aes_wrap.c

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#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "common.h"
#include "aes_wrap.h"
#include "crypto.h"

#ifndef EAP_TLS_FUNCS
#include "aes.c"
#endif /* EAP_TLS_FUNCS */


int aes_wrap(const u8 *kek, int n, const u8 *plain, u8 *cipher)
{
        u8 *a, *r, b[16];
        int i, j;
        void *ctx;

        a = cipher;
        r = cipher + 8;

        /* 1) Initialize variables. */
        memset(a, 0xa6, 8);
        memcpy(r, plain, 8 * n);

        ctx = aes_encrypt_init(kek, 16);
        if (ctx == NULL)
                return -1;

        /* 2) Calculate intermediate values.
         * For j = 0 to 5
         *     For i=1 to n
         *         B = AES(K, A | R[i])
         *         A = MSB(64, B) ^ t where t = (n*j)+i
         *         R[i] = LSB(64, B)
         */
        for (j = 0; j <= 5; j++) {
                r = cipher + 8;
                for (i = 1; i <= n; i++) {
                        memcpy(b, a, 8);
                        memcpy(b + 8, r, 8);
                        aes_encrypt(ctx, b, b);
                        memcpy(a, b, 8);
                        a[7] ^= n * j + i;
                        memcpy(r, b + 8, 8);
                        r += 8;
                }
        }
        aes_encrypt_deinit(ctx);

        /* 3) Output the results.
         *
         * These are already in @cipher due to the location of temporary
         * variables.
         */

        return 0;
}


int aes_unwrap(const u8 *kek, int n, const u8 *cipher, u8 *plain)
{
        u8 a[8], *r, b[16];
        int i, j;
        void *ctx;

        /* 1) Initialize variables. */
        memcpy(a, cipher, 8);
        r = plain;
        memcpy(r, cipher + 8, 8 * n);

        ctx = aes_decrypt_init(kek, 16);
        if (ctx == NULL)
                return -1;

        /* 2) Compute intermediate values.
         * For j = 5 to 0
         *     For i = n to 1
         *         B = AES-1(K, (A ^ t) | R[i]) where t = n*j+i
         *         A = MSB(64, B)
         *         R[i] = LSB(64, B)
         */
        for (j = 5; j >= 0; j--) {
                r = plain + (n - 1) * 8;
                for (i = n; i >= 1; i--) {
                        memcpy(b, a, 8);
                        b[7] ^= n * j + i;

                        memcpy(b + 8, r, 8);
                        aes_decrypt(ctx, b, b);
                        memcpy(a, b, 8);
                        memcpy(r, b + 8, 8);
                        r -= 8;
                }
        }
        aes_decrypt_deinit(ctx);

        /* 3) Output results.
         *
         * These are already in @plain due to the location of temporary
         * variables. Just verify that the IV matches with the expected value.
         */
        for (i = 0; i < 8; i++) {
                if (a[i] != 0xa6)
                        return -1;
        }

        return 0;
}


#define BLOCK_SIZE 16

static void gf_mulx(u8 *pad)
{
        int i, carry;

        carry = pad[0] & 0x80;
        for (i = 0; i < BLOCK_SIZE - 1; i++)
                pad[i] = (pad[i] << 1) | (pad[i + 1] >> 7);
        pad[BLOCK_SIZE - 1] <<= 1;
        if (carry)
                pad[BLOCK_SIZE - 1] ^= 0x87;
}


int omac1_aes_128(const u8 *key, const u8 *data, size_t data_len, u8 *mac)
{
        void *ctx;
        u8 cbc[BLOCK_SIZE], pad[BLOCK_SIZE];
        const u8 *pos = data;
        int i;
        size_t left = data_len;

        ctx = aes_encrypt_init(key, 16);
        if (ctx == NULL)
                return -1;
        memset(cbc, 0, BLOCK_SIZE);

        while (left >= BLOCK_SIZE) {
                for (i = 0; i < BLOCK_SIZE; i++)
                        cbc[i] ^= *pos++;
                if (left > BLOCK_SIZE)
                        aes_encrypt(ctx, cbc, cbc);
                left -= BLOCK_SIZE;
        }

