source/smbd/dosmode.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    dos mode handling functions
   5    Copyright (C) Andrew Tridgell 1992-1998
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23
  24 extern int DEBUGLEVEL;
  25
  26 /****************************************************************************
  27   change a dos mode to a unix mode
  28     base permission for files:
  29          if inheriting
  30            apply read/write bits from parent directory.
  31          else
  32            everybody gets read bit set
  33          dos readonly is represented in unix by removing everyone's write bit
  34          dos archive is represented in unix by the user's execute bit
  35          dos system is represented in unix by the group's execute bit
  36          dos hidden is represented in unix by the other's execute bit
  37          if !inheriting {
  38            Then apply create mask,
  39            then add force bits.
  40          }
  41     base permission for directories:
  42          dos directory is represented in unix by unix's dir bit and the exec bit
  43          if !inheriting {
  44            Then apply create mask,
  45            then add force bits.
  46          }
  47 ****************************************************************************/
  48 mode_t unix_mode(connection_struct *conn,int dosmode,const char *fname)
  49 {
  50   mode_t result = (S_IRUSR | S_IRGRP | S_IROTH);
  51   mode_t dir_mode = 0; /* Mode of the parent directory if inheriting. */
  52
  53   if ( !IS_DOS_READONLY(dosmode) )
  54     result |= (S_IWUSR | S_IWGRP | S_IWOTH);
  55
  56   if (fname && lp_inherit_perms(SNUM(conn))) {
  57     char *dname;
  58     SMB_STRUCT_STAT sbuf;
  59
  60     dname = parent_dirname(fname);
  61     DEBUG(2,("unix_mode(%s) inheriting from %s\n",fname,dname));
  62     if (vfs_stat(conn,dname,&sbuf) != 0) {
  63       DEBUG(4,("unix_mode(%s) failed, [dir %s]: %s\n",fname,dname,strerror(errno)));
  64       return(0);      /* *** shouldn't happen! *** */
  65     }
  66
  67     /* Save for later - but explicitly remove setuid bit for safety. */
  68     dir_mode = sbuf.st_mode & ~S_ISUID;
  69     DEBUG(2,("unix_mode(%s) inherit mode %o\n",fname,(int)dir_mode));
  70     /* Clear "result" */
  71     result = 0;
  72   }
  73
  74   if (IS_DOS_DIR(dosmode)) {
  75     /* We never make directories read only for the owner as under DOS a user
  76        can always create a file in a read-only directory. */
  77     result |= (S_IFDIR | S_IWUSR);
  78
  79     if (dir_mode) {
  80       /* Inherit mode of parent directory. */
  81       result |= dir_mode;
  82     } else {
  83       /* Provisionally add all 'x' bits */
  84       result |= (S_IXUSR | S_IXGRP | S_IXOTH);
  85
  86       /* Apply directory mask */
  87       result &= lp_dir_mask(SNUM(conn));
  88       /* Add in force bits */
  89       result |= lp_force_dir_mode(SNUM(conn));
  90     }
  91   } else {
  92     if (lp_map_archive(SNUM(conn)) && IS_DOS_ARCHIVE(dosmode))
  93       result |= S_IXUSR;
  94
  95     if (lp_map_system(SNUM(conn)) && IS_DOS_SYSTEM(dosmode))
  96       result |= S_IXGRP;
  97
  98     if (lp_map_hidden(SNUM(conn)) && IS_DOS_HIDDEN(dosmode))
  99       result |= S_IXOTH;
 100
 101     if (dir_mode) {
 102       /* Inherit 666 component of parent directory mode */
 103       result |= dir_mode
 104         &  (S_IRUSR | S_IRGRP | S_IROTH | S_IWUSR | S_IWGRP | S_IWOTH);
 105     } else {
 106       /* Apply mode mask */
 107       result &= lp_create_mask(SNUM(conn));
 108       /* Add in force bits */
