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 krb5_error_code
  31 k5_size_checksum(krb5_checksum *checksum, size_t *sizep)
  32 {
  33     krb5_error_code     kret;
  34
  35     /*
  36      * krb5_checksum requires:
  37      *  krb5_int32              for KV5M_CHECKSUM
  38      *  krb5_int32              for checksum_type
  39      *  krb5_int32              for length
  40      *  krb5_int32              for KV5M_CHECKSUM
  41      *  checksum->length        for contents
  42      */
  43     kret = EINVAL;
  44     if (checksum != NULL) {
  45         *sizep += (sizeof(krb5_int32) +
  46                    sizeof(krb5_int32) +
  47                    sizeof(krb5_int32) +
  48                    sizeof(krb5_int32) +
  49                    (size_t) checksum->length);
  50         kret = 0;
  51     }
  52     return(kret);
  53 }
  54
  55 krb5_error_code
  56 k5_externalize_checksum(krb5_checksum *checksum,
  57                         krb5_octet **buffer, size_t *lenremain)
  58 {
  59     krb5_error_code     kret;
  60     size_t              required;
  61     krb5_octet          *bp;
  62     size_t              remain;
  63
  64     required = 0;
  65     bp = *buffer;
  66     remain = *lenremain;
  67     kret = EINVAL;
  68     if (checksum != NULL) {
  69         kret = ENOMEM;
  70         if (!k5_size_checksum(checksum, &required) && required <= remain) {
  71             /* Our identifier */
  72             (void) krb5_ser_pack_int32(KV5M_CHECKSUM, &bp, &remain);
  73
  74             /* Our checksum_type */
  75             (void) krb5_ser_pack_int32((krb5_int32) checksum->checksum_type,
  76                                        &bp, &remain);
  77
  78             /* Our length */
  79             (void) krb5_ser_pack_int32((krb5_int32) checksum->length,
  80                                        &bp, &remain);
  81
  82             /* Our contents */
  83             (void) krb5_ser_pack_bytes(checksum->contents,
  84                                        (size_t) checksum->length,
  85                                        &bp, &remain);
  86
  87             /* Finally, our trailer */
  88             (void) krb5_ser_pack_int32(KV5M_CHECKSUM, &bp, &remain);
  89
  90             kret = 0;
  91             *buffer = bp;
  92             *lenremain = remain;
  93         }
  94     }
  95     return(kret);
  96 }
  97
  98 krb5_error_code
  99 k5_internalize_checksum(krb5_checksum **argp,
 100                         krb5_octet **buffer, size_t *lenremain)
 101 {
 102     krb5_error_code     kret;
 103     krb5_checksum       *checksum;
 104     krb5_int32          ibuf;
 105     krb5_octet          *bp;
 106     size_t              remain;
 107
 108     bp = *buffer;
 109     remain = *lenremain;
 110     kret = EINVAL;
 111     /* Read our magic number */
 112     if (krb5_ser_unpack_int32(&ibuf, &bp, &remain))
 113         ibuf = 0;
 114     if (ibuf == KV5M_CHECKSUM) {
 115         kret = ENOMEM;
 116
 117         /* Get a checksum */
 118         if ((remain >= (2*sizeof(krb5_int32))) &&
 119             (checksum = (krb5_checksum *) calloc(1, sizeof(krb5_checksum)))) {
 120             /* Get the checksum_type */
 121             (void) krb5_ser_unpack_int32(&ibuf, &bp, &remain);
 122             checksum->checksum_type = (krb5_cksumtype) ibuf;
 123
 124             /* Get the length */
 125             (void) krb5_ser_unpack_int32(&ibuf, &bp, &remain);
 126             checksum->length = (int) ibuf;
 127
 128             /* Get the string */
 129             if (!ibuf ||
 130                 ((checksum->contents = (krb5_octet *)
 131                   malloc((size_t) (ibuf))) &&
 132                  !(kret = krb5_ser_unpack_bytes(checksum->contents,
 133                                                 (size_t) ibuf,
 134                                                 &bp, &remain)))) {
 135
 136                 /* Get the trailer */
 137                 kret = krb5_ser_unpack_int32(&ibuf, &bp, &remain);
 138                 if (!kret && (ibuf == KV5M_CHECKSUM)) {
 139                     checksum->magic = KV5M_CHECKSUM;
 140                     *buffer = bp;
 141                     *lenremain = remain;
 142                     *argp = checksum;
 143                 }
 144                 else
 145                     kret = EINVAL;
 146             }
 147             if (kret) {
 148                 if (checksum->contents)
 149                     free(checksum->contents);
 150                 free(checksum);
 151             }
 152         }
 153     }
 154     return(kret);
 155 }