Add EVP_aead_chacha20_poly1305_ietf() - The informational RFC 7539,

"ChaCha20 and Poly1305 for IETF Protocols", introduced a modified AEAD
construction that is incompatible with the common style that has been
already used in TLS with EVP_aead_chacha20_poly1305().  The IETF
version also adds a constant (salt) that is prepended to the nonce.

OK mikeb@ jsing@

7 files changed, 298 insertions, 41 deletions

diff --git a/src/lib/libcrypto/evp/e_chacha20poly1305.c b/src/lib/libcrypto/evp/e_chacha20poly1305.c
index 9deb40b72a..47551c4578 100644
--- a/src/lib/libcrypto/evp/e_chacha20poly1305.c
+++ b/src/lib/libcrypto/evp/e_chacha20poly1305.c
@@ -1,5 +1,7 @@
-/* $OpenBSD: e_chacha20poly1305.c,v 1.10 2015/09/10 15:56:25 jsing Exp $ */
+/* $OpenBSD: e_chacha20poly1305.c,v 1.11 2015/11/02 15:40:53 reyk Exp $ */
+
 /*
+ * Copyright (c) 2015 Reyk Floter <reyk@openbsd.org>
  * Copyright (c) 2014, Google Inc.
  *
  * Permission to use, copy, modify, and/or distribute this software for any
@@ -32,6 +34,16 @@
 #define POLY1305_TAG_LEN 16
 #define CHACHA20_NONCE_LEN 8
 
+/*
+ * The informational RFC 7539, "ChaCha20 and Poly1305 for IETF Protocols",
+ * introduced a modified AEAD construction that is incompatible with the
+ * common style that that has been already used in TLS.  The IETF version
+ * also adds a constant (salt) that is prepended to the nonce.
+ */
+#define CHACHA20_CONSTANT_LEN 4
+#define CHACHA20_IV_LEN 8
+#define CHACHA20_NONCE_LEN_IETF (CHACHA20_CONSTANT_LEN + CHACHA20_IV_LEN)
+
 struct aead_chacha20_poly1305_ctx {
         unsigned char key[32];
         unsigned char tag_len;
@@ -88,10 +100,27 @@ poly1305_update_with_length(poly1305_state *poly1305,
                 j >>= 8;
         }
 
-        CRYPTO_poly1305_update(poly1305, data, data_len);
+        if (data != NULL)
+                CRYPTO_poly1305_update(poly1305, data, data_len);
         CRYPTO_poly1305_update(poly1305, length_bytes, sizeof(length_bytes));
 }
 
+static void
+poly1305_update_with_pad16(poly1305_state *poly1305,
+    const unsigned char *data, size_t data_len)
+{
+        static const unsigned char zero_pad16[16];
+        size_t pad_len;
+
+        CRYPTO_poly1305_update(poly1305, data, data_len);
+
+        /* pad16() is defined in RFC 7539 2.8.1. */
+        if ((pad_len = data_len % 16) == 0)
+                return;
+
+        CRYPTO_poly1305_update(poly1305, zero_pad16, 16 - pad_len);
+}
+
 static int
 aead_chacha20_poly1305_seal(const EVP_AEAD_CTX *ctx, unsigned char *out,
     size_t *out_len, size_t max_out_len, const unsigned char *nonce,
@@ -101,7 +130,9 @@ aead_chacha20_poly1305_seal(const EVP_AEAD_CTX *ctx, unsigned char *out,
         const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
         unsigned char poly1305_key[32];
         poly1305_state poly1305;
+        const unsigned char *iv;
         const uint64_t in_len_64 = in_len;
+        uint64_t ctr;
 
         /* The underlying ChaCha implementation may not overflow the block
          * counter into the second counter word. Therefore we disallow
@@ -121,19 +152,40 @@ aead_chacha20_poly1305_seal(const EVP_AEAD_CTX *ctx, unsigned char *out,
                 return 0;
         }
 
