/work/mbedtls-2.28.8/library/ccm.c

Source
/*
 *  NIST SP800-38C compliant CCM implementation
 *
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 */

/*
 * Definition of CCM:
 * http://csrc.nist.gov/publications/nistpubs/800-38C/SP800-38C_updated-July20_2007.pdf
 * RFC 3610 "Counter with CBC-MAC (CCM)"
 *
 * Related:
 * RFC 5116 "An Interface and Algorithms for Authenticated Encryption"
 */

#include "common.h"

#if defined(MBEDTLS_CCM_C)

#include "mbedtls/ccm.h"
#include "mbedtls/platform_util.h"
#include "mbedtls/error.h"
#include "mbedtls/constant_time.h"

#include <string.h>

#include "mbedtls/platform.h"

#if !defined(MBEDTLS_CCM_ALT)

#define CCM_VALIDATE_RET(cond) \
    MBEDTLS_INTERNAL_VALIDATE_RET(cond, MBEDTLS_ERR_CCM_BAD_INPUT)
#define CCM_VALIDATE(cond) \
    MBEDTLS_INTERNAL_VALIDATE(cond)

#define CCM_ENCRYPT 0
#define CCM_DECRYPT 1

/*
 * Initialize context
 */
void mbedtls_ccm_init(mbedtls_ccm_context *ctx)
{
    CCM_VALIDATE(ctx != NULL);
    memset(ctx, 0, sizeof(mbedtls_ccm_context));
}

int mbedtls_ccm_setkey(mbedtls_ccm_context *ctx,
                       mbedtls_cipher_id_t cipher,
                       const unsigned char *key,
                       unsigned int keybits)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    const mbedtls_cipher_info_t *cipher_info;

    CCM_VALIDATE_RET(ctx != NULL);
    CCM_VALIDATE_RET(key != NULL);

    cipher_info = mbedtls_cipher_info_from_values(cipher, keybits,
                                                  MBEDTLS_MODE_ECB);
    if (cipher_info == NULL) {
        return MBEDTLS_ERR_CCM_BAD_INPUT;
    }

    if (cipher_info->block_size != 16) {
        return MBEDTLS_ERR_CCM_BAD_INPUT;
    }

    mbedtls_cipher_free(&ctx->cipher_ctx);

    if ((ret = mbedtls_cipher_setup(&ctx->cipher_ctx, cipher_info)) != 0) {
        return ret;
    }

    if ((ret = mbedtls_cipher_setkey(&ctx->cipher_ctx, key, keybits,
                                     MBEDTLS_ENCRYPT)) != 0) {
        return ret;
    }

    return 0;
}

/*
 * Free context
 */
void mbedtls_ccm_free(mbedtls_ccm_context *ctx)
{
    if (ctx == NULL) {
        return;
    }
    mbedtls_cipher_free(&ctx->cipher_ctx);
    mbedtls_platform_zeroize(ctx, sizeof(mbedtls_ccm_context));
}

/*
 * Macros for common operations.
 * Results in smaller compiled code than static inline functions.
 */

/*
 * Update the CBC-MAC state in y using a block in b
 * (Always using b as the source helps the compiler optimise a bit better.)
 */
#define UPDATE_CBC_MAC                                                      \
    for (i = 0; i < 16; i++)                                               \
    y[i] ^= b[i];                                                       \
                                                                            \
    if ((ret = mbedtls_cipher_update(&ctx->cipher_ctx, y, 16, y, &olen)) != 0) \
    return ret;

/*
 * Encrypt or decrypt a partial block with CTR
 * Warning: using b for temporary storage! src and dst must not be b!
 * This avoids allocating one more 16 bytes buffer while allowing src == dst.
 */
#define CTR_CRYPT(dst, src, len)                                            \
    do                                                                  \
    {                                                                   \
        if ((ret = mbedtls_cipher_update(&ctx->cipher_ctx, ctr,       \
                                         16, b, &olen)) != 0)      \
        {                                                               \
            return ret;                                              \
        }                                                               \
                                                                      \
        for (i = 0; i < (len); i++)                                    \
        (dst)[i] = (src)[i] ^ b[i];                                 \
    } while (0)

/*
 * Authenticated encryption or decryption
 */
static int ccm_auth_crypt(mbedtls_ccm_context *ctx, int mode, size_t length,
                          const unsigned char *iv, size_t iv_len,
                          const unsigned char *add, size_t add_len,
                          const unsigned char *input, unsigned char *output,
                          unsigned char *tag, size_t tag_len)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    unsigned char i;
    unsigned char q;
    size_t len_left, olen;
    unsigned char b[16];
    unsigned char y[16];
    unsigned char ctr[16];
    const unsigned char *src;
    unsigned char *dst;

