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-rw-r--r--crypto/cipher/aes_icm.c512
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diff --git a/crypto/cipher/aes_icm.c b/crypto/cipher/aes_icm.c
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+/*
+ * aes_icm.c
+ *
+ * AES Integer Counter Mode
+ *
+ * David A. McGrew
+ * Cisco Systems, Inc.
+ */
+
+/*
+ *
+ * Copyright (c) 2001-2006, 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.
+ *
+ */
+
+
+#define ALIGN_32 0
+
+#include "aes_icm.h"
+#include "alloc.h"
+
+
+debug_module_t mod_aes_icm = {
+ 0, /* debugging is off by default */
+ "aes icm" /* printable module name */
+};
+
+/*
+ * integer counter mode works as follows:
+ *
+ * 16 bits
+ * <----->
+ * +------+------+------+------+------+------+------+------+
+ * | nonce | pakcet index | ctr |---+
+ * +------+------+------+------+------+------+------+------+ |
+ * |
+ * +------+------+------+------+------+------+------+------+ v
+ * | salt |000000|->(+)
+ * +------+------+------+------+------+------+------+------+ |
+ * |
+ * +---------+
+ * | encrypt |
+ * +---------+
+ * |
+ * +------+------+------+------+------+------+------+------+ |
+ * | keystream block |<--+
+ * +------+------+------+------+------+------+------+------+
+ *
+ * All fields are big-endian
+ *
+ * ctr is the block counter, which increments from zero for
+ * each packet (16 bits wide)
+ *
+ * packet index is distinct for each packet (48 bits wide)
+ *
+ * nonce can be distinct across many uses of the same key, or
+ * can be a fixed value per key, or can be per-packet randomness
+ * (64 bits)
+ *
+ */
+
+err_status_t
+aes_icm_alloc_ismacryp(cipher_t **c, int key_len, int forIsmacryp) {
+ extern cipher_type_t aes_icm;
+ uint8_t *pointer;
+ int tmp;
+
+ debug_print(mod_aes_icm,
+ "allocating cipher with key length %d", key_len);
+
+ /*
+ * Ismacryp, for example, uses 16 byte key + 8 byte
+ * salt so this function is called with key_len = 24.
+ * The check for key_len = 30 does not apply. Our usage
+ * of aes functions with key_len = values other than 30
+ * has not broken anything. Don't know what would be the
+ * effect of skipping this check for srtp in general.
+ */
+ if (!forIsmacryp && key_len != 30)
+ return err_status_bad_param;
+
+ /* allocate memory a cipher of type aes_icm */
+ tmp = (sizeof(aes_icm_ctx_t) + sizeof(cipher_t));
+ pointer = (uint8_t*)crypto_alloc(tmp);
+ if (pointer == NULL)
+ return err_status_alloc_fail;
+
+ /* set pointers */
+ *c = (cipher_t *)pointer;
+ (*c)->type = &aes_icm;
+ (*c)->state = pointer + sizeof(cipher_t);
+
+ /* increment ref_count */
+ aes_icm.ref_count++;
+
+ /* set key size */
+ (*c)->key_len = key_len;
+
+ return err_status_ok;
+}
+
+err_status_t aes_icm_alloc(cipher_t **c, int key_len, int forIsmacryp) {
+ return aes_icm_alloc_ismacryp(c, key_len, 0);
+}
+
+err_status_t
+aes_icm_dealloc(cipher_t *c) {
+ extern cipher_type_t aes_icm;
+
+ /* zeroize entire state*/
+ octet_string_set_to_zero((uint8_t *)c,
+ sizeof(aes_icm_ctx_t) + sizeof(cipher_t));
+
+ /* free memory */
+ crypto_free(c);
+
+ /* decrement ref_count */
+ aes_icm.ref_count--;
+
+ return err_status_ok;
+}
+
+
+/*
+ * aes_icm_context_init(...) initializes the aes_icm_context
+ * using the value in key[].
