source3/lib/username.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Username handling
   4    Copyright (C) Andrew Tridgell 1992-1998
   5    Copyright (C) Jeremy Allison 1997-2001.
   6    Copyright (C) Andrew Bartlett 2002
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "memcache.h"
  24
  25 /* internal functions */
  26 static struct passwd *uname_string_combinations(char *s, TALLOC_CTX *mem_ctx,
  27                                                 struct passwd * (*fn) (TALLOC_CTX *mem_ctx, const char *),
  28                                                 int N);
  29 static struct passwd *uname_string_combinations2(char *s, TALLOC_CTX *mem_ctx, int offset,
  30                                                  struct passwd * (*fn) (TALLOC_CTX *mem_ctx, const char *),
  31                                                  int N);
  32
  33 static struct passwd *getpwnam_alloc(TALLOC_CTX *mem_ctx, const char *name)
  34 {
  35         struct passwd *pw, *for_cache;
  36
  37         pw = (struct passwd *)memcache_lookup_talloc(
  38                 NULL, GETPWNAM_CACHE, data_blob_string_const_null(name));
  39         if (pw != NULL) {
  40                 return tcopy_passwd(mem_ctx, pw);
  41         }
  42
  43         pw = sys_getpwnam(name);
  44         if (pw == NULL) {
  45                 return NULL;
  46         }
  47
  48         for_cache = tcopy_passwd(talloc_tos(), pw);
  49         if (for_cache == NULL) {
  50                 return NULL;
  51         }
  52
  53         memcache_add_talloc(NULL, GETPWNAM_CACHE,
  54                         data_blob_string_const_null(name), &for_cache);
  55
  56         return tcopy_passwd(mem_ctx, pw);
  57 }
  58
  59 /****************************************************************************
  60  talloc copy a struct passwd.
  61 ****************************************************************************/
  62
  63 struct passwd *tcopy_passwd(TALLOC_CTX *mem_ctx, const struct passwd *from)
  64 {
  65         struct passwd *ret = TALLOC_P(mem_ctx, struct passwd);
  66         if (!ret) {
  67                 return NULL;
  68         }
  69         ret->pw_name = talloc_strdup(ret, from->pw_name);
  70         ret->pw_passwd = talloc_strdup(ret, from->pw_passwd);
  71         ret->pw_uid = from->pw_uid;
  72         ret->pw_gid = from->pw_gid;
  73         ret->pw_gecos = talloc_strdup(ret, from->pw_gecos);
  74         ret->pw_dir = talloc_strdup(ret, from->pw_dir);
  75         ret->pw_shell = talloc_strdup(ret, from->pw_shell);
  76         return ret;
  77 }
  78
  79 /****************************************************************************
  80  Flush all cached passwd structs.
  81 ****************************************************************************/
  82
  83 void flush_pwnam_cache(void)
  84 {
  85         memcache_flush(NULL, GETPWNAM_CACHE);
  86 }
  87
  88 /****************************************************************************
  89  talloc'ed version of getpwuid.
  90 ****************************************************************************/
  91
  92 struct passwd *getpwuid_alloc(TALLOC_CTX *mem_ctx, uid_t uid)
  93 {
  94         struct passwd *temp = sys_getpwuid(uid);
  95
  96         if (!temp) {
  97                 return NULL;
  98         }
  99
 100         return tcopy_passwd(mem_ctx, temp);
 101 }
 102
 103 /****************************************************************************
 104  Get a users home directory.
 105 ****************************************************************************/
 106
 107 char *get_user_home_dir(TALLOC_CTX *mem_ctx, const char *user)
 108 {
 109         struct passwd *pass;
 110         char *result;
 111
 112         /* Ensure the user exists. */
 113
 114         pass = Get_Pwnam_alloc(mem_ctx, user);
 115
 116         if (!pass)
 117                 return(NULL);
 118
 119         /* Return home directory from struct passwd. */
 120
 121         result = talloc_move(mem_ctx, &pass->pw_dir);
 122
 123         TALLOC_FREE(pass);
 124         return result;
 125 }
 126
 127 /****************************************************************************
 128  * A wrapper for sys_getpwnam().  The following variations are tried:
 129  *   - as transmitted
 130  *   - in all lower case if this differs from transmitted
 131  *   - in all upper case if this differs from transmitted
 132  *   - using lp_usernamelevel() for permutations.