    /*
     * Check length requirements: SP800-38C A.1
     * Additional requirement: a < 2^16 - 2^8 to simplify the code.
     * 'length' checked later (when writing it to the first block)
     *
     * Also, loosen the requirements to enable support for CCM* (IEEE 802.15.4).
     */
    if (tag_len == 2 || tag_len > 16 || tag_len % 2 != 0) {
        return MBEDTLS_ERR_CCM_BAD_INPUT;
    }

    /* Also implies q is within bounds */
    if (iv_len < 7 || iv_len > 13) {
        return MBEDTLS_ERR_CCM_BAD_INPUT;
    }

    if (add_len >= 0xFF00) {
        return MBEDTLS_ERR_CCM_BAD_INPUT;
    }

    q = 16 - 1 - (unsigned char) iv_len;

    /*
     * First block B_0:
     * 0        .. 0        flags
     * 1        .. iv_len   nonce (aka iv)
     * iv_len+1 .. 15       length
     *
     * With flags as (bits):
     * 7        0
     * 6        add present?
     * 5 .. 3   (t - 2) / 2
     * 2 .. 0   q - 1
     */
    b[0] = 0;
    b[0] |= (add_len > 0) << 6;
    b[0] |= ((tag_len - 2) / 2) << 3;
    b[0] |= q - 1;

    memcpy(b + 1, iv, iv_len);

    for (i = 0, len_left = length; i < q; i++, len_left >>= 8) {
        b[15-i] = MBEDTLS_BYTE_0(len_left);
    }

    if (len_left > 0) {
        return MBEDTLS_ERR_CCM_BAD_INPUT;
    }


    /* Start CBC-MAC with first block */
    memset(y, 0, 16);
    UPDATE_CBC_MAC;

    /*
     * If there is additional data, update CBC-MAC with
     * add_len, add, 0 (padding to a block boundary)
     */
    if (add_len > 0) {
        size_t use_len;
        len_left = add_len;
        src = add;

        memset(b, 0, 16);
        MBEDTLS_PUT_UINT16_BE(add_len, b, 0);

        use_len = len_left < 16 - 2 ? len_left : 16 - 2;
        memcpy(b + 2, src, use_len);
        len_left -= use_len;
        src += use_len;

        UPDATE_CBC_MAC;

        while (len_left > 0) {
            use_len = len_left > 16 ? 16 : len_left;

            memset(b, 0, 16);
            memcpy(b, src, use_len);
            UPDATE_CBC_MAC;

            len_left -= use_len;
            src += use_len;
        }
    }

    /*
     * Prepare counter block for encryption:
     * 0        .. 0        flags
     * 1        .. iv_len   nonce (aka iv)
     * iv_len+1 .. 15       counter (initially 1)
     *
     * With flags as (bits):
     * 7 .. 3   0
     * 2 .. 0   q - 1
     */
    ctr[0] = q - 1;
    memcpy(ctr + 1, iv, iv_len);
    memset(ctr + 1 + iv_len, 0, q);
    ctr[15] = 1;

    /*
     * Authenticate and {en,de}crypt the message.
     *
     * The only difference between encryption and decryption is
     * the respective order of authentication and {en,de}cryption.
     */
    len_left = length;
    src = input;
    dst = output;

    while (len_left > 0) {
        size_t use_len = len_left > 16 ? 16 : len_left;

        if (mode == CCM_ENCRYPT) {
            memset(b, 0, 16);
            memcpy(b, src, use_len);
            UPDATE_CBC_MAC;
        }

        CTR_CRYPT(dst, src, use_len);

        if (mode == CCM_DECRYPT) {
            memset(b, 0, 16);
            memcpy(b, dst, use_len);
            UPDATE_CBC_MAC;
        }

        dst += use_len;
        src += use_len;
        len_left -= use_len;

        /*
         * Increment counter.
         * No need to check for overflow thanks to the length check above.
         */
        for (i = 0; i < q; i++) {
            if (++ctr[15-i] != 0) {
                break;
            }
        }
    }

    /*
     * Authentication: reset counter and crypt/mask internal tag
     */
    for (i = 0; i < q; i++) {
        ctr[15-i] = 0;
    }

    CTR_CRYPT(y, y, 16);
    memcpy(tag, y, tag_len);

    return 0;
}

/*
 * Authenticated encryption
 */
int mbedtls_ccm_star_encrypt_and_tag(mbedtls_ccm_context *ctx, size_t length,
                                     const unsigned char *iv, size_t iv_len,
                                     const unsigned char *add, size_t add_len,
                                     const unsigned char *input, unsigned char *output,
                                     unsigned char *tag, size_t tag_len)
{
    CCM_VALIDATE_RET(ctx != NULL);
    CCM_VALIDATE_RET(iv != NULL);
    CCM_VALIDATE_RET(add_len == 0 || add != NULL);
    CCM_VALIDATE_RET(length == 0 || input != NULL);
    CCM_VALIDATE_RET(length == 0 || output != NULL);
    CCM_VALIDATE_RET(tag_len == 0 || tag != NULL);
    return ccm_auth_crypt(ctx, CCM_ENCRYPT, length, iv, iv_len,
                          add, add_len, input, output, tag, tag_len);
}

