new digest in the ssl_ciph.c and increment SSL_MD_NUM_IDX make
  * sure to update this constant too
  */
-# define SSL_MAX_DIGEST 9
-
-# define TLS1_PRF_DGST_SHIFT 10
-# define TLS1_PRF_MD5 (SSL_HANDSHAKE_MAC_MD5 << TLS1_PRF_DGST_SHIFT)
-# define TLS1_PRF_SHA1 (SSL_HANDSHAKE_MAC_SHA << TLS1_PRF_DGST_SHIFT)
-# define TLS1_PRF_SHA256 (SSL_HANDSHAKE_MAC_SHA256 << TLS1_PRF_DGST_SHIFT)
-# define TLS1_PRF_SHA384 (SSL_HANDSHAKE_MAC_SHA384 << TLS1_PRF_DGST_SHIFT)
-# define TLS1_PRF_GOST94 (SSL_HANDSHAKE_MAC_GOST94 << TLS1_PRF_DGST_SHIFT)
-# define TLS1_PRF_GOST12_256 (SSL_HANDSHAKE_MAC_GOST12_256 << TLS1_PRF_DGST_SHIFT)
-# define TLS1_PRF_GOST12_512 (SSL_HANDSHAKE_MAC_GOST12_512 << TLS1_PRF_DGST_SHIFT)
-# define TLS1_PRF (TLS1_PRF_MD5 | TLS1_PRF_SHA1)
+
+# define SSL_MD_MD5_IDX  0
+# define SSL_MD_SHA1_IDX 1
+# define SSL_MD_GOST94_IDX 2
+# define SSL_MD_GOST89MAC_IDX 3
+# define SSL_MD_SHA256_IDX 4
+# define SSL_MD_SHA384_IDX 5
+# define SSL_MD_GOST12_256_IDX  6
+# define SSL_MD_GOST89MAC12_IDX 7
+# define SSL_MD_GOST12_512_IDX  8
+# define SSL_MD_MD5_SHA1_IDX 9
+# define SSL_MAX_DIGEST 10
+
+/* Bits for algorithm2 (handshake digests and other extra flags) */
+
+/* Bits 0-7 are handshake MAC */
+# define SSL_HANDSHAKE_MAC_MASK  0xFF
+# define SSL_HANDSHAKE_MAC_MD5_SHA1 SSL_MD_MD5_SHA1_IDX
+# define SSL_HANDSHAKE_MAC_SHA256   SSL_MD_SHA256_IDX
+# define SSL_HANDSHAKE_MAC_SHA384   SSL_MD_SHA384_IDX
+# define SSL_HANDSHAKE_MAC_GOST94 SSL_MD_GOST94_IDX
+# define SSL_HANDSHAKE_MAC_GOST12_256 SSL_MD_GOST12_256_IDX
+# define SSL_HANDSHAKE_MAC_GOST12_512 SSL_MD_GOST12_512_IDX
+# define SSL_HANDSHAKE_MAC_DEFAULT  SSL_HANDSHAKE_MAC_MD5_SHA1
+
+/* Bits 8-15 bits are PRF */
+# define TLS1_PRF_DGST_SHIFT 8
+# define TLS1_PRF_SHA1_MD5 (SSL_MD_MD5_SHA1_IDX << TLS1_PRF_DGST_SHIFT)
+# define TLS1_PRF_SHA256 (SSL_MD_SHA256_IDX << TLS1_PRF_DGST_SHIFT)
+# define TLS1_PRF_SHA384 (SSL_MD_SHA384_IDX << TLS1_PRF_DGST_SHIFT)
+# define TLS1_PRF_GOST94 (SSL_MD_GOST94_IDX << TLS1_PRF_DGST_SHIFT)
+# define TLS1_PRF_GOST12_256 (SSL_MD_GOST12_256_IDX << TLS1_PRF_DGST_SHIFT)
+# define TLS1_PRF_GOST12_512 (SSL_MD_GOST12_512_IDX << TLS1_PRF_DGST_SHIFT)
+# define TLS1_PRF            (SSL_MD_MD5_SHA1_IDX << TLS1_PRF_DGST_SHIFT)
 
 /*
  * Stream MAC for GOST ciphersuites from cryptopro draft (currently this also
  * goes into algorithm2)
  */
-# define TLS1_STREAM_MAC 0x04
+# define TLS1_STREAM_MAC 0x10000
 
