nss_afs.c

   1
   2 /*
   3  * libnss_afs.c
   4  *
   5  * Copyright 2008, licensed under GNU Library General Public License (LGPL)
   6  * see COPYING file for details
   7  *
   8  * derived from Frank Burkhardt's libnss_ptdb,
   9  * which was derived from Todd M. Lewis' libnss_pts
  10  */
  11
  12 /*
  13  * if you are reading this code for the first time, start at the
  14  * bottom and work your way upwards
  15  */
  16
  17 #include <ctype.h>
  18 #include <err.h>
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <getopt.h>
  22 #include <grp.h>
  23 #include <netinet/in.h>
  24 #include <nss.h>
  25 #include <pthread.h>
  26 #include <pwd.h>
  27 #include <rx/rx.h>
  28 #include <rx/xdr.h>
  29 #include <signal.h>
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <sys/select.h>
  34 #include <sys/socket.h>
  35 #include <sys/time.h>
  36 #include <sys/types.h>
  37 #include <unistd.h>
  38 #include <afs/afs.h>
  39 #include <afs/afsutil.h>
  40 #include <afs/cellconfig.h>
  41 #include <afs/com_err.h>
  42 #include <afs/param.h>
  43 #include <afs/ptclient.h>
  44 #include <afs/pterror.h>
  45 #include <afs/stds.h>
  46
  47 #define HOMEDIR_AUTO 0
  48 #define HOMEDIR_ADMINLINK 1
  49 #define HOMEDIR_PREFIX 2
  50 #define SHELL_BASH 0
  51 #define SHELL_ADMINLINK 1
  52 #define SHELL_USERLINK 2
  53
  54 #define AFS_MAGIC_ANONYMOUS_USERID 32766
  55 #define MIN_PAG_GID 0x41000000L
  56 #define MAX_PAG_GID 0x41FFFFFFL
  57
  58 static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
  59
  60 extern int cpstr( char *str, char **buf, size_t *buflen);
  61
  62 extern struct ubik_client *pruclient;
  63
  64 int  afs_initialized = 0;
  65 char cellname[256];
  66 char homedir_prefix[300];
  67 int  homedir_prefix_len=0;
  68 char homedirs_method=0;
  69 char shells_method=0;
  70
  71 int cpstr( char *str, char **buf, size_t *buflen) {
  72     int len = strlen(str);
  73     if ( len >= *buflen-1 ) return 0;
  74     strcpy(*buf,str);
  75     *buflen -= len + 1;
  76     *buf    += len + 1;
  77     return len;
  78 }
  79
  80
  81 /*
  82  * Look up the name corresponding to uid, store in buffer.
  83  *
  84  * returns NSS_STATUS_SUCCESS, NSS_STATUS_NOTFOUND, or NSS_STATUS_UNAVAIL
  85  */
  86 int ptsid2name(int uid, char **buffer, int *buflen) {
  87   int ret, i;
  88   idlist lid;
  89   namelist lnames;
  90
  91   init_afs();
  92
  93   if (uid==AFS_MAGIC_ANONYMOUS_USERID) {
  94     if (!cpstr("anonymous", buffer, buflen)) return NSS_STATUS_UNAVAIL;
  95     return NSS_STATUS_SUCCESS;
  96   }
  97
  98   if (pthread_mutex_lock(&mutex)) return NSS_STATUS_UNAVAIL;
  99
 100   lid.idlist_val = (afs_int32*)&uid;
 101   lid.idlist_len = 1;
 102   lnames.namelist_val = 0;
 103   lnames.namelist_len = 0;
 104
 105   if (ubik_Call(PR_IDToName,pruclient,0,&lid,&lnames) != PRSUCCESS) {
 106     pthread_mutex_unlock(&mutex);
 107     return NSS_STATUS_UNAVAIL;
 108   }
 109
 110   ret = NSS_STATUS_NOTFOUND;
 111   for (i=0;i<lnames.namelist_len;i++) {
 112     int delta = strlen(lnames.namelist_val[i]);
 113     if ( (delta < buflen) && islower(*(lnames.namelist_val[i])) ) {
 114       cpstr(lnames.namelist_val[i], buffer, buflen);
 115       ret = NSS_STATUS_SUCCESS;
 116     }
 117   }
 118   free(lnames.namelist_val);
 119   /* free(lid.idlist_val); */
 120   lid.idlist_val = 0;
 121   lid.idlist_len = 0;
 122
 123   pthread_mutex_unlock(&mutex);
 124   return ret;
 125 }
 126
 127 /*
 128  * Look up the uid corresponding to name, stores it in *uid.