int mbedtls_ccm_encrypt_and_tag(mbedtls_ccm_context *ctx, size_t length,
                                const unsigned char *iv, size_t iv_len,
                                const unsigned char *add, size_t add_len,
                                const unsigned char *input, unsigned char *output,
                                unsigned char *tag, size_t tag_len)
{
    CCM_VALIDATE_RET(ctx != NULL);
    CCM_VALIDATE_RET(iv != NULL);
    CCM_VALIDATE_RET(add_len == 0 || add != NULL);
    CCM_VALIDATE_RET(length == 0 || input != NULL);
    CCM_VALIDATE_RET(length == 0 || output != NULL);
    CCM_VALIDATE_RET(tag_len == 0 || tag != NULL);
    if (tag_len == 0) {
        return MBEDTLS_ERR_CCM_BAD_INPUT;
    }

    return mbedtls_ccm_star_encrypt_and_tag(ctx, length, iv, iv_len, add,
                                            add_len, input, output, tag, tag_len);
}

/*
 * Authenticated decryption
 */
int mbedtls_ccm_star_auth_decrypt(mbedtls_ccm_context *ctx, size_t length,
                                  const unsigned char *iv, size_t iv_len,
                                  const unsigned char *add, size_t add_len,
                                  const unsigned char *input, unsigned char *output,
                                  const unsigned char *tag, size_t tag_len)
{
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
    unsigned char check_tag[16];
    int diff;

    CCM_VALIDATE_RET(ctx != NULL);
    CCM_VALIDATE_RET(iv != NULL);
    CCM_VALIDATE_RET(add_len == 0 || add != NULL);
    CCM_VALIDATE_RET(length == 0 || input != NULL);
    CCM_VALIDATE_RET(length == 0 || output != NULL);
    CCM_VALIDATE_RET(tag_len == 0 || tag != NULL);

    if ((ret = ccm_auth_crypt(ctx, CCM_DECRYPT, length,
                              iv, iv_len, add, add_len,
                              input, output, check_tag, tag_len)) != 0) {
        return ret;
    }

    /* Check tag in "constant-time" */
    diff = mbedtls_ct_memcmp(tag, check_tag, tag_len);

    if (diff != 0) {
        mbedtls_platform_zeroize(output, length);
        return MBEDTLS_ERR_CCM_AUTH_FAILED;
    }

    return 0;
}

int mbedtls_ccm_auth_decrypt(mbedtls_ccm_context *ctx, size_t length,
                             const unsigned char *iv, size_t iv_len,
                             const unsigned char *add, size_t add_len,
                             const unsigned char *input, unsigned char *output,
                             const unsigned char *tag, size_t tag_len)
{
    CCM_VALIDATE_RET(ctx != NULL);
    CCM_VALIDATE_RET(iv != NULL);
    CCM_VALIDATE_RET(add_len == 0 || add != NULL);
    CCM_VALIDATE_RET(length == 0 || input != NULL);
    CCM_VALIDATE_RET(length == 0 || output != NULL);
    CCM_VALIDATE_RET(tag_len == 0 || tag != NULL);

    if (tag_len == 0) {
        return MBEDTLS_ERR_CCM_BAD_INPUT;
    }

    return mbedtls_ccm_star_auth_decrypt(ctx, length, iv, iv_len, add,
                                         add_len, input, output, tag, tag_len);
}
#endif /* !MBEDTLS_CCM_ALT */

#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
/*
 * Examples 1 to 3 from SP800-38C Appendix C
 */

#define NB_TESTS 3
#define CCM_SELFTEST_PT_MAX_LEN 24
#define CCM_SELFTEST_CT_MAX_LEN 32
/*
 * The data is the same for all tests, only the used length changes
 */
static const unsigned char key_test_data[] = {
    0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
    0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f
};

static const unsigned char iv_test_data[] = {
    0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
    0x18, 0x19, 0x1a, 0x1b
};

static const unsigned char ad_test_data[] = {
    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
    0x10, 0x11, 0x12, 0x13
};

static const unsigned char msg_test_data[CCM_SELFTEST_PT_MAX_LEN] = {
    0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
    0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
    0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
};

static const size_t iv_len_test_data[NB_TESTS] = { 7, 8,  12 };
static const size_t add_len_test_data[NB_TESTS] = { 8, 16, 20 };
static const size_t msg_len_test_data[NB_TESTS] = { 4, 16, 24 };
static const size_t tag_len_test_data[NB_TESTS] = { 4, 6,  8  };

