rxkad/lifetime.c

   1 /*
   2  * Ticket lifetime.  This defines the table used to lookup lifetime
   3  * for the fixed part of rande of the one byte lifetime field.  Values
   4  * less than 0x80 are intrpreted as the number of 5 minute intervals.
   5  * Values from 0x80 to 0xBF should be looked up in this table.  The
   6  * value of 0x80 is the same using both methods: 10 and two-thirds
   7  * hours .  The lifetime of 0xBF is 30 days.  The intervening values
   8  * of have a fixed ratio of roughly 1.06914.  The value 0xFF is
   9  * defined to mean a ticket has no expiration time.  This should be
  10  * used advisedly since individual servers may impose defacto
  11  * upperbounds on ticket lifetimes.
  12  */
  13
  14 #include "rxkad_locl.h"
  15
  16 #ifndef HAVE_KRB4
  17
  18 #include "krb4.h"
  19
  20 RCSID("$Id$");
  21
  22 /* If you want to disable this feature */
  23 int krb4_no_long_lifetimes = 0;
  24
  25 #define TKTLIFENUMFIXED 64
  26 #define TKTLIFEMINFIXED 0x80
  27 #define TKTLIFEMAXFIXED 0xBF
  28 #define TKTLIFENOEXPIRE 0xFF
  29 #define MAXTKTLIFETIME  (30*24*3600)    /* 30 days */
  30 #ifndef NEVERDATE
  31 #define NEVERDATE ((unsigned long)0x7fffffffL)
  32 #endif
  33
  34 static const int tkt_lifetimes[TKTLIFENUMFIXED] = {
  35     38400,                              /* 10.67 hours, 0.44 days */
  36     41055,                              /* 11.40 hours, 0.48 days */
  37     43894,                              /* 12.19 hours, 0.51 days */
  38     46929,                              /* 13.04 hours, 0.54 days */
  39     50174,                              /* 13.94 hours, 0.58 days */
  40     53643,                              /* 14.90 hours, 0.62 days */
  41     57352,                              /* 15.93 hours, 0.66 days */
  42     61318,                              /* 17.03 hours, 0.71 days */
  43     65558,                              /* 18.21 hours, 0.76 days */
  44     70091,                              /* 19.47 hours, 0.81 days */
  45     74937,                              /* 20.82 hours, 0.87 days */
  46     80119,                              /* 22.26 hours, 0.93 days */
  47     85658,                              /* 23.79 hours, 0.99 days */
  48     91581,                              /* 25.44 hours, 1.06 days */
  49     97914,                              /* 27.20 hours, 1.13 days */
  50     104684,                             /* 29.08 hours, 1.21 days */
  51     111922,                             /* 31.09 hours, 1.30 days */
  52     119661,                             /* 33.24 hours, 1.38 days */
  53     127935,                             /* 35.54 hours, 1.48 days */
  54     136781,                             /* 37.99 hours, 1.58 days */
  55     146239,                             /* 40.62 hours, 1.69 days */
  56     156350,                             /* 43.43 hours, 1.81 days */
  57     167161,                             /* 46.43 hours, 1.93 days */
  58     178720,                             /* 49.64 hours, 2.07 days */
  59     191077,                             /* 53.08 hours, 2.21 days */
  60     204289,                             /* 56.75 hours, 2.36 days */
  61     218415,                             /* 60.67 hours, 2.53 days */
  62     233517,                             /* 64.87 hours, 2.70 days */
  63     249664,                             /* 69.35 hours, 2.89 days */
  64     266926,                             /* 74.15 hours, 3.09 days */
  65     285383,                             /* 79.27 hours, 3.30 days */
  66     305116,                             /* 84.75 hours, 3.53 days */
  67     326213,                             /* 90.61 hours, 3.78 days */
  68     348769,                             /* 96.88 hours, 4.04 days */
  69     372885,                             /* 103.58 hours, 4.32 days */
  70     398668,                             /* 110.74 hours, 4.61 days */
  71     426234,                             /* 118.40 hours, 4.93 days */
  72     455705,                             /* 126.58 hours, 5.27 days */
  73     487215,                             /* 135.34 hours, 5.64 days */
  74     520904,                             /* 144.70 hours, 6.03 days */
  75     556921,                             /* 154.70 hours, 6.45 days */
  76     595430,                             /* 165.40 hours, 6.89 days */
  77     636601,                             /* 176.83 hours, 7.37 days */
  78     680618,                             /* 189.06 hours, 7.88 days */
  79     727680,                             /* 202.13 hours, 8.42 days */
  80     777995,                             /* 216.11 hours, 9.00 days */
  81     831789,                             /* 231.05 hours, 9.63 days */
  82     889303,                             /* 247.03 hours, 10.29 days */
  83     950794,                             /* 264.11 hours, 11.00 days */
  84     1016537,                            /* 282.37 hours, 11.77 days */
  85     1086825,                            /* 301.90 hours, 12.58 days */
  86     1161973,                            /* 322.77 hours, 13.45 days */
  87     1242318,                            /* 345.09 hours, 14.38 days */
  88     1328218,                            /* 368.95 hours, 15.37 days */
  89     1420057,                            /* 394.46 hours, 16.44 days */
  90     1518247,                            /* 421.74 hours, 17.57 days */
  91     1623226,                            /* 450.90 hours, 18.79 days */
  92     1735464,                            /* 482.07 hours, 20.09 days */
  93     1855462,                            /* 515.41 hours, 21.48 days */
  94     1983758,                            /* 551.04 hours, 22.96 days */
  95     2120925,                            /* 589.15 hours, 24.55 days */
  96     2267576,                            /* 629.88 hours, 26.25 days */
  97     2424367,                            /* 673.44 hours, 28.06 days */
  98     2592000};                           /* 720.00 hours, 30.00 days */
  99
 100 /*
 101  * krb_life_to_time - takes a start time and a Kerberos standard
 102  * lifetime char and returns the corresponding end time.  There are
 103  * four simple cases to be handled.  The first is a life of 0xff,
 104  * meaning no expiration, and results in an end time of 0xffffffff.