-        if (nonce_len != CHACHA20_NONCE_LEN) {
+        if (nonce_len != ctx->aead->nonce_len) {
                 EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_SEAL, EVP_R_IV_TOO_LARGE);
                 return 0;
         }
 
-        memset(poly1305_key, 0, sizeof(poly1305_key));
-        CRYPTO_chacha_20(poly1305_key, poly1305_key, sizeof(poly1305_key),
-            c20_ctx->key, nonce, 0);
-
-        CRYPTO_poly1305_init(&poly1305, poly1305_key);
-        poly1305_update_with_length(&poly1305, ad, ad_len);
-        CRYPTO_chacha_20(out, in, in_len, c20_ctx->key, nonce, 1);
-        poly1305_update_with_length(&poly1305, out, in_len);
+        if (nonce_len == CHACHA20_NONCE_LEN) {
+                /* Google's draft-agl-tls-chacha20poly1305-04, Nov 2013 */
+
+                memset(poly1305_key, 0, sizeof(poly1305_key));
+                CRYPTO_chacha_20(poly1305_key, poly1305_key,
+                    sizeof(poly1305_key), c20_ctx->key, nonce, 0);
+
+                CRYPTO_poly1305_init(&poly1305, poly1305_key);
+                poly1305_update_with_length(&poly1305, ad, ad_len);
+                CRYPTO_chacha_20(out, in, in_len, c20_ctx->key, nonce, 1);
+                poly1305_update_with_length(&poly1305, out, in_len);
+        } else if (nonce_len == CHACHA20_NONCE_LEN_IETF) {
+                /* RFC 7539, May 2015 */
+
+                ctr = (uint64_t)(nonce[0] | nonce[1] << 8 |
+                    nonce[2] << 16 | nonce[3] << 24) << 32;
+                iv = nonce + CHACHA20_CONSTANT_LEN;
+
+                memset(poly1305_key, 0, sizeof(poly1305_key));
+                CRYPTO_chacha_20(poly1305_key, poly1305_key,
+                    sizeof(poly1305_key), c20_ctx->key, iv, ctr);
+
+                CRYPTO_poly1305_init(&poly1305, poly1305_key);
+                poly1305_update_with_pad16(&poly1305, ad, ad_len);
+                CRYPTO_chacha_20(out, in, in_len, c20_ctx->key, iv, ctr + 1);
+                poly1305_update_with_pad16(&poly1305, out, in_len);
+                poly1305_update_with_length(&poly1305, NULL, ad_len);
+                poly1305_update_with_length(&poly1305, NULL, in_len);
+        }
 
         if (c20_ctx->tag_len != POLY1305_TAG_LEN) {
                 unsigned char tag[POLY1305_TAG_LEN];
@@ -157,9 +209,11 @@ aead_chacha20_poly1305_open(const EVP_AEAD_CTX *ctx, unsigned char *out,
         const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
         unsigned char mac[POLY1305_TAG_LEN];
         unsigned char poly1305_key[32];
+        const unsigned char *iv;
         poly1305_state poly1305;
         const uint64_t in_len_64 = in_len;
         size_t plaintext_len;
+        uint64_t ctr;
 
         if (in_len < c20_ctx->tag_len) {
                 EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_OPEN, EVP_R_BAD_DECRYPT);
@@ -178,7 +232,7 @@ aead_chacha20_poly1305_open(const EVP_AEAD_CTX *ctx, unsigned char *out,
                 return 0;
         }
 
-        if (nonce_len != CHACHA20_NONCE_LEN) {
+        if (nonce_len != ctx->aead->nonce_len) {
                 EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_OPEN, EVP_R_IV_TOO_LARGE);
                 return 0;
         }
@@ -191,13 +245,34 @@ aead_chacha20_poly1305_open(const EVP_AEAD_CTX *ctx, unsigned char *out,
                 return 0;
         }
 
