view libtomcrypt/src/mac/blake2/blake2smac_memory.c @ 1715:3974f087d9c0

Disallow leading lines before the ident for server (#102) Per RFC4253 4.2 clients must be able to process other lines of data before the version string, server behavior is not defined neither with MUST/SHOULD nor with MAY. If server process up to 50 lines too - it may cause too long hanging session with invalid/evil client that consume host resources and potentially may lead to DDoS on poor embedded boxes. Let's require first line from client to be version string and fail early if it's not - matches both RFC and real OpenSSH behavior.
author Vladislav Grishenko <themiron@users.noreply.github.com>
date Mon, 15 Jun 2020 18:22:18 +0500
parents 6dba84798cd5
children
line wrap: on
line source

/* 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"

#ifdef LTC_BLAKE2SMAC

/**
   BLAKE2S MAC a block of memory to produce the authentication tag
   @param key       The secret key
   @param keylen    The length of the secret key (octets)
   @param in        The data to BLAKE2S MAC
   @param inlen     The length of the data to BLAKE2S MAC (octets)
   @param mac       [out] Destination of the authentication tag
   @param maclen    [in/out] Max size and resulting size of authentication tag
   @return CRYPT_OK if successful
*/
int blake2smac_memory(const unsigned char *key, unsigned long keylen, const unsigned char *in, unsigned long inlen, unsigned char *mac, unsigned long *maclen)
{
   blake2smac_state st;
   int err;

   LTC_ARGCHK(key    != NULL);
   LTC_ARGCHK(in     != NULL);
   LTC_ARGCHK(mac    != NULL);
   LTC_ARGCHK(maclen != NULL);

   if ((err = blake2smac_init(&st, *maclen, key, keylen))  != CRYPT_OK) { goto LBL_ERR; }
   if ((err = blake2smac_process(&st, in, inlen)) != CRYPT_OK) { goto LBL_ERR; }
   err = blake2smac_done(&st, mac, maclen);
LBL_ERR:
#ifdef LTC_CLEAN_STACK
   zeromem(&st, sizeof(blake2smac_state));
#endif
   return err;
}

#endif

/* ref:         $Format:%D$ */
/* git commit:  $Format:%H$ */
/* commit time: $Format:%ai$ */