AEAD support.

This change adds an AEAD interface to EVP and an AES-GCM implementation
suitable for use in TLS.

7 files changed, 652 insertions, 23 deletions

diff --git a/crypto/evp/Makefile b/crypto/evp/Makefile
index 2dfafb93b5..dada0d83c1 100644
--- a/crypto/evp/Makefile
+++ b/crypto/evp/Makefile
@@ -29,7 +29,8 @@ LIBSRC= encode.c digest.c evp_enc.c evp_key.c evp_acnf.c evp_cnf.c \
 	c_all.c c_allc.c c_alld.c evp_lib.c bio_ok.c \
 	evp_pkey.c evp_pbe.c p5_crpt.c p5_crpt2.c \
 	e_old.c pmeth_lib.c pmeth_fn.c pmeth_gn.c m_sigver.c \
-	e_aes_cbc_hmac_sha1.c e_aes_cbc_hmac_sha256.c e_rc4_hmac_md5.c
+	e_aes_cbc_hmac_sha1.c e_aes_cbc_hmac_sha256.c e_rc4_hmac_md5.c \
+	evp_aead.c
 
 LIBOBJ=	encode.o digest.o evp_enc.o evp_key.o evp_acnf.o evp_cnf.o \
 	e_des.o e_bf.o e_idea.o e_des3.o e_camellia.o\
@@ -42,7 +43,8 @@ LIBOBJ=	encode.o digest.o evp_enc.o evp_key.o evp_acnf.o evp_cnf.o \
 	c_all.o c_allc.o c_alld.o evp_lib.o bio_ok.o \
 	evp_pkey.o evp_pbe.o p5_crpt.o p5_crpt2.o \
 	e_old.o pmeth_lib.o pmeth_fn.o pmeth_gn.o m_sigver.o \
-	e_aes_cbc_hmac_sha1.o e_aes_cbc_hmac_sha256.o e_rc4_hmac_md5.o
+	e_aes_cbc_hmac_sha1.o e_aes_cbc_hmac_sha256.o e_rc4_hmac_md5.o \
+	evp_aead.o
 
 SRC= $(LIBSRC)
 
diff --git a/crypto/evp/e_aes.c b/crypto/evp/e_aes.c
index 5278001a21..463de1cfe6 100644
--- a/crypto/evp/e_aes.c
+++ b/crypto/evp/e_aes.c
@@ -1227,47 +1227,48 @@ static int aes_gcm_ctrl(EVP_CIPHER_CTX *c, int type, int arg, void *ptr)
 		}
 	}
 
-static int aes_gcm_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
-                        const unsigned char *iv, int enc)
+static ctr128_f aes_gcm_set_key(AES_KEY *aes_key, GCM128_CONTEXT *gcm_ctx,
+				const unsigned char *key, size_t key_len)
 	{
-	EVP_AES_GCM_CTX *gctx = ctx->cipher_data;
-	if (!iv && !key)
-		return 1;
-	if (key)
-		{ do {
 #ifdef BSAES_CAPABLE
 		if (BSAES_CAPABLE)
 			{
-			AES_set_encrypt_key(key,ctx->key_len*8,&gctx->ks.ks);
-			CRYPTO_gcm128_init(&gctx->gcm,&gctx->ks,
+			AES_set_encrypt_key(key,key_len*8,aes_key);
+			CRYPTO_gcm128_init(gcm_ctx,aes_key,
 					(block128_f)AES_encrypt);
-			gctx->ctr = (ctr128_f)bsaes_ctr32_encrypt_blocks;
-			break;
+			return (ctr128_f)bsaes_ctr32_encrypt_blocks;
 			}
-		else
 #endif
 #ifdef VPAES_CAPABLE
 		if (VPAES_CAPABLE)
 			{
-			vpaes_set_encrypt_key(key,ctx->key_len*8,&gctx->ks.ks);
-			CRYPTO_gcm128_init(&gctx->gcm,&gctx->ks,
+			vpaes_set_encrypt_key(key,key_len*8,aes_key);
+			CRYPTO_gcm128_init(gcm_ctx,aes_key,
 					(block128_f)vpaes_encrypt);
-			gctx->ctr = NULL;
-			break;
+			return NULL;
 			}
 		else
 #endif
 		(void)0;	/* terminate potentially open 'else' */
 
-		AES_set_encrypt_key(key, ctx->key_len * 8, &gctx->ks.ks);
-		CRYPTO_gcm128_init(&gctx->gcm, &gctx->ks, (block128_f)AES_encrypt);
+	AES_set_encrypt_key(key, key_len*8, aes_key);
+	CRYPTO_gcm128_init(gcm_ctx, aes_key, (block128_f)AES_encrypt);
 #ifdef AES_CTR_ASM
-		gctx->ctr = (ctr128_f)AES_ctr32_encrypt;
+	return (ctr128_f)AES_ctr32_encrypt;
 #else
-		gctx->ctr = NULL;
+	return NULL;
 #endif
-		} while (0);
+	}
 
