view libtomcrypt/src/mac/blake2/blake2smac.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
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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"

#ifdef LTC_BLAKE2SMAC

/**
   Initialize an BLAKE2S MAC context.
   @param st       The BLAKE2S MAC state
   @param outlen   The size of the MAC output (octets)
   @param key      The secret key
   @param keylen   The length of the secret key (octets)
   @return CRYPT_OK if successful
*/
int blake2smac_init(blake2smac_state *st, unsigned long outlen, const unsigned char *key, unsigned long keylen)
{
   LTC_ARGCHK(st  != NULL);
   LTC_ARGCHK(key != NULL);
   return blake2s_init(st, outlen, key, keylen);
}

/**
  Process data through BLAKE2S MAC
  @param st      The BLAKE2S MAC state
  @param in      The data to send through HMAC
  @param inlen   The length of the data to HMAC (octets)
  @return CRYPT_OK if successful
*/
int blake2smac_process(blake2smac_state *st, const unsigned char *in, unsigned long inlen)
{
   if (inlen == 0) return CRYPT_OK; /* nothing to do */
   LTC_ARGCHK(st != NULL);
   LTC_ARGCHK(in != NULL);
   return blake2s_process(st, in, inlen);
}

/**
   Terminate a BLAKE2S MAC session
   @param st      The BLAKE2S MAC state
   @param mac     [out] The destination of the BLAKE2S MAC authentication tag
   @param maclen  [in/out]  The max size and resulting size of the BLAKE2S MAC authentication tag
   @return CRYPT_OK if successful
*/
int blake2smac_done(blake2smac_state *st, unsigned char *mac, unsigned long *maclen)
{
   LTC_ARGCHK(st     != NULL);
   LTC_ARGCHK(mac    != NULL);
   LTC_ARGCHK(maclen != NULL);
   LTC_ARGCHK(*maclen >= st->blake2s.outlen);

   *maclen = st->blake2s.outlen;
   return blake2s_done(st, mac);
}

#endif

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