118 lines
3.7 KiB
C
118 lines
3.7 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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/**
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@file gcm_memory.c
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GCM implementation, process a packet, by Tom St Denis
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*/
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#include "tomcrypt_private.h"
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#pragma clang diagnostic push
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#pragma clang diagnostic ignored "-Wconversion"
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#pragma clang diagnostic ignored "-Wshorten-64-to-32"
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#ifdef LTC_GCM_MODE
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/**
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Process an entire GCM packet in one call.
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@param cipher Index of cipher to use
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@param key The secret key
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@param keylen The length of the secret key
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@param IV The initialization vector
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@param IVlen The length of the initialization vector
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@param adata The additional authentication data (header)
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@param adatalen The length of the adata
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@param pt The plaintext
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@param ptlen The length of the plaintext (ciphertext length is the same)
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@param ct The ciphertext
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@param tag [out] The MAC tag
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@param taglen [in/out] The MAC tag length
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@param direction Encrypt or Decrypt mode (GCM_ENCRYPT or GCM_DECRYPT)
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@return CRYPT_OK on success
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*/
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int gcm_memory( int cipher,
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const unsigned char *key, unsigned long keylen,
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const unsigned char *IV, unsigned long IVlen,
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const unsigned char *adata, unsigned long adatalen,
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unsigned char *pt, unsigned long ptlen,
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unsigned char *ct,
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unsigned char *tag, unsigned long *taglen,
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int direction)
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{
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void *orig;
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gcm_state *gcm;
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int err;
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if ((err = cipher_is_valid(cipher)) != CRYPT_OK) {
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return err;
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}
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if (cipher_descriptor[cipher].accel_gcm_memory != NULL) {
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return cipher_descriptor[cipher].accel_gcm_memory
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(key, keylen,
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IV, IVlen,
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adata, adatalen,
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pt, ptlen,
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ct,
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tag, taglen,
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direction);
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}
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#ifndef LTC_GCM_TABLES_SSE2
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orig = gcm = XMALLOC(sizeof(*gcm));
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#else
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orig = gcm = XMALLOC(sizeof(*gcm) + 16);
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#endif
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if (gcm == NULL) {
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return CRYPT_MEM;
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}
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/* Force GCM to be on a multiple of 16 so we can use 128-bit aligned operations
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* note that we only modify gcm and keep orig intact. This code is not portable
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* but again it's only for SSE2 anyways, so who cares?
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*/
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#ifdef LTC_GCM_TABLES_SSE2
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gcm = LTC_ALIGN_BUF(gcm, 16);
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#endif
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if ((err = gcm_init(gcm, cipher, key, keylen)) != CRYPT_OK) {
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goto LTC_ERR;
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}
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if ((err = gcm_add_iv(gcm, IV, IVlen)) != CRYPT_OK) {
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goto LTC_ERR;
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}
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if ((err = gcm_add_aad(gcm, adata, adatalen)) != CRYPT_OK) {
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goto LTC_ERR;
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}
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if ((err = gcm_process(gcm, pt, ptlen, ct, direction)) != CRYPT_OK) {
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goto LTC_ERR;
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}
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if (direction == GCM_ENCRYPT) {
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if ((err = gcm_done(gcm, tag, taglen)) != CRYPT_OK) {
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goto LTC_ERR;
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}
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}
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else if (direction == GCM_DECRYPT) {
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unsigned char buf[MAXBLOCKSIZE];
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unsigned long buflen = sizeof(buf);
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if ((err = gcm_done(gcm, buf, &buflen)) != CRYPT_OK) {
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goto LTC_ERR;
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}
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if (buflen != *taglen || XMEM_NEQ(buf, tag, buflen) != 0) {
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err = CRYPT_ERROR;
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}
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}
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else {
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err = CRYPT_INVALID_ARG;
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}
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LTC_ERR:
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gcm_reset(gcm);
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XFREE(orig);
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return err;
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}
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#endif
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#pragma clang diagnostic pop
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