+static int aes_gcm_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
+                        const unsigned char *iv, int enc)
+	{
+	EVP_AES_GCM_CTX *gctx = ctx->cipher_data;
+	if (!iv && !key)
+		return 1;
+	if (key)
+		{
+		gctx->ctr = aes_gcm_set_key(&gctx->ks.ks, &gctx->gcm, key, ctx->key_len);
 		/* If we have an iv can set it directly, otherwise use
 		 * saved IV.
 		 */
@@ -1977,4 +1978,193 @@ const EVP_CIPHER *EVP_aes_256_wrap(void)
 	return &aes_256_wrap;
 	}
 
+#define EVP_AEAD_AES_GCM_TAG_LEN 16
+
+struct aead_aes_gcm_ctx {
+	union { double align; AES_KEY ks; } ks;
+	GCM128_CONTEXT gcm;
+	ctr128_f ctr;
+	unsigned char tag_len;
+};
+
+static int aead_aes_gcm_init(EVP_AEAD_CTX *ctx,
+	const unsigned char *key, size_t key_len, size_t tag_len)
+	{
+	struct aead_aes_gcm_ctx *gcm_ctx;
+	const size_t key_bits = key_len * 8;
+
+	if (key_bits != 128 && key_bits != 256)
+		{
+		EVPerr(EVP_F_AEAD_AES_GCM_INIT, EVP_R_BAD_KEY_LENGTH);
+		return 0;  /* EVP_AEAD_CTX_init should catch this. */
+		}
+
+	if (tag_len == EVP_AEAD_DEFAULT_TAG_LENGTH)
+		tag_len = EVP_AEAD_AES_GCM_TAG_LEN;
+
+	if (tag_len > EVP_AEAD_AES_GCM_TAG_LEN)
+		{
+		EVPerr(EVP_F_AEAD_AES_GCM_INIT, EVP_R_TAG_TOO_LARGE);
+		return 0;
+		}
+
+	gcm_ctx = OPENSSL_malloc(sizeof(struct aead_aes_gcm_ctx));
+	if (gcm_ctx == NULL)
+		return 0;
+
+#ifdef AESNI_CAPABLE
+	if (AESNI_CAPABLE)
+		{
+		aesni_set_encrypt_key(key, key_bits, &gcm_ctx->ks.ks);
+		CRYPTO_gcm128_init(&gcm_ctx->gcm, &gcm_ctx->ks.ks,
+				   (block128_f)aesni_encrypt);
+		gcm_ctx->ctr = (ctr128_f) aesni_ctr32_encrypt_blocks;
+		}
+	else
+#endif
+		{
+		gcm_ctx->ctr = aes_gcm_set_key(&gcm_ctx->ks.ks, &gcm_ctx->gcm,
+					       key, key_len);
+		}
+	gcm_ctx->tag_len = tag_len;
+	ctx->aead_state = gcm_ctx;
+
+	return 1;
+	}
+
+static void aead_aes_gcm_cleanup(EVP_AEAD_CTX *ctx)
+	{
+	struct aead_aes_gcm_ctx *gcm_ctx = ctx->aead_state;
+	OPENSSL_free(gcm_ctx);
+	}
+
+static ssize_t aead_aes_gcm_seal(const EVP_AEAD_CTX *ctx,
+	unsigned char *out, size_t max_out_len,
+	const unsigned char *nonce, size_t nonce_len,
+	const unsigned char *in, size_t in_len,
+	const unsigned char *ad, size_t ad_len)
+	{
+	size_t bulk = 0;
+	const struct aead_aes_gcm_ctx *gcm_ctx = ctx->aead_state;
+	GCM128_CONTEXT gcm;
+
+	if (max_out_len < in_len + gcm_ctx->tag_len)
+		{
+		EVPerr(EVP_F_AEAD_AES_GCM_SEAL, EVP_R_BUFFER_TOO_SMALL);
+		return -1;
+		}
+
+	memcpy(&gcm, &gcm_ctx->gcm, sizeof(gcm));
+	CRYPTO_gcm128_setiv(&gcm, nonce, nonce_len);
+
+	if (ad_len > 0 && CRYPTO_gcm128_aad(&gcm, ad, ad_len))
+		return -1;
+
+	if (gcm_ctx->ctr)
+		{
+		if (CRYPTO_gcm128_encrypt_ctr32(&gcm, in + bulk, out + bulk,