static const unsigned char res_test_data[NB_TESTS][CCM_SELFTEST_CT_MAX_LEN] = {
    {   0x71, 0x62, 0x01, 0x5b, 0x4d, 0xac, 0x25, 0x5d },
    {   0xd2, 0xa1, 0xf0, 0xe0, 0x51, 0xea, 0x5f, 0x62,
        0x08, 0x1a, 0x77, 0x92, 0x07, 0x3d, 0x59, 0x3d,
        0x1f, 0xc6, 0x4f, 0xbf, 0xac, 0xcd },
    {   0xe3, 0xb2, 0x01, 0xa9, 0xf5, 0xb7, 0x1a, 0x7a,
        0x9b, 0x1c, 0xea, 0xec, 0xcd, 0x97, 0xe7, 0x0b,
        0x61, 0x76, 0xaa, 0xd9, 0xa4, 0x42, 0x8a, 0xa5,
        0x48, 0x43, 0x92, 0xfb, 0xc1, 0xb0, 0x99, 0x51 }
};

int mbedtls_ccm_self_test(int verbose)
{
    mbedtls_ccm_context ctx;
    /*
     * Some hardware accelerators require the input and output buffers
     * would be in RAM, because the flash is not accessible.
     * Use buffers on the stack to hold the test vectors data.
     */
    unsigned char plaintext[CCM_SELFTEST_PT_MAX_LEN];
    unsigned char ciphertext[CCM_SELFTEST_CT_MAX_LEN];
    size_t i;
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

    mbedtls_ccm_init(&ctx);

    if (mbedtls_ccm_setkey(&ctx, MBEDTLS_CIPHER_ID_AES, key_test_data,
                           8 * sizeof(key_test_data)) != 0) {
        if (verbose != 0) {
            mbedtls_printf("  CCM: setup failed");
        }

        return 1;
    }

    for (i = 0; i < NB_TESTS; i++) {
        if (verbose != 0) {
            mbedtls_printf("  CCM-AES #%u: ", (unsigned int) i + 1);
        }

        memset(plaintext, 0, CCM_SELFTEST_PT_MAX_LEN);
        memset(ciphertext, 0, CCM_SELFTEST_CT_MAX_LEN);
        memcpy(plaintext, msg_test_data, msg_len_test_data[i]);

        ret = mbedtls_ccm_encrypt_and_tag(&ctx, msg_len_test_data[i],
                                          iv_test_data, iv_len_test_data[i],
                                          ad_test_data, add_len_test_data[i],
                                          plaintext, ciphertext,
                                          ciphertext + msg_len_test_data[i],
                                          tag_len_test_data[i]);

        if (ret != 0 ||
            memcmp(ciphertext, res_test_data[i],
                   msg_len_test_data[i] + tag_len_test_data[i]) != 0) {
            if (verbose != 0) {
                mbedtls_printf("failed\n");
            }

            return 1;
        }
        memset(plaintext, 0, CCM_SELFTEST_PT_MAX_LEN);

        ret = mbedtls_ccm_auth_decrypt(&ctx, msg_len_test_data[i],
                                       iv_test_data, iv_len_test_data[i],
                                       ad_test_data, add_len_test_data[i],
                                       ciphertext, plaintext,
                                       ciphertext + msg_len_test_data[i],
                                       tag_len_test_data[i]);

        if (ret != 0 ||
            memcmp(plaintext, msg_test_data, msg_len_test_data[i]) != 0) {
            if (verbose != 0) {
                mbedtls_printf("failed\n");
            }

            return 1;
        }

        if (verbose != 0) {
            mbedtls_printf("passed\n");
        }
    }

    mbedtls_ccm_free(&ctx);