-        memset(poly1305_key, 0, sizeof(poly1305_key));
-        CRYPTO_chacha_20(poly1305_key, poly1305_key, sizeof(poly1305_key),
-            c20_ctx->key, nonce, 0);
+        if (nonce_len == CHACHA20_NONCE_LEN) {
+                /* Google's draft-agl-tls-chacha20poly1305-04, Nov 2013 */
+
+                memset(poly1305_key, 0, sizeof(poly1305_key));
+                CRYPTO_chacha_20(poly1305_key, poly1305_key,
+                    sizeof(poly1305_key), c20_ctx->key, nonce, 0);
+
+                CRYPTO_poly1305_init(&poly1305, poly1305_key);
+                poly1305_update_with_length(&poly1305, ad, ad_len);
+                poly1305_update_with_length(&poly1305, in, plaintext_len);
+        } else if (nonce_len == CHACHA20_NONCE_LEN_IETF) {
+                /* RFC 7539, May 2015 */
+
+                ctr = (uint64_t)(nonce[0] | nonce[1] << 8 |
+                    nonce[2] << 16 | nonce[3] << 24) << 32;
+                iv = nonce + CHACHA20_CONSTANT_LEN;
+
+                memset(poly1305_key, 0, sizeof(poly1305_key));
+                CRYPTO_chacha_20(poly1305_key, poly1305_key,
+                    sizeof(poly1305_key), c20_ctx->key, iv, ctr);
+
+                CRYPTO_poly1305_init(&poly1305, poly1305_key);
+                poly1305_update_with_pad16(&poly1305, ad, ad_len);
+                poly1305_update_with_pad16(&poly1305, in, plaintext_len);
+                poly1305_update_with_length(&poly1305, NULL, ad_len);
+                poly1305_update_with_length(&poly1305, NULL, plaintext_len);
+        }
 
-        CRYPTO_poly1305_init(&poly1305, poly1305_key);
-        poly1305_update_with_length(&poly1305, ad, ad_len);
-        poly1305_update_with_length(&poly1305, in, plaintext_len);
         CRYPTO_poly1305_finish(&poly1305, mac);
 
         if (timingsafe_memcmp(mac, in + plaintext_len, c20_ctx->tag_len) != 0) {
@@ -222,10 +297,28 @@ static const EVP_AEAD aead_chacha20_poly1305 = {
         .open = aead_chacha20_poly1305_open,
 };
 
+static const EVP_AEAD aead_chacha20_poly1305_ietf = {
+        .key_len = 32,
+        .nonce_len = CHACHA20_NONCE_LEN_IETF,
+        .overhead = POLY1305_TAG_LEN,
+        .max_tag_len = POLY1305_TAG_LEN,
+
+        .init = aead_chacha20_poly1305_init,
+        .cleanup = aead_chacha20_poly1305_cleanup,
+        .seal = aead_chacha20_poly1305_seal,
+        .open = aead_chacha20_poly1305_open,
+};
+
 const EVP_AEAD *
 EVP_aead_chacha20_poly1305()
 {
         return &aead_chacha20_poly1305;
 }
 
+const EVP_AEAD *
+EVP_aead_chacha20_poly1305_ietf()
+{
+        return &aead_chacha20_poly1305_ietf;
+}
+
 #endif  /* !OPENSSL_NO_CHACHA && !OPENSSL_NO_POLY1305 */
diff --git a/src/lib/libcrypto/evp/evp.h b/src/lib/libcrypto/evp/evp.h
index 2ddbf6142e..1ec24879c0 100644
--- a/src/lib/libcrypto/evp/evp.h
+++ b/src/lib/libcrypto/evp/evp.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: evp.h,v 1.48 2015/09/14 01:45:03 doug Exp $ */
+/* $OpenBSD: evp.h,v 1.49 2015/11/02 15:40:53 reyk Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1215,6 +1215,7 @@ const EVP_AEAD *EVP_aead_aes_256_gcm(void);
 #if !defined(OPENSSL_NO_CHACHA) && !defined(OPENSSL_NO_POLY1305)
 /* EVP_aead_chacha20_poly1305 is ChaCha20 with a Poly1305 authenticator. */
 const EVP_AEAD *EVP_aead_chacha20_poly1305(void);
+const EVP_AEAD *EVP_aead_chacha20_poly1305_ietf(void);
 #endif
 
