Implement the IETF ChaCha20-Poly1305 cipher suites.

Rename the existing ChaCha20-Poly1305 cipher suites with an "-OLD" suffix,
effectively replaces the original Google implementation. We continue to
support both the IETF and Google versions, however the existing names
now refer to the ciphers from draft-ietf-tls-chacha20-poly1305-04.

Feedback from doug@

1 files changed, 81 insertions, 28 deletions

diff --git a/src/lib/libssl/t1_enc.c b/src/lib/libssl/t1_enc.c
index 5d95419e7e..53570b2d4f 100644
--- a/src/lib/libssl/t1_enc.c
+++ b/src/lib/libssl/t1_enc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: t1_enc.c,v 1.84 2016/03/06 14:52:15 beck Exp $ */
+/* $OpenBSD: t1_enc.c,v 1.85 2016/04/28 16:39:45 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -471,14 +471,26 @@ tls1_change_cipher_state_aead(SSL *s, char is_read, const unsigned char *key,
         aead_ctx->variable_nonce_in_record =
             (s->s3->tmp.new_cipher->algorithm2 &
             SSL_CIPHER_ALGORITHM2_VARIABLE_NONCE_IN_RECORD) != 0;
-        if (aead_ctx->variable_nonce_len + aead_ctx->fixed_nonce_len !=
-            EVP_AEAD_nonce_length(aead)) {
-                SSLerr(SSL_F_TLS1_CHANGE_CIPHER_STATE_AEAD,
-                    ERR_R_INTERNAL_ERROR);
-                return (0);
-        }
+        aead_ctx->xor_fixed_nonce =
+            s->s3->tmp.new_cipher->algorithm_enc == SSL_CHACHA20POLY1305;
         aead_ctx->tag_len = EVP_AEAD_max_overhead(aead);
 
+        if (aead_ctx->xor_fixed_nonce) {
+                if (aead_ctx->fixed_nonce_len != EVP_AEAD_nonce_length(aead) ||
+                    aead_ctx->variable_nonce_len > EVP_AEAD_nonce_length(aead)) {
+                        SSLerr(SSL_F_TLS1_CHANGE_CIPHER_STATE_AEAD,
+                            ERR_R_INTERNAL_ERROR);
+                        return (0);
+                }
+        } else {
+                if (aead_ctx->variable_nonce_len + aead_ctx->fixed_nonce_len !=
+                    EVP_AEAD_nonce_length(aead)) {
+                        SSLerr(SSL_F_TLS1_CHANGE_CIPHER_STATE_AEAD,
+                            ERR_R_INTERNAL_ERROR);
+                        return (0);
+                }
+        }
+
         return (1);
 }
 
@@ -819,8 +831,8 @@ tls1_enc(SSL *s, int send)
 
         if (aead) {
                 unsigned char ad[13], *in, *out, nonce[16];
-                unsigned nonce_used;
-                size_t out_len;
+                size_t out_len, pad_len = 0;
+                unsigned int nonce_used;
 
                 if (SSL_IS_DTLS(s)) {
                         dtls1_build_sequence_number(ad, seq,
@@ -834,13 +846,20 @@ tls1_enc(SSL *s, int send)
                 ad[9] = (unsigned char)(s->version >> 8);
                 ad[10] = (unsigned char)(s->version);
 
-                if (aead->fixed_nonce_len +
-                    aead->variable_nonce_len > sizeof(nonce) ||
-                    aead->variable_nonce_len > 8)
-                        return -1;  /* internal error - should never happen. */
+                if (aead->variable_nonce_len > 8 ||
+                    aead->variable_nonce_len > sizeof(nonce))
+                        return -1;
 
-                memcpy(nonce, aead->fixed_nonce, aead->fixed_nonce_len);
-                nonce_used = aead->fixed_nonce_len;
+                if (aead->xor_fixed_nonce) {
+                        if (aead->fixed_nonce_len > sizeof(nonce) ||
+                            aead->variable_nonce_len > aead->fixed_nonce_len)
+                                return -1;  /* Should never happen. */
+                        pad_len = aead->fixed_nonce_len - aead->variable_nonce_len;
+                } else {
+                        if (aead->fixed_nonce_len +
+                            aead->variable_nonce_len > sizeof(nonce))
+                                return -1;  /* Should never happen. */
+                }
 
                 if (send) {
                         size_t len = rec->length;
@@ -848,15 +867,30 @@ tls1_enc(SSL *s, int send)
                         in = rec->input;
                         out = rec->data;
 
-                        /*
-                         * When sending we use the sequence number as the
-                         * variable part of the nonce.
-                         */
-                        if (aead->variable_nonce_len > 8)
-                                return -1;
-                        memcpy(nonce + nonce_used, ad,
-                            aead->variable_nonce_len);
-                        nonce_used += aead->variable_nonce_len;
+                        if (aead->xor_fixed_nonce) {
+                                /*
+                                 * The sequence number is left zero
+                                 * padded, then xored with the fixed
+                                 * nonce.
+                                 */
+                                memset(nonce, 0, pad_len);
+                                memcpy(nonce + pad_len, ad,
+                                    aead->variable_nonce_len);
+                                for (i = 0; i < aead->fixed_nonce_len; i++)
+                                        nonce[i] ^= aead->fixed_nonce[i];
+                                nonce_used = aead->fixed_nonce_len;
+                        } else {
+                                /*
+                                 * When sending we use the sequence number as
+                                 * the variable part of the nonce.
+                                 */
+                                memcpy(nonce, aead->fixed_nonce,
+                                    aead->fixed_nonce_len);
+                                nonce_used = aead->fixed_nonce_len;
+                                memcpy(nonce + nonce_used, ad,
+                                    aead->variable_nonce_len);
+                                nonce_used += aead->variable_nonce_len;
+                        }
 
                         /*
                          * In do_ssl3_write, rec->input is moved forward by
@@ -890,10 +924,29 @@ tls1_enc(SSL *s, int send)
 
                         if (len < aead->variable_nonce_len)
                                 return 0;
-                        memcpy(nonce + nonce_used,
-                            aead->variable_nonce_in_record ? in : ad,
-                            aead->variable_nonce_len);
-                        nonce_used += aead->variable_nonce_len;
+
+                        if (aead->xor_fixed_nonce) {
+                                /*
+                                 * The sequence number is left zero
+                                 * padded, then xored with the fixed
+                                 * nonce.
+                                 */
+                                memset(nonce, 0, pad_len);
+                                memcpy(nonce + pad_len, ad,
+                                    aead->variable_nonce_len);
+                                for (i = 0; i < aead->fixed_nonce_len; i++)
+                                        nonce[i] ^= aead->fixed_nonce[i];
+                                nonce_used = aead->fixed_nonce_len;
+                        } else {
+                                memcpy(nonce, aead->fixed_nonce,
+                                    aead->fixed_nonce_len);
+                                nonce_used = aead->fixed_nonce_len;
+
+                                memcpy(nonce + nonce_used,
+                                    aead->variable_nonce_in_record ? in : ad,
+                                    aead->variable_nonce_len);
+                                nonce_used += aead->variable_nonce_len;
+                        }
 
                         if (aead->variable_nonce_in_record) {
                                 in += aead->variable_nonce_len;