    if (verbose != 0) {
        mbedtls_printf("\n");
    }

    return 0;
}

#endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */

#endif /* MBEDTLS_CCM_C */

Coverage Report

Created: 2025-10-28 06:49

Line	Count	Source
1		/*
2		* NIST SP800-38C compliant CCM implementation
3		*
4		* Copyright The Mbed TLS Contributors
5		* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6		*/
7
8		/*
9		* Definition of CCM:
10		* http://csrc.nist.gov/publications/nistpubs/800-38C/SP800-38C_updated-July20_2007.pdf
11		* RFC 3610 "Counter with CBC-MAC (CCM)"
12		*
13		* Related:
14		* RFC 5116 "An Interface and Algorithms for Authenticated Encryption"
15		*/
16
17		#include "common.h"
18
19		#if defined(MBEDTLS_CCM_C)
20
21		#include "mbedtls/ccm.h"
22		#include "mbedtls/platform_util.h"
23		#include "mbedtls/error.h"
24		#include "mbedtls/constant_time.h"
25
26		#include <string.h>
27
28		#include "mbedtls/platform.h"
29
30		#if !defined(MBEDTLS_CCM_ALT)
31
32		#define CCM_VALIDATE_RET(cond) \
33	0	MBEDTLS_INTERNAL_VALIDATE_RET(cond, MBEDTLS_ERR_CCM_BAD_INPUT)
34		#define CCM_VALIDATE(cond) \
35	0	MBEDTLS_INTERNAL_VALIDATE(cond)
36
37	0	#define CCM_ENCRYPT 0
38	0	#define CCM_DECRYPT 1
39
40		/*
41		* Initialize context
42		*/
43		void mbedtls_ccm_init(mbedtls_ccm_context *ctx)
44	0	{
45	0	CCM_VALIDATE(ctx != NULL);
46	0	memset(ctx, 0, sizeof(mbedtls_ccm_context));
47	0	}
48
49		int mbedtls_ccm_setkey(mbedtls_ccm_context *ctx,
50		mbedtls_cipher_id_t cipher,
51		const unsigned char *key,
52		unsigned int keybits)
53	0	{
54	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
55	0	const mbedtls_cipher_info_t *cipher_info;
56
57	0	CCM_VALIDATE_RET(ctx != NULL);
58	0	CCM_VALIDATE_RET(key != NULL);
59
60	0	cipher_info = mbedtls_cipher_info_from_values(cipher, keybits,
61	0	MBEDTLS_MODE_ECB);
62	0	if (cipher_info == NULL) {
63	0	return MBEDTLS_ERR_CCM_BAD_INPUT;
64	0	}
65
66	0	if (cipher_info->block_size != 16) {
67	0	return MBEDTLS_ERR_CCM_BAD_INPUT;
68	0	}
69
70	0	mbedtls_cipher_free(&ctx->cipher_ctx);
71
72	0	if ((ret = mbedtls_cipher_setup(&ctx->cipher_ctx, cipher_info)) != 0) {
73	0	return ret;
74	0	}
75
76	0	if ((ret = mbedtls_cipher_setkey(&ctx->cipher_ctx, key, keybits,
77	0	MBEDTLS_ENCRYPT)) != 0) {
78	0	return ret;
79	0	}
80
81	0	return 0;
82	0	}
83
84		/*
85		* Free context
86		*/
87		void mbedtls_ccm_free(mbedtls_ccm_context *ctx)
88	0	{
89	0	if (ctx == NULL) {
90	0	return;
91	0	}
92	0	mbedtls_cipher_free(&ctx->cipher_ctx);
93	0	mbedtls_platform_zeroize(ctx, sizeof(mbedtls_ccm_context));
94	0	}
95
96		/*
97		* Macros for common operations.
98		* Results in smaller compiled code than static inline functions.
99		*/
100
101		/*
102		* Update the CBC-MAC state in y using a block in b
103		* (Always using b as the source helps the compiler optimise a bit better.)
104		*/
105		#define UPDATE_CBC_MAC \
106	0	for (i = 0; i < 16; i++) \
107	0	y[i] ^= b[i]; \
108	0	\
109	0	if ((ret = mbedtls_cipher_update(&ctx->cipher_ctx, y, 16, y, &olen)) != 0) \
110	0	return ret;
111
112		/*
113		* Encrypt or decrypt a partial block with CTR
114		* Warning: using b for temporary storage! src and dst must not be b!
115		* This avoids allocating one more 16 bytes buffer while allowing src == dst.
116		*/
117		#define CTR_CRYPT(dst, src, len) \
118	0	do \
119	0	{ \
120	0	if ((ret = mbedtls_cipher_update(&ctx->cipher_ctx, ctr, \
121	0	16, b, &olen)) != 0) \
122	0	{ \
123	0	return ret; \
124	0	} \
125	0	\
126	0	for (i = 0; i < (len); i++) \
127	0	(dst)[i] = (src)[i] ^ b[i]; \
128	0	} while (0)
129
130		/*
131		* Authenticated encryption or decryption
132		*/
133		static int ccm_auth_crypt(mbedtls_ccm_context *ctx, int mode, size_t length,
134		const unsigned char *iv, size_t iv_len,
135		const unsigned char *add, size_t add_len,
136		const unsigned char input, unsigned char output,
137		unsigned char *tag, size_t tag_len)
138	0	{
