/*
 * aes_gcm_ossl.c
 *
 * AES Galois Counter Mode
 *
 * John A. Foley
 * Cisco Systems, Inc.
 *
 */

/*
 *
 * Copyright (c) 2013, Cisco Systems, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 *   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.
 *
 *   Neither the name of the Cisco Systems, Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "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
 * COPYRIGHT HOLDERS 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.
 *
 */

#ifdef HAVE_CONFIG_H
    #include <config.h>
#endif

#include <openssl/evp.h>
#include "aes_icm_ossl.h"
#include "aes_gcm_ossl.h"
#include "alloc.h"
#include "crypto_types.h"


debug_module_t mod_aes_gcm = {
    0,               /* debugging is off by default */
    "aes gcm"        /* printable module name       */
};

/*
 * The following are the global singleton instances for the
 * 128-bit and 256-bit GCM ciphers.
 */
extern cipher_type_t aes_gcm_128_openssl;
extern cipher_type_t aes_gcm_256_openssl;

/*
 * For now we only support 8 and 16 octet tags.  The spec allows for
 * optional 12 byte tag, which may be supported in the future.  
 */
#define GCM_AUTH_TAG_LEN    16
#define GCM_AUTH_TAG_LEN_8  8


/*
 * This function allocates a new instance of this crypto engine.
 * The key_len parameter should be one of 28 or 44 for
 * AES-128-GCM or AES-256-GCM respectively.  Note that the 
 * key length includes the 14 byte salt value that is used when
 * initializing the KDF.
 */
err_status_t aes_gcm_openssl_alloc (cipher_t **c, int key_len, int tlen)
{
    aes_gcm_ctx_t *gcm;
    int tmp;
    uint8_t *allptr;

    debug_print(mod_aes_gcm, "allocating cipher with key length %d", key_len);
    debug_print(mod_aes_gcm, "allocating cipher with tag length %d", tlen);

    /*
     * Verify the key_len is valid for one of: AES-128/256
     */
    if (key_len != AES_128_GCM_KEYSIZE_WSALT && 
	key_len != AES_256_GCM_KEYSIZE_WSALT) {
        return (err_status_bad_param);
    }

    if (tlen != GCM_AUTH_TAG_LEN &&
	tlen != GCM_AUTH_TAG_LEN_8) {
        return (err_status_bad_param);
    }

    /* allocate memory a cipher of type aes_gcm */
    tmp = sizeof(cipher_t) + sizeof(aes_gcm_ctx_t);
    allptr = crypto_alloc(tmp);
    if (allptr == NULL) {
        return (err_status_alloc_fail);
    }

    /* set pointers */
    *c = (cipher_t*)allptr;
    (*c)->state = allptr + sizeof(cipher_t);
    gcm = (aes_gcm_ctx_t *)(*c)->state;

    gcm->ctx = EVP_CIPHER_CTX_new();
    if (gcm->ctx == NULL) {
        crypto_free(*c);
        *c = NULL;
        return (err_status_alloc_fail);
    }

    /* increment ref_count */
    switch (key_len) {
    case AES_128_GCM_KEYSIZE_WSALT:
        (*c)->type = &aes_gcm_128_openssl;
        (*c)->algorithm = AES_128_GCM;
        aes_gcm_128_openssl.ref_count++;
        ((aes_gcm_ctx_t*)(*c)->state)->key_size = AES_128_KEYSIZE;
        ((aes_gcm_ctx_t*)(*c)->state)->tag_len = tlen;  
        break;
    case AES_256_GCM_KEYSIZE_WSALT:
        (*c)->type = &aes_gcm_256_openssl;
        (*c)->algorithm = AES_256_GCM;
        aes_gcm_256_openssl.ref_count++;
        ((aes_gcm_ctx_t*)(*c)->state)->key_size = AES_256_KEYSIZE;
        ((aes_gcm_ctx_t*)(*c)->state)->tag_len = tlen;  
        break;
    }

    /* set key size        */
    (*c)->key_len = key_len;

    return (err_status_ok);
}


/*
 * This function deallocates a GCM session 
 */
err_status_t aes_gcm_openssl_dealloc (cipher_t *c)
{
    aes_gcm_ctx_t *ctx;

    ctx = (aes_gcm_ctx_t*)c->state;
    if (ctx) {
	EVP_CIPHER_CTX_free(ctx->ctx);
        /* decrement ref_count for the appropriate engine */
        switch (ctx->key_size) {
        case AES_256_KEYSIZE:
            aes_gcm_256_openssl.ref_count--;
            break;
        case AES_128_KEYSIZE:
            aes_gcm_128_openssl.ref_count--;
            break;
        default:
            return (err_status_dealloc_fail);
            break;
        }
    }