+ *
+ * the key is the secret key
+ *
+ * the salt is unpredictable (but not necessarily secret) data which
+ * randomizes the starting point in the keystream
+ */
+
+err_status_t
+aes_icm_context_init(aes_icm_ctx_t *c, const uint8_t *key) {
+ v128_t tmp_key;
+ int i;
+
+ /* set counter and initial values to 'offset' value */
+ /* FIX!!! this assumes the salt is at key + 16, and thus that the */
+ /* FIX!!! cipher key length is 16! */
+ for (i = 0; i < 14; i++) {
+ c->counter.v8[i] = key[16 + i];
+ c->offset.v8[i] = key[16 + i];
+ }
+
+ /* force last two octets of the offset to zero (for srtp compatibility) */
+ c->offset.v8[14] = c->offset.v8[15] = 0;
+ c->counter.v8[14] = c->counter.v8[15] = 0;
+
+ /* set tmp_key (for alignment) */
+ v128_copy_octet_string(&tmp_key, key);
+
+ debug_print(mod_aes_icm,
+ "key: %s", v128_hex_string(&tmp_key));
+ debug_print(mod_aes_icm,
+ "offset: %s", v128_hex_string(&c->offset));
+
+ /* expand key */
+ aes_expand_encryption_key(&tmp_key, c->expanded_key);
+
+ /* indicate that the keystream_buffer is empty */
+ c->bytes_in_buffer = 0;
+
+ return err_status_ok;
+}
+
+/*
+ * aes_icm_set_octet(c, i) sets the counter of the context which it is
+ * passed so that the next octet of keystream that will be generated
+ * is the ith octet
+ */
+
+err_status_t
+aes_icm_set_octet(aes_icm_ctx_t *c,
+ uint64_t octet_num) {
+
+#ifdef NO_64BIT_MATH
+ int tail_num = low32(octet_num) & 0x0f;
+ /* 64-bit right-shift 4 */
+ uint64_t block_num = make64(high32(octet_num) >> 4,
+ ((high32(octet_num) & 0x0f)<<(32-4)) |
+ (low32(octet_num) >> 4));
+#else
+ int tail_num = (int)(octet_num % 16);
+ uint64_t block_num = octet_num / 16;
+#endif
+
+
+ /* set counter value */
+ /* FIX - There's no way this is correct */
+ c->counter.v64[0] = c->offset.v64[0];
+#ifdef NO_64BIT_MATH
+ c->counter.v64[0] = make64(high32(c->offset.v64[0]) ^ high32(block_num),
+ low32(c->offset.v64[0]) ^ low32(block_num));
+#else
+ c->counter.v64[0] = c->offset.v64[0] ^ block_num;
+#endif
+
+ debug_print(mod_aes_icm,
+ "set_octet: %s", v128_hex_string(&c->counter));
+
+ /* fill keystream buffer, if needed */
+ if (tail_num) {
+ v128_copy(&c->keystream_buffer, &c->counter);
+ aes_encrypt(&c->keystream_buffer, c->expanded_key);
+ c->bytes_in_buffer = sizeof(v128_t);
+
+ debug_print(mod_aes_icm, "counter: %s",
+ v128_hex_string(&c->counter));
+ debug_print(mod_aes_icm, "ciphertext: %s",
+ v128_hex_string(&c->keystream_buffer));
+
+ /* indicate number of bytes in keystream_buffer */
+ c->bytes_in_buffer = sizeof(v128_t) - tail_num;
+
+ } else {
+
+ /* indicate that keystream_buffer is empty */
+ c->bytes_in_buffer = 0;
+ }
+
+ return err_status_ok;
+}
+
+/*
+ * aes_icm_set_iv(c, iv) sets the counter value to the exor of iv with
+ * the offset
+ */
+
+err_status_t
+aes_icm_set_iv(aes_icm_ctx_t *c, void *iv) {
+ v128_t *nonce = (v128_t *) iv;
+
+ debug_print(mod_aes_icm,
+ "setting iv: %s", v128_hex_string(nonce));
+
+ v128_xor(&c->counter, &c->offset, nonce);
