contrib/ntp/libntp/authreadkeys.c

   1 /*
   2  * authreadkeys.c - routines to support the reading of the key file
   3  */
   4 #include <stdio.h>
   5 #include <ctype.h>
   6
   7 #include "ntp_fp.h"
   8 #include "ntp.h"
   9 #include "ntp_syslog.h"
  10 #include "ntp_stdlib.h"
  11
  12 /*
  13  *  Arbitrary long string of ASCII characters.
  14  */
  15 #define KEY_TYPE_MD5    4
  16
  17 /* Forwards */
  18 static char *nexttok P((char **));
  19
  20 /*
  21  * nexttok - basic internal tokenizing routine
  22  */
  23 static char *
  24 nexttok(
  25         char **str
  26         )
  27 {
  28         register char *cp;
  29         char *starttok;
  30
  31         cp = *str;
  32
  33         /*
  34          * Space past white space
  35          */
  36         while (*cp == ' ' || *cp == '\t')
  37             cp++;
  38
  39         /*
  40          * Save this and space to end of token
  41          */
  42         starttok = cp;
  43         while (*cp != '\0' && *cp != '\n' && *cp != ' '
  44                && *cp != '\t' && *cp != '#')
  45             cp++;
  46
  47         /*
  48          * If token length is zero return an error, else set end of
  49          * token to zero and return start.
  50          */
  51         if (starttok == cp)
  52             return 0;
  53
  54         if (*cp == ' ' || *cp == '\t')
  55             *cp++ = '\0';
  56         else
  57             *cp = '\0';
  58
  59         *str = cp;
  60         return starttok;
  61 }
  62
  63
  64 /*
  65  * authreadkeys - (re)read keys from a file.
  66  */
  67 int
  68 authreadkeys(
  69         const char *file
  70         )
  71 {
  72         FILE *fp;
  73         char *line;
  74         char *token;
  75         u_long keyno;
  76         int keytype;
  77         char buf[512];          /* lots of room for line */
  78
  79         /*
  80          * Open file.  Complain and return if it can't be opened.
  81          */
  82         fp = fopen(file, "r");
  83         if (fp == NULL) {
  84                 msyslog(LOG_ERR, "can't open key file %s: %m", file);
  85                 return 0;
  86         }
  87
  88         /*
  89          * Remove all existing keys
  90          */
  91         auth_delkeys();
  92
  93         /*
  94          * Now read lines from the file, looking for key entries
  95          */
  96         while ((line = fgets(buf, sizeof buf, fp)) != NULL) {
  97                 token = nexttok(&line);
  98                 if (token == 0)
  99                     continue;
 100
 101                 /*
 102                  * First is key number.  See if it is okay.
 103                  */
 104                 keyno = atoi(token);
 105                 if (keyno == 0) {
 106                         msyslog(LOG_ERR,
 107                                 "cannot change keyid 0, key entry `%s' ignored",
 108                                 token);
 109                         continue;
 110                 }
 111
 112                 if (keyno > NTP_MAXKEY) {
 113                         msyslog(LOG_ERR,
 114                                 "keyid's > %d reserved for autokey, key entry `%s' ignored",
 115                                 NTP_MAXKEY, token);
 116                         continue;
 117                 }
 118
 119                 /*
 120                  * Next is keytype.  See if that is all right.
 121                  */
 122                 token = nexttok(&line);
 123                 if (token == 0) {
 124                         msyslog(LOG_ERR,
 125                                 "no key type for key number %ld, entry ignored",
 126                                 keyno);
 127                         continue;
 128                 }
 129                 switch (*token) {
 130                     case 'M':
 131                     case 'm':
 132                         keytype = KEY_TYPE_MD5; break;
 133                     default:
 134                         msyslog(LOG_ERR,
 135                                 "invalid key type for key number %ld, entry ignored",
 136                                 keyno);
 137                         continue;
 138                 }
 139
 140                 /*
 141                  * Finally, get key and insert it
 142                  */
 143                 token = nexttok(&line);
 144                 if (token == 0) {
 145                         msyslog(LOG_ERR,
 146                                 "no key for number %ld entry, entry ignored",
 147                                 keyno);
 148                 } else {
 149                         switch(keytype) {
 150                             case KEY_TYPE_MD5:
 151                                 if (!authusekey(keyno, keytype,
 152                                                 (u_char *)token))
 153                                     msyslog(LOG_ERR,
 154                                             "format/parity error for MD5 key %ld, not used",
 155                                             keyno);
 156                                 break;
 157                         }
 158                 }
 159         }
 160         (void) fclose(fp);
 161         return 1;
 162 }