 /*
  * Export and cipher strength information. For each cipher we have to decide
@@ -1239,10 +1251,10 @@ typedef struct ssl3_state_st {
     /* used during startup, digest all incoming/outgoing packets */
     BIO *handshake_buffer;
     /*
-     * When set of handshake digests is determined, buffer is hashed and
-     * freed and MD_CTX-es for all required digests are stored in this array
+     * When handshake digest is determined, buffer is hashed and
+     * freed and MD_CTX for the required digest is stored here.
      */
-    EVP_MD_CTX **handshake_dgst;
+    EVP_MD_CTX *handshake_dgst;
     /*
      * Set whenever an expected ChangeCipherSpec message is processed.
      * Unset when the peer's Finished message is received.
@@ -1890,7 +1902,6 @@ void ssl_update_cache(SSL *s, int mode);
 __owur int ssl_cipher_get_evp(const SSL_SESSION *s, const EVP_CIPHER **enc,
                        const EVP_MD **md, int *mac_pkey_type,
                        int *mac_secret_size, SSL_COMP **comp, int use_etm);
-__owur int ssl_get_handshake_digest(int i, long *mask, const EVP_MD **md);
 __owur int ssl_cipher_get_cert_index(const SSL_CIPHER *c);
 __owur const SSL_CIPHER *ssl_get_cipher_by_char(SSL *ssl, const unsigned char *ptr);
 __owur int ssl_cert_set0_chain(SSL *s, SSL_CTX *ctx, STACK_OF(X509) *chain);
@@ -2128,6 +2139,8 @@ __owur int ssl_add_serverhello_use_srtp_ext(SSL *s, unsigned char *p, int *len,
 __owur int ssl_parse_serverhello_use_srtp_ext(SSL *s, PACKET *pkt, int *al);
 
 __owur int ssl_handshake_hash(SSL *s, unsigned char *out, int outlen);
+__owur const EVP_MD *ssl_handshake_md(SSL *s);
+__owur const EVP_MD *ssl_prf_md(SSL *s);
 
 /* s3_cbc.c */
 __owur char ssl3_cbc_record_digest_supported(const EVP_MD_CTX *ctx);
diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c
index 906029c8fc..ae1d36c71e 100644
--- a/ssl/t1_enc.c
+++ b/ssl/t1_enc.c
@@ -236,7 +236,7 @@ static int tls1_P_hash(const EVP_MD *md, const unsigned char *sec,
 }
 
 /* seed1 through seed5 are virtually concatenated */
-static int tls1_PRF(long digest_mask,
+static int tls1_PRF(SSL *s,
                     const void *seed1, int seed1_len,
                     const void *seed2, int seed2_len,
                     const void *seed3, int seed3_len,
@@ -245,55 +245,44 @@ static int tls1_PRF(long digest_mask,
                     const unsigned char *sec, int slen,
                     unsigned char *out1, unsigned char *out2, int olen)
 {
-    int len, i, idx, count;
-    const unsigned char *S1;
-    long m;
-    const EVP_MD *md;
-    int ret = 0;
+    const EVP_MD *md = ssl_prf_md(s);
 
-    /* Count number of digests and partition sec evenly */
-    count = 0;
-    for (idx = 0; ssl_get_handshake_digest(idx, &m, &md); idx++) {
-        if ((m << TLS1_PRF_DGST_SHIFT) & digest_mask)
-            count++;
-    }
-    if (!count) {
+    if (md == NULL) {
         /* Should never happen */
         SSLerr(SSL_F_TLS1_PRF, ERR_R_INTERNAL_ERROR);
-        goto err;
+        return 0;
     }
-    len = slen / count;
-    if (count == 1)
-        slen = 0;
-    S1 = sec;
-    memset(out1, 0, olen);
-    for (idx = 0; ssl_get_handshake_digest(idx, &m, &md); idx++) {
-        if ((m << TLS1_PRF_DGST_SHIFT) & digest_mask) {
-            if (!md) {
-                SSLerr(SSL_F_TLS1_PRF, SSL_R_UNSUPPORTED_DIGEST_TYPE);
-                goto err;
-            }
-            if (!tls1_P_hash(md, S1, len + (slen & 1),
-                             seed1, seed1_len, seed2, seed2_len, seed3,
-                             seed3_len, seed4, seed4_len, seed5, seed5_len,
-                             out2, olen))
-                goto err;
-            S1 += len;
-            for (i = 0; i < olen; i++) {
-                out1[i] ^= out2[i];
-            }
-        }
+    if (EVP_MD_type(md) == NID_md5_sha1) {
+        int i;
+        if (!tls1_P_hash(EVP_md5(), sec, slen/2 + (slen & 1),
+                         seed1, seed1_len, seed2, seed2_len, seed3,
+                         seed3_len, seed4, seed4_len, seed5, seed5_len,
+                         out1, olen))
+            return 0;
+        if (!tls1_P_hash(EVP_sha1(), sec + slen/2, slen/2 + (slen & 1),
+                         seed1, seed1_len, seed2, seed2_len, seed3,
+                         seed3_len, seed4, seed4_len, seed5, seed5_len,
+                         out2, olen))
+            return 0;
+        for (i = 0; i < olen; i++)
+            out1[i] ^= out2[i];
+        return 1;
     }
-    ret = 1;
- err:
-    return ret;
+    memset(out2, 0, olen);
+    if (!tls1_P_hash(md, sec, slen,
+                     seed1, seed1_len, seed2, seed2_len, seed3,
+                     seed3_len, seed4, seed4_len, seed5, seed5_len,
+                     out1, olen))
+        return 0;
+
+    return 1;
 }
 