    /* zeroize entire state*/
    octet_string_set_to_zero((uint8_t*)c, sizeof(cipher_t) + sizeof(aes_gcm_ctx_t));

    /* free memory */
    crypto_free(c);

    return (err_status_ok);
}

/*
 * aes_gcm_openssl_context_init(...) initializes the aes_gcm_context
 * using the value in key[].
 *
 * the key is the secret key
 */
err_status_t aes_gcm_openssl_context_init (aes_gcm_ctx_t *c, const uint8_t *key)
{
    c->dir = direction_any;

    /* copy key to be used later when CiscoSSL crypto context is created */
    v128_copy_octet_string((v128_t*)&c->key, key);

    if (c->key_size == AES_256_KEYSIZE) {
        debug_print(mod_aes_gcm, "Copying last 16 bytes of key: %s",
                    v128_hex_string((v128_t*)(key + AES_128_KEYSIZE)));
        v128_copy_octet_string(((v128_t*)(&c->key.v8)) + 1, 
		               key + AES_128_KEYSIZE);
    }

    debug_print(mod_aes_gcm, "key:  %s", v128_hex_string((v128_t*)&c->key));

    EVP_CIPHER_CTX_cleanup(c->ctx);

    return (err_status_ok);
}


/*
 * aes_gcm_openssl_set_iv(c, iv) sets the counter value to the exor of iv with
 * the offset
 */
err_status_t aes_gcm_openssl_set_iv (aes_gcm_ctx_t *c, void *iv,
	                             int direction)
{
    const EVP_CIPHER *evp;

    if (direction != direction_encrypt && direction != direction_decrypt) {
        return (err_status_bad_param);
    }
    c->dir = direction;

    debug_print(mod_aes_gcm, "setting iv: %s", v128_hex_string(iv));

    switch (c->key_size) {
    case AES_256_KEYSIZE:
        evp = EVP_aes_256_gcm();
        break;
    case AES_128_KEYSIZE:
        evp = EVP_aes_128_gcm();
        break;
    default:
        return (err_status_bad_param);
        break;
    }

    if (!EVP_CipherInit_ex(c->ctx, evp, NULL, (const unsigned char*)&c->key.v8,
                           NULL, (c->dir == direction_encrypt ? 1 : 0))) {
        return (err_status_init_fail);
    }

    /* set IV len  and the IV value, the followiong 3 calls are required */
    if (!EVP_CIPHER_CTX_ctrl(c->ctx, EVP_CTRL_GCM_SET_IVLEN, 12, 0)) {
        return (err_status_init_fail);
    }
    if (!EVP_CIPHER_CTX_ctrl(c->ctx, EVP_CTRL_GCM_SET_IV_FIXED, -1, iv)) {
        return (err_status_init_fail);
    }
    if (!EVP_CIPHER_CTX_ctrl(c->ctx, EVP_CTRL_GCM_IV_GEN, 0, iv)) {
        return (err_status_init_fail);
    }

    return (err_status_ok);
}

/*
 * This function processes the AAD
 *
 * Parameters:
 *	c	Crypto context
 *	aad	Additional data to process for AEAD cipher suites
 *	aad_len	length of aad buffer
 */
err_status_t aes_gcm_openssl_set_aad (aes_gcm_ctx_t *c, unsigned char *aad, 
	                              unsigned int aad_len)
{
    int rv;

    /*
     * Set dummy tag, OpenSSL requires the Tag to be set before
     * processing AAD
     */
    EVP_CIPHER_CTX_ctrl(c->ctx, EVP_CTRL_GCM_SET_TAG, c->tag_len, aad);

    rv = EVP_Cipher(c->ctx, NULL, aad, aad_len);
    if (rv != aad_len) {
        return (err_status_algo_fail);
    } else {
        return (err_status_ok);
    }
}

/*
 * This function encrypts a buffer using AES GCM mode
 *
 * Parameters:
 *	c	Crypto context
 *	buf	data to encrypt
 *	enc_len	length of encrypt buffer
 */
err_status_t aes_gcm_openssl_encrypt (aes_gcm_ctx_t *c, unsigned char *buf, 
	                              unsigned int *enc_len)
{
    if (c->dir != direction_encrypt && c->dir != direction_decrypt) {
        return (err_status_bad_param);
    }