+						in_len - bulk, gcm_ctx->ctr))
+			return -1;
+		}
+	else
+		{
+		if (CRYPTO_gcm128_encrypt(&gcm, in + bulk, out + bulk,
+					  in_len - bulk))
+			return -1;
+		}
+
+	CRYPTO_gcm128_tag(&gcm, out + in_len, gcm_ctx->tag_len);
+	return in_len + gcm_ctx->tag_len;
+	}
+
+static ssize_t aead_aes_gcm_open(const EVP_AEAD_CTX *ctx,
+	unsigned char *out, size_t max_out_len,
+	const unsigned char *nonce, size_t nonce_len,
+	const unsigned char *in, size_t in_len,
+	const unsigned char *ad, size_t ad_len)
+	{
+	size_t bulk = 0;
+	const struct aead_aes_gcm_ctx *gcm_ctx = ctx->aead_state;
+	unsigned char tag[EVP_AEAD_AES_GCM_TAG_LEN];
+	size_t out_len;
+	GCM128_CONTEXT gcm;
+
+	if (in_len < gcm_ctx->tag_len)
+		{
+		EVPerr(EVP_F_AEAD_AES_GCM_OPEN, EVP_R_BAD_DECRYPT);
+		return -1;
+		}
+
+	out_len = in_len - gcm_ctx->tag_len;
+
+	if (max_out_len < out_len)
+		{
+		EVPerr(EVP_F_AEAD_AES_GCM_OPEN, EVP_R_BUFFER_TOO_SMALL);
+		return -1;
+		}
+
+	memcpy(&gcm, &gcm_ctx->gcm, sizeof(gcm));
+	CRYPTO_gcm128_setiv(&gcm, nonce, nonce_len);
+
+	if (CRYPTO_gcm128_aad(&gcm, ad, ad_len))
+		return -1;
+
+	if (gcm_ctx->ctr)
+		{
+		if (CRYPTO_gcm128_decrypt_ctr32(&gcm, in + bulk, out + bulk,
+						in_len-bulk-gcm_ctx->tag_len,
+						gcm_ctx->ctr))
+			return -1;
+		}
+	else
+		{
+		if (CRYPTO_gcm128_decrypt(&gcm, in + bulk, out + bulk,
+					  in_len - bulk - gcm_ctx->tag_len))
+			return -1;
+		}
+
+	CRYPTO_gcm128_tag(&gcm, tag, gcm_ctx->tag_len);
+	if (CRYPTO_memcmp(tag, in + out_len, gcm_ctx->tag_len) != 0)
+		{
+		EVPerr(EVP_F_AEAD_AES_GCM_OPEN, EVP_R_BAD_DECRYPT);
+		return -1;
+		}
+
+	return out_len;
+	}
+
+static const EVP_AEAD aead_aes_128_gcm = {
+	16,  /* key len */
+	12,  /* nonce len */
+	EVP_AEAD_AES_GCM_TAG_LEN,  /* overhead */
+	EVP_AEAD_AES_GCM_TAG_LEN,  /* max tag length */
+
+	aead_aes_gcm_init,
+	aead_aes_gcm_cleanup,
+	aead_aes_gcm_seal,
+	aead_aes_gcm_open,
+};
+
+static const EVP_AEAD aead_aes_256_gcm = {
+	32,  /* key len */
+	12,  /* nonce len */
+	EVP_AEAD_AES_GCM_TAG_LEN,  /* overhead */
+	EVP_AEAD_AES_GCM_TAG_LEN,  /* max tag length */
+
+	aead_aes_gcm_init,
+	aead_aes_gcm_cleanup,
+	aead_aes_gcm_seal,
+	aead_aes_gcm_open,
+};
+
+const EVP_AEAD *EVP_aead_aes_128_gcm()
+	{
+	return &aead_aes_128_gcm;
+	}
+
+const EVP_AEAD *EVP_aead_aes_256_gcm()
+	{
+	return &aead_aes_256_gcm;
+	}
+
 #endif
diff --git a/crypto/evp/evp.h b/crypto/evp/evp.h
index e330075dd7..af99604661 100644
--- a/crypto/evp/evp.h
+++ b/crypto/evp/evp.h
@@ -1266,6 +1266,111 @@ void EVP_PKEY_meth_set_ctrl(EVP_PKEY_METHOD *pmeth,
 	int (*ctrl_str)(EVP_PKEY_CTX *ctx,
 					const char *type, const char *value));
 