 /* EVP_AEAD_key_length returns the length of the keys used. */
diff --git a/src/lib/libcrypto/man/EVP_AEAD_CTX_init.3 b/src/lib/libcrypto/man/EVP_AEAD_CTX_init.3
index a2b4efea54..e6abc282d3 100644
--- a/src/lib/libcrypto/man/EVP_AEAD_CTX_init.3
+++ b/src/lib/libcrypto/man/EVP_AEAD_CTX_init.3
@@ -1,4 +1,4 @@
-.\" $OpenBSD: EVP_AEAD_CTX_init.3,v 1.2 2015/10/14 09:11:25 schwarze Exp $
+.\" $OpenBSD: EVP_AEAD_CTX_init.3,v 1.3 2015/11/02 15:40:53 reyk Exp $
 .\"
 .\" Copyright (c) 2014, Google Inc.
 .\" Parts of the text were written by Adam Langley and David Benjamin.
@@ -16,7 +16,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: October 14 2015 $
+.Dd $Mdocdate: November 2 2015 $
 .Dt EVP_AEAD_CTX_INIT 3
 .Os
 .Sh NAME
@@ -30,7 +30,8 @@
 .Nm EVP_AEAD_nonce_length ,
 .Nm EVP_aead_aes_128_gcm ,
 .Nm EVP_aead_aes_256_gcm ,
-.Nm EVP_aead_chacha20_poly1305
+.Nm EVP_aead_chacha20_poly1305 ,
+.Nm EVP_aead_chacha20_poly1305_ietf
 .Nd authenticated encryption with additional data
 .Sh SYNOPSIS
 .In openssl/evp.h
@@ -101,6 +102,10 @@
 .Fo EVP_aead_chacha20_poly1305
 .Fa void
 .Fc
+.Ft const EVP_AEAD *
+.Fo EVP_aead_chacha20_poly1305_ietf
+.Fa void
+.Fc
 .Sh DESCRIPTION
 AEAD (Authenticated Encryption with Additional Data) couples
 confidentiality and integrity in a single primitive.
@@ -219,6 +224,11 @@ AES-128 in Galois Counter Mode.
 AES-256 in Galois Counter Mode.
 .It Fn EVP_aead_chacha20_poly1305
 ChaCha20 with a Poly1305 authenticator.
+.It Fn EVP_aead_chacha20_poly1305_ietf
+ChaCha20 with a Poly1305 authenticator for IETF Protocols.
+The IETF standardised variant of the AEAD is incompatible with the
+original version.
+It uses a constant salt that is prepended to the nonce.
 .El
 .Pp
 Where possible the
@@ -270,6 +280,23 @@ EVP_AEAD_CTX_cleanup(&ctx);
 .Ed
 .Sh SEE ALSO
 .Xr evp 3
+.Sh STANDARDS
+.Rs
+.%A A. Langley
+.%A W. Chang
+.%D November 2013
+.%R draft-agl-tls-chacha20poly1305-04
+.%T ChaCha20 and Poly1305 based Cipher Suites for TLS
+.Re
+.Pp
+.Rs
+.%A Y. Nir
+.%A A. Langley
+.%D May 2015
+.%R RFC 7539
+.%T ChaCha20 and Poly1305 for IETF Protocols
+.Re
+.Pp
 .Sh HISTORY
 AEAD is based on the implementation by
 .An Adam Langley
diff --git a/src/lib/libssl/src/crypto/evp/e_chacha20poly1305.c b/src/lib/libssl/src/crypto/evp/e_chacha20poly1305.c
index 9deb40b72a..47551c4578 100644
--- a/src/lib/libssl/src/crypto/evp/e_chacha20poly1305.c
+++ b/src/lib/libssl/src/crypto/evp/e_chacha20poly1305.c
@@ -1,5 +1,7 @@
-/* $OpenBSD: e_chacha20poly1305.c,v 1.10 2015/09/10 15:56:25 jsing Exp $ */
+/* $OpenBSD: e_chacha20poly1305.c,v 1.11 2015/11/02 15:40:53 reyk Exp $ */
+
 /*
+ * Copyright (c) 2015 Reyk Floter <reyk@openbsd.org>
  * Copyright (c) 2014, Google Inc.
  *
  * Permission to use, copy, modify, and/or distribute this software for any
@@ -32,6 +34,16 @@
 #define POLY1305_TAG_LEN 16
 #define CHACHA20_NONCE_LEN 8
 
