annotate libtomcrypt/src/stream/chacha/chacha_ivctr64.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
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
1471
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1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
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2 *
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3 * LibTomCrypt is a library that provides various cryptographic
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4 * algorithms in a highly modular and flexible manner.
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5 *
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6 * The library is free for all purposes without any express
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7 * guarantee it works.
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8 */
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9
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10 /* The implementation is based on:
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11 * chacha-ref.c version 20080118
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12 * Public domain from D. J. Bernstein
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13 */
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14
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15 #include "tomcrypt.h"
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16
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17 #ifdef LTC_CHACHA
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18
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19 /**
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20 Set IV + counter data to the ChaCha state
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21 @param st The ChaCha20 state
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22 @param iv The IV data to add
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23 @param ivlen The length of the IV (must be 8)
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24 @param counter 64bit (unsigned) initial counter value
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25 @return CRYPT_OK on success
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26 */
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27 int chacha_ivctr64(chacha_state *st, const unsigned char *iv, unsigned long ivlen, ulong64 counter)
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28 {
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29 LTC_ARGCHK(st != NULL);
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30 LTC_ARGCHK(iv != NULL);
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31 /* 64bit IV + 64bit counter */
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32 LTC_ARGCHK(ivlen == 8);
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33
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34 st->input[12] = (ulong32)(counter & 0xFFFFFFFF);
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35 st->input[13] = (ulong32)(counter >> 32);
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36 LOAD32L(st->input[14], iv + 0);
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37 LOAD32L(st->input[15], iv + 4);
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38 st->ksleft = 0;
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39 st->ivlen = ivlen;
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40 return CRYPT_OK;
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41 }
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42
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43 #endif
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44
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45 /* ref: $Format:%D$ */
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46 /* git commit: $Format:%H$ */
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47 /* commit time: $Format:%ai$ */