        memset(pad, 0, BLOCK_SIZE);
        aes_encrypt(ctx, pad, pad);
        gf_mulx(pad);

        if (left || data_len == 0) {
                for (i = 0; i < left; i++)
                        cbc[i] ^= *pos++;
                cbc[left] ^= 0x80;
                gf_mulx(pad);
        }

        for (i = 0; i < BLOCK_SIZE; i++)
                pad[i] ^= cbc[i];
        aes_encrypt(ctx, pad, mac);
        aes_encrypt_deinit(ctx);
        return 0;
}


int aes_128_encrypt_block(const u8 *key, const u8 *in, u8 *out)
{
        void *ctx;
        ctx = aes_encrypt_init(key, 16);
        if (ctx == NULL)
                return -1;
        aes_encrypt(ctx, in, out);
        aes_encrypt_deinit(ctx);
        return 0;
}


int aes_128_ctr_encrypt(const u8 *key, const u8 *nonce,
                        u8 *data, size_t data_len)
{
        void *ctx;
        size_t len, left = data_len;
        int i;
        u8 *pos = data;
        u8 counter[BLOCK_SIZE], buf[BLOCK_SIZE];

        ctx = aes_encrypt_init(key, 16);
        if (ctx == NULL)
                return -1;
        memcpy(counter, nonce, BLOCK_SIZE);

        while (left > 0) {
                aes_encrypt(ctx, counter, buf);

                len = (left < BLOCK_SIZE) ? left : BLOCK_SIZE;
                for (i = 0; i < len; i++)
                        pos[i] ^= buf[i];
                pos += len;
                left -= len;

                for (i = BLOCK_SIZE - 1; i >= 0; i--) {
                        counter[i]++;
                        if (counter[i])
                                break;
                }
        }
        aes_encrypt_deinit(ctx);
        return 0;
}


int aes_128_eax_encrypt(const u8 *key, const u8 *nonce, size_t nonce_len,
                        const u8 *hdr, size_t hdr_len,
                        u8 *data, size_t data_len, u8 *tag)
{
        u8 *buf;
        size_t buf_len;
        u8 nonce_mac[BLOCK_SIZE], hdr_mac[BLOCK_SIZE], data_mac[BLOCK_SIZE];
        int i;

        if (nonce_len > data_len)
                buf_len = nonce_len;
        else
                buf_len = data_len;
        if (hdr_len > buf_len)
                buf_len = hdr_len;
        buf_len += 16;

        buf = malloc(buf_len);
        if (buf == NULL)
                return -1;

        memset(buf, 0, 15);

        buf[15] = 0;
        memcpy(buf + 16, nonce, nonce_len);
        omac1_aes_128(key, buf, 16 + nonce_len, nonce_mac);

        buf[15] = 1;
        memcpy(buf + 16, hdr, hdr_len);
        omac1_aes_128(key, buf, 16 + hdr_len, hdr_mac);

        aes_128_ctr_encrypt(key, nonce_mac, data, data_len);
        buf[15] = 2;
        memcpy(buf + 16, data, data_len);
        omac1_aes_128(key, buf, 16 + data_len, data_mac);

        free(buf);

        for (i = 0; i < BLOCK_SIZE; i++)
                tag[i] = nonce_mac[i] ^ data_mac[i] ^ hdr_mac[i];

        return 0;
}


int aes_128_eax_decrypt(const u8 *key, const u8 *nonce, size_t nonce_len,
                        const u8 *hdr, size_t hdr_len,
                        u8 *data, size_t data_len, const u8 *tag)
{
        u8 *buf;
        size_t buf_len;
        u8 nonce_mac[BLOCK_SIZE], hdr_mac[BLOCK_SIZE], data_mac[BLOCK_SIZE];
        int i;

        if (nonce_len > data_len)
                buf_len = nonce_len;
        else
                buf_len = data_len;
        if (hdr_len > buf_len)
                buf_len = hdr_len;
        buf_len += 16;

        buf = malloc(buf_len);
        if (buf == NULL)
                return -1;

        memset(buf, 0, 15);

