Provide a rolling handshake hash that commences as soon as the cipher

suite has been selected, and convert the final finish MAC to use this
handshake hash.

This is a first step towards cleaning up the current handshake
buffer/digest code.

ok beck@ inoguchi@

1 files changed, 110 insertions, 0 deletions

diff --git a/src/lib/libssl/t1_hash.c b/src/lib/libssl/t1_hash.c
new file mode 100644
index 0000000000..94410e4127
--- /dev/null
+++ b/src/lib/libssl/t1_hash.c
@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2017 Joel Sing <jsing@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "ssl_locl.h"
+
+#include <openssl/ssl.h>
+
+int
+tls1_handshake_hash_init(SSL *s)
+{
+        const EVP_MD *md;
+        long dlen;
+        void *data;
+
+        tls1_handshake_hash_free(s);
+
+        if (!ssl_get_handshake_evp_md(s, &md)) {
+                SSLerrorx(ERR_R_INTERNAL_ERROR);
+                goto err;
+        }
+
+        if ((S3I(s)->handshake_hash = EVP_MD_CTX_create()) == NULL) {
+                SSLerror(s, ERR_R_MALLOC_FAILURE);
+                goto err;
+        }
+        if (!EVP_DigestInit_ex(S3I(s)->handshake_hash, md, NULL)) {
+                SSLerror(s, ERR_R_EVP_LIB);
+                goto err;
+        }
+
+        dlen = BIO_get_mem_data(S3I(s)->handshake_buffer, &data);
+        if (dlen <= 0) {
+                SSLerror(s, SSL_R_BAD_HANDSHAKE_LENGTH);
+                goto err;
+        }
+        if (!tls1_handshake_hash_update(s, data, dlen)) {
+                SSLerror(s, ERR_R_EVP_LIB);
+                goto err;
+        }
+                
+        return 1;
+
+ err:
+        tls1_handshake_hash_free(s);
+
+        return 0;
+}
+
+int
+tls1_handshake_hash_update(SSL *s, const unsigned char *buf, size_t len)
+{
+        if (S3I(s)->handshake_hash == NULL)
+                return 1;
+
+        return EVP_DigestUpdate(S3I(s)->handshake_hash, buf, len);
+}
+
+int
+tls1_handshake_hash_value(SSL *s, const unsigned char *out, size_t len,
+    size_t *outlen)
+{
+        EVP_MD_CTX *mdctx = NULL;
+        unsigned int mdlen;
+        int ret = 0;
+
+        if (EVP_MD_CTX_size(S3I(s)->handshake_hash) > len)
+                goto err;
+
+        if ((mdctx = EVP_MD_CTX_create()) == NULL) {
+                SSLerror(s, ERR_R_MALLOC_FAILURE);
+                goto err;
+        }
+        if (!EVP_MD_CTX_copy_ex(mdctx, S3I(s)->handshake_hash)) {
+                SSLerror(s, ERR_R_EVP_LIB);
+                goto err;
+        }
+        if (!EVP_DigestFinal_ex(mdctx, (unsigned char *)out, &mdlen)) {
+                SSLerror(s, ERR_R_EVP_LIB);
+                goto err;
+        }
+        if (outlen != NULL)
+                *outlen = mdlen;
+
+        ret = 1;
+
+ err:
+        EVP_MD_CTX_destroy(mdctx);
+
+        return (ret);
+}
+
+void
+tls1_handshake_hash_free(SSL *s)
+{
+        EVP_MD_CTX_destroy(S3I(s)->handshake_hash);
+        S3I(s)->handshake_hash = NULL;
+}