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annotate libtomcrypt/src/encauth/chachapoly/chacha20poly1305_decrypt.c @ 1861:2b3a8026a6ce

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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 6dba84798cd5
children
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6dba84798cd5 Update to libtomcrypt 1.18.1, merged with Dropbear changes
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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 #include "tomcrypt.h"
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11
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12 #ifdef LTC_CHACHA20POLY1305_MODE
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13
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14 /**
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15 Decrypt bytes of ciphertext with ChaCha20Poly1305
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16 @param st The ChaCha20Poly1305 state
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17 @param in The ciphertext
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18 @param inlen The length of the input (octets)
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19 @param out [out] The plaintext (length inlen)
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20 @return CRYPT_OK if successful
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21 */
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22 int chacha20poly1305_decrypt(chacha20poly1305_state *st, const unsigned char *in, unsigned long inlen, unsigned char *out)
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23 {
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24 unsigned char padzero[16] = { 0 };
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25 unsigned long padlen;
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26 int err;
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27
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28 if (inlen == 0) return CRYPT_OK; /* nothing to do */
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29 LTC_ARGCHK(st != NULL);
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30
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31 if (st->aadflg) {
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32 padlen = 16 - (unsigned long)(st->aadlen % 16);
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33 if (padlen < 16) {
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34 if ((err = poly1305_process(&st->poly, padzero, padlen)) != CRYPT_OK) return err;
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35 }
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36 st->aadflg = 0; /* no more AAD */
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37 }
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38 if (st->aadflg) st->aadflg = 0; /* no more AAD */
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39 if ((err = poly1305_process(&st->poly, in, inlen)) != CRYPT_OK) return err;
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40 if ((err = chacha_crypt(&st->chacha, in, inlen, out)) != CRYPT_OK) return err;
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41 st->ctlen += (ulong64)inlen;
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42 return CRYPT_OK;
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43 }
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44
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45 #endif
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46
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47 /* ref: $Format:%D$ */
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48 /* git commit: $Format:%H$ */
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49 /* commit time: $Format:%ai$ */