+/* Authenticated Encryption with Additional Data.
+ *
+ * AEAD couples confidentiality and integrity in a single primtive. AEAD
+ * algorithms take a key and then can seal and open individual messages. Each
+ * message has a unique, per-message nonce and, optionally, additional data
+ * which is authenticated but not included in the output. */
+
+struct evp_aead_st;
+typedef struct evp_aead_st EVP_AEAD;
+
+#ifndef OPENSSL_NO_AES
+/* EVP_aes_128_gcm is AES-128 in Galois Counter Mode. */
+const EVP_AEAD *EVP_aead_aes_128_gcm(void);
+/* EVP_aes_256_gcm is AES-256 in Galois Counter Mode. */
+const EVP_AEAD *EVP_aead_aes_256_gcm(void);
+#endif
+
+/* EVP_AEAD_key_length returns the length, in bytes, of the keys used by
+ * |aead|. */
+size_t EVP_AEAD_key_length(const EVP_AEAD *aead);
+
+/* EVP_AEAD_nonce_length returns the length, in bytes, of the per-message nonce
+ * for |aead|. */
+size_t EVP_AEAD_nonce_length(const EVP_AEAD *aead);
+
+/* EVP_AEAD_max_overhead returns the maximum number of additional bytes added
+ * by the act of sealing data with |aead|. */
+size_t EVP_AEAD_max_overhead(const EVP_AEAD *aead);
+
+/* EVP_AEAD_max_tag_len returns the maximum tag length when using |aead|. This
+ * is the largest value that can be passed as |tag_len| to
+ * |EVP_AEAD_CTX_init|. */
+size_t EVP_AEAD_max_tag_len(const EVP_AEAD *aead);
+
+/* An EVP_AEAD_CTX represents an AEAD algorithm configured with a specific key
+ * and message-independent IV. */
+typedef struct evp_aead_ctx_st {
+	const EVP_AEAD *aead;
+	/* aead_state is an opaque pointer to whatever state the AEAD needs to
+	 * maintain. */
+	void *aead_state;
+} EVP_AEAD_CTX;
+
+#define EVP_AEAD_DEFAULT_TAG_LENGTH 0
+
+/* EVP_AEAD_init initializes |ctx| for the given AEAD algorithm from |impl|.
+ * The |impl| argument may be NULL to choose the default implementation.
+ * Authentication tags may be truncated by passing a size as |tag_len|. A
+ * |tag_len| of zero indicates the default tag length and this is defined as
+ * EVP_AEAD_DEFAULT_TAG_LENGTH for readability.
+ * Returns 1 on success. Otherwise returns 0 and pushes to the error stack. */
+int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead,
+		      const unsigned char *key, size_t key_len,
+		      size_t tag_len, ENGINE *impl);
+
+/* EVP_AEAD_CTX_cleanup frees any data allocated by |ctx|. */
+void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx);
+
+/* EVP_AEAD_CTX_seal encrypts and authenticates |in_len| bytes from |in| and
+ * authenticates |ad_len| bytes from |ad| and writes the result to |out|,
+ * returning the number of bytes written, or -1 on error.
+ *
+ * This function may be called (with the same EVP_AEAD_CTX) concurrently with
+ * itself or EVP_AEAD_CTX_open.
+ *
+ * At most |max_out_len| bytes are written to |out| and, in order to ensure
+ * success, |max_out_len| should be |in_len| plus the result of
+ * EVP_AEAD_overhead.
+ *
+ * The length of |nonce|, |nonce_len|, must be equal to the result of
+ * EVP_AEAD_nonce_length for this AEAD.
+ *
+ * EVP_AEAD_CTX_seal never results in a partial output. If |max_out_len| is
+ * insufficient, -1 will be returned.
+ *
+ * If |in| and |out| alias then |out| must be <= |in|. */
+ssize_t EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx,
+			  unsigned char *out, size_t max_out_len,
+			  const unsigned char *nonce, size_t nonce_len,
+			  const unsigned char *in, size_t in_len,
+			  const unsigned char *ad, size_t ad_len);
+
+/* EVP_AEAD_CTX_open authenticates |in_len| bytes from |in| and |ad_len| bytes
+ * from |ad| and decrypts at most |in_len| bytes into |out|. It returns the
+ * number of bytes written, or -1 on error.
+ *
+ * This function may be called (with the same EVP_AEAD_CTX) concurrently with
+ * itself or EVP_AEAD_CTX_seal.
+ *
+ * At most |in_len| bytes are written to |out|. In order to ensure success,
+ * |max_out_len| should be at least |in_len|.
+ *
+ * The length of |nonce|, |nonce_len|, must be equal to the result of
+ * EVP_AEAD_nonce_length for this AEAD.
+ *
+ * EVP_AEAD_CTX_open never results in a partial output. If |max_out_len| is
+ * insufficient, -1 will be returned.
+ *
+ * If |in| and |out| alias then |out| must be <= |in|. */
+ssize_t EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx,
+			  unsigned char *out, size_t max_out_len,
+			  const unsigned char *nonce, size_t nonce_len,
+			  const unsigned char *in, size_t in_len,
+			  const unsigned char *ad, size_t ad_len);
+
 void EVP_add_alg_module(void);
 