+/*
+ * The informational RFC 7539, "ChaCha20 and Poly1305 for IETF Protocols",
+ * introduced a modified AEAD construction that is incompatible with the
+ * common style that that has been already used in TLS.  The IETF version
+ * also adds a constant (salt) that is prepended to the nonce.
+ */
+#define CHACHA20_CONSTANT_LEN 4
+#define CHACHA20_IV_LEN 8
+#define CHACHA20_NONCE_LEN_IETF (CHACHA20_CONSTANT_LEN + CHACHA20_IV_LEN)
+
 struct aead_chacha20_poly1305_ctx {
         unsigned char key[32];
         unsigned char tag_len;
@@ -88,10 +100,27 @@ poly1305_update_with_length(poly1305_state *poly1305,
                 j >>= 8;
         }
 
-        CRYPTO_poly1305_update(poly1305, data, data_len);
+        if (data != NULL)
+                CRYPTO_poly1305_update(poly1305, data, data_len);
         CRYPTO_poly1305_update(poly1305, length_bytes, sizeof(length_bytes));
 }
 
+static void
+poly1305_update_with_pad16(poly1305_state *poly1305,
+    const unsigned char *data, size_t data_len)
+{
+        static const unsigned char zero_pad16[16];
+        size_t pad_len;
+
+        CRYPTO_poly1305_update(poly1305, data, data_len);
+
+        /* pad16() is defined in RFC 7539 2.8.1. */
+        if ((pad_len = data_len % 16) == 0)
+                return;
+
+        CRYPTO_poly1305_update(poly1305, zero_pad16, 16 - pad_len);
+}
+
 static int
 aead_chacha20_poly1305_seal(const EVP_AEAD_CTX *ctx, unsigned char *out,
     size_t *out_len, size_t max_out_len, const unsigned char *nonce,
@@ -101,7 +130,9 @@ aead_chacha20_poly1305_seal(const EVP_AEAD_CTX *ctx, unsigned char *out,
         const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
         unsigned char poly1305_key[32];
         poly1305_state poly1305;
+        const unsigned char *iv;
         const uint64_t in_len_64 = in_len;
+        uint64_t ctr;
 
         /* The underlying ChaCha implementation may not overflow the block
          * counter into the second counter word. Therefore we disallow
@@ -121,19 +152,40 @@ aead_chacha20_poly1305_seal(const EVP_AEAD_CTX *ctx, unsigned char *out,
                 return 0;
         }
 
-        if (nonce_len != CHACHA20_NONCE_LEN) {
+        if (nonce_len != ctx->aead->nonce_len) {
                 EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_SEAL, EVP_R_IV_TOO_LARGE);
                 return 0;
         }
 