+
+ debug_print(mod_aes_icm,
+ "set_counter: %s", v128_hex_string(&c->counter));
+
+ /* indicate that the keystream_buffer is empty */
+ c->bytes_in_buffer = 0;
+
+ return err_status_ok;
+}
+
+
+
+/*
+ * aes_icm_advance(...) refills the keystream_buffer and
+ * advances the block index of the sicm_context forward by one
+ *
+ * this is an internal, hopefully inlined function
+ */
+
+static inline void
+aes_icm_advance_ismacryp(aes_icm_ctx_t *c, uint8_t forIsmacryp) {
+ /* fill buffer with new keystream */
+ v128_copy(&c->keystream_buffer, &c->counter);
+ aes_encrypt(&c->keystream_buffer, c->expanded_key);
+ c->bytes_in_buffer = sizeof(v128_t);
+
+ debug_print(mod_aes_icm, "counter: %s",
+ v128_hex_string(&c->counter));
+ debug_print(mod_aes_icm, "ciphertext: %s",
+ v128_hex_string(&c->keystream_buffer));
+
+ /* clock counter forward */
+
+ if (forIsmacryp) {
+ uint32_t temp;
+ //alex's clock counter forward
+ temp = ntohl(c->counter.v32[3]);
+ c->counter.v32[3] = htonl(++temp);
+ } else {
+ if (!++(c->counter.v8[15]))
+ ++(c->counter.v8[14]);
+ }
+}
+
+inline void aes_icm_advance(aes_icm_ctx_t *c) {
+ aes_icm_advance_ismacryp(c, 0);
+}
+
+
+/*e
+ * icm_encrypt deals with the following cases:
+ *
+ * bytes_to_encr < bytes_in_buffer
+ * - add keystream into data
+ *
+ * bytes_to_encr > bytes_in_buffer
+ * - add keystream into data until keystream_buffer is depleted
+ * - loop over blocks, filling keystream_buffer and then
+ * adding keystream into data
+ * - fill buffer then add in remaining (< 16) bytes of keystream
+ */
+
+err_status_t
+aes_icm_encrypt_ismacryp(aes_icm_ctx_t *c,
+ unsigned char *buf, unsigned int *enc_len,
+ int forIsmacryp) {
+ unsigned int bytes_to_encr = *enc_len;
+ unsigned int i;
+ uint32_t *b;
+
+ /* check that there's enough segment left but not for ismacryp*/
+ if (!forIsmacryp && (bytes_to_encr + htons(c->counter.v16[7])) > 0xffff)
+ return err_status_terminus;
+
+ debug_print(mod_aes_icm, "block index: %d",
+ htons(c->counter.v16[7]));
+ if (bytes_to_encr <= (unsigned int)c->bytes_in_buffer) {
+
+ /* deal with odd case of small bytes_to_encr */
+ for (i = (sizeof(v128_t) - c->bytes_in_buffer);
+ i < (sizeof(v128_t) - c->bytes_in_buffer + bytes_to_encr); i++)
+ {
+ *buf++ ^= c->keystream_buffer.v8[i];
+ }
+
+ c->bytes_in_buffer -= bytes_to_encr;
+
+ /* return now to avoid the main loop */
+ return err_status_ok;
+
+ } else {
+
+ /* encrypt bytes until the remaining data is 16-byte aligned */
+ for (i=(sizeof(v128_t) - c->bytes_in_buffer); i < sizeof(v128_t); i++)
+ *buf++ ^= c->keystream_buffer.v8[i];
+
+ bytes_to_encr -= c->bytes_in_buffer;
+ c->bytes_in_buffer = 0;
+
+ }
+
+ /* now loop over entire 16-byte blocks of keystream */
+ for (i=0; i < (bytes_to_encr/sizeof(v128_t)); i++) {
+
+ /* fill buffer with new keystream */
+ aes_icm_advance_ismacryp(c, forIsmacryp);
+
+ /*
+ * add keystream into the data buffer (this would be a lot faster
+ * if we could assume 32-bit alignment!)
