4a219ecbf1
An analysis by Tim Ruffing [1] shows that a length extension attack adding valid extension fields to NTPv4 packets is possible with some specific key lengths and hash functions using little-endian length like MD5 and RIPEMD160. chronyd currently doesn't process or generate any extension fields, but it could be a problem in future when a non-authentication extension field is supported. Drop support for all RIPEMD functions as they don't seem to be secure in the context of the NTPv4 MAC. MD5 is kept only for compatibility. [1] https://mailarchive.ietf.org/arch/msg/ntp/gvibuB6bTbDRBumfHNdJ84Kq4kA
119 lines
2.9 KiB
C
119 lines
2.9 KiB
C
/*
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chronyd/chronyc - Programs for keeping computer clocks accurate.
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**********************************************************************
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* Copyright (C) Miroslav Lichvar 2018
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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**********************************************************************
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=======================================================================
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Routines implementing crypto hashing using the nettle library.
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*/
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#include "config.h"
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#include "sysincl.h"
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#include <nettle/nettle-meta.h>
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#include "hash.h"
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#include "memory.h"
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struct hash {
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const char *name;
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const char *int_name;
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const struct nettle_hash *nettle_hash;
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void *context;
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};
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static struct hash hashes[] = {
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{ "MD5", "md5", NULL, NULL },
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{ "SHA1", "sha1", NULL, NULL },
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{ "SHA256", "sha256", NULL, NULL },
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{ "SHA384", "sha384", NULL, NULL },
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{ "SHA512", "sha512", NULL, NULL },
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{ "SHA3-224", "sha3_224", NULL, NULL },
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{ "SHA3-256", "sha3_256", NULL, NULL },
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{ "SHA3-384", "sha3_384", NULL, NULL },
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{ "SHA3-512", "sha3_512", NULL, NULL },
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{ NULL, NULL, NULL, NULL }
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};
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int
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HSH_GetHashId(const char *name)
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{
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int id, nid;
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for (id = 0; hashes[id].name; id++) {
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if (!strcmp(name, hashes[id].name))
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break;
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}
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if (!hashes[id].name)
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return -1;
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if (hashes[id].context)
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return id;
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for (nid = 0; nettle_hashes[nid]; nid++) {
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if (!strcmp(hashes[id].int_name, nettle_hashes[nid]->name))
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break;
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}
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if (!nettle_hashes[nid] || !nettle_hashes[nid]->context_size || !nettle_hashes[nid]->init)
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return -1;
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hashes[id].nettle_hash = nettle_hashes[nid];
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hashes[id].context = Malloc(hashes[id].nettle_hash->context_size);
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return id;
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}
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unsigned int
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HSH_Hash(int id, const unsigned char *in1, unsigned int in1_len,
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const unsigned char *in2, unsigned int in2_len,
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unsigned char *out, unsigned int out_len)
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{
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const struct nettle_hash *hash;
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void *context;
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hash = hashes[id].nettle_hash;
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context = hashes[id].context;
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if (out_len > hash->digest_size)
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out_len = hash->digest_size;
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hash->init(context);
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hash->update(context, in1_len, in1);
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if (in2)
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hash->update(context, in2_len, in2);
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hash->digest(context, out_len, out);
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return out_len;
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}
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void
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HSH_Finalise(void)
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{
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int i;
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for (i = 0; hashes[i].name; i++) {
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if (hashes[i].context)
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Free(hashes[i].context);
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}
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}
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