NetBSD/lib/libntp/a_md5encrypt.c

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/* $NetBSD: a_md5encrypt.c,v 1.6 1999/07/03 12:30:28 simonb Exp $ */
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/*
* md5crypt - MD5 based authentication routines
*/
#include "ntp_types.h"
#include "ntp_string.h"
#include "md5.h"
#include "ntp_stdlib.h"
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extern u_int32 cache_keyid;
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extern char *cache_key;
extern int cache_keylen;
#ifndef HAVE_MEMMOVE
extern void *memmove P((void *, const void *, size_t));
#endif
/*
* Stat counters, imported from data base module
*/
extern u_int32 authencryptions;
extern u_int32 authdecryptions;
extern u_int32 authkeyuncached;
extern u_int32 authnokey;
/*
* For our purposes an NTP packet looks like:
*
* a variable amount of encrypted data, multiple of 8 bytes, followed by:
* NOCRYPT_OCTETS worth of unencrypted data, followed by:
* BLOCK_OCTETS worth of ciphered checksum.
*/
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#define NOCRYPT_OCTETS 4
#define BLOCK_OCTETS 16
#define NOCRYPT_int32S ((NOCRYPT_OCTETS)/sizeof(u_int32))
#define BLOCK_int32S ((BLOCK_OCTETS)/sizeof(u_int32))
int
MD5authencrypt(keyno, pkt, length)
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u_int32 keyno;
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u_int32 *pkt;
int length; /* length of encrypted portion of packet */
{
MD5_CTX ctx;
int len; /* in 4 byte quantities */
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#ifdef __NetBSD__
unsigned char hash[16];
#endif
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authencryptions++;
if (keyno != cache_keyid) {
authkeyuncached++;
if (!authhavekey(keyno)) {
authnokey++;
return 0;
}
}
len = length / sizeof(u_int32);
/*
* Generate the authenticator.
*/
MD5Init(&ctx);
MD5Update(&ctx, (unsigned const char *)cache_key, cache_keylen);
MD5Update(&ctx, (unsigned const char *)pkt, length);
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#ifdef __NetBSD__
MD5Final(hash, &ctx);
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#else
MD5Final(&ctx);
#endif
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memmove((char *)&pkt[NOCRYPT_int32S + len],
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#ifdef __NetBSD__
(char *) hash,
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#else
(char *) ctx.digest,
#endif
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BLOCK_OCTETS);
return (4 + BLOCK_OCTETS); /* return size of key and MAC */
}