139	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
140	0	unsigned char i;
141	0	unsigned char q;
142	0	size_t len_left, olen;
143	0	unsigned char b[16];
144	0	unsigned char y[16];
145	0	unsigned char ctr[16];
146	0	const unsigned char *src;
147	0	unsigned char *dst;
148
149		/*
150		* Check length requirements: SP800-38C A.1
151		* Additional requirement: a < 2^16 - 2^8 to simplify the code.
152		* 'length' checked later (when writing it to the first block)
153		*
154		* Also, loosen the requirements to enable support for CCM* (IEEE 802.15.4).
155		*/
156	0	if (tag_len == 2 \|\| tag_len > 16 \|\| tag_len % 2 != 0) {
157	0	return MBEDTLS_ERR_CCM_BAD_INPUT;
158	0	}
159
160		/* Also implies q is within bounds */
161	0	if (iv_len < 7 \|\| iv_len > 13) {
162	0	return MBEDTLS_ERR_CCM_BAD_INPUT;
163	0	}
164
165	0	if (add_len >= 0xFF00) {
166	0	return MBEDTLS_ERR_CCM_BAD_INPUT;
167	0	}
168
169	0	q = 16 - 1 - (unsigned char) iv_len;
170
171		/*
172		* First block B_0:
173		* 0 .. 0 flags
174		* 1 .. iv_len nonce (aka iv)
175		* iv_len+1 .. 15 length
176		*
177		* With flags as (bits):
178		* 7 0
179		* 6 add present?
180		* 5 .. 3 (t - 2) / 2
181		* 2 .. 0 q - 1
182		*/
183	0	b[0] = 0;
184	0	b[0] \|= (add_len > 0) << 6;
185	0	b[0] \|= ((tag_len - 2) / 2) << 3;
186	0	b[0] \|= q - 1;
187
188	0	memcpy(b + 1, iv, iv_len);
189
190	0	for (i = 0, len_left = length; i < q; i++, len_left >>= 8) {
191	0	b[15-i] = MBEDTLS_BYTE_0(len_left);
192	0	}
193
194	0	if (len_left > 0) {
195	0	return MBEDTLS_ERR_CCM_BAD_INPUT;
196	0	}
197
198
199		/* Start CBC-MAC with first block */
200	0	memset(y, 0, 16);
201	0	UPDATE_CBC_MAC;
202
203		/*
204		* If there is additional data, update CBC-MAC with
205		* add_len, add, 0 (padding to a block boundary)
206		*/
207	0	if (add_len > 0) {
208	0	size_t use_len;
209	0	len_left = add_len;
210	0	src = add;
211
212	0	memset(b, 0, 16);
213	0	MBEDTLS_PUT_UINT16_BE(add_len, b, 0);
214
215	0	use_len = len_left < 16 - 2 ? len_left : 16 - 2;
216	0	memcpy(b + 2, src, use_len);
217	0	len_left -= use_len;
218	0	src += use_len;
219
220	0	UPDATE_CBC_MAC;
221
222	0	while (len_left > 0) {
223	0	use_len = len_left > 16 ? 16 : len_left;
224
225	0	memset(b, 0, 16);
226	0	memcpy(b, src, use_len);
227	0	UPDATE_CBC_MAC;
228
229	0	len_left -= use_len;
230	0	src += use_len;
231	0	}
232	0	}
233
234		/*
235		* Prepare counter block for encryption:
236		* 0 .. 0 flags
237		* 1 .. iv_len nonce (aka iv)
238		* iv_len+1 .. 15 counter (initially 1)
239		*
240		* With flags as (bits):
241		* 7 .. 3 0
242		* 2 .. 0 q - 1
243		*/
244	0	ctr[0] = q - 1;
245	0	memcpy(ctr + 1, iv, iv_len);
246	0	memset(ctr + 1 + iv_len, 0, q);
247	0	ctr[15] = 1;
248
249		/*
250		* Authenticate and {en,de}crypt the message.
251		*
252		* The only difference between encryption and decryption is
253		* the respective order of authentication and {en,de}cryption.
254		*/
255	0	len_left = length;
256	0	src = input;
257	0	dst = output;
258
259	0	while (len_left > 0) {
260	0	size_t use_len = len_left > 16 ? 16 : len_left;
261
262	0	if (mode == CCM_ENCRYPT) {
263	0	memset(b, 0, 16);
264	0	memcpy(b, src, use_len);
265	0	UPDATE_CBC_MAC;
266	0	}
267
268	0	CTR_CRYPT(dst, src, use_len);
269
270	0	if (mode == CCM_DECRYPT) {
271	0	memset(b, 0, 16);
272	0	memcpy(b, dst, use_len);
273	0	UPDATE_CBC_MAC;
274	0	}
275
276	0	dst += use_len;
277	0	src += use_len;
278	0	len_left -= use_len;
279
280		/*
281		* Increment counter.
282		* No need to check for overflow thanks to the length check above.
283		*/
284	0	for (i = 0; i < q; i++) {
285	0	if (++ctr[15-i] != 0) {
286	0	break;
287	0	}
288	0	}
289	0	}
290
291		/*
292		* Authentication: reset counter and crypt/mask internal tag
293		*/
294	0	for (i = 0; i < q; i++) {
295	0	ctr[15-i] = 0;
296	0	}
297
298	0	CTR_CRYPT(y, y, 16);
299	0	memcpy(tag, y, tag_len);
300
301	0	return 0;
302	0	}
303
304		/*
305		* Authenticated encryption