    /*
     * Encrypt the data
     */
    EVP_Cipher(c->ctx, buf, buf, *enc_len);

    return (err_status_ok);
}

/*
 * This function calculates and returns the GCM tag for a given context.
 * This should be called after encrypting the data.  The *len value 
 * is increased by the tag size.  The caller must ensure that *buf has
 * enough room to accept the appended tag.
 *
 * Parameters:
 *	c	Crypto context
 *	buf	data to encrypt
 *	len	length of encrypt buffer
 */
err_status_t aes_gcm_openssl_get_tag (aes_gcm_ctx_t *c, unsigned char *buf, 
	                              int *len)
{
    /*
     * Calculate the tag
     */
    EVP_Cipher(c->ctx, NULL, NULL, 0);

    /*
     * Retreive the tag
     */
    EVP_CIPHER_CTX_ctrl(c->ctx, EVP_CTRL_GCM_GET_TAG, c->tag_len, buf);

    /*
     * Increase encryption length by desired tag size
     */
    *len = c->tag_len;

    return (err_status_ok);
}


/*
 * This function decrypts a buffer using AES GCM mode
 *
 * Parameters:
 *	c	Crypto context
 *	buf	data to encrypt
 *	enc_len	length of encrypt buffer
 */
err_status_t aes_gcm_openssl_decrypt (aes_gcm_ctx_t *c, unsigned char *buf, 
	                              unsigned int *enc_len)
{
    if (c->dir != direction_encrypt && c->dir != direction_decrypt) {
        return (err_status_bad_param);
    }

    /*
     * Set the tag before decrypting
     */
    EVP_CIPHER_CTX_ctrl(c->ctx, EVP_CTRL_GCM_SET_TAG, c->tag_len, 
	                buf + (*enc_len - c->tag_len));
    EVP_Cipher(c->ctx, buf, buf, *enc_len - c->tag_len);

    /*
     * Check the tag
     */
    if (EVP_Cipher(c->ctx, NULL, NULL, 0)) {
        return (err_status_auth_fail);
    }

    /*
     * Reduce the buffer size by the tag length since the tag
     * is not part of the original payload
     */
    *enc_len -= c->tag_len;

    return (err_status_ok);
}



/*
 * Name of this crypto engine
 */
char aes_gcm_128_openssl_description[] = "AES-128 GCM using openssl";
char aes_gcm_256_openssl_description[] = "AES-256 GCM using openssl";


/*
 * KAT values for AES self-test.  These
 * values we're derived from independent test code 
 * using OpenSSL.
 */
uint8_t aes_gcm_test_case_0_key[AES_128_GCM_KEYSIZE_WSALT] = {
    0xfe, 0xff, 0xe9, 0x92, 0x86, 0x65, 0x73, 0x1c,
    0x6d, 0x6a, 0x8f, 0x94, 0x67, 0x30, 0x83, 0x08,
    0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
    0x09, 0x0a, 0x0b, 0x0c,  
};

uint8_t aes_gcm_test_case_0_iv[12] = {
    0xca, 0xfe, 0xba, 0xbe, 0xfa, 0xce, 0xdb, 0xad, 
    0xde, 0xca, 0xf8, 0x88
};

uint8_t aes_gcm_test_case_0_plaintext[60] =  {
    0xd9, 0x31, 0x32, 0x25, 0xf8, 0x84, 0x06, 0xe5,
    0xa5, 0x59, 0x09, 0xc5, 0xaf, 0xf5, 0x26, 0x9a,
    0x86, 0xa7, 0xa9, 0x53, 0x15, 0x34, 0xf7, 0xda,
    0x2e, 0x4c, 0x30, 0x3d, 0x8a, 0x31, 0x8a, 0x72,
    0x1c, 0x3c, 0x0c, 0x95, 0x95, 0x68, 0x09, 0x53,
    0x2f, 0xcf, 0x0e, 0x24, 0x49, 0xa6, 0xb5, 0x25,
    0xb1, 0x6a, 0xed, 0xf5, 0xaa, 0x0d, 0xe6, 0x57,
    0xba, 0x63, 0x7b, 0x39
};

uint8_t aes_gcm_test_case_0_aad[20] = {
    0xfe, 0xed, 0xfa, 0xce, 0xde, 0xad, 0xbe, 0xef,
    0xfe, 0xed, 0xfa, 0xce, 0xde, 0xad, 0xbe, 0xef,
    0xab, 0xad, 0xda, 0xd2
};