        buf[15] = 0;
        memcpy(buf + 16, nonce, nonce_len);
        omac1_aes_128(key, buf, 16 + nonce_len, nonce_mac);

        buf[15] = 1;
        memcpy(buf + 16, hdr, hdr_len);
        omac1_aes_128(key, buf, 16 + hdr_len, hdr_mac);

        buf[15] = 2;
        memcpy(buf + 16, data, data_len);
        omac1_aes_128(key, buf, 16 + data_len, data_mac);

        free(buf);

        for (i = 0; i < BLOCK_SIZE; i++) {
                if (tag[i] != (nonce_mac[i] ^ data_mac[i] ^ hdr_mac[i]))
                        return -2;
        }

        aes_128_ctr_encrypt(key, nonce_mac, data, data_len);

        return 0;
}


int aes_128_cbc_encrypt(const u8 *key, const u8 *iv, u8 *data, size_t data_len)
{
        void *ctx;
        u8 cbc[BLOCK_SIZE];
        u8 *pos = data;
        int i, j, blocks;

        ctx = aes_encrypt_init(key, 16);
        if (ctx == NULL)
                return -1;
        memcpy(cbc, iv, BLOCK_SIZE);

        blocks = data_len / BLOCK_SIZE;
        for (i = 0; i < blocks; i++) {
                for (j = 0; j < BLOCK_SIZE; j++)
                        cbc[j] ^= pos[j];
                aes_encrypt(ctx, cbc, cbc);
                memcpy(pos, cbc, BLOCK_SIZE);
                pos += BLOCK_SIZE;
        }
        aes_encrypt_deinit(ctx);
        return 0;
}


int aes_128_cbc_decrypt(const u8 *key, const u8 *iv, u8 *data, size_t data_len)
{
        void *ctx;
        u8 cbc[BLOCK_SIZE], tmp[BLOCK_SIZE];
        u8 *pos = data;
        int i, j, blocks;

        ctx = aes_decrypt_init(key, 16);
        if (ctx == NULL)
                return -1;
        memcpy(cbc, iv, BLOCK_SIZE);

        blocks = data_len / BLOCK_SIZE;
        for (i = 0; i < blocks; i++) {
                memcpy(tmp, pos, BLOCK_SIZE);
                aes_decrypt(ctx, pos, pos);
                for (j = 0; j < BLOCK_SIZE; j++)
                        pos[j] ^= cbc[j];
                memcpy(cbc, tmp, BLOCK_SIZE);
                pos += BLOCK_SIZE;
        }
        aes_decrypt_deinit(ctx);
        return 0;
}


#ifdef TEST_MAIN

#ifdef __i386__
#define rdtscll(val) \
     __asm__ __volatile__("rdtsc" : "=A" (val))

static void test_aes_perf(void)
{
        const int num_iters = 10;
        int i;
        unsigned int start, end;
        u8 key[16], pt[16], ct[16];
        void *ctx;

        printf("keySetupEnc:");
        for (i = 0; i < num_iters; i++) {
                rdtscll(start);
                ctx = aes_encrypt_init(key, 16);
                rdtscll(end);
                aes_encrypt_deinit(ctx);
                printf(" %d", end - start);
        }
        printf("\n");

        printf("Encrypt:");
        ctx = aes_encrypt_init(key, 16);
        for (i = 0; i < num_iters; i++) {
                rdtscll(start);
                aes_encrypt(ctx, pt, ct);
                rdtscll(end);
                printf(" %d", end - start);
        }
        aes_encrypt_deinit(ctx);
        printf("\n");
}
#endif /* __i386__ */


static int test_eax(void)
{
        u8 msg[] = { 0xF7, 0xFB };
        u8 key[] = { 0x91, 0x94, 0x5D, 0x3F, 0x4D, 0xCB, 0xEE, 0x0B,
                     0xF4, 0x5E, 0xF5, 0x22, 0x55, 0xF0, 0x95, 0xA4 };
        u8 nonce[] = { 0xBE, 0xCA, 0xF0, 0x43, 0xB0, 0xA2, 0x3D, 0x84,
                       0x31, 0x94, 0xBA, 0x97, 0x2C, 0x66, 0xDE, 0xBD };
        u8 hdr[] = { 0xFA, 0x3B, 0xFD, 0x48, 0x06, 0xEB, 0x53, 0xFA };
        u8 cipher[] = { 0x19, 0xDD, 0x5C, 0x4C, 0x93, 0x31, 0x04, 0x9D,
                        0x0B, 0xDA, 0xB0, 0x27, 0x74, 0x08, 0xF6, 0x79,
                        0x67, 0xE5 };
        u8 data[sizeof(msg)], tag[BLOCK_SIZE];