 /* BEGIN ERROR CODES */
@@ -1277,6 +1382,11 @@ void ERR_load_EVP_strings(void);
 /* Error codes for the EVP functions. */
 
 /* Function codes. */
+#define EVP_F_AEAD_AES_GCM_INIT				 187
+#define EVP_F_AEAD_AES_GCM_OPEN				 188
+#define EVP_F_AEAD_AES_GCM_SEAL				 189
+#define EVP_F_AEAD_CTX_OPEN				 185
+#define EVP_F_AEAD_CTX_SEAL				 186
 #define EVP_F_AESNI_INIT_KEY				 165
 #define EVP_F_AESNI_XTS_CIPHER				 176
 #define EVP_F_AES_INIT_KEY				 133
@@ -1293,6 +1403,9 @@ void ERR_load_EVP_strings(void);
 #define EVP_F_DSA_PKEY2PKCS8				 135
 #define EVP_F_ECDSA_PKEY2PKCS8				 129
 #define EVP_F_ECKEY_PKEY2PKCS8				 132
+#define EVP_F_EVP_AEAD_CTX_INIT				 180
+#define EVP_F_EVP_AEAD_CTX_OPEN				 190
+#define EVP_F_EVP_AEAD_CTX_SEAL				 191
 #define EVP_F_EVP_CIPHERINIT_EX				 123
 #define EVP_F_EVP_CIPHER_CTX_COPY			 163
 #define EVP_F_EVP_CIPHER_CTX_CTRL			 124
@@ -1408,10 +1521,12 @@ void ERR_load_EVP_strings(void);
 #define EVP_R_NO_VERIFY_FUNCTION_CONFIGURED		 105
 #define EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE	 150
 #define EVP_R_OPERATON_NOT_INITIALIZED			 151
+#define EVP_R_OUTPUT_ALIASES_INPUT			 172
 #define EVP_R_PKCS8_UNKNOWN_BROKEN_TYPE			 117
 #define EVP_R_PRIVATE_KEY_DECODE_ERROR			 145
 #define EVP_R_PRIVATE_KEY_ENCODE_ERROR			 146
 #define EVP_R_PUBLIC_KEY_NOT_RSA			 106
+#define EVP_R_TAG_TOO_LARGE				 171
 #define EVP_R_TOO_LARGE					 164
 #define EVP_R_UNKNOWN_CIPHER				 160
 #define EVP_R_UNKNOWN_DIGEST				 161
diff --git a/crypto/evp/evp_aead.c b/crypto/evp/evp_aead.c
new file mode 100644
index 0000000000..aa2ed8d603
--- /dev/null
+++ b/crypto/evp/evp_aead.c
@@ -0,0 +1,192 @@
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
+ * All rights reserved.
+ *
+ * This package is an SSL implementation written
+ * by Eric Young (eay@cryptsoft.com).
+ * The implementation was written so as to conform with Netscapes SSL.
+ * 
+ * This library is free for commercial and non-commercial use as long as
+ * the following conditions are aheared to.  The following conditions
+ * apply to all code found in this distribution, be it the RC4, RSA,
+ * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
+ * included with this distribution is covered by the same copyright terms
+ * except that the holder is Tim Hudson (tjh@cryptsoft.com).
+ * 
+ * Copyright remains Eric Young's, and as such any Copyright notices in
+ * the code are not to be removed.
+ * If this package is used in a product, Eric Young should be given attribution
+ * as the author of the parts of the library used.
+ * This can be in the form of a textual message at program startup or
+ * in documentation (online or textual) provided with the package.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *    "This product includes cryptographic software written by
+ *     Eric Young (eay@cryptsoft.com)"
+ *    The word 'cryptographic' can be left out if the rouines from the library
+ *    being used are not cryptographic related :-).
+ * 4. If you include any Windows specific code (or a derivative thereof) from 
+ *    the apps directory (application code) you must include an acknowledgement:
+ *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
+ * 
+ * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * 
+ * The licence and distribution terms for any publically available version or
+ * derivative of this code cannot be changed.  i.e. this code cannot simply be
+ * copied and put under another distribution licence
+ * [including the GNU Public Licence.]
+ */
+
+#include <limits.h>
+#include <string.h>
