src/lib/krb5/krb/ser_cksum.c

   1 /* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
   2 /* lib/krb5/krb/ser_cksum.c - Serialize krb5_checksum structure */
   3 /*
   4  * Copyright 1995, 2008 by the Massachusetts Institute of Technology.
   5  * All Rights Reserved.
   6  *
   7  * Export of this software from the United States of America may
   8  *   require a specific license from the United States Government.
   9  *   It is the responsibility of any person or organization contemplating
  10  *   export to obtain such a license before exporting.
  11  *
  12  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
  13  * distribute this software and its documentation for any purpose and
  14  * without fee is hereby granted, provided that the above copyright
  15  * notice appear in all copies and that both that copyright notice and
  16  * this permission notice appear in supporting documentation, and that
  17  * the name of M.I.T. not be used in advertising or publicity pertaining
  18  * to distribution of the software without specific, written prior
  19  * permission.  Furthermore if you modify this software you must label
  20  * your software as modified software and not distribute it in such a
  21  * fashion that it might be confused with the original M.I.T. software.
  22  * M.I.T. makes no representations about the suitability of
  23  * this software for any purpose.  It is provided "as is" without express
  24  * or implied warranty.
  25  */
  26
  27 #include "k5-int.h"
  28 #include "int-proto.h"
  29
  30 /*
  31  * Routines to deal with externalizing the krb5_checksum:
  32  *      krb5_checksum_esize();
  33  *      krb5_checksum_externalize();
  34  *      krb5_checksum_internalize();
  35  */
  36 static krb5_error_code krb5_checksum_esize
  37 (krb5_context, krb5_pointer, size_t *);
  38 static krb5_error_code krb5_checksum_externalize
  39 (krb5_context, krb5_pointer, krb5_octet **, size_t *);
  40 static krb5_error_code krb5_checksum_internalize
  41 (krb5_context,krb5_pointer *, krb5_octet **, size_t *);
  42
  43 /* Local data */
  44 static const krb5_ser_entry krb5_checksum_ser_entry = {
  45     KV5M_CHECKSUM,                      /* Type                 */
  46     krb5_checksum_esize,                /* Sizer routine        */
  47     krb5_checksum_externalize,          /* Externalize routine  */
  48     krb5_checksum_internalize           /* Internalize routine  */
  49 };
  50
  51 /*
  52  * krb5_checksum_esize()        - Determine the size required to externalize
  53  *                                the krb5_checksum.
  54  */
  55 static krb5_error_code
  56 krb5_checksum_esize(krb5_context kcontext, krb5_pointer arg, size_t *sizep)
  57 {
  58     krb5_error_code     kret;
  59     krb5_checksum       *checksum;
  60
  61     /*
  62      * krb5_checksum requires:
  63      *  krb5_int32              for KV5M_CHECKSUM
  64      *  krb5_int32              for checksum_type
  65      *  krb5_int32              for length
  66      *  krb5_int32              for KV5M_CHECKSUM
  67      *  checksum->length        for contents
  68      */
  69     kret = EINVAL;
  70     if ((checksum = (krb5_checksum *) arg)) {
  71         *sizep += (sizeof(krb5_int32) +
  72                    sizeof(krb5_int32) +
  73                    sizeof(krb5_int32) +
  74                    sizeof(krb5_int32) +
  75                    (size_t) checksum->length);
  76         kret = 0;
  77     }
  78     return(kret);
  79 }
  80
  81 /*
  82  * krb5_checksum_externalize()  - Externalize the krb5_checksum.
