view libtomcrypt/src/mac/pmac/pmac_done.c @ 1861:2b3a8026a6ce

Add re-exec for server This allows ASLR to re-randomize the address space for every connection, preventing some vulnerabilities from being exploitable by repeated probing. Overhead (memory and time) is yet to be confirmed. At present this is only enabled on Linux. Other BSD platforms with fexecve() would probably also work though have not been tested.
author Matt Johnston <matt@ucc.asn.au>
date Sun, 30 Jan 2022 10:14:56 +0800
parents 6dba84798cd5
children
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/* 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.
 */
#include "tomcrypt.h"

/**
  @file pmac_done.c
  PMAC implementation, terminate a session, by Tom St Denis
*/

#ifdef LTC_PMAC

int pmac_done(pmac_state *state, unsigned char *out, unsigned long *outlen)
{
   int err, x;

   LTC_ARGCHK(state != NULL);
   LTC_ARGCHK(out   != NULL);
   if ((err = cipher_is_valid(state->cipher_idx)) != CRYPT_OK) {
      return err;
   }

   if ((state->buflen > (int)sizeof(state->block)) || (state->buflen < 0) ||
       (state->block_len > (int)sizeof(state->block)) || (state->buflen > state->block_len)) {
      return CRYPT_INVALID_ARG;
   }


   /* handle padding.  If multiple xor in L/x */

   if (state->buflen == state->block_len) {
      /* xor Lr against the checksum */
      for (x = 0; x < state->block_len; x++) {
          state->checksum[x] ^= state->block[x] ^ state->Lr[x];
      }
   } else {
      /* otherwise xor message bytes then the 0x80 byte */
      for (x = 0; x < state->buflen; x++) {
          state->checksum[x] ^= state->block[x];
      }
      state->checksum[x] ^= 0x80;
   }

   /* encrypt it */
   if ((err = cipher_descriptor[state->cipher_idx].ecb_encrypt(state->checksum, state->checksum, &state->key)) != CRYPT_OK) {
      return err;
   }
   cipher_descriptor[state->cipher_idx].done(&state->key);

   /* store it */
   for (x = 0; x < state->block_len && x < (int)*outlen; x++) {
       out[x] = state->checksum[x];
   }
   *outlen = x;

#ifdef LTC_CLEAN_STACK
   zeromem(state, sizeof(*state));
#endif
   return CRYPT_OK;
}

#endif


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