        memcpy(data, msg, sizeof(msg));
        if (aes_128_eax_encrypt(key, nonce, sizeof(nonce), hdr, sizeof(hdr),
                                data, sizeof(data), tag)) {
                printf("AES-128 EAX mode encryption failed\n");
                return 1;
        }
        if (memcmp(data, cipher, sizeof(data)) != 0) {
                printf("AES-128 EAX mode encryption returned invalid cipher "
                       "text\n");
                return 1;
        }
        if (memcmp(tag, cipher + sizeof(data), BLOCK_SIZE) != 0) {
                printf("AES-128 EAX mode encryption returned invalid tag\n");
                return 1;
        }

        if (aes_128_eax_decrypt(key, nonce, sizeof(nonce), hdr, sizeof(hdr),
                                data, sizeof(data), tag)) {
                printf("AES-128 EAX mode decryption failed\n");
                return 1;
        }
        if (memcmp(data, msg, sizeof(data)) != 0) {
                printf("AES-128 EAX mode decryption returned invalid plain "
                       "text\n");
                return 1;
        }

        return 0;
}


static int test_cbc(void)
{
        struct cbc_test_vector {
                u8 key[16];
                u8 iv[16];
                u8 plain[32];
                u8 cipher[32];
                size_t len;
        } vectors[] = {
                {
                        { 0x06, 0xa9, 0x21, 0x40, 0x36, 0xb8, 0xa1, 0x5b,
                          0x51, 0x2e, 0x03, 0xd5, 0x34, 0x12, 0x00, 0x06 },
                        { 0x3d, 0xaf, 0xba, 0x42, 0x9d, 0x9e, 0xb4, 0x30,
                          0xb4, 0x22, 0xda, 0x80, 0x2c, 0x9f, 0xac, 0x41 },
                        "Single block msg",
                        { 0xe3, 0x53, 0x77, 0x9c, 0x10, 0x79, 0xae, 0xb8,
                          0x27, 0x08, 0x94, 0x2d, 0xbe, 0x77, 0x18, 0x1a },
                        16
                },
                {
                        { 0xc2, 0x86, 0x69, 0x6d, 0x88, 0x7c, 0x9a, 0xa0,
                          0x61, 0x1b, 0xbb, 0x3e, 0x20, 0x25, 0xa4, 0x5a },
                        { 0x56, 0x2e, 0x17, 0x99, 0x6d, 0x09, 0x3d, 0x28,
                          0xdd, 0xb3, 0xba, 0x69, 0x5a, 0x2e, 0x6f, 0x58 },
                        { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
                          0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
                          0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
                          0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f },
                        { 0xd2, 0x96, 0xcd, 0x94, 0xc2, 0xcc, 0xcf, 0x8a,
                          0x3a, 0x86, 0x30, 0x28, 0xb5, 0xe1, 0xdc, 0x0a,
                          0x75, 0x86, 0x60, 0x2d, 0x25, 0x3c, 0xff, 0xf9,
                          0x1b, 0x82, 0x66, 0xbe, 0xa6, 0xd6, 0x1a, 0xb1 },
                        32
                }
        };
        int i, ret = 0;
        u8 *buf;

        for (i = 0; i < sizeof(vectors) / sizeof(vectors[0]); i++) {
                struct cbc_test_vector *tv = &vectors[i];
                buf = malloc(tv->len);
                if (buf == NULL) {
                        ret++;
                        break;
                }
                memcpy(buf, tv->plain, tv->len);
                aes_128_cbc_encrypt(tv->key, tv->iv, buf, tv->len);
                if (memcmp(buf, tv->cipher, tv->len) != 0) {
                        printf("AES-CBC encrypt %d failed\n", i);
                        ret++;
                }
                memcpy(buf, tv->cipher, tv->len);
                aes_128_cbc_decrypt(tv->key, tv->iv, buf, tv->len);
                if (memcmp(buf, tv->plain, tv->len) != 0) {
                        printf("AES-CBC decrypt %d failed\n", i);
                        ret++;
                }
                free(buf);
        }