+
+#include <openssl/evp.h>
+#include <openssl/err.h>
+
+#include "evp_locl.h"
+
+size_t EVP_AEAD_key_length(const EVP_AEAD *aead)
+	{
+	return aead->key_len;
+	}
+
+size_t EVP_AEAD_nonce_length(const EVP_AEAD *aead)
+	{
+	return aead->nonce_len;
+	}
+
+size_t EVP_AEAD_max_overhead(const EVP_AEAD *aead)
+	{
+	return aead->overhead;
+	}
+
+size_t EVP_AEAD_max_tag_len(const EVP_AEAD *aead)
+	{
+	return aead->max_tag_len;
+	}
+
+int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead,
+		      const unsigned char *key, size_t key_len,
+		      size_t tag_len, ENGINE *impl)
+	{
+	ctx->aead = aead;
+	if (key_len != aead->key_len)
+		{
+		EVPerr(EVP_F_EVP_AEAD_CTX_INIT,EVP_R_UNSUPPORTED_KEY_SIZE);
+		return 0;
+		}
+	return aead->init(ctx, key, key_len, tag_len);
+	}
+
+void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx)
+	{
+	if (ctx->aead == NULL)
+		return;
+	ctx->aead->cleanup(ctx);
+	ctx->aead = NULL;
+	}
+
+/* check_alias returns 0 if |out| points within the buffer determined by |in|
+ * and |in_len| and 1 otherwise.
+ *
+ * When processing, there's only an issue if |out| points within in[:in_len]
+ * and isn't equal to |in|. If that's the case then writing the output will
+ * stomp input that hasn't been read yet.
+ *
+ * This function checks for that case. */
+static int check_alias(const unsigned char *in, size_t in_len,
+		       const unsigned char *out)
+	{
+	if (out <= in)
+		return 1;
+	if (in + in_len < out)
+		return 1;
+	return 0;
+	}
+
+ssize_t EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx,
+			  unsigned char *out, size_t max_out_len,
+			  const unsigned char *nonce, size_t nonce_len,
+			  const unsigned char *in, size_t in_len,
+			  const unsigned char *ad, size_t ad_len)
+	{
+	size_t possible_out_len = in_len + ctx->aead->overhead;
+	ssize_t r;
+
+	if (possible_out_len < in_len /* overflow */ ||
+	    possible_out_len > SSIZE_MAX /* return value cannot be
+					    represented */)
+		{
+		EVPerr(EVP_F_EVP_AEAD_CTX_SEAL, EVP_R_TOO_LARGE);
+		goto error;
+		}
+
+	if (!check_alias(in, in_len, out))
+		{
+		EVPerr(EVP_F_EVP_AEAD_CTX_SEAL, EVP_R_OUTPUT_ALIASES_INPUT);
+		goto error;
+		}
+
+	r = ctx->aead->seal(ctx, out, max_out_len, nonce, nonce_len,
+			    in, in_len, ad, ad_len);
+	if (r >= 0)
+		return r;
+
+error:
+	/* In the event of an error, clear the output buffer so that a caller
+	 * that doesn't check the return value doesn't send raw data. */
+	memset(out, 0, max_out_len);
+	return -1;
+	}
+
+ssize_t EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx,
+			 unsigned char *out, size_t max_out_len,
+			 const unsigned char *nonce, size_t nonce_len,
+			 const unsigned char *in, size_t in_len,
+			 const unsigned char *ad, size_t ad_len)
+	{
+	ssize_t r;
+
+	if (in_len > SSIZE_MAX)
+		{
+		EVPerr(EVP_F_EVP_AEAD_CTX_OPEN, EVP_R_TOO_LARGE);
+		goto error;  /* may not be able to represent return value. */
+		}
+
+	if (!check_alias(in, in_len, out))
+		{
+		EVPerr(EVP_F_EVP_AEAD_CTX_OPEN, EVP_R_OUTPUT_ALIASES_INPUT);
+		goto error;
+		}
+
+	r = ctx->aead->open(ctx, out, max_out_len, nonce, nonce_len,
+			    in, in_len, ad, ad_len);
+
+	if (r >= 0)
+		return r;
+
+error:
+	/* In the event of an error, clear the output buffer so that a caller
+	 * that doesn't check the return value doesn't try and process bad
+	 * data. */
+	memset(out, 0, max_out_len);
+	return -1;
+	}
diff --git a/crypto/evp/evp_err.c b/crypto/evp/evp_err.c
index 0a433d7252..acf223994f 100644
--- a/crypto/evp/evp_err.c
+++ b/crypto/evp/evp_err.c
@@ -70,6 +70,11 @@
 
