crypto_internal.c

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#include "includes.h"

#include "common.h"
#include "crypto.h"
#include "md5.h"
#include "sha1.h"
#include "aes.h"
#include "tls/rsa.h"
#include "tls/bignum.h"
#include "tls/pkcs1.h"
#include "tls/pkcs8.h"
#include "sha1_i.h"
#include "md5_i.h"
#include "des_i.h"

#ifdef CONFIG_TLS_INTERNAL

struct crypto_hash {
        enum crypto_hash_alg alg;
        union {
                struct MD5Context md5;
                struct SHA1Context sha1;
        } u;
        u8 key[64];
        size_t key_len;
};


struct crypto_hash * crypto_hash_init(enum crypto_hash_alg alg, const u8 *key,
                                      size_t key_len)
{
        struct crypto_hash *ctx;
        u8 k_pad[64];
        u8 tk[20];
        size_t i;

        ctx = os_zalloc(sizeof(*ctx));
        if (ctx == NULL)
                return NULL;

        ctx->alg = alg;

        switch (alg) {
        case CRYPTO_HASH_ALG_MD5:
                MD5Init(&ctx->u.md5);
                break;
        case CRYPTO_HASH_ALG_SHA1:
                SHA1Init(&ctx->u.sha1);
                break;
        case CRYPTO_HASH_ALG_HMAC_MD5:
                if (key_len > sizeof(k_pad)) {
                        MD5Init(&ctx->u.md5);
                        MD5Update(&ctx->u.md5, key, key_len);
                        MD5Final(tk, &ctx->u.md5);
                        key = tk;
                        key_len = 16;
                }
                os_memcpy(ctx->key, key, key_len);
                ctx->key_len = key_len;

                os_memcpy(k_pad, key, key_len);
                os_memset(k_pad + key_len, 0, sizeof(k_pad) - key_len);
                for (i = 0; i < sizeof(k_pad); i++)
                        k_pad[i] ^= 0x36;
                MD5Init(&ctx->u.md5);
                MD5Update(&ctx->u.md5, k_pad, sizeof(k_pad));
                break;
        case CRYPTO_HASH_ALG_HMAC_SHA1:
                if (key_len > sizeof(k_pad)) {
                        SHA1Init(&ctx->u.sha1);
                        SHA1Update(&ctx->u.sha1, key, key_len);
                        SHA1Final(tk, &ctx->u.sha1);
                        key = tk;
                        key_len = 20;
                }
                os_memcpy(ctx->key, key, key_len);
                ctx->key_len = key_len;

                os_memcpy(k_pad, key, key_len);
                os_memset(k_pad + key_len, 0, sizeof(k_pad) - key_len);
                for (i = 0; i < sizeof(k_pad); i++)
                        k_pad[i] ^= 0x36;
                SHA1Init(&ctx->u.sha1);
                SHA1Update(&ctx->u.sha1, k_pad, sizeof(k_pad));
                break;
        default:
                os_free(ctx);
                return NULL;
        }

        return ctx;
}


void crypto_hash_update(struct crypto_hash *ctx, const u8 *data, size_t len)
{
        if (ctx == NULL)
                return;

        switch (ctx->alg) {
        case CRYPTO_HASH_ALG_MD5:
        case CRYPTO_HASH_ALG_HMAC_MD5:
                MD5Update(&ctx->u.md5, data, len);
                break;
        case CRYPTO_HASH_ALG_SHA1:
        case CRYPTO_HASH_ALG_HMAC_SHA1:
                SHA1Update(&ctx->u.sha1, data, len);
                break;
        }
}


int crypto_hash_finish(struct crypto_hash *ctx, u8 *mac, size_t *len)
{
        u8 k_pad[64];
        size_t i;

        if (ctx == NULL)
                return -2;

        if (mac == NULL || len == NULL) {
                os_free(ctx);
                return 0;
        }

        switch (ctx->alg) {
        case CRYPTO_HASH_ALG_MD5:
                if (*len < 16) {
                        *len = 16;
                        os_free(ctx);
                        return -1;
                }
                *len = 16;
                MD5Final(mac, &ctx->u.md5);
                break;
        case CRYPTO_HASH_ALG_SHA1:
                if (*len < 20) {
                        *len = 20;
                        os_free(ctx);
                        return -1;
                }
                *len = 20;
                SHA1Final(mac, &ctx->u.sha1);
                break;
        case CRYPTO_HASH_ALG_HMAC_MD5:
                if (*len < 16) {
                        *len = 16;
                        os_free(ctx);
                        return -1;
                }
                *len = 16;