306		*/
307		int mbedtls_ccm_star_encrypt_and_tag(mbedtls_ccm_context *ctx, size_t length,
308		const unsigned char *iv, size_t iv_len,
309		const unsigned char *add, size_t add_len,
310		const unsigned char input, unsigned char output,
311		unsigned char *tag, size_t tag_len)
312	0	{
313	0	CCM_VALIDATE_RET(ctx != NULL);
314	0	CCM_VALIDATE_RET(iv != NULL);
315	0	CCM_VALIDATE_RET(add_len == 0 \|\| add != NULL);
316	0	CCM_VALIDATE_RET(length == 0 \|\| input != NULL);
317	0	CCM_VALIDATE_RET(length == 0 \|\| output != NULL);
318	0	CCM_VALIDATE_RET(tag_len == 0 \|\| tag != NULL);
319	0	return ccm_auth_crypt(ctx, CCM_ENCRYPT, length, iv, iv_len,
320	0	add, add_len, input, output, tag, tag_len);
321	0	}
322
323		int mbedtls_ccm_encrypt_and_tag(mbedtls_ccm_context *ctx, size_t length,
324		const unsigned char *iv, size_t iv_len,
325		const unsigned char *add, size_t add_len,
326		const unsigned char input, unsigned char output,
327		unsigned char *tag, size_t tag_len)
328	0	{
329	0	CCM_VALIDATE_RET(ctx != NULL);
330	0	CCM_VALIDATE_RET(iv != NULL);
331	0	CCM_VALIDATE_RET(add_len == 0 \|\| add != NULL);
332	0	CCM_VALIDATE_RET(length == 0 \|\| input != NULL);
333	0	CCM_VALIDATE_RET(length == 0 \|\| output != NULL);
334	0	CCM_VALIDATE_RET(tag_len == 0 \|\| tag != NULL);
335	0	if (tag_len == 0) {
336	0	return MBEDTLS_ERR_CCM_BAD_INPUT;
337	0	}
338
339	0	return mbedtls_ccm_star_encrypt_and_tag(ctx, length, iv, iv_len, add,
340	0	add_len, input, output, tag, tag_len);
341	0	}
342
343		/*
344		* Authenticated decryption
345		*/
346		int mbedtls_ccm_star_auth_decrypt(mbedtls_ccm_context *ctx, size_t length,
347		const unsigned char *iv, size_t iv_len,
348		const unsigned char *add, size_t add_len,
349		const unsigned char input, unsigned char output,
350		const unsigned char *tag, size_t tag_len)
351	0	{
352	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
353	0	unsigned char check_tag[16];
354	0	int diff;
355
356	0	CCM_VALIDATE_RET(ctx != NULL);
357	0	CCM_VALIDATE_RET(iv != NULL);
358	0	CCM_VALIDATE_RET(add_len == 0 \|\| add != NULL);
359	0	CCM_VALIDATE_RET(length == 0 \|\| input != NULL);
360	0	CCM_VALIDATE_RET(length == 0 \|\| output != NULL);
361	0	CCM_VALIDATE_RET(tag_len == 0 \|\| tag != NULL);
362
363	0	if ((ret = ccm_auth_crypt(ctx, CCM_DECRYPT, length,
364	0	iv, iv_len, add, add_len,
365	0	input, output, check_tag, tag_len)) != 0) {
366	0	return ret;
367	0	}
368
369		/* Check tag in "constant-time" */
370	0	diff = mbedtls_ct_memcmp(tag, check_tag, tag_len);
371
372	0	if (diff != 0) {
373	0	mbedtls_platform_zeroize(output, length);
374	0	return MBEDTLS_ERR_CCM_AUTH_FAILED;
375	0	}
376
377	0	return 0;
378	0	}
379
380		int mbedtls_ccm_auth_decrypt(mbedtls_ccm_context *ctx, size_t length,
381		const unsigned char *iv, size_t iv_len,
382		const unsigned char *add, size_t add_len,
383		const unsigned char input, unsigned char output,
384		const unsigned char *tag, size_t tag_len)
385	0	{
386	0	CCM_VALIDATE_RET(ctx != NULL);
387	0	CCM_VALIDATE_RET(iv != NULL);
388	0	CCM_VALIDATE_RET(add_len == 0 \|\| add != NULL);
389	0	CCM_VALIDATE_RET(length == 0 \|\| input != NULL);
390	0	CCM_VALIDATE_RET(length == 0 \|\| output != NULL);
391	0	CCM_VALIDATE_RET(tag_len == 0 \|\| tag != NULL);
392
393	0	if (tag_len == 0) {
394	0	return MBEDTLS_ERR_CCM_BAD_INPUT;
395	0	}
396
397	0	return mbedtls_ccm_star_auth_decrypt(ctx, length, iv, iv_len, add,
398	0	add_len, input, output, tag, tag_len);
399	0	}
400		#endif /* !MBEDTLS_CCM_ALT */
401
402		#if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
403		/*
404		* Examples 1 to 3 from SP800-38C Appendix C
405		*/
406
407	0	#define NB_TESTS 3
408	0	#define CCM_SELFTEST_PT_MAX_LEN 24
409	0	#define CCM_SELFTEST_CT_MAX_LEN 32
410		/*
411		* The data is the same for all tests, only the used length changes
412		*/
413		static const unsigned char key_test_data[] = {