-        memset(poly1305_key, 0, sizeof(poly1305_key));
-        CRYPTO_chacha_20(poly1305_key, poly1305_key, sizeof(poly1305_key),
-            c20_ctx->key, nonce, 0);
-
-        CRYPTO_poly1305_init(&poly1305, poly1305_key);
-        poly1305_update_with_length(&poly1305, ad, ad_len);
-        CRYPTO_chacha_20(out, in, in_len, c20_ctx->key, nonce, 1);
-        poly1305_update_with_length(&poly1305, out, in_len);
+        if (nonce_len == CHACHA20_NONCE_LEN) {
+                /* Google's draft-agl-tls-chacha20poly1305-04, Nov 2013 */
+
+                memset(poly1305_key, 0, sizeof(poly1305_key));
+                CRYPTO_chacha_20(poly1305_key, poly1305_key,
+                    sizeof(poly1305_key), c20_ctx->key, nonce, 0);
+
+                CRYPTO_poly1305_init(&poly1305, poly1305_key);
+                poly1305_update_with_length(&poly1305, ad, ad_len);
+                CRYPTO_chacha_20(out, in, in_len, c20_ctx->key, nonce, 1);
+                poly1305_update_with_length(&poly1305, out, in_len);
+        } else if (nonce_len == CHACHA20_NONCE_LEN_IETF) {
+                /* RFC 7539, May 2015 */
+
+                ctr = (uint64_t)(nonce[0] | nonce[1] << 8 |
+                    nonce[2] << 16 | nonce[3] << 24) << 32;
+                iv = nonce + CHACHA20_CONSTANT_LEN;
+
+                memset(poly1305_key, 0, sizeof(poly1305_key));
+                CRYPTO_chacha_20(poly1305_key, poly1305_key,
+                    sizeof(poly1305_key), c20_ctx->key, iv, ctr);
+
+                CRYPTO_poly1305_init(&poly1305, poly1305_key);
+                poly1305_update_with_pad16(&poly1305, ad, ad_len);
+                CRYPTO_chacha_20(out, in, in_len, c20_ctx->key, iv, ctr + 1);
+                poly1305_update_with_pad16(&poly1305, out, in_len);
+                poly1305_update_with_length(&poly1305, NULL, ad_len);
+                poly1305_update_with_length(&poly1305, NULL, in_len);
+        }
 
         if (c20_ctx->tag_len != POLY1305_TAG_LEN) {
                 unsigned char tag[POLY1305_TAG_LEN];
@@ -157,9 +209,11 @@ aead_chacha20_poly1305_open(const EVP_AEAD_CTX *ctx, unsigned char *out,
         const struct aead_chacha20_poly1305_ctx *c20_ctx = ctx->aead_state;
         unsigned char mac[POLY1305_TAG_LEN];
         unsigned char poly1305_key[32];
+        const unsigned char *iv;
         poly1305_state poly1305;
         const uint64_t in_len_64 = in_len;
         size_t plaintext_len;
+        uint64_t ctr;
 
         if (in_len < c20_ctx->tag_len) {
                 EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_OPEN, EVP_R_BAD_DECRYPT);
@@ -178,7 +232,7 @@ aead_chacha20_poly1305_open(const EVP_AEAD_CTX *ctx, unsigned char *out,
                 return 0;
         }
 
-        if (nonce_len != CHACHA20_NONCE_LEN) {
+        if (nonce_len != ctx->aead->nonce_len) {
                 EVPerr(EVP_F_AEAD_CHACHA20_POLY1305_OPEN, EVP_R_IV_TOO_LARGE);
                 return 0;
         }
@@ -191,13 +245,34 @@ aead_chacha20_poly1305_open(const EVP_AEAD_CTX *ctx, unsigned char *out,
                 return 0;
         }
 