uint8_t aes_gcm_test_case_0_ciphertext[76] = {
    0x42, 0x83, 0x1e, 0xc2, 0x21, 0x77, 0x74, 0x24,
    0x4b, 0x72, 0x21, 0xb7, 0x84, 0xd0, 0xd4, 0x9c,
    0xe3, 0xaa, 0x21, 0x2f, 0x2c, 0x02, 0xa4, 0xe0,
    0x35, 0xc1, 0x7e, 0x23, 0x29, 0xac, 0xa1, 0x2e,
    0x21, 0xd5, 0x14, 0xb2, 0x54, 0x66, 0x93, 0x1c,
    0x7d, 0x8f, 0x6a, 0x5a, 0xac, 0x84, 0xaa, 0x05,
    0x1b, 0xa3, 0x0b, 0x39, 0x6a, 0x0a, 0xac, 0x97,
    0x3d, 0x58, 0xe0, 0x91,
    /* the last 16 bytes are the tag */
    0x5b, 0xc9, 0x4f, 0xbc, 0x32, 0x21, 0xa5, 0xdb,
    0x94, 0xfa, 0xe9, 0x5a, 0xe7, 0x12, 0x1a, 0x47,
};

cipher_test_case_t aes_gcm_test_case_0a = {
    AES_128_GCM_KEYSIZE_WSALT,             /* octets in key            */
    aes_gcm_test_case_0_key,               /* key                      */
    aes_gcm_test_case_0_iv,                /* packet index             */
    60,                                    /* octets in plaintext      */
    aes_gcm_test_case_0_plaintext,         /* plaintext                */
    68,                                    /* octets in ciphertext     */
    aes_gcm_test_case_0_ciphertext,        /* ciphertext  + tag        */
    20,                                    /* octets in AAD            */
    aes_gcm_test_case_0_aad,               /* AAD                      */
    GCM_AUTH_TAG_LEN_8,
    NULL                                   /* pointer to next testcase */
};

cipher_test_case_t aes_gcm_test_case_0 = {
    AES_128_GCM_KEYSIZE_WSALT,             /* octets in key            */
    aes_gcm_test_case_0_key,               /* key                      */
    aes_gcm_test_case_0_iv,                /* packet index             */
    60,                                    /* octets in plaintext      */
    aes_gcm_test_case_0_plaintext,         /* plaintext                */
    76,                                    /* octets in ciphertext     */
    aes_gcm_test_case_0_ciphertext,        /* ciphertext  + tag        */
    20,                                    /* octets in AAD            */
    aes_gcm_test_case_0_aad,               /* AAD                      */
    GCM_AUTH_TAG_LEN,
    &aes_gcm_test_case_0a                  /* pointer to next testcase */
};

uint8_t aes_gcm_test_case_1_key[AES_256_GCM_KEYSIZE_WSALT] = {
    0xfe, 0xff, 0xe9, 0x92, 0x86, 0x65, 0x73, 0x1c,
    0xa5, 0x59, 0x09, 0xc5, 0x54, 0x66, 0x93, 0x1c,
    0xaf, 0xf5, 0x26, 0x9a, 0x21, 0xd5, 0x14, 0xb2, 
    0x6d, 0x6a, 0x8f, 0x94, 0x67, 0x30, 0x83, 0x08,
    0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
    0x09, 0x0a, 0x0b, 0x0c,  

};

uint8_t aes_gcm_test_case_1_iv[12] = {
    0xca, 0xfe, 0xba, 0xbe, 0xfa, 0xce, 0xdb, 0xad, 
    0xde, 0xca, 0xf8, 0x88
};

uint8_t aes_gcm_test_case_1_plaintext[60] =  {
    0xd9, 0x31, 0x32, 0x25, 0xf8, 0x84, 0x06, 0xe5,
    0xa5, 0x59, 0x09, 0xc5, 0xaf, 0xf5, 0x26, 0x9a,
    0x86, 0xa7, 0xa9, 0x53, 0x15, 0x34, 0xf7, 0xda,
    0x2e, 0x4c, 0x30, 0x3d, 0x8a, 0x31, 0x8a, 0x72,
    0x1c, 0x3c, 0x0c, 0x95, 0x95, 0x68, 0x09, 0x53,
    0x2f, 0xcf, 0x0e, 0x24, 0x49, 0xa6, 0xb5, 0x25,
    0xb1, 0x6a, 0xed, 0xf5, 0xaa, 0x0d, 0xe6, 0x57,
    0xba, 0x63, 0x7b, 0x39
};

uint8_t aes_gcm_test_case_1_aad[20] = {
    0xfe, 0xed, 0xfa, 0xce, 0xde, 0xad, 0xbe, 0xef,
    0xfe, 0xed, 0xfa, 0xce, 0xde, 0xad, 0xbe, 0xef,
    0xab, 0xad, 0xda, 0xd2
};