                MD5Final(mac, &ctx->u.md5);

                os_memcpy(k_pad, ctx->key, ctx->key_len);
                os_memset(k_pad + ctx->key_len, 0,
                          sizeof(k_pad) - ctx->key_len);
                for (i = 0; i < sizeof(k_pad); i++)
                        k_pad[i] ^= 0x5c;
                MD5Init(&ctx->u.md5);
                MD5Update(&ctx->u.md5, k_pad, sizeof(k_pad));
                MD5Update(&ctx->u.md5, mac, 16);
                MD5Final(mac, &ctx->u.md5);
                break;
        case CRYPTO_HASH_ALG_HMAC_SHA1:
                if (*len < 20) {
                        *len = 20;
                        os_free(ctx);
                        return -1;
                }
                *len = 20;

                SHA1Final(mac, &ctx->u.sha1);

                os_memcpy(k_pad, ctx->key, ctx->key_len);
                os_memset(k_pad + ctx->key_len, 0,
                          sizeof(k_pad) - ctx->key_len);
                for (i = 0; i < sizeof(k_pad); i++)
                        k_pad[i] ^= 0x5c;
                SHA1Init(&ctx->u.sha1);
                SHA1Update(&ctx->u.sha1, k_pad, sizeof(k_pad));
                SHA1Update(&ctx->u.sha1, mac, 20);
                SHA1Final(mac, &ctx->u.sha1);
                break;
        }

        os_free(ctx);

        return 0;
}


struct crypto_cipher {
        enum crypto_cipher_alg alg;
        union {
                struct {
                        size_t used_bytes;
                        u8 key[16];
                        size_t keylen;
                } rc4;
                struct {
                        u8 cbc[32];
                        size_t block_size;
                        void *ctx_enc;
                        void *ctx_dec;
                } aes;
                struct {
                        struct des3_key_s key;
                        u8 cbc[8];
                } des3;
                struct {
                        u32 ek[32];
                        u32 dk[32];
                        u8 cbc[8];
                } des;
        } u;
};


struct crypto_cipher * crypto_cipher_init(enum crypto_cipher_alg alg,
                                          const u8 *iv, const u8 *key,
                                          size_t key_len)
{
        struct crypto_cipher *ctx;

        ctx = os_zalloc(sizeof(*ctx));
        if (ctx == NULL)
                return NULL;

        ctx->alg = alg;

        switch (alg) {
        case CRYPTO_CIPHER_ALG_RC4:
                if (key_len > sizeof(ctx->u.rc4.key)) {
                        os_free(ctx);
                        return NULL;
                }
                ctx->u.rc4.keylen = key_len;
                os_memcpy(ctx->u.rc4.key, key, key_len);
                break;
        case CRYPTO_CIPHER_ALG_AES:
                if (key_len > sizeof(ctx->u.aes.cbc)) {
                        os_free(ctx);
                        return NULL;
                }
                ctx->u.aes.ctx_enc = aes_encrypt_init(key, key_len);
                if (ctx->u.aes.ctx_enc == NULL) {
                        os_free(ctx);
                        return NULL;
                }
                ctx->u.aes.ctx_dec = aes_decrypt_init(key, key_len);
                if (ctx->u.aes.ctx_dec == NULL) {
                        aes_encrypt_deinit(ctx->u.aes.ctx_enc);
                        os_free(ctx);
                        return NULL;
                }
                ctx->u.aes.block_size = key_len;
                os_memcpy(ctx->u.aes.cbc, iv, ctx->u.aes.block_size);
                break;
        case CRYPTO_CIPHER_ALG_3DES:
                if (key_len != 24) {
                        os_free(ctx);
                        return NULL;
                }
                des3_key_setup(key, &ctx->u.des3.key);
                os_memcpy(ctx->u.des3.cbc, iv, 8);
                break;
        case CRYPTO_CIPHER_ALG_DES:
                if (key_len != 8) {
                        os_free(ctx);
                        return NULL;
                }
                des_key_setup(key, ctx->u.des.ek, ctx->u.des.dk);
                os_memcpy(ctx->u.des.cbc, iv, 8);
                break;
        default:
                os_free(ctx);
                return NULL;
        }

        return ctx;
}


int crypto_cipher_encrypt(struct crypto_cipher *ctx, const u8 *plain,
                          u8 *crypt, size_t len)
{
        size_t i, j, blocks;