 static ERR_STRING_DATA EVP_str_functs[]=
 	{
+{ERR_FUNC(EVP_F_AEAD_AES_GCM_INIT),	"AEAD_AES_GCM_INIT"},
+{ERR_FUNC(EVP_F_AEAD_AES_GCM_OPEN),	"AEAD_AES_GCM_OPEN"},
+{ERR_FUNC(EVP_F_AEAD_AES_GCM_SEAL),	"AEAD_AES_GCM_SEAL"},
+{ERR_FUNC(EVP_F_AEAD_CTX_OPEN),	"AEAD_CTX_OPEN"},
+{ERR_FUNC(EVP_F_AEAD_CTX_SEAL),	"AEAD_CTX_SEAL"},
 {ERR_FUNC(EVP_F_AESNI_INIT_KEY),	"AESNI_INIT_KEY"},
 {ERR_FUNC(EVP_F_AESNI_XTS_CIPHER),	"AESNI_XTS_CIPHER"},
 {ERR_FUNC(EVP_F_AES_INIT_KEY),	"AES_INIT_KEY"},
@@ -86,6 +91,9 @@ static ERR_STRING_DATA EVP_str_functs[]=
 {ERR_FUNC(EVP_F_DSA_PKEY2PKCS8),	"DSA_PKEY2PKCS8"},
 {ERR_FUNC(EVP_F_ECDSA_PKEY2PKCS8),	"ECDSA_PKEY2PKCS8"},
 {ERR_FUNC(EVP_F_ECKEY_PKEY2PKCS8),	"ECKEY_PKEY2PKCS8"},
+{ERR_FUNC(EVP_F_EVP_AEAD_CTX_INIT),	"EVP_AEAD_CTX_init"},
+{ERR_FUNC(EVP_F_EVP_AEAD_CTX_OPEN),	"EVP_AEAD_CTX_open"},
+{ERR_FUNC(EVP_F_EVP_AEAD_CTX_SEAL),	"EVP_AEAD_CTX_seal"},
 {ERR_FUNC(EVP_F_EVP_CIPHERINIT_EX),	"EVP_CipherInit_ex"},
 {ERR_FUNC(EVP_F_EVP_CIPHER_CTX_COPY),	"EVP_CIPHER_CTX_copy"},
 {ERR_FUNC(EVP_F_EVP_CIPHER_CTX_CTRL),	"EVP_CIPHER_CTX_ctrl"},
@@ -204,10 +212,12 @@ static ERR_STRING_DATA EVP_str_reasons[]=
 {ERR_REASON(EVP_R_NO_VERIFY_FUNCTION_CONFIGURED),"no verify function configured"},
 {ERR_REASON(EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE),"operation not supported for this keytype"},
 {ERR_REASON(EVP_R_OPERATON_NOT_INITIALIZED),"operaton not initialized"},
+{ERR_REASON(EVP_R_OUTPUT_ALIASES_INPUT)  ,"output aliases input"},
 {ERR_REASON(EVP_R_PKCS8_UNKNOWN_BROKEN_TYPE),"pkcs8 unknown broken type"},
 {ERR_REASON(EVP_R_PRIVATE_KEY_DECODE_ERROR),"private key decode error"},
 {ERR_REASON(EVP_R_PRIVATE_KEY_ENCODE_ERROR),"private key encode error"},
 {ERR_REASON(EVP_R_PUBLIC_KEY_NOT_RSA)    ,"public key not rsa"},
+{ERR_REASON(EVP_R_TAG_TOO_LARGE)         ,"tag too large"},
 {ERR_REASON(EVP_R_TOO_LARGE)             ,"too large"},
 {ERR_REASON(EVP_R_UNKNOWN_CIPHER)        ,"unknown cipher"},
 {ERR_REASON(EVP_R_UNKNOWN_DIGEST)        ,"unknown digest"},
diff --git a/crypto/evp/evp_locl.h b/crypto/evp/evp_locl.h
index 08c0a66d39..c0f9fdf50b 100644
--- a/crypto/evp/evp_locl.h
+++ b/crypto/evp/evp_locl.h
@@ -348,6 +348,30 @@ int PKCS5_v2_PBKDF2_keyivgen(EVP_CIPHER_CTX *ctx, const char *pass, int passlen,
 			     ASN1_TYPE *param,
 			     const EVP_CIPHER *c, const EVP_MD *md, int en_de);
 