 129  *
 130  * returns NSS_STATUS_SUCCESS, NSS_STATUS_NOTFOUND, or NSS_STATUS_UNAVAIL
 131  */
 132 int ptsname2id(char *name, uid_t* uid) {
 133   int res;
 134   idlist lid;
 135   namelist lnames;
 136
 137   init_afs();
 138
 139   if (!strcmp(name,"anonymous")) {
 140     *uid = AFS_MAGIC_ANONYMOUS_USERID;
 141     return NSS_STATUS_SUCCESS;
 142   }
 143
 144   if (pthread_mutex_lock(&mutex)) return NSS_STATUS_UNAVAIL;
 145
 146   lid.idlist_val = 0;
 147   lid.idlist_len = 0;
 148   lnames.namelist_val = (prname*)name;
 149   lnames.namelist_len = 1;
 150
 151   if (ubik_Call(PR_NameToID,pruclient,0,&lnames,&lid) != PRSUCCESS) {
 152     pthread_mutex_unlock(&mutex);
 153     return NSS_STATUS_UNAVAIL;
 154   }
 155   pthread_mutex_unlock(&mutex);
 156
 157   res = (uid_t)lid.idlist_val[0];
 158   if (res == AFS_MAGIC_ANONYMOUS_USERID) return NSS_STATUS_NOTFOUND;
 159   *uid = res;
 160   return NSS_STATUS_SUCCESS;
 161 }
 162
 163 /*
 164  *  returns zero on success
 165  */
 166 int init_afs() {
 167   FILE *thiscell;
 168   int len;
 169
 170   if (afs_initialized) return 0;
 171
 172   if (pthread_mutex_lock(&mutex)) return -1;
 173   do {
 174     homedirs_method=HOMEDIR_PREFIX;
 175     shells_method=SHELL_USERLINK;
 176
 177     thiscell=fopen("/etc/openafs/ThisCell","r");
 178     if (thiscell == NULL) break;
 179     len=fread(cellname,1,256,thiscell);
 180     if (!feof(thiscell)) {
 181       // Cellname too long
 182       fclose(thiscell);
 183       strcpy(homedir_prefix,"/tmp/\0");
 184       homedir_prefix_len=5;
 185       break;
 186     }
 187     fclose(thiscell);
 188     if (cellname[len-1] == '\n') len--;
 189     cellname[len]='\0';
 190     sprintf(homedir_prefix,"/afs/%s/user/",cellname);
 191     homedir_prefix_len=strlen(homedir_prefix);
 192
 193     if (pr_Initialize(0L,AFSDIR_CLIENT_ETC_DIRPATH, 0)) break;
 194
 195     afs_initialized = 1;
 196     pthread_mutex_unlock(&mutex);
 197     return 0;
 198
 199   } while(0);
 200   pthread_mutex_unlock(&mutex);
 201   return -1;
 202 }
 203
 204
 205 /*
 206   result=get_homedir(char *name,char **buffer,size_t *buflen)
 207   Writes the guessed Homedirectory of a given user 'name' into
 208   '*buffer', increasing *buflen accordingly.
 209   result == 1, only if the buffer was big enough.
 210 */
 211 int get_homedir(char *name, char **buffer, size_t *buflen) {
 212   char buf[256];
 213   int temp;
 214   char *b;
 215   b=*buffer;
 216   switch (homedirs_method) {
 217     case HOMEDIR_PREFIX:
 218       homedir_prefix[homedir_prefix_len+0]=name[0];
 219       homedir_prefix[homedir_prefix_len+1]='/';
 220       homedir_prefix[homedir_prefix_len+2]=name[0];
 221       homedir_prefix[homedir_prefix_len+3]=name[1];
 222       homedir_prefix[homedir_prefix_len+4]='/';
 223       homedir_prefix[homedir_prefix_len+5]=0;
 224       strncpy(&homedir_prefix[homedir_prefix_len+5],name,40);
 225       if (! cpstr(homedir_prefix,buffer,buflen) ) return -1;
 226       break;
 227     case HOMEDIR_AUTO:
 228       homedir_prefix[homedir_prefix_len]=0;
 229       strncpy(&homedir_prefix[homedir_prefix_len],name,40);
 230       if (! cpstr(homedir_prefix,buffer,buflen) ) return -1;
 231       break;
 232     case HOMEDIR_ADMINLINK:
 233       if ( snprintf(buf,256,"/afs/%s/admin/homedirs/%s",cellname,name) > 0 ) {
 234         temp=readlink(buf,*buffer,*buflen);
 235         if ( temp > -1) {
 236           b[temp]=0;
 237           *buflen = *buflen - temp - 1;
 238           return -1;
 239         }
 240       }
 241       if (! cpstr("/tmp",buffer,buflen) ) return -1;
 242       break;
 243   }
 244   return 0;
 245 }
 246
 247 int get_shell(char *name, char **buffer, size_t *buflen) {
 248   char buf[256];
 249   int temp;
 250   char *b;
 251   char* bufx = buf;
 252   int bufxlen = 256;
 253   b=*buffer;
 254
 255   switch (shells_method) {
 256     case SHELL_BASH:
 257       if (!cpstr("/bin/bash",buffer, buflen)) return -1;
 258       break;
 259
 260     case SHELL_ADMINLINK:
 261       if ( snprintf(buf,256,"/afs/%s/admin/shells/%s",cellname,name) > 0 ) {