414		0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
415		0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f
416		};
417
418		static const unsigned char iv_test_data[] = {
419		0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
420		0x18, 0x19, 0x1a, 0x1b
421		};
422
423		static const unsigned char ad_test_data[] = {
424		0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
425		0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
426		0x10, 0x11, 0x12, 0x13
427		};
428
429		static const unsigned char msg_test_data[CCM_SELFTEST_PT_MAX_LEN] = {
430		0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
431		0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
432		0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
433		};
434
435		static const size_t iv_len_test_data[NB_TESTS] = { 7, 8, 12 };
436		static const size_t add_len_test_data[NB_TESTS] = { 8, 16, 20 };
437		static const size_t msg_len_test_data[NB_TESTS] = { 4, 16, 24 };
438		static const size_t tag_len_test_data[NB_TESTS] = { 4, 6, 8 };
439
440		static const unsigned char res_test_data[NB_TESTS][CCM_SELFTEST_CT_MAX_LEN] = {
441		{ 0x71, 0x62, 0x01, 0x5b, 0x4d, 0xac, 0x25, 0x5d },
442		{ 0xd2, 0xa1, 0xf0, 0xe0, 0x51, 0xea, 0x5f, 0x62,
443		0x08, 0x1a, 0x77, 0x92, 0x07, 0x3d, 0x59, 0x3d,
444		0x1f, 0xc6, 0x4f, 0xbf, 0xac, 0xcd },
445		{ 0xe3, 0xb2, 0x01, 0xa9, 0xf5, 0xb7, 0x1a, 0x7a,
446		0x9b, 0x1c, 0xea, 0xec, 0xcd, 0x97, 0xe7, 0x0b,
447		0x61, 0x76, 0xaa, 0xd9, 0xa4, 0x42, 0x8a, 0xa5,
448		0x48, 0x43, 0x92, 0xfb, 0xc1, 0xb0, 0x99, 0x51 }
449		};
450
451		int mbedtls_ccm_self_test(int verbose)
452	0	{
453	0	mbedtls_ccm_context ctx;
454		/*
455		* Some hardware accelerators require the input and output buffers
456		* would be in RAM, because the flash is not accessible.
457		* Use buffers on the stack to hold the test vectors data.
458		*/
459	0	unsigned char plaintext[CCM_SELFTEST_PT_MAX_LEN];
460	0	unsigned char ciphertext[CCM_SELFTEST_CT_MAX_LEN];
461	0	size_t i;
462	0	int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
463
464	0	mbedtls_ccm_init(&ctx);
465
466	0	if (mbedtls_ccm_setkey(&ctx, MBEDTLS_CIPHER_ID_AES, key_test_data,
467	0	8 * sizeof(key_test_data)) != 0) {
468	0	if (verbose != 0) {
469	0	mbedtls_printf(" CCM: setup failed");
470	0	}
471
472	0	return 1;
473	0	}
474
475	0	for (i = 0; i < NB_TESTS; i++) {
476	0	if (verbose != 0) {
477	0	mbedtls_printf(" CCM-AES #%u: ", (unsigned int) i + 1);
478	0	}
479
480	0	memset(plaintext, 0, CCM_SELFTEST_PT_MAX_LEN);
481	0	memset(ciphertext, 0, CCM_SELFTEST_CT_MAX_LEN);
482	0	memcpy(plaintext, msg_test_data, msg_len_test_data[i]);
483
484	0	ret = mbedtls_ccm_encrypt_and_tag(&ctx, msg_len_test_data[i],
485	0	iv_test_data, iv_len_test_data[i],
486	0	ad_test_data, add_len_test_data[i],
487	0	plaintext, ciphertext,
488	0	ciphertext + msg_len_test_data[i],
489	0	tag_len_test_data[i]);
490
491	0	if (ret != 0 \|\|
492	0	memcmp(ciphertext, res_test_data[i],
493	0	msg_len_test_data[i] + tag_len_test_data[i]) != 0) {
494	0	if (verbose != 0) {
495	0	mbedtls_printf("failed\n");
496	0	}
497
498	0	return 1;
499	0	}
500	0	memset(plaintext, 0, CCM_SELFTEST_PT_MAX_LEN);
501
502	0	ret = mbedtls_ccm_auth_decrypt(&ctx, msg_len_test_data[i],
503	0	iv_test_data, iv_len_test_data[i],
504	0	ad_test_data, add_len_test_data[i],
505	0	ciphertext, plaintext,
506	0	ciphertext + msg_len_test_data[i],
507	0	tag_len_test_data[i]);
508
509	0	if (ret != 0 \|\|
510	0	memcmp(plaintext, msg_test_data, msg_len_test_data[i]) != 0) {
511	0	if (verbose != 0) {
512	0	mbedtls_printf("failed\n");
513	0	}
514
515	0	return 1;
516	0	}
517
518	0	if (verbose != 0) {
519	0	mbedtls_printf("passed\n");
520	0	}
521	0	}
522
523	0	mbedtls_ccm_free(&ctx);
524
525	0	if (verbose != 0) {
526	0	mbedtls_printf("\n");
527	0	}
528
529	0	return 0;
530	0	}
531
532		#endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
533
534		#endif /* MBEDTLS_CCM_C */