view libtomcrypt/src/mac/poly1305/poly1305_memory_multi.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.
 */

/* The implementation is based on:
 * Public Domain poly1305 from Andrew Moon
 * https://github.com/floodyberry/poly1305-donna
 */

#include "tomcrypt.h"
#include <stdarg.h>

#ifdef LTC_POLY1305

/**
   POLY1305 multiple blocks of memory to produce the authentication tag
   @param key       The secret key
   @param keylen    The length of the secret key (octets)
   @param mac       [out] Destination of the authentication tag
   @param maclen    [in/out] Max size and resulting size of authentication tag
   @param in        The data to POLY1305
   @param inlen     The length of the data to POLY1305 (octets)
   @param ...       tuples of (data,len) pairs to POLY1305, terminated with a (NULL,x) (x=don't care)
   @return CRYPT_OK if successful
*/
int poly1305_memory_multi(const unsigned char *key, unsigned long keylen, unsigned char *mac, unsigned long *maclen, const unsigned char *in,  unsigned long inlen, ...)
{
   poly1305_state st;
   int err;
   va_list args;
   const unsigned char *curptr;
   unsigned long curlen;

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

   va_start(args, inlen);
   curptr = in;
   curlen = inlen;
   if ((err = poly1305_init(&st, key, keylen)) != CRYPT_OK)          { goto LBL_ERR; }
   for (;;) {
      if ((err = poly1305_process(&st, curptr, curlen)) != CRYPT_OK) { goto LBL_ERR; }
      curptr = va_arg(args, const unsigned char*);
      if (curptr == NULL) break;
      curlen = va_arg(args, unsigned long);
   }
   err = poly1305_done(&st, mac, maclen);
LBL_ERR:
#ifdef LTC_CLEAN_STACK
   zeromem(&st, sizeof(poly1305_state));
#endif
   va_end(args);
   return err;
}

#endif

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