 262         temp=readlink(buf,*buffer,*buflen);
 263         if ( temp > -1) {
 264           b[temp]=0;
 265           *buflen = *buflen - temp - 1;
 266           return -1;
 267         }
 268       }
 269       if (! cpstr("/bin/bash",buffer,buflen) )
 270         return -1;
 271       break;
 272
 273     case SHELL_USERLINK:
 274       if (get_homedir(name, &bufx, &bufxlen)) return -1;
 275       strncpy(buf+strlen(buf),"/.loginshell",bufxlen);
 276       temp=readlink(buf,*buffer,*buflen);
 277       if ( temp > -1) {
 278         b[temp]=0;
 279         *buflen = *buflen - temp - 1;
 280         return -1;
 281       }
 282       if (! cpstr("/bin/bash",buffer,buflen) )
 283         return -1;
 284       break;
 285   }
 286   return 0;
 287 }
 288
 289
 290 /**
 291  *  this function is invoked by glibc to resolve the name of a numeric groupid
 292  */
 293 enum nss_status _nss_afs_getgrgid_r (gid_t gid, struct group *result,
 294                                      char *buffer, size_t buflen, int *errnop) {
 295   int length;
 296   if ( gid < MIN_PAG_GID  || gid > MAX_PAG_GID) {
 297     *errnop=ENOENT;
 298     return NSS_STATUS_NOTFOUND;
 299   }
 300   do {
 301     result->gr_gid=gid;
 302
 303     result->gr_name=buffer;
 304     length=snprintf(buffer,buflen,"AfsPag-%x",gid-MIN_PAG_GID);
 305
 306     if (length < 0) break;
 307     length += 1;
 308     buflen -= length;
 309     buffer += length;
 310
 311     result->gr_passwd=buffer;
 312
 313     if (!cpstr("x",&buffer,&buflen)) break;
 314
 315     if (buflen < sizeof(char*)) break;
 316     result->gr_mem=buffer;
 317     result->gr_mem[0] = NULL;
 318
 319     *errnop=errno;
 320     return NSS_STATUS_SUCCESS;
 321
 322   } while(0);
 323   *errnop=ENOENT;
 324   return NSS_STATUS_UNAVAIL;
 325 }
 326
 327 /*
 328   This is a the ptdb-getpwuid-function.
 329 */
 330 enum nss_status _nss_afs_getpwuid_r (uid_t uid, struct passwd *result_buf, char *buffer, size_t buflen, int *errnop) {
 331   int temp;
 332
 333   if (init_afs()) return NSS_STATUS_UNAVAIL;
 334
 335   result_buf->pw_name = buffer;
 336   temp = ptsid2name( uid, &buffer, &buflen);
 337   if (temp != NSS_STATUS_SUCCESS) {
 338     *errnop = ENOENT;
 339     return temp;
 340   }
 341
 342 #ifdef LIMIT_USERNAME_CHARS
 343   if ( strlen(result_buf->pw_name) > LIMIT_USERNAME_CHARS ) {
 344     result_buf->pw_name[LIMIT_USERNAME_CHARS] = '\0';
 345     buflen = buflen + ( buffer - &result_buf->pw_name[LIMIT_USERNAME_CHARS+1] );
 346     buffer = &result_buf->pw_name[LIMIT_USERNAME_CHARS+1];
 347   }
 348 #endif
 349
 350   do {
 351     /* set the password to "x" */
 352     result_buf->pw_passwd = buffer;
 353     if ( ! cpstr("x",&buffer, &buflen) ) break;
 354     /* the uid and gid are both the uid passed in */
 355     result_buf->pw_uid = uid;
 356     result_buf->pw_gid = 65534;
 357     /* make the gecos the same as the PTS name */
 358     result_buf->pw_gecos = buffer;
 359     if ( ! cpstr(result_buf->pw_name, &buffer, &buflen ) ) break;
 360
 361     // Set the homedirectory
 362     result_buf->pw_dir = buffer;
 363     if ( get_homedir(result_buf->pw_name,&buffer,&buflen) ) break;
 364
 365     // Set the login shell
 366     result_buf->pw_shell = buffer;
 367     if ( get_shell(result_buf->pw_name,&buffer,&buflen) ) break;
 368
 369     *errnop = errno;
 370     return NSS_STATUS_SUCCESS;
 371   } while(0);
 372
 373   *errnop = ERANGE;
 374   return NSS_STATUS_UNAVAIL;
 375 }
 376
 377
 378 /*
 379  * This is the ptdb-getpwnam-function.
 380  */
 381 enum nss_status _nss_afs_getpwnam_r (char *name, struct passwd *result_buf, char *buffer, size_t buflen, int *errnop) {
 382   uid_t uid;
 383   int temp;
 384
 385   if (init_afs()) return NSS_STATUS_UNAVAIL;
 386
 387   temp = ptsname2id(name,&uid);
 388   if (temp != NSS_STATUS_SUCCESS) {
 389     *errnop = ENOENT;
 390     return temp;
 391   }
 392
 393   // This causes an additional PTDB-lookup and should be removed in the future
 394   return _nss_afs_getpwuid_r (uid, result_buf,buffer,buflen, errnop);
 395 }
 396