uint8_t aes_gcm_test_case_1_ciphertext[76] = {
    0x0b, 0x11, 0xcf, 0xaf, 0x68, 0x4d, 0xae, 0x46, 
    0xc7, 0x90, 0xb8, 0x8e, 0xb7, 0x6a, 0x76, 0x2a, 
    0x94, 0x82, 0xca, 0xab, 0x3e, 0x39, 0xd7, 0x86, 
    0x1b, 0xc7, 0x93, 0xed, 0x75, 0x7f, 0x23, 0x5a, 
    0xda, 0xfd, 0xd3, 0xe2, 0x0e, 0x80, 0x87, 0xa9, 
    0x6d, 0xd7, 0xe2, 0x6a, 0x7d, 0x5f, 0xb4, 0x80, 
    0xef, 0xef, 0xc5, 0x29, 0x12, 0xd1, 0xaa, 0x10, 
    0x09, 0xc9, 0x86, 0xc1, 
    /* the last 16 bytes are the tag */
    0x45, 0xbc, 0x03, 0xe6, 0xe1, 0xac, 0x0a, 0x9f, 
    0x81, 0xcb, 0x8e, 0x5b, 0x46, 0x65, 0x63, 0x1d,
};

cipher_test_case_t aes_gcm_test_case_1a = {
    AES_256_GCM_KEYSIZE_WSALT,                 /* octets in key            */
    aes_gcm_test_case_1_key,               /* key                      */
    aes_gcm_test_case_1_iv,                /* packet index             */
    60,                                    /* octets in plaintext      */
    aes_gcm_test_case_1_plaintext,         /* plaintext                */
    68,                                    /* octets in ciphertext     */
    aes_gcm_test_case_1_ciphertext,        /* ciphertext  + tag        */
    20,                                    /* octets in AAD            */
    aes_gcm_test_case_1_aad,               /* AAD                      */
    GCM_AUTH_TAG_LEN_8,
    NULL                                   /* pointer to next testcase */
};

cipher_test_case_t aes_gcm_test_case_1 = {
    AES_256_GCM_KEYSIZE_WSALT,                 /* octets in key            */
    aes_gcm_test_case_1_key,               /* key                      */
    aes_gcm_test_case_1_iv,                /* packet index             */
    60,                                    /* octets in plaintext      */
    aes_gcm_test_case_1_plaintext,         /* plaintext                */
    76,                                    /* octets in ciphertext     */
    aes_gcm_test_case_1_ciphertext,        /* ciphertext  + tag        */
    20,                                    /* octets in AAD            */
    aes_gcm_test_case_1_aad,               /* AAD                      */
    GCM_AUTH_TAG_LEN,
    &aes_gcm_test_case_1a                  /* pointer to next testcase */
};

/*
 * This is the vector function table for this crypto engine.
 */
cipher_type_t aes_gcm_128_openssl = {
    (cipher_alloc_func_t)	aes_gcm_openssl_alloc,
    (cipher_dealloc_func_t)	aes_gcm_openssl_dealloc,
    (cipher_init_func_t)	aes_gcm_openssl_context_init,
    (cipher_set_aad_func_t)	aes_gcm_openssl_set_aad,
    (cipher_encrypt_func_t)	aes_gcm_openssl_encrypt,
    (cipher_decrypt_func_t)	aes_gcm_openssl_decrypt,
    (cipher_set_iv_func_t)	aes_gcm_openssl_set_iv,
    (cipher_get_tag_func_t)     aes_gcm_openssl_get_tag,
    (char*)			aes_gcm_128_openssl_description,
    (int)			0,         /* instance count */
    (cipher_test_case_t*)	&aes_gcm_test_case_0,
    (debug_module_t*)		&mod_aes_gcm,
    (cipher_type_id_t)          AES_128_GCM
};

/*
 * This is the vector function table for this crypto engine.
 */
cipher_type_t aes_gcm_256_openssl = {
    (cipher_alloc_func_t)	aes_gcm_openssl_alloc,
    (cipher_dealloc_func_t)	aes_gcm_openssl_dealloc,
    (cipher_init_func_t)	aes_gcm_openssl_context_init,
    (cipher_set_aad_func_t)	aes_gcm_openssl_set_aad,
    (cipher_encrypt_func_t)	aes_gcm_openssl_encrypt,
    (cipher_decrypt_func_t)	aes_gcm_openssl_decrypt,
    (cipher_set_iv_func_t)	aes_gcm_openssl_set_iv,
    (cipher_get_tag_func_t)     aes_gcm_openssl_get_tag,
    (char*)			aes_gcm_256_openssl_description,
    (int)			0,         /* instance count */
    (cipher_test_case_t*)	&aes_gcm_test_case_1,
    (debug_module_t*)		&mod_aes_gcm,
    (cipher_type_id_t)          AES_256_GCM
};

