view libtomcrypt/demos/constants.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 e9dba7abd939
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"

#if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L
#include <libgen.h>
#else
#define basename(x) x
#endif

/**
  @file demo_crypt_constants.c

  Demo how to get various constants to dynamic languages
  like Python

  Larry Bugbee, February 2013
*/

static void _print_line(const char* cmd, const char* desc)
{
   printf("  %-16s - %s\n", cmd, desc);
}

int main(int argc, char **argv)
{
   if (argc == 1) {
      /* given a specific constant name, get and print its value */
      char name[] = "CTR_COUNTER_BIG_ENDIAN";
      int value;
      char *names_list;
      unsigned int names_list_len;

      if (crypt_get_constant(name, &value) != 0) exit(EXIT_FAILURE);
      printf("\n  %s is %d \n\n", name, value);

      /* get and print the length of the names (and values) list */

      if (crypt_list_all_constants(NULL, &names_list_len) != 0) exit(EXIT_FAILURE);
      printf("  need to allocate %u bytes \n\n", names_list_len);

      /* get and print the names (and values) list */
      if ((names_list = malloc(names_list_len)) == NULL) exit(EXIT_FAILURE);
      if (crypt_list_all_constants(names_list, &names_list_len) != 0) exit(EXIT_FAILURE);
      printf("  supported constants:\n\n%s\n\n", names_list);
      free(names_list);
   } else if (argc == 2) {
      if (strcmp(argv[1], "-h") == 0 || strcmp(argv[1], "--help") == 0) {
         char* base = strdup(basename(argv[0]));
         printf("Usage: %s [-a] [-s name]\n\n", base);
         _print_line("<no argument>", "The old behavior of the demo");
         _print_line("-a", "Only lists all constants");
         _print_line("-s name", "List a single constant given as argument");
         _print_line("-h", "The help you're looking at");
         free(base);
      } else if (strcmp(argv[1], "-a") == 0) {
         char *names_list;
         unsigned int names_list_len;
         /* get and print the length of the names (and values) list */
         if (crypt_list_all_constants(NULL, &names_list_len) != 0) exit(EXIT_FAILURE);
         /* get and print the names (and values) list */
         if ((names_list = malloc(names_list_len)) == NULL) exit(EXIT_FAILURE);
         if (crypt_list_all_constants(names_list, &names_list_len) != 0) exit(EXIT_FAILURE);
         printf("%s\n", names_list);
         free(names_list);
      }
   } else if (argc == 3) {
      if (strcmp(argv[1], "-s") == 0) {
         int value;
         if (crypt_get_constant(argv[2], &value) != 0) exit(EXIT_FAILURE);
         printf("%s,%u\n", argv[2], value);
      }
   }

   return 0;
}


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