 133 ****************************************************************************/
 134
 135 static struct passwd *Get_Pwnam_internals(TALLOC_CTX *mem_ctx,
 136                                           const char *user, char *user2)
 137 {
 138         struct passwd *ret = NULL;
 139
 140         if (!user2 || !(*user2))
 141                 return(NULL);
 142
 143         if (!user || !(*user))
 144                 return(NULL);
 145
 146         /* Try in all lower case first as this is the most
 147            common case on UNIX systems */
 148         strlower_m(user2);
 149         DEBUG(5,("Trying _Get_Pwnam(), username as lowercase is %s\n",user2));
 150         ret = getpwnam_alloc(mem_ctx, user2);
 151         if(ret)
 152                 goto done;
 153
 154         /* Try as given, if username wasn't originally lowercase */
 155         if(strcmp(user, user2) != 0) {
 156                 DEBUG(5,("Trying _Get_Pwnam(), username as given is %s\n",
 157                          user));
 158                 ret = getpwnam_alloc(mem_ctx, user);
 159                 if(ret)
 160                         goto done;
 161         }
 162
 163         /* Try as uppercase, if username wasn't originally uppercase */
 164         strupper_m(user2);
 165         if(strcmp(user, user2) != 0) {
 166                 DEBUG(5,("Trying _Get_Pwnam(), username as uppercase is %s\n",
 167                          user2));
 168                 ret = getpwnam_alloc(mem_ctx, user2);
 169                 if(ret)
 170                         goto done;
 171         }
 172
 173         /* Try all combinations up to usernamelevel */
 174         strlower_m(user2);
 175         DEBUG(5,("Checking combinations of %d uppercase letters in %s\n",
 176                  lp_usernamelevel(), user2));
 177         ret = uname_string_combinations(user2, mem_ctx, getpwnam_alloc,
 178                                         lp_usernamelevel());
 179
 180 done:
 181         DEBUG(5,("Get_Pwnam_internals %s find user [%s]!\n",ret ?
 182                  "did":"didn't", user));
 183
 184         return ret;
 185 }
 186
 187 /****************************************************************************
 188  Get_Pwnam wrapper without modification.
 189   NOTE: This with NOT modify 'user'!
 190   This will return an allocated structure
 191 ****************************************************************************/
 192
 193 struct passwd *Get_Pwnam_alloc(TALLOC_CTX *mem_ctx, const char *user)
 194 {
 195         fstring user2;
 196         struct passwd *ret;
 197
 198         if ( *user == '\0' ) {
 199                 DEBUG(10,("Get_Pwnam: empty username!\n"));
 200                 return NULL;
 201         }
 202
 203         fstrcpy(user2, user);
 204
 205         DEBUG(5,("Finding user %s\n", user));
 206
 207         ret = Get_Pwnam_internals(mem_ctx, user, user2);
 208
 209         return ret;
 210 }
 211
 212 /* The functions below have been taken from password.c and slightly modified */
 213 /****************************************************************************
 214  Apply a function to upper/lower case combinations
 215  of a string and return true if one of them returns true.
 216  Try all combinations with N uppercase letters.
 217  offset is the first char to try and change (start with 0)
 218  it assumes the string starts lowercased
 219 ****************************************************************************/
 220
 221 static struct passwd *uname_string_combinations2(char *s, TALLOC_CTX *mem_ctx,
 222                                                  int offset,
 223                                                  struct passwd *(*fn)(TALLOC_CTX *mem_ctx, const char *),
 224                                                  int N)
 225 {
 226         ssize_t len = (ssize_t)strlen(s);
 227         int i;
 228         struct passwd *ret;
 229
 230         if (N <= 0 || offset >= len)
 231                 return(fn(mem_ctx, s));
 232
 233         for (i=offset;i<(len-(N-1));i++) {
 234                 char c = s[i];
 235                 if (!islower_ascii((int)c))
 236                         continue;
 237                 s[i] = toupper_ascii(c);
 238                 ret = uname_string_combinations2(s, mem_ctx, i+1, fn, N-1);
 239                 if(ret)
 240                         return(ret);
 241                 s[i] = c;
 242         }
 243         return(NULL);
 244 }
 245
 246 /****************************************************************************
 247  Apply a function to upper/lower case combinations
 248  of a string and return true if one of them returns true.
 249  Try all combinations with up to N uppercase letters.
 250  offset is the first char to try and change (start with 0)
 251  it assumes the string starts lowercased
 252 ****************************************************************************/
 253
 254 static struct passwd * uname_string_combinations(char *s, TALLOC_CTX *mem_ctx,
 255                                                  struct passwd * (*fn)(TALLOC_CTX *mem_ctx, const char *),
 256                                                  int N)
 257 {
 258         int n;
 259         struct passwd *ret;
 260
 261         for (n=1;n<=N;n++) {
 262                 ret = uname_string_combinations2(s,mem_ctx,0,fn,n);
 263                 if(ret)
 264                         return(ret);
 265         }
 266         return(NULL);
 267 }
 268