+ */
+
+#if ALIGN_32
+ b = (uint32_t *)buf;
+ *b++ ^= c->keystream_buffer.v32[0];
+ *b++ ^= c->keystream_buffer.v32[1];
+ *b++ ^= c->keystream_buffer.v32[2];
+ *b++ ^= c->keystream_buffer.v32[3];
+ buf = (uint8_t *)b;
+#else
+ if ((((unsigned long) buf) & 0x03) != 0) {
+ *buf++ ^= c->keystream_buffer.v8[0];
+ *buf++ ^= c->keystream_buffer.v8[1];
+ *buf++ ^= c->keystream_buffer.v8[2];
+ *buf++ ^= c->keystream_buffer.v8[3];
+ *buf++ ^= c->keystream_buffer.v8[4];
+ *buf++ ^= c->keystream_buffer.v8[5];
+ *buf++ ^= c->keystream_buffer.v8[6];
+ *buf++ ^= c->keystream_buffer.v8[7];
+ *buf++ ^= c->keystream_buffer.v8[8];
+ *buf++ ^= c->keystream_buffer.v8[9];
+ *buf++ ^= c->keystream_buffer.v8[10];
+ *buf++ ^= c->keystream_buffer.v8[11];
+ *buf++ ^= c->keystream_buffer.v8[12];
+ *buf++ ^= c->keystream_buffer.v8[13];
+ *buf++ ^= c->keystream_buffer.v8[14];
+ *buf++ ^= c->keystream_buffer.v8[15];
+ } else {
+ b = (uint32_t *)buf;
+ *b++ ^= c->keystream_buffer.v32[0];
+ *b++ ^= c->keystream_buffer.v32[1];
+ *b++ ^= c->keystream_buffer.v32[2];
+ *b++ ^= c->keystream_buffer.v32[3];
+ buf = (uint8_t *)b;
+ }
+#endif /* #if ALIGN_32 */
+
+ }
+
+ /* if there is a tail end of the data, process it */
+ if ((bytes_to_encr & 0xf) != 0) {
+
+ /* fill buffer with new keystream */
+ aes_icm_advance_ismacryp(c, forIsmacryp);
+
+ for (i=0; i < (bytes_to_encr & 0xf); i++)
+ *buf++ ^= c->keystream_buffer.v8[i];
+
+ /* reset the keystream buffer size to right value */
+ c->bytes_in_buffer = sizeof(v128_t) - i;
+ } else {
+
+ /* no tail, so just reset the keystream buffer size to zero */
+ c->bytes_in_buffer = 0;
+
+ }
+
+ return err_status_ok;
+}
+
+err_status_t
+aes_icm_encrypt(aes_icm_ctx_t *c, unsigned char *buf, unsigned int *enc_len) {
+ return aes_icm_encrypt_ismacryp(c, buf, enc_len, 0);
+}
+
+err_status_t
+aes_icm_output(aes_icm_ctx_t *c, uint8_t *buffer, int num_octets_to_output) {
+ unsigned int len = num_octets_to_output;
+
+ /* zeroize the buffer */
+ octet_string_set_to_zero(buffer, num_octets_to_output);
+
+ /* exor keystream into buffer */
+ return aes_icm_encrypt(c, buffer, &len);
+}
+
+
+char
+aes_icm_description[] = "aes integer counter mode";
+
+uint8_t aes_icm_test_case_0_key[30] = {
+ 0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
+ 0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c,
+ 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
+ 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd
+};
+
+uint8_t aes_icm_test_case_0_nonce[16] = {
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+};
+
+uint8_t aes_icm_test_case_0_plaintext[32] = {
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+};
+
+uint8_t aes_icm_test_case_0_ciphertext[32] = {
+ 0xe0, 0x3e, 0xad, 0x09, 0x35, 0xc9, 0x5e, 0x80,
+ 0xe1, 0x66, 0xb1, 0x6d, 0xd9, 0x2b, 0x4e, 0xb4,
+ 0xd2, 0x35, 0x13, 0x16, 0x2b, 0x02, 0xd0, 0xf7,
+ 0x2a, 0x43, 0xa2, 0xfe, 0x4a, 0x5f, 0x97, 0xab
+};
+
+cipher_test_case_t aes_icm_test_case_0 = {
+ 30, /* octets in key */
+ aes_icm_test_case_0_key, /* key */
+ aes_icm_test_case_0_nonce, /* packet index */
+ 32, /* octets in plaintext */
+ aes_icm_test_case_0_plaintext, /* plaintext */
+ 32, /* octets in ciphertext */
+ aes_icm_test_case_0_ciphertext, /* ciphertext */
+ NULL /* pointer to next testcase */
+};
+
+
+/*
+ * note: the encrypt function is identical to the decrypt function
+ */
+
+cipher_type_t aes_icm = {
+ (cipher_alloc_func_t) aes_icm_alloc,
+ (cipher_dealloc_func_t) aes_icm_dealloc,
+ (cipher_init_func_t) aes_icm_context_init,
+ (cipher_encrypt_func_t) aes_icm_encrypt,
+ (cipher_decrypt_func_t) aes_icm_encrypt,
+ (cipher_set_iv_func_t) aes_icm_set_iv,
+ (char *) aes_icm_description,
+ (int) 0, /* instance count */
+ (cipher_test_case_t *) &aes_icm_test_case_0,
+ (debug_module_t *) &mod_aes_icm
+};
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