 static int tls1_generate_key_block(SSL *s, unsigned char *km,
                                    unsigned char *tmp, int num)
 {
     int ret;
-    ret = tls1_PRF(ssl_get_algorithm2(s),
+    ret = tls1_PRF(s,
                    TLS_MD_KEY_EXPANSION_CONST,
                    TLS_MD_KEY_EXPANSION_CONST_SIZE, s->s3->server_random,
                    SSL3_RANDOM_SIZE, s->s3->client_random, SSL3_RANDOM_SIZE,
@@ -489,7 +478,7 @@ int tls1_change_cipher_state(SSL *s, int which)
          * In here I set both the read and write key/iv to the same value
          * since only the correct one will be used :-).
          */
-        if (!tls1_PRF(ssl_get_algorithm2(s),
+        if (!tls1_PRF(s,
                       exp_label, exp_label_len,
                       s->s3->client_random, SSL3_RANDOM_SIZE,
                       s->s3->server_random, SSL3_RANDOM_SIZE,
@@ -499,7 +488,7 @@ int tls1_change_cipher_state(SSL *s, int which)
         key = tmp1;
 
         if (k > 0) {
-            if (!tls1_PRF(ssl_get_algorithm2(s),
+            if (!tls1_PRF(s,
                           TLS_MD_IV_BLOCK_CONST, TLS_MD_IV_BLOCK_CONST_SIZE,
                           s->s3->client_random, SSL3_RANDOM_SIZE,
                           s->s3->server_random, SSL3_RANDOM_SIZE,
@@ -702,7 +691,7 @@ int tls1_final_finish_mac(SSL *s, const char *str, int slen,
                           unsigned char *out)
 {
     int hashlen;
-    unsigned char hash[2 * EVP_MAX_MD_SIZE];
+    unsigned char hash[EVP_MAX_MD_SIZE];
     unsigned char buf2[12];
 
     if (!ssl3_digest_cached_records(s, 0))
@@ -713,7 +702,7 @@ int tls1_final_finish_mac(SSL *s, const char *str, int slen,
     if (hashlen == 0)
         return 0;
 
-    if (!tls1_PRF(ssl_get_algorithm2(s),
+    if (!tls1_PRF(s,
                   str, slen, hash, hashlen, NULL, 0, NULL, 0, NULL, 0,
                   s->session->master_key, s->session->master_key_length,
                   out, buf2, sizeof buf2))
@@ -743,7 +732,7 @@ int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
         fprintf(stderr, "Handshake hashes:\n");
         BIO_dump_fp(stderr, (char *)hash, hashlen);
 #endif
-        tls1_PRF(ssl_get_algorithm2(s),
+        tls1_PRF(s,
                  TLS_MD_EXTENDED_MASTER_SECRET_CONST,
                  TLS_MD_EXTENDED_MASTER_SECRET_CONST_SIZE,
                  hash, hashlen,
@@ -752,7 +741,7 @@ int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
                  NULL, 0, p, len, s->session->master_key, buff, sizeof buff);
         OPENSSL_cleanse(hash, hashlen);
     } else {
-        tls1_PRF(ssl_get_algorithm2(s),
+        tls1_PRF(s,
                  TLS_MD_MASTER_SECRET_CONST,
                  TLS_MD_MASTER_SECRET_CONST_SIZE,
                  s->s3->client_random, SSL3_RANDOM_SIZE,
@@ -858,7 +847,7 @@ int tls1_export_keying_material(SSL *s, unsigned char *out, size_t olen,
                TLS_MD_KEY_EXPANSION_CONST_SIZE) == 0)
         goto err1;
 
-    rv = tls1_PRF(ssl_get_algorithm2(s),
+    rv = tls1_PRF(s,
                   val, vallen,
                   NULL, 0,
                   NULL, 0,