        switch (ctx->alg) {
        case CRYPTO_CIPHER_ALG_RC4:
                if (plain != crypt)
                        os_memcpy(crypt, plain, len);
                rc4_skip(ctx->u.rc4.key, ctx->u.rc4.keylen,
                         ctx->u.rc4.used_bytes, crypt, len);
                ctx->u.rc4.used_bytes += len;
                break;
        case CRYPTO_CIPHER_ALG_AES:
                if (len % ctx->u.aes.block_size)
                        return -1;
                blocks = len / ctx->u.aes.block_size;
                for (i = 0; i < blocks; i++) {
                        for (j = 0; j < ctx->u.aes.block_size; j++)
                                ctx->u.aes.cbc[j] ^= plain[j];
                        aes_encrypt(ctx->u.aes.ctx_enc, ctx->u.aes.cbc,
                                    ctx->u.aes.cbc);
                        os_memcpy(crypt, ctx->u.aes.cbc,
                                  ctx->u.aes.block_size);
                        plain += ctx->u.aes.block_size;
                        crypt += ctx->u.aes.block_size;
                }
                break;
        case CRYPTO_CIPHER_ALG_3DES:
                if (len % 8)
                        return -1;
                blocks = len / 8;
                for (i = 0; i < blocks; i++) {
                        for (j = 0; j < 8; j++)
                                ctx->u.des3.cbc[j] ^= plain[j];
                        des3_encrypt(ctx->u.des3.cbc, &ctx->u.des3.key,
                                     ctx->u.des3.cbc);
                        os_memcpy(crypt, ctx->u.des3.cbc, 8);
                        plain += 8;
                        crypt += 8;
                }
                break;
        case CRYPTO_CIPHER_ALG_DES:
                if (len % 8)
                        return -1;
                blocks = len / 8;
                for (i = 0; i < blocks; i++) {
                        for (j = 0; j < 8; j++)
                                ctx->u.des3.cbc[j] ^= plain[j];
                        des_block_encrypt(ctx->u.des.cbc, ctx->u.des.ek,
                                          ctx->u.des.cbc);
                        os_memcpy(crypt, ctx->u.des.cbc, 8);
                        plain += 8;
                        crypt += 8;
                }
                break;
        default:
                return -1;
        }

        return 0;
}


int crypto_cipher_decrypt(struct crypto_cipher *ctx, const u8 *crypt,
                          u8 *plain, size_t len)
{
        size_t i, j, blocks;
        u8 tmp[32];

        switch (ctx->alg) {
        case CRYPTO_CIPHER_ALG_RC4:
                if (plain != crypt)
                        os_memcpy(plain, crypt, len);
                rc4_skip(ctx->u.rc4.key, ctx->u.rc4.keylen,
                         ctx->u.rc4.used_bytes, plain, len);
                ctx->u.rc4.used_bytes += len;
                break;
        case CRYPTO_CIPHER_ALG_AES:
                if (len % ctx->u.aes.block_size)
                        return -1;
                blocks = len / ctx->u.aes.block_size;
                for (i = 0; i < blocks; i++) {
                        os_memcpy(tmp, crypt, ctx->u.aes.block_size);
                        aes_decrypt(ctx->u.aes.ctx_dec, crypt, plain);
                        for (j = 0; j < ctx->u.aes.block_size; j++)
                                plain[j] ^= ctx->u.aes.cbc[j];
                        os_memcpy(ctx->u.aes.cbc, tmp, ctx->u.aes.block_size);
                        plain += ctx->u.aes.block_size;
                        crypt += ctx->u.aes.block_size;
                }
                break;
        case CRYPTO_CIPHER_ALG_3DES:
                if (len % 8)
                        return -1;
                blocks = len / 8;
                for (i = 0; i < blocks; i++) {
                        os_memcpy(tmp, crypt, 8);
                        des3_decrypt(crypt, &ctx->u.des3.key, plain);
                        for (j = 0; j < 8; j++)
                                plain[j] ^= ctx->u.des3.cbc[j];
                        os_memcpy(ctx->u.des3.cbc, tmp, 8);
                        plain += 8;
                        crypt += 8;
                }
                break;
        case CRYPTO_CIPHER_ALG_DES:
                if (len % 8)
                        return -1;
                blocks = len / 8;
                for (i = 0; i < blocks; i++) {
                        os_memcpy(tmp, crypt, 8);
                        des_block_decrypt(crypt, ctx->u.des.dk, plain);
                        for (j = 0; j < 8; j++)
                                plain[j] ^= ctx->u.des.cbc[j];
                        os_memcpy(ctx->u.des.cbc, tmp, 8);
                        plain += 8;
                        crypt += 8;
                }
                break;
        default:
                return -1;
        }

        return 0;
}


void crypto_cipher_deinit(struct crypto_cipher *ctx)
{
        switch (ctx->alg) {
        case CRYPTO_CIPHER_ALG_AES:
                aes_encrypt_deinit(ctx->u.aes.ctx_enc);
                aes_decrypt_deinit(ctx->u.aes.ctx_dec);
                break;
        case CRYPTO_CIPHER_ALG_3DES:
                break;
        default:
                break;
        }
        os_free(ctx);
}