  83  */
  84 static krb5_error_code
  85 krb5_checksum_externalize(krb5_context kcontext, krb5_pointer arg, krb5_octet **buffer, size_t *lenremain)
  86 {
  87     krb5_error_code     kret;
  88     krb5_checksum       *checksum;
  89     size_t              required;
  90     krb5_octet          *bp;
  91     size_t              remain;
  92
  93     required = 0;
  94     bp = *buffer;
  95     remain = *lenremain;
  96     kret = EINVAL;
  97     if ((checksum = (krb5_checksum *) arg)) {
  98         kret = ENOMEM;
  99         if (!krb5_checksum_esize(kcontext, arg, &required) &&
 100             (required <= remain)) {
 101             /* Our identifier */
 102             (void) krb5_ser_pack_int32(KV5M_CHECKSUM, &bp, &remain);
 103
 104             /* Our checksum_type */
 105             (void) krb5_ser_pack_int32((krb5_int32) checksum->checksum_type,
 106                                        &bp, &remain);
 107
 108             /* Our length */
 109             (void) krb5_ser_pack_int32((krb5_int32) checksum->length,
 110                                        &bp, &remain);
 111
 112             /* Our contents */
 113             (void) krb5_ser_pack_bytes(checksum->contents,
 114                                        (size_t) checksum->length,
 115                                        &bp, &remain);
 116
 117             /* Finally, our trailer */
 118             (void) krb5_ser_pack_int32(KV5M_CHECKSUM, &bp, &remain);
 119
 120             kret = 0;
 121             *buffer = bp;
 122             *lenremain = remain;
 123         }
 124     }
 125     return(kret);
 126 }
 127
 128 /*
 129  * krb5_checksum_internalize()  - Internalize the krb5_checksum.
 130  */
 131 static krb5_error_code
 132 krb5_checksum_internalize(krb5_context kcontext, krb5_pointer *argp, krb5_octet **buffer, size_t *lenremain)
 133 {
 134     krb5_error_code     kret;
 135     krb5_checksum       *checksum;
 136     krb5_int32          ibuf;
 137     krb5_octet          *bp;
 138     size_t              remain;
 139
 140     bp = *buffer;
 141     remain = *lenremain;
 142     kret = EINVAL;
 143     /* Read our magic number */
 144     if (krb5_ser_unpack_int32(&ibuf, &bp, &remain))
 145         ibuf = 0;
 146     if (ibuf == KV5M_CHECKSUM) {
 147         kret = ENOMEM;
 148
 149         /* Get a checksum */
 150         if ((remain >= (2*sizeof(krb5_int32))) &&
 151             (checksum = (krb5_checksum *) calloc(1, sizeof(krb5_checksum)))) {
 152             /* Get the checksum_type */
 153             (void) krb5_ser_unpack_int32(&ibuf, &bp, &remain);
 154             checksum->checksum_type = (krb5_cksumtype) ibuf;
 155
 156             /* Get the length */
 157             (void) krb5_ser_unpack_int32(&ibuf, &bp, &remain);
 158             checksum->length = (int) ibuf;
 159
 160             /* Get the string */
 161             if (!ibuf ||
 162                 ((checksum->contents = (krb5_octet *)
 163                   malloc((size_t) (ibuf))) &&
 164                  !(kret = krb5_ser_unpack_bytes(checksum->contents,
 165                                                 (size_t) ibuf,
 166                                                 &bp, &remain)))) {
 167
 168                 /* Get the trailer */
 169                 kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain);
 170                 if (!kret && (ibuf == KV5M_CHECKSUM)) {
 171                     checksum->magic = KV5M_CHECKSUM;
 172                     *buffer = bp;
 173                     *lenremain = remain;
 174                     *argp = (krb5_pointer) checksum;
 175                 }
 176                 else
 177                     kret = EINVAL;
 178             }
 179             if (kret) {
 180                 if (checksum->contents)
 181                     free(checksum->contents);
 182                 free(checksum);
 183             }
 184         }
 185     }
 186     return(kret);
 187 }
 188
 189 /*
 190  * Register the checksum serializer.
 191  */
 192 krb5_error_code
 193 krb5_ser_checksum_init(krb5_context kcontext)
 194 {
 195     return(krb5_register_serializer(kcontext, &krb5_checksum_ser_entry));
 196 }