contrib/bind-9.2.4rc7/lib/isc/hmacmd5.c

   1 /*
   2  * Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2000, 2001  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id: hmacmd5.c,v 1.5.2.1 2004/03/09 06:11:46 marka Exp $ */
  19
  20 /*
  21  * This code implements the HMAC-MD5 keyed hash algorithm
  22  * described in RFC 2104.
  23  */
  24
  25 #include "config.h"
  26
  27 #include <isc/assertions.h>
  28 #include <isc/hmacmd5.h>
  29 #include <isc/md5.h>
  30 #include <isc/string.h>
  31 #include <isc/types.h>
  32 #include <isc/util.h>
  33
  34 #define PADLEN 64
  35 #define IPAD 0x36
  36 #define OPAD 0x5C
  37
  38 /*
  39  * Start HMAC-MD5 process.  Initialize an md5 context and digest the key.
  40  */
  41 void
  42 isc_hmacmd5_init(isc_hmacmd5_t *ctx, const unsigned char *key,
  43                  unsigned int len)
  44 {
  45         unsigned char ipad[PADLEN];
  46         int i;
  47
  48         memset(ctx->key, 0, sizeof (ctx->key));
  49         if (len > sizeof(ctx->key)) {
  50                 isc_md5_t md5ctx;
  51                 isc_md5_init(&md5ctx);
  52                 isc_md5_update(&md5ctx, key, len);
  53                 isc_md5_final(&md5ctx, ctx->key);
  54         } else
  55                 memcpy(ctx->key, key, len);
  56
  57         isc_md5_init(&ctx->md5ctx);
  58         memset(ipad, IPAD, sizeof (ipad));
  59         for (i = 0; i < PADLEN; i++)
  60                 ipad[i] ^= ctx->key[i];
  61         isc_md5_update(&ctx->md5ctx, ipad, sizeof(ipad));
  62 }
  63
  64 void
  65 isc_hmacmd5_invalidate(isc_hmacmd5_t *ctx) {
  66         isc_md5_invalidate(&ctx->md5ctx);
  67         memset(ctx->key, 0, sizeof (ctx->key));
  68         memset(ctx, 0, sizeof (ctx));
  69 }
  70
  71 /*
  72  * Update context to reflect the concatenation of another buffer full
  73  * of bytes.
  74  */
  75 void
  76 isc_hmacmd5_update(isc_hmacmd5_t *ctx, const unsigned char *buf,
  77                    unsigned int len)
  78 {
  79         isc_md5_update(&ctx->md5ctx, buf, len);
  80 }
  81
  82 /*
  83  * Compute signature - finalize MD5 operation and reapply MD5.
  84  */
  85 void
  86 isc_hmacmd5_sign(isc_hmacmd5_t *ctx, unsigned char *digest) {
  87         unsigned char opad[PADLEN];
  88         int i;
  89
  90         isc_md5_final(&ctx->md5ctx, digest);
  91
  92         memset(opad, OPAD, sizeof (opad));
  93         for (i = 0; i < PADLEN; i++)
  94                 opad[i] ^= ctx->key[i];
  95
  96         isc_md5_init(&ctx->md5ctx);
  97         isc_md5_update(&ctx->md5ctx, opad, sizeof(opad));
  98         isc_md5_update(&ctx->md5ctx, digest, ISC_MD5_DIGESTLENGTH);
  99         isc_md5_final(&ctx->md5ctx, digest);
 100         isc_hmacmd5_invalidate(ctx);
 101 }
 102
 103 /*
 104  * Verify signature - finalize MD5 operation and reapply MD5, then
 105  * compare to the supplied digest.
 106  */
 107 isc_boolean_t
 108 isc_hmacmd5_verify(isc_hmacmd5_t *ctx, unsigned char *digest) {
 109         unsigned char newdigest[ISC_MD5_DIGESTLENGTH];
 110
 111         isc_hmacmd5_sign(ctx, newdigest);
 112         return (ISC_TF(memcmp(digest, newdigest, ISC_MD5_DIGESTLENGTH) == 0));
 113 }