+/* EVP_AEAD represents a specific AEAD algorithm. */
+struct evp_aead_st {
+	unsigned char key_len;
+	unsigned char nonce_len;
+	unsigned char overhead;
+	unsigned char max_tag_len;
+
+	int (*init) (struct evp_aead_ctx_st*, const unsigned char *key,
+		     size_t key_len, size_t tag_len);
+	void (*cleanup) (struct evp_aead_ctx_st*);
+
+	ssize_t (*seal) (const struct evp_aead_ctx_st *ctx,
+			 unsigned char *out, size_t max_out_len,
+			 const unsigned char *nonce, size_t nonce_len,
+			 const unsigned char *in, size_t in_len,
+			 const unsigned char *ad, size_t ad_len);
+
+	ssize_t (*open) (const struct evp_aead_ctx_st *ctx,
+			 unsigned char *out, size_t max_out_len,
+			 const unsigned char *nonce, size_t nonce_len,
+			 const unsigned char *in, size_t in_len,
+			 const unsigned char *ad, size_t ad_len);
+};
+
 #ifdef OPENSSL_FIPS
 
 #ifdef OPENSSL_DOING_MAKEDEPEND
diff --git a/doc/crypto/EVP_AEAD_CTX_init.pod b/doc/crypto/EVP_AEAD_CTX_init.pod
new file mode 100644
index 0000000000..20e455d5ad
--- /dev/null
+++ b/doc/crypto/EVP_AEAD_CTX_init.pod
@@ -0,0 +1,96 @@
+=pod
+
+=head1 NAME
+
+EVP_AEAD_CTX_init, EVP_AEAD_CTX_cleanup, EVP_AEAD_CTX_seal, EVP_AEAD_CTX_open - authenticated encryption functions.
+
+=head1 SYNOPSIS
+
+ #include <openssl/evp.h>
+
+ int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead,
+                       const unsigned char *key, size_t key_len,
+                       size_t tag_len, ENGINE *impl);
+ void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx);
+ ssize_t EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx,
+                           unsigned char *out, size_t max_out_len,
+                           const unsigned char *nonce, size_t nonce_len,
+                           const unsigned char *in, size_t in_len,
+                           const unsigned char *ad, size_t ad_len);
+ ssize_t EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx,
+                           unsigned char *out, size_t max_out_len,
+                           const unsigned char *nonce, size_t nonce_len,
+                           const unsigned char *in, size_t in_len,
+                           const unsigned char *ad, size_t ad_len);
+
+=head1 DESCRIPTION
+
+The EVP_AEAD_CTX_init() function initialises an B<EVP_AEAD_CTX> structure and
+performs any precomputation needed to use B<aead> with B<key>. The length of
+the key, B<key_len>, is given in bytes.
+
+The B<tag_len> argument contains the length of the tags, in bytes, and allows
+for the processing of truncated authenticators. A zero value indicates that the
+default tag length should be used and this is defined as
+C<EVP_AEAD_DEFAULT_TAG_LENGTH> in order to make the code clear. Using truncated
+tags increases an attacker's chance of creating a valid forgery. Be aware that
+the attacker's chance may increase more than exponentially as would naively be
+expected.
+
+When no longer needed, the initialised B<EVP_AEAD_CTX> structure must be passed
+to EVP_AEAD_CTX_cleanup(), which will deallocate any memory used.
+
+With an B<EVP_AEAD_CTX> in hand, one can seal and open messages. These
+operations are intended to meet the standard notions of privacy and
+authenticity for authenticated encryption. For formal definitions see I<Bellare
+and Namprempre>, "Authenticated encryption: relations among notions and
+analysis of the generic composition paradigm," Lecture Notes in Computer
+Science B<1976> (2000), 531–545,
+L<http://www-cse.ucsd.edu/~mihir/papers/oem.html>.
+
+When sealing messages, a nonce must be given. The length of the nonce is fixed
+by the AEAD in use and is returned by EVP_AEAD_nonce_length(). I<The nonce must
+be unique for all messages with the same key>. This is critically important -
+nonce reuse may completely undermine the security of the AEAD. Nonces may be
+predictable and public, so long as they are unique. Uniqueness may be achieved
+with a simple counter or, if long enough, may be generated randomly. The nonce
+must be passed into the "open" operation by the receiver so must either be
+implicit (e.g. a counter), or must be transmitted along with the sealed message.
+
+The "seal" and "open" operations are atomic - an entire message must be
+encrypted or decrypted in a single call. Large messages may have to be split up
+in order to accomodate this. When doing so, be mindful of the need not to
+repeat nonces and the possibility that an attacker could duplicate, reorder or
+drop message chunks. For example, using a single key for a given (large)
+message and sealing chunks with nonces counting from zero would be secure as
+long as the number of chunks was securely transmitted. (Otherwise an attacker
+could truncate the message by dropping chunks from the end.)
+
+The number of chunks could be transmitted by prefixing it to the plaintext, for
+example. This also assumes that no other message would ever use the same key
+otherwise the rule that nonces must be unique for a given key would be
+violated.
+
+The "seal" and "open" operations also permit additional data to be
+authenticated via the B<ad> parameter. This data is not included in the
+ciphertext and must be identical for both the "seal" and "open" call. This
+permits implicit context to be authenticated but may be C<NULL> if not needed.
+
+The "seal" and "open" operations may work inplace if the B<out> and B<in>
+arguments are equal. They may also be used to shift the data left inside the
+same buffer if B<out> is less than B<in>. However, B<out> may not point inside
+the input data otherwise the input may be overwritten before it has been read.
+This case will cause an error.
+
+=head1 RETURN VALUES
+
+The "seal" and "open" operations return an C<ssize_t> with value -1 on error,
+otherwise they return the number of output bytes written. An error will be
+returned if the input length is large enough that the output size exceeds the
+range of a C<ssize_t>.
+
+=head1 HISTORY
+
+These functions were first added to OpenSSL 1.0.2.
+
+=cut