-        memset(poly1305_key, 0, sizeof(poly1305_key));
-        CRYPTO_chacha_20(poly1305_key, poly1305_key, sizeof(poly1305_key),
-            c20_ctx->key, nonce, 0);
+        if (nonce_len == CHACHA20_NONCE_LEN) {
+                /* Google's draft-agl-tls-chacha20poly1305-04, Nov 2013 */
+
+                memset(poly1305_key, 0, sizeof(poly1305_key));
+                CRYPTO_chacha_20(poly1305_key, poly1305_key,
+                    sizeof(poly1305_key), c20_ctx->key, nonce, 0);
+
+                CRYPTO_poly1305_init(&poly1305, poly1305_key);
+                poly1305_update_with_length(&poly1305, ad, ad_len);
+                poly1305_update_with_length(&poly1305, in, plaintext_len);
+        } else if (nonce_len == CHACHA20_NONCE_LEN_IETF) {
+                /* RFC 7539, May 2015 */
+
+                ctr = (uint64_t)(nonce[0] | nonce[1] << 8 |
+                    nonce[2] << 16 | nonce[3] << 24) << 32;
+                iv = nonce + CHACHA20_CONSTANT_LEN;
+
+                memset(poly1305_key, 0, sizeof(poly1305_key));
+                CRYPTO_chacha_20(poly1305_key, poly1305_key,
+                    sizeof(poly1305_key), c20_ctx->key, iv, ctr);
+
+                CRYPTO_poly1305_init(&poly1305, poly1305_key);
+                poly1305_update_with_pad16(&poly1305, ad, ad_len);
+                poly1305_update_with_pad16(&poly1305, in, plaintext_len);
+                poly1305_update_with_length(&poly1305, NULL, ad_len);
+                poly1305_update_with_length(&poly1305, NULL, plaintext_len);
+        }
 
-        CRYPTO_poly1305_init(&poly1305, poly1305_key);
-        poly1305_update_with_length(&poly1305, ad, ad_len);
-        poly1305_update_with_length(&poly1305, in, plaintext_len);
         CRYPTO_poly1305_finish(&poly1305, mac);
 
         if (timingsafe_memcmp(mac, in + plaintext_len, c20_ctx->tag_len) != 0) {
@@ -222,10 +297,28 @@ static const EVP_AEAD aead_chacha20_poly1305 = {
         .open = aead_chacha20_poly1305_open,
 };
 
+static const EVP_AEAD aead_chacha20_poly1305_ietf = {
+        .key_len = 32,
+        .nonce_len = CHACHA20_NONCE_LEN_IETF,
+        .overhead = POLY1305_TAG_LEN,
+        .max_tag_len = POLY1305_TAG_LEN,
+
+        .init = aead_chacha20_poly1305_init,
+        .cleanup = aead_chacha20_poly1305_cleanup,
+        .seal = aead_chacha20_poly1305_seal,
+        .open = aead_chacha20_poly1305_open,
+};
+
 const EVP_AEAD *
 EVP_aead_chacha20_poly1305()
 {
         return &aead_chacha20_poly1305;
 }
 
+const EVP_AEAD *
+EVP_aead_chacha20_poly1305_ietf()
+{
+        return &aead_chacha20_poly1305_ietf;
+}
+
 #endif  /* !OPENSSL_NO_CHACHA && !OPENSSL_NO_POLY1305 */
diff --git a/src/lib/libssl/src/crypto/evp/evp.h b/src/lib/libssl/src/crypto/evp/evp.h
index 2ddbf6142e..1ec24879c0 100644
--- a/src/lib/libssl/src/crypto/evp/evp.h
+++ b/src/lib/libssl/src/crypto/evp/evp.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: evp.h,v 1.48 2015/09/14 01:45:03 doug Exp $ */
+/* $OpenBSD: evp.h,v 1.49 2015/11/02 15:40:53 reyk Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1215,6 +1215,7 @@ const EVP_AEAD *EVP_aead_aes_256_gcm(void);
 #if !defined(OPENSSL_NO_CHACHA) && !defined(OPENSSL_NO_POLY1305)
 /* EVP_aead_chacha20_poly1305 is ChaCha20 with a Poly1305 authenticator. */
 const EVP_AEAD *EVP_aead_chacha20_poly1305(void);
+const EVP_AEAD *EVP_aead_chacha20_poly1305_ietf(void);
 #endif
 