/* Dummy structures; these are just typecast to struct crypto_rsa_key */
struct crypto_public_key;
struct crypto_private_key;


struct crypto_public_key * crypto_public_key_import(const u8 *key, size_t len)
{
        return (struct crypto_public_key *)
                crypto_rsa_import_public_key(key, len);
}


struct crypto_private_key * crypto_private_key_import(const u8 *key,
                                                      size_t len,
                                                      const char *passwd)
{
        struct crypto_private_key *res;

        /* First, check for possible PKCS #8 encoding */
        res = pkcs8_key_import(key, len);
        if (res)
                return res;

        if (passwd) {
                /* Try to parse as encrypted PKCS #8 */
                res = pkcs8_enc_key_import(key, len, passwd);
                if (res)
                        return res;
        }

        /* Not PKCS#8, so try to import PKCS #1 encoded RSA private key */
        wpa_printf(MSG_DEBUG, "Trying to parse PKCS #1 encoded RSA private "
                   "key");
        return (struct crypto_private_key *)
                crypto_rsa_import_private_key(key, len);
}


struct crypto_public_key * crypto_public_key_from_cert(const u8 *buf,
                                                       size_t len)
{
        /* No X.509 support in crypto_internal.c */
        return NULL;
}


int crypto_public_key_encrypt_pkcs1_v15(struct crypto_public_key *key,
                                        const u8 *in, size_t inlen,
                                        u8 *out, size_t *outlen)
{
        return pkcs1_encrypt(2, (struct crypto_rsa_key *) key,
                             0, in, inlen, out, outlen);
}


int crypto_private_key_decrypt_pkcs1_v15(struct crypto_private_key *key,
                                         const u8 *in, size_t inlen,
                                         u8 *out, size_t *outlen)
{
        return pkcs1_v15_private_key_decrypt((struct crypto_rsa_key *) key,
                                             in, inlen, out, outlen);
}


int crypto_private_key_sign_pkcs1(struct crypto_private_key *key,
                                  const u8 *in, size_t inlen,
                                  u8 *out, size_t *outlen)
{
        return pkcs1_encrypt(1, (struct crypto_rsa_key *) key,
                             1, in, inlen, out, outlen);
}


void crypto_public_key_free(struct crypto_public_key *key)
{
        crypto_rsa_free((struct crypto_rsa_key *) key);
}


void crypto_private_key_free(struct crypto_private_key *key)
{
        crypto_rsa_free((struct crypto_rsa_key *) key);
}


int crypto_public_key_decrypt_pkcs1(struct crypto_public_key *key,
                                    const u8 *crypt, size_t crypt_len,
                                    u8 *plain, size_t *plain_len)
{
        return pkcs1_decrypt_public_key((struct crypto_rsa_key *) key,
                                        crypt, crypt_len, plain, plain_len);
}


int crypto_global_init(void)
{
        return 0;
}


void crypto_global_deinit(void)
{
}
#endif /* CONFIG_TLS_INTERNAL */


#ifdef CONFIG_MODEXP

int crypto_mod_exp(const u8 *base, size_t base_len,
                   const u8 *power, size_t power_len,
                   const u8 *modulus, size_t modulus_len,
                   u8 *result, size_t *result_len)
{
        struct bignum *bn_base, *bn_exp, *bn_modulus, *bn_result;
        int ret = -1;

        bn_base = bignum_init();
        bn_exp = bignum_init();
        bn_modulus = bignum_init();
        bn_result = bignum_init();

        if (bn_base == NULL || bn_exp == NULL || bn_modulus == NULL ||
            bn_result == NULL)
                goto error;

        if (bignum_set_unsigned_bin(bn_base, base, base_len) < 0 ||
            bignum_set_unsigned_bin(bn_exp, power, power_len) < 0 ||
            bignum_set_unsigned_bin(bn_modulus, modulus, modulus_len) < 0)
                goto error;

        if (bignum_exptmod(bn_base, bn_exp, bn_modulus, bn_result) < 0)
                goto error;

        ret = bignum_get_unsigned_bin(bn_result, result, result_len);

error:
        bignum_deinit(bn_base);
        bignum_deinit(bn_exp);
        bignum_deinit(bn_modulus);
        bignum_deinit(bn_result);
        return ret;
}

#endif /* CONFIG_MODEXP */