        return ret;
}


/* OMAC1 AES-128 test vectors from
 * http://csrc.nist.gov/CryptoToolkit/modes/proposedmodes/omac/omac-ad.pdf
 */

struct omac1_test_vector {
        u8 k[16];
        u8 msg[64];
        int msg_len;
        u8 tag[16];
};

static struct omac1_test_vector test_vectors[] =
{
        {
                { 0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
                  0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c },
                { },
                0,
                { 0xbb, 0x1d, 0x69, 0x29, 0xe9, 0x59, 0x37, 0x28,
                  0x7f, 0xa3, 0x7d, 0x12, 0x9b, 0x75, 0x67, 0x46 }
        },
        {
                { 0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
                  0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c },
                { 0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
                  0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a},
                16,
                { 0x07, 0x0a, 0x16, 0xb4, 0x6b, 0x4d, 0x41, 0x44,
                  0xf7, 0x9b, 0xdd, 0x9d, 0xd0, 0x4a, 0x28, 0x7c }
        },
        {
                { 0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
                  0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c },
                { 0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
                  0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
                  0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
                  0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
                  0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11 },
                40,
                { 0xdf, 0xa6, 0x67, 0x47, 0xde, 0x9a, 0xe6, 0x30,
                  0x30, 0xca, 0x32, 0x61, 0x14, 0x97, 0xc8, 0x27 }
        },
        {
                { 0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
                  0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c },
                { 0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
                  0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
                  0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
                  0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
                  0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,
                  0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
                  0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17,
                  0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10 },
                64,
                { 0x51, 0xf0, 0xbe, 0xbf, 0x7e, 0x3b, 0x9d, 0x92,
                  0xfc, 0x49, 0x74, 0x17, 0x79, 0x36, 0x3c, 0xfe }
        },
};


int main(int argc, char *argv[])
{
        u8 kek[] = {
                0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
                0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
        };
        u8 plain[] = {
                0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
                0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff
        };
        u8 crypt[] = {
                0x1F, 0xA6, 0x8B, 0x0A, 0x81, 0x12, 0xB4, 0x47,
                0xAE, 0xF3, 0x4B, 0xD8, 0xFB, 0x5A, 0x7B, 0x82,
                0x9D, 0x3E, 0x86, 0x23, 0x71, 0xD2, 0xCF, 0xE5
        };
        u8 result[24];
        int ret = 0, i;
        struct omac1_test_vector *tv;

        if (aes_wrap(kek, 2, plain, result)) {
                printf("AES-WRAP-128-128 reported failure\n");
                ret++;
        }
        if (memcmp(result, crypt, 24) != 0) {
                printf("AES-WRAP-128-128 failed\n");
                ret++;
        }
        if (aes_unwrap(kek, 2, crypt, result)) {
                printf("AES-UNWRAP-128-128 reported failure\n");
                ret++;
        }
        if (memcmp(result, plain, 16) != 0) {
                int i;
                printf("AES-UNWRAP-128-128 failed\n");
                ret++;
                for (i = 0; i < 16; i++)
                        printf(" %02x", result[i]);
                printf("\n");
        }

#ifdef __i386__
        test_aes_perf();
#endif /* __i386__ */

        for (i = 0; i < sizeof(test_vectors) / sizeof(test_vectors[0]); i++) {
                tv = &test_vectors[i];
                omac1_aes_128(tv->k, tv->msg, tv->msg_len, result);
                if (memcmp(result, tv->tag, 16) != 0) {
                        printf("OMAC1-AES-128 test vector %d failed\n", i);
                        ret++;
                }
        }

        ret += test_eax();

        ret += test_cbc();

        if (ret)
                printf("FAILED!\n");

        return ret;
}
#endif /* TEST_MAIN */

---