 105  * The second is when life is less than the values covered by the
 106  * table.  In this case, the end time is the start time plus the
 107  * number of 5 minute intervals specified by life.  The third case
 108  * returns start plus the MAXTKTLIFETIME if life is greater than
 109  * TKTLIFEMAXFIXED.  The last case, uses the life value (minus
 110  * TKTLIFEMINFIXED) as an index into the table to extract the lifetime
 111  * in seconds, which is added to start to produce the end time.
 112  */
 113 u_int32_t
 114 krb4_life_to_time(u_int32_t start, int life_)
 115 {
 116     unsigned char life = (unsigned char) life_;
 117
 118     if (krb4_no_long_lifetimes) return start + life*5*60;
 119
 120     if (life == TKTLIFENOEXPIRE) return NEVERDATE;
 121     if (life < TKTLIFEMINFIXED) return start + life*5*60;
 122     if (life > TKTLIFEMAXFIXED) return start + MAXTKTLIFETIME;
 123     return start + tkt_lifetimes[life - TKTLIFEMINFIXED];
 124 }
 125
 126 /*
 127  * krb_time_to_life - takes start and end times for the ticket and
 128  * returns a Kerberos standard lifetime char, possibily using the
 129  * tkt_lifetimes table for lifetimes above 127*5 minutes.  First, the
 130  * special case of (end == NEVERDATE) is handled to mean no
 131  * expiration.  Then negative lifetimes and those greater than the
 132  * maximum ticket lifetime are rejected.  Then lifetimes less than the
 133  * first table entry are handled by rounding the requested lifetime
 134  * *up* to the next 5 minute interval.  The final step is to search
 135  * the table for the smallest entry *greater than or equal* to the
 136  * requested entry.
 137  */
 138 int krb_time_to_life(u_int32_t start, u_int32_t end)
 139 {
 140     int i;
 141     long lifetime = end - start;
 142
 143     if (krb4_no_long_lifetimes) return (lifetime + 5*60 - 1)/(5*60);
 144
 145     if (end >= NEVERDATE) return TKTLIFENOEXPIRE;
 146     if (lifetime > MAXTKTLIFETIME || lifetime <= 0) return 0;
 147     if (lifetime < tkt_lifetimes[0]) return (lifetime + 5*60 - 1)/(5*60);
 148     for (i=0; i<TKTLIFENUMFIXED; i++) {
 149         if (lifetime <= tkt_lifetimes[i]) {
 150             return i+TKTLIFEMINFIXED;
 151         }
 152     }
 153     return 0;
 154 }
 155
 156 char *
 157 krb4_life_to_atime(int life)
 158 {
 159     static char atime[11+1+2+1+2+1+2+1];
 160     unsigned long when;
 161     int secs, mins, hours;
 162
 163     if (life == TKTLIFENOEXPIRE && !krb4_no_long_lifetimes)
 164         return("Forever");
 165     when = krb4_life_to_time(0, life);
 166     secs = when%60;
 167     when /= 60;
 168     mins = when%60;
 169     when /= 60;
 170     hours = when%24;
 171     when /= 24;
 172     snprintf(atime, sizeof(atime), "%d+%02d:%02d:%02d", (int)when, hours, mins, secs);
 173     return(atime);
 174 }
 175
 176 int
 177 krb4_atime_to_life(char *atime)
 178 {
 179     unsigned long when = 0;
 180     char *cp;
 181     int colon = 0, plus = 0;
 182     int n = 0;
 183
 184     if (strcasecmp(atime, "forever") == 0)
 185         return(TKTLIFENOEXPIRE);
 186
 187     for (cp=atime; *cp; cp++) {
 188         switch(*cp) {
 189             case '0': case '1': case '2': case '3': case '4':
 190             case '5': case '6': case '7': case '8': case '9':
 191                 n = n*10 + *cp-'0';
 192                 break;
 193             case '+':
 194                 plus++;
 195                 when += n;
 196                 when *= 24;
 197                 n = 0;
 198                 break;
 199             case ':':
 200                 colon++;
 201                 when += n;
 202                 when *= 60;
 203                 n = 0;
 204                 break;
 205             default:
 206                 break;
 207         }
 208     }
 209     when += n;
 210     if (plus == 0 && colon == 0)
 211         return((unsigned char)when);
 212     while (colon < 2) {
 213         when *= 60;
 214         colon++;
 215     }
 216     return(krb_time_to_life(0,when));
 217 }
 218
 219 #endif
 220