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 #include "../lib/util/util_pw.h"
  25
  26 /* internal functions */
  27 static struct passwd *uname_string_combinations(char *s, TALLOC_CTX *mem_ctx,
  28                                                 struct passwd * (*fn) (TALLOC_CTX *mem_ctx, const char *),
  29                                                 int N);
  30 static struct passwd *uname_string_combinations2(char *s, TALLOC_CTX *mem_ctx, int offset,
  31                                                  struct passwd * (*fn) (TALLOC_CTX *mem_ctx, const char *),
  32                                                  int N);
  33
  34 static struct passwd *getpwnam_alloc_cached(TALLOC_CTX *mem_ctx, const char *name)
  35 {
  36         struct passwd *pw, *for_cache;
  37
  38         pw = (struct passwd *)memcache_lookup_talloc(
  39                 NULL, GETPWNAM_CACHE, data_blob_string_const_null(name));
  40         if (pw != NULL) {
  41                 return tcopy_passwd(mem_ctx, pw);
  42         }
  43
  44         pw = sys_getpwnam(name);
  45         if (pw == NULL) {
  46                 return NULL;
  47         }
  48
  49         for_cache = tcopy_passwd(talloc_tos(), pw);
  50         if (for_cache == NULL) {
  51                 return NULL;
  52         }
  53
  54         memcache_add_talloc(NULL, GETPWNAM_CACHE,
  55                         data_blob_string_const_null(name), &for_cache);
  56
  57         return tcopy_passwd(mem_ctx, pw);
  58 }
  59
  60 /****************************************************************************
  61  talloc copy a struct passwd.
  62 ****************************************************************************/
  63
  64 struct passwd *tcopy_passwd(TALLOC_CTX *mem_ctx, const struct passwd *from)
  65 {
  66         struct passwd *ret = TALLOC_P(mem_ctx, struct passwd);
  67         if (!ret) {
  68                 return NULL;
  69         }
  70         ret->pw_name = talloc_strdup(ret, from->pw_name);
  71         ret->pw_passwd = talloc_strdup(ret, from->pw_passwd);
  72         ret->pw_uid = from->pw_uid;
  73         ret->pw_gid = from->pw_gid;
  74         ret->pw_gecos = talloc_strdup(ret, from->pw_gecos);
  75         ret->pw_dir = talloc_strdup(ret, from->pw_dir);
  76         ret->pw_shell = talloc_strdup(ret, from->pw_shell);
  77         return ret;
  78 }
  79
  80 /****************************************************************************
  81  Flush all cached passwd structs.
  82 ****************************************************************************/
  83
  84 void flush_pwnam_cache(void)
  85 {
  86         memcache_flush(NULL, GETPWNAM_CACHE);
  87 }
  88
  89 /****************************************************************************
  90  talloc'ed version of getpwuid.
  91 ****************************************************************************/
  92
  93 struct passwd *getpwuid_alloc(TALLOC_CTX *mem_ctx, uid_t uid)
  94 {
  95         struct passwd *temp = sys_getpwuid(uid);
  96
  97         if (!temp) {
  98                 return NULL;
  99         }
 100
 101         return tcopy_passwd(mem_ctx, temp);
 102 }
 103
 104 /****************************************************************************
 105  Get a users home directory.
 106 ****************************************************************************/
 107
 108 char *get_user_home_dir(TALLOC_CTX *mem_ctx, const char *user)
 109 {
 110         struct passwd *pass;
 111         char *result;
 112
 113         /* Ensure the user exists. */
 114
 115         pass = Get_Pwnam_alloc(mem_ctx, user);
 116
 117         if (!pass)
 118                 return(NULL);
 119
 120         /* Return home directory from struct passwd. */
 121
 122         result = talloc_move(mem_ctx, &pass->pw_dir);
 123
 124         TALLOC_FREE(pass);
 125         return result;
 126 }
 127
 128 /****************************************************************************
 129  * A wrapper for sys_getpwnam().  The following variations are tried:
 130  *   - as transmitted
 131  *   - in all lower case if this differs from transmitted
 132  *   - in all upper case if this differs from transmitted
 133  *   - using lp_usernamelevel() for permutations.