 /* EVP_AEAD_key_length returns the length of the keys used. */
diff --git a/src/regress/lib/libcrypto/aead/aeadtest.c b/src/regress/lib/libcrypto/aead/aeadtest.c
index 6b1ad206c4..72209f5caa 100644
--- a/src/regress/lib/libcrypto/aead/aeadtest.c
+++ b/src/regress/lib/libcrypto/aead/aeadtest.c
@@ -134,6 +134,12 @@ aead_from_name(const EVP_AEAD **aead, const char *name)
 #else
                 fprintf(stderr, "No chacha20-poly1305 support.\n");
 #endif
+        } else if (strcmp(name, "chacha20-poly1305-ietf") == 0) {
+#if !defined(OPENSSL_NO_CHACHA) && !defined(OPENSSL_NO_POLY1305)
+                *aead = EVP_aead_chacha20_poly1305_ietf();
+#else
+                fprintf(stderr, "No chacha20-poly1305-ietf support.\n");
+#endif
         } else {
                 fprintf(stderr, "Unknown AEAD: %s\n", name);
                 return -1;
diff --git a/src/regress/lib/libcrypto/aead/aeadtests.txt b/src/regress/lib/libcrypto/aead/aeadtests.txt
index dc881911e4..6c4002c1cc 100644
--- a/src/regress/lib/libcrypto/aead/aeadtests.txt
+++ b/src/regress/lib/libcrypto/aead/aeadtests.txt
@@ -659,3 +659,39 @@ AD: 00000000000000061703030251
 CT: 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
 TAG: 1df6f94253edb794e81221d3bc838599
 
+# Test vector from RFC7539 2.8.2
+AEAD: chacha20-poly1305-ietf
+KEY: 808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9f
+NONCE: 070000004041424344454647
+IN: 4c616469657320616e642047656e746c656d656e206f662074686520636c617373206f66202739393a204966204920636f756c64206f6666657220796f75206f6e6c79206f6e652074697020666f7220746865206675747572652c2073756e73637265656e20776f756c642062652069742e
+AD: 50515253c0c1c2c3c4c5c6c7
+CT: d31a8d34648e60db7b86afbc53ef7ec2a4aded51296e08fea9e2b5a736ee62d63dbea45e8ca9671282fafb69da92728b1a71de0a9e060b2905d6a5b67ecd3b3692ddbd7f2d778b8c9803aee328091b58fab324e4fad675945585808b4831d7bc3ff4def08e4b7a9de576d26586cec64b6116
+TAG: 1ae10b594f09e26a7e902ecbd0600691
+
+# Test vector from RFC7539 Appendix A.5
+AEAD: chacha20-poly1305-ietf
+KEY: 1c9240a5eb55d38af333888604f6b5f0473917c1402b80099dca5cbc207075c0
+NONCE: 000000000102030405060708
+IN: 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
+AD: f33388860000000000004e91
+CT: 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
+TAG: eead9d67890cbb22392336fea1851f38
+
+# Test vector from RFC7634 Appendix A
+AEAD: chacha20-poly1305-ietf
+KEY: 808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9f
+NONCE: a0a1a2a31011121314151617
+IN: 45000054a6f200004001e778c6336405c000020508005b7a3a080000553bec100007362708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f303132333435363701020204
+AD: 0102030400000005
+CT: 24039428b97f417e3c13753a4f05087b67c352e6a7fab1b982d466ef407ae5c614ee8099d52844eb61aa95dfab4c02f72aa71e7c4c4f64c9befe2facc638e8f3cbec163fac469b502773f6fb94e664da9165b82829f641e0
+TAG: 76aaa8266b7fb0f7b11b369907e1ad43
+
+# Test vector from RFC7634 Appendix B
+AEAD: chacha20-poly1305-ietf
+KEY: 808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9f
+NONCE: a0a1a2a31011121314151617
+IN: 0000000c000040010000000a00
+AD: c0c1c2c3c4c5c6c7d0d1d2d3d4d5d6d72e202500000000090000004529000029
+CT: 610394701f8d017f7c12924889
+TAG: 6b71bfe25236efd7cdc67066906315b2
+