dist/ntp/libntp/a_md5encrypt.c

   1 /*      $NetBSD: a_md5encrypt.c,v 1.2 2003/12/04 16:23:36 drochner Exp $        */
   2
   3 /*
   4  *      MD5 interface for rsaref2.0
   5  *
   6  * These routines implement an interface for the RSA Laboratories
   7  * implementation of the Message Digest 5 (MD5) algorithm. This
   8  * algorithm is included in the rsaref2.0 package available from RSA in
   9  * the US and foreign countries. Further information is available at
  10  * www.rsa.com.
  11  */
  12
  13 #ifdef HAVE_CONFIG_H
  14 #include <config.h>
  15 #endif
  16
  17 #include "ntp_fp.h"
  18 #include "ntp_string.h"
  19 #include "ntp_stdlib.h"
  20
  21 /* Disable the openssl md5 includes, because they'd clash with ours. */
  22 /* #define NO_MD5 */
  23 /* #define OPENSSL_NO_MD5 */
  24 #undef OPENSSL
  25
  26 #include "ntp.h"
  27 #include "global.h"
  28 #include "ntp_md5.h"
  29
  30 /*
  31  * MD5authencrypt - generate MD5 message authenticator
  32  *
  33  * Returns length of authenticator field.
  34  */
  35 int
  36 MD5authencrypt(
  37         u_char *key,            /* key pointer */
  38         u_int32 *pkt,           /* packet pointer */
  39         int length              /* packet length */
  40         )
  41 {
  42         MD5_CTX md5;
  43         u_char digest[16];
  44
  45         /*
  46          * MD5 with key identifier concatenated with packet.
  47          */
  48         MD5Init(&md5);
  49         MD5Update(&md5, key, (u_int)cache_keylen);
  50         MD5Update(&md5, (u_char *)pkt, (u_int)length);
  51         MD5Final(digest, &md5);
  52         memmove((u_char *)pkt + length + 4, digest, 16);
  53         return (16 + 4);
  54 }
  55
  56
  57 /*
  58  * MD5authdecrypt - verify MD5 message authenticator
  59  *
  60  * Returns one if authenticator valid, zero if invalid.
  61  */
  62 int
  63 MD5authdecrypt(
  64         u_char *key,            /* key pointer */
  65         u_int32 *pkt,           /* packet pointer */
  66         int length,             /* packet length */
  67         int size                /* MAC size */
  68         )
  69 {
  70         MD5_CTX md5;
  71         u_char digest[16];
  72
  73         /*
  74          * MD5 with key identifier concatenated with packet.
  75          */
  76         MD5Init(&md5);
  77         MD5Update(&md5, key, (u_int)cache_keylen);
  78         MD5Update(&md5, (u_char *)pkt, (u_int)length);
  79         MD5Final(digest, &md5);
  80         if (size != 16 + 4)
  81                 return (0);
  82         return (!memcmp(digest, (char *)pkt + length + 4, 16));
  83 }
  84
  85 /*
  86  * Calculate the reference id from the address. If it is an IPv4
  87  * address, use it as is. If it is an IPv6 address, do a md5 on
  88  * it and use the bottom 4 bytes.
  89  */
  90 u_int32
  91 addr2refid(struct sockaddr_storage *addr)
  92 {
  93         MD5_CTX md5;
  94         u_char digest[16];
  95         u_int32 addr_refid;
  96
  97         if (addr->ss_family == AF_INET)
  98                 return (GET_INADDR(*addr));
  99
 100         MD5Init(&md5);
 101         MD5Update(&md5, (u_char *)&GET_INADDR6(*addr),
 102             sizeof(struct in6_addr));
 103         MD5Final(digest, &md5);
 104         memcpy(&addr_refid, digest, 4);
 105         return (addr_refid);
 106 }