diff options
Diffstat (limited to 'core/lib/libtomcrypt/src/encauth/ccm/ccm_memory.c')
| -rw-r--r-- | core/lib/libtomcrypt/src/encauth/ccm/ccm_memory.c | 432 |
1 files changed, 432 insertions, 0 deletions
diff --git a/core/lib/libtomcrypt/src/encauth/ccm/ccm_memory.c b/core/lib/libtomcrypt/src/encauth/ccm/ccm_memory.c new file mode 100644 index 0000000..d68988a --- /dev/null +++ b/core/lib/libtomcrypt/src/encauth/ccm/ccm_memory.c @@ -0,0 +1,432 @@ +/* + * Copyright (c) 2001-2007, Tom St Denis + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 2. 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. + * + * 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 HOLDER 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. + */ + +/* LibTomCrypt, modular cryptographic library -- Tom St Denis + * + * LibTomCrypt is a library that provides various cryptographic + * algorithms in a highly modular and flexible manner. + * + * The library is free for all purposes without any express + * guarantee it works. + * + * Tom St Denis, tomstdenis@gmail.com, http://libtom.org + */ +#include "tomcrypt.h" + +/** + @file ccm_memory.c + CCM support, process a block of memory, Tom St Denis +*/ + +#ifdef LTC_CCM_MODE + +/** + CCM encrypt/decrypt and produce an authentication tag + + *1 'pt', 'ct' and 'tag' can both be 'in' or 'out', depending on 'direction' + + @param cipher The index of the cipher desired + @param key The secret key to use + @param keylen The length of the secret key (octets) + @param uskey A previously scheduled key [optional can be NULL] + @param nonce The session nonce [use once] + @param noncelen The length of the nonce + @param header The header for the session + @param headerlen The length of the header (octets) + @param pt [*1] The plaintext + @param ptlen The length of the plaintext (octets) + @param ct [*1] The ciphertext + @param tag [*1] The destination tag + @param taglen The max size and resulting size of the authentication tag + @param direction Encrypt or Decrypt direction (0 or 1) + @return CRYPT_OK if successful +*/ +int ccm_memory(int cipher, + const unsigned char *key, unsigned long keylen, + symmetric_key *uskey, + const unsigned char *nonce, unsigned long noncelen, + const unsigned char *header, unsigned long headerlen, + unsigned char *pt, unsigned long ptlen, + unsigned char *ct, + unsigned char *tag, unsigned long *taglen, + int direction) +{ + unsigned char PAD[16], ctr[16], CTRPAD[16], ptTag[16], b, *pt_real; + unsigned char *pt_work = NULL; + symmetric_key *skey; + int err; + unsigned long len, L, x, y, z, CTRlen; +#ifdef LTC_FAST + LTC_FAST_TYPE fastMask = -1; /* initialize fastMask at all zeroes */ +#endif + unsigned char mask = 0xff; /* initialize mask at all zeroes */ + + if (uskey == NULL) { + LTC_ARGCHK(key != NULL); + } + LTC_ARGCHK(nonce != NULL); + if (headerlen > 0) { + LTC_ARGCHK(header != NULL); + } + LTC_ARGCHK(pt != NULL); + LTC_ARGCHK(ct != NULL); + LTC_ARGCHK(tag != NULL); + LTC_ARGCHK(taglen != NULL); + + pt_real = pt; + +#ifdef LTC_FAST + if (16 % sizeof(LTC_FAST_TYPE)) { + return CRYPT_INVALID_ARG; + } +#endif + + /* check cipher input */ + if ((err = cipher_is_valid(cipher)) != CRYPT_OK) { + return err; + } + if (cipher_descriptor[cipher].block_length != 16) { + return CRYPT_INVALID_CIPHER; + } + + /* make sure the taglen is even and <= 16 */ + *taglen &= ~1; + if (*taglen > 16) { + *taglen = 16; + } + + /* can't use < 4 */ + if (*taglen < 4) { + return CRYPT_INVALID_ARG; + } + + /* is there an accelerator? */ + if (cipher_descriptor[cipher].accel_ccm_memory != NULL) { + return cipher_descriptor[cipher].accel_ccm_memory( + key, keylen, + uskey, + nonce, noncelen, + header, headerlen, + pt, ptlen, + ct, + tag, taglen, + direction); + } + + /* let's get the L value */ + len = ptlen; + L = 0; + while (len) { + ++L; + len >>= 8; + } + if (L <= 1) { + L = 2; + } + + /* increase L to match the nonce len */ + noncelen = (noncelen > 13) ? 13 : noncelen; + if ((15 - noncelen) > L) { + L = 15 - noncelen; + } + + /* allocate mem for the symmetric key */ + if (uskey == NULL) { + skey = XMALLOC(sizeof(*skey)); + if (skey == NULL) { + return CRYPT_MEM; + } + + /* initialize the cipher */ + if ((err = cipher_descriptor[cipher].setup(key, keylen, 0, skey)) != CRYPT_OK) { + XFREE(skey); + return err; + } + } else { + skey = uskey; + } + + /* initialize buffer for pt */ + if (direction == CCM_DECRYPT) { + pt_work = XMALLOC(ptlen); + if (pt_work == NULL) { + goto error; + } + pt = pt_work; + } + + /* form B_0 == flags | Nonce N | l(m) */ + x = 0; + PAD[x++] = (unsigned char)(((headerlen > 0) ? (1<<6) : 0) | + (((*taglen - 2)>>1)<<3) | + (L-1)); + + /* nonce */ + for (y = 0; y < (16 - (L + 1)); y++) { + PAD[x++] = nonce[y]; + } + + /* store len */ + len = ptlen; + + /* shift len so the upper bytes of len are the contents of the length */ + for (y = L; y < 4; y++) { + len <<= 8; + } + + /* store l(m) (only store 32-bits) */ + for (y = 0; L > 4 && (L-y)>4; y++) { + PAD[x++] = 0; + } + for (; y < L; y++) { + PAD[x++] = (unsigned char)((len >> 24) & 255); + len <<= 8; + } + + /* encrypt PAD */ + if ((err = cipher_descriptor[cipher].ecb_encrypt(PAD, PAD, skey)) != CRYPT_OK) { + goto error; + } + + /* handle header */ + if (headerlen > 0) { + x = 0; + + /* store length */ + if (headerlen < ((1UL<<16) - (1UL<<8))) { + PAD[x++] ^= (headerlen>>8) & 255; + PAD[x++] ^= headerlen & 255; + } else { + PAD[x++] ^= 0xFF; + PAD[x++] ^= 0xFE; + PAD[x++] ^= (headerlen>>24) & 255; + PAD[x++] ^= (headerlen>>16) & 255; + PAD[x++] ^= (headerlen>>8) & 255; + PAD[x++] ^= headerlen & 255; + } + + /* now add the data */ + for (y = 0; y < headerlen; y++) { + if (x == 16) { + /* full block so let's encrypt it */ + if ((err = cipher_descriptor[cipher].ecb_encrypt(PAD, PAD, skey)) != CRYPT_OK) { + goto error; + } + x = 0; + } + PAD[x++] ^= header[y]; + } + + /* remainder */ + if ((err = cipher_descriptor[cipher].ecb_encrypt(PAD, PAD, skey)) != CRYPT_OK) { + goto error; + } + } + + /* setup the ctr counter */ + x = 0; + + /* flags */ + ctr[x++] = (unsigned char)L-1; + + /* nonce */ + for (y = 0; y < (16 - (L+1)); ++y) { + ctr[x++] = nonce[y]; + } + /* offset */ + while (x < 16) { + ctr[x++] = 0; + } + + x = 0; + CTRlen = 16; + + /* now handle the PT */ + if (ptlen > 0) { + y = 0; +#ifdef LTC_FAST + if (ptlen & ~15) { + if (direction == CCM_ENCRYPT) { + for (; y < (ptlen & ~15); y += 16) { + /* increment the ctr? */ + for (z = 15; z > 15-L; z--) { + ctr[z] = (ctr[z] + 1) & 255; + if (ctr[z]) break; + } + if ((err = cipher_descriptor[cipher].ecb_encrypt(ctr, CTRPAD, skey)) != CRYPT_OK) { + goto error; + } + + /* xor the PT against the pad first */ + for (z = 0; z < 16; z += sizeof(LTC_FAST_TYPE)) { + *((LTC_FAST_TYPE*)(&PAD[z])) ^= *((LTC_FAST_TYPE*)(&pt[y+z])); + *((LTC_FAST_TYPE*)(&ct[y+z])) = *((LTC_FAST_TYPE*)(&pt[y+z])) ^ *((LTC_FAST_TYPE*)(&CTRPAD[z])); + } + if ((err = cipher_descriptor[cipher].ecb_encrypt(PAD, PAD, skey)) != CRYPT_OK) { + goto error; + } + } + } else { /* direction == CCM_DECRYPT */ + for (; y < (ptlen & ~15); y += 16) { + /* increment the ctr? */ + for (z = 15; z > 15-L; z--) { + ctr[z] = (ctr[z] + 1) & 255; + if (ctr[z]) break; + } + if ((err = cipher_descriptor[cipher].ecb_encrypt(ctr, CTRPAD, skey)) != CRYPT_OK) { + goto error; + } + + /* xor the PT against the pad last */ + for (z = 0; z < 16; z += sizeof(LTC_FAST_TYPE)) { + *((LTC_FAST_TYPE*)(&pt[y+z])) = *((LTC_FAST_TYPE*)(&ct[y+z])) ^ *((LTC_FAST_TYPE*)(&CTRPAD[z])); + *((LTC_FAST_TYPE*)(&PAD[z])) ^= *((LTC_FAST_TYPE*)(&pt[y+z])); + } + if ((err = cipher_descriptor[cipher].ecb_encrypt(PAD, PAD, skey)) != CRYPT_OK) { + goto error; + } + } + } + } +#endif + + for (; y < ptlen; y++) { + /* increment the ctr? */ + if (CTRlen == 16) { + for (z = 15; z > 15-L; z--) { + ctr[z] = (ctr[z] + 1) & 255; + if (ctr[z]) break; + } + if ((err = cipher_descriptor[cipher].ecb_encrypt(ctr, CTRPAD, skey)) != CRYPT_OK) { + goto error; + } + CTRlen = 0; + } + + /* if we encrypt we add the bytes to the MAC first */ + if (direction == CCM_ENCRYPT) { + b = pt[y]; + ct[y] = b ^ CTRPAD[CTRlen++]; + } else { + b = ct[y] ^ CTRPAD[CTRlen++]; + pt[y] = b; + } + + if (x == 16) { + if ((err = cipher_descriptor[cipher].ecb_encrypt(PAD, PAD, skey)) != CRYPT_OK) { + goto error; + } + x = 0; + } + PAD[x++] ^= b; + } + + if (x != 0) { + if ((err = cipher_descriptor[cipher].ecb_encrypt(PAD, PAD, skey)) != CRYPT_OK) { + goto error; + } + } + } + + /* setup CTR for the TAG (zero the count) */ + for (y = 15; y > 15 - L; y--) { + ctr[y] = 0x00; + } + if ((err = cipher_descriptor[cipher].ecb_encrypt(ctr, CTRPAD, skey)) != CRYPT_OK) { + goto error; + } + + if (skey != uskey) { + cipher_descriptor[cipher].done(skey); + } + + if (direction == CCM_ENCRYPT) { + /* store the TAG */ + for (x = 0; x < 16 && x < *taglen; x++) { + tag[x] = PAD[x] ^ CTRPAD[x]; + } + *taglen = x; + } else { /* direction == CCM_DECRYPT */ + /* decrypt the tag */ + for (x = 0; x < 16 && x < *taglen; x++) { + ptTag[x] = tag[x] ^ CTRPAD[x]; + } + *taglen = x; + + /* check validity of the decrypted tag against the computed PAD (in constant time) */ + /* HACK: the boolean value of XMEM_NEQ becomes either 0 (CRYPT_OK) or 1 (CRYPT_ERR). + * there should be a better way of setting the correct error code in constant + * time. + */ + err = XMEM_NEQ(ptTag, PAD, *taglen); + + /* Zero the plaintext if the tag was invalid (in constant time) */ + if (ptlen > 0) { + y = 0; + mask *= 1 - err; /* mask = ( err ? 0 : 0xff ) */ +#ifdef LTC_FAST + fastMask *= 1 - err; + if (ptlen & ~15) { + for (; y < (ptlen & ~15); y += 16) { + for (z = 0; z < 16; z += sizeof(LTC_FAST_TYPE)) { + *((LTC_FAST_TYPE*)(&pt_real[y+z])) = *((LTC_FAST_TYPE*)(&pt[y+z])) & fastMask; + } + } + } +#endif + for (; y < ptlen; y++) { + pt_real[y] = pt[y] & mask; + } + } + } + +#ifdef LTC_CLEAN_STACK + fastMask = 0; + mask = 0; + zeromem(skey, sizeof(*skey)); + zeromem(PAD, sizeof(PAD)); + zeromem(CTRPAD, sizeof(CTRPAD)); + if (pt_work != NULL) { + zeromem(pt_work, ptlen); + } +#endif +error: + if (pt_work) { + XFREE(pt_work); + } + if (skey != uskey) { + XFREE(skey); + } + + return err; +} + +#endif + +/* $Source$ */ +/* $Revision$ */ +/* $Date$ */ |