 134 ****************************************************************************/
 135
 136 static struct passwd *Get_Pwnam_internals(TALLOC_CTX *mem_ctx,
 137                                           const char *user, char *user2)
 138 {
 139         struct passwd *ret = NULL;
 140
 141         if (!user2 || !(*user2))
 142                 return(NULL);
 143
 144         if (!user || !(*user))
 145                 return(NULL);
 146
 147         /* Try in all lower case first as this is the most
 148            common case on UNIX systems */
 149         strlower_m(user2);
 150         DEBUG(5,("Trying _Get_Pwnam(), username as lowercase is %s\n",user2));
 151         ret = getpwnam_alloc_cached(mem_ctx, user2);
 152         if(ret)
 153                 goto done;
 154
 155         /* Try as given, if username wasn't originally lowercase */
 156         if(strcmp(user, user2) != 0) {
 157                 DEBUG(5,("Trying _Get_Pwnam(), username as given is %s\n",
 158                          user));
 159                 ret = getpwnam_alloc_cached(mem_ctx, user);
 160                 if(ret)
 161                         goto done;
 162         }
 163
 164         /* Try as uppercase, if username wasn't originally uppercase */
 165         strupper_m(user2);
 166         if(strcmp(user, user2) != 0) {
 167                 DEBUG(5,("Trying _Get_Pwnam(), username as uppercase is %s\n",
 168                          user2));
 169                 ret = getpwnam_alloc_cached(mem_ctx, user2);
 170                 if(ret)
 171                         goto done;
 172         }
 173
 174         /* Try all combinations up to usernamelevel */
 175         strlower_m(user2);
 176         DEBUG(5,("Checking combinations of %d uppercase letters in %s\n",
 177                  lp_usernamelevel(), user2));
 178         ret = uname_string_combinations(user2, mem_ctx, getpwnam_alloc_cached,
 179                                         lp_usernamelevel());
 180
 181 done:
 182         DEBUG(5,("Get_Pwnam_internals %s find user [%s]!\n",ret ?
 183                  "did":"didn't", user));
 184
 185         return ret;
 186 }
 187
 188 /****************************************************************************
 189  Get_Pwnam wrapper without modification.
 190   NOTE: This with NOT modify 'user'!
 191   This will return an allocated structure
 192 ****************************************************************************/
 193
 194 struct passwd *Get_Pwnam_alloc(TALLOC_CTX *mem_ctx, const char *user)
 195 {
 196         fstring user2;
 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         return Get_Pwnam_internals(mem_ctx, user, user2);
 208 }
 209
 210 /* The functions below have been taken from password.c and slightly modified */
 211 /****************************************************************************
 212  Apply a function to upper/lower case combinations
 213  of a string and return true if one of them returns true.
 214  Try all combinations with N uppercase letters.
 215  offset is the first char to try and change (start with 0)
 216  it assumes the string starts lowercased
 217 ****************************************************************************/
 218
 219 static struct passwd *uname_string_combinations2(char *s, TALLOC_CTX *mem_ctx,
 220                                                  int offset,
 221                                                  struct passwd *(*fn)(TALLOC_CTX *mem_ctx, const char *),
 222                                                  int N)
 223 {
 224         ssize_t len = (ssize_t)strlen(s);
 225         int i;
 226         struct passwd *ret;
 227
 228         if (N <= 0 || offset >= len)
 229                 return(fn(mem_ctx, s));
 230
 231         for (i=offset;i<(len-(N-1));i++) {
 232                 char c = s[i];
 233                 if (!islower_ascii((int)c))
 234                         continue;
 235                 s[i] = toupper_ascii(c);
 236                 ret = uname_string_combinations2(s, mem_ctx, i+1, fn, N-1);
 237                 if(ret)
 238                         return(ret);
 239                 s[i] = c;
 240         }
 241         return(NULL);
 242 }
 243
 244 /****************************************************************************
 245  Apply a function to upper/lower case combinations
 246  of a string and return true if one of them returns true.
 247  Try all combinations with up to N uppercase letters.
 248  offset is the first char to try and change (start with 0)
 249  it assumes the string starts lowercased
 250 ****************************************************************************/
 251
 252 static struct passwd * uname_string_combinations(char *s, TALLOC_CTX *mem_ctx,
 253                                                  struct passwd * (*fn)(TALLOC_CTX *mem_ctx, const char *),
 254                                                  int N)
 255 {
 256         int n;
 257         struct passwd *ret;
 258
 259         for (n=1;n<=N;n++) {
 260                 ret = uname_string_combinations2(s,mem_ctx,0,fn,n);
 261                 if(ret)
 262                         return(ret);
 263         }
 264         return(NULL);
 265 }
 266