 109       result |= lp_force_create_mode(SNUM(conn));
 110     }
 111   }
 112
 113   DEBUG(3,("unix_mode(%s) returning 0%o\n",fname,(int)result ));
 114   return(result);
 115 }
 116
 117
 118 /****************************************************************************
 119   change a unix mode to a dos mode
 120 ****************************************************************************/
 121 int dos_mode(connection_struct *conn,char *path,SMB_STRUCT_STAT *sbuf)
 122 {
 123   int result = 0;
 124
 125   DEBUG(8,("dos_mode: %s\n", path));
 126
 127   if ((sbuf->st_mode & S_IWUSR) == 0)
 128       result |= aRONLY;
 129
 130   if (MAP_ARCHIVE(conn) && ((sbuf->st_mode & S_IXUSR) != 0))
 131     result |= aARCH;
 132
 133   if (MAP_SYSTEM(conn) && ((sbuf->st_mode & S_IXGRP) != 0))
 134     result |= aSYSTEM;
 135
 136   if (MAP_HIDDEN(conn) && ((sbuf->st_mode & S_IXOTH) != 0))
 137     result |= aHIDDEN;
 138
 139   if (S_ISDIR(sbuf->st_mode))
 140     result = aDIR | (result & aRONLY);
 141
 142 #ifdef S_ISLNK
 143 #if LINKS_READ_ONLY
 144   if (S_ISLNK(sbuf->st_mode) && S_ISDIR(sbuf->st_mode))
 145     result |= aRONLY;
 146 #endif
 147 #endif
 148
 149   /* hide files with a name starting with a . */
 150   if (lp_hide_dot_files(SNUM(conn)))
 151     {
 152       char *p = strrchr_m(path,'/');
 153       if (p)
 154         p++;
 155       else
 156         p = path;
 157
 158       if (p[0] == '.' && p[1] != '.' && p[1] != 0)
 159         result |= aHIDDEN;
 160     }
 161
 162   /* Optimization : Only call is_hidden_path if it's not already
 163      hidden. */
 164   if (!(result & aHIDDEN) && IS_HIDDEN_PATH(conn,path))
 165   {
 166     result |= aHIDDEN;
 167   }
 168
 169   DEBUG(8,("dos_mode returning "));
 170
 171   if (result & aHIDDEN) DEBUG(8, ("h"));
 172   if (result & aRONLY ) DEBUG(8, ("r"));
 173   if (result & aSYSTEM) DEBUG(8, ("s"));
 174   if (result & aDIR   ) DEBUG(8, ("d"));
 175   if (result & aARCH  ) DEBUG(8, ("a"));
 176
 177   DEBUG(8,("\n"));
 178
 179   return(result);
 180 }
 181
 182 /*******************************************************************
 183 chmod a file - but preserve some bits
 184 ********************************************************************/
 185 int file_chmod(connection_struct *conn,char *fname,int dosmode,SMB_STRUCT_STAT *st)
 186 {
 187         SMB_STRUCT_STAT st1;
 188         int mask=0;
 189         mode_t tmp;
 190         mode_t unixmode;
 191         int ret = -1;
 192
 193         if (!st) {
 194                 st = &st1;
 195                 if (vfs_stat(conn,fname,st))
 196                         return(-1);
 197         }
 198
 199         if (S_ISDIR(st->st_mode))
 200                 dosmode |= aDIR;
 201
 202         if (dos_mode(conn,fname,st) == dosmode)
 203                 return(0);
 204
 205         unixmode = unix_mode(conn,dosmode,fname);
 206
 207         /* preserve the s bits */
 208         mask |= (S_ISUID | S_ISGID);
 209
 210         /* preserve the t bit */
 211 #ifdef S_ISVTX
 212         mask |= S_ISVTX;
 213 #endif
 214
 215         /* possibly preserve the x bits */
 216         if (!MAP_ARCHIVE(conn))
 217                 mask |= S_IXUSR;
 218         if (!MAP_SYSTEM(conn))
 219                 mask |= S_IXGRP;
 220         if (!MAP_HIDDEN(conn))
 221                 mask |= S_IXOTH;
 222
 223         unixmode |= (st->st_mode & mask);
 224
 225         /* if we previously had any r bits set then leave them alone */
 226         if ((tmp = st->st_mode & (S_IRUSR|S_IRGRP|S_IROTH))) {
 227                 unixmode &= ~(S_IRUSR|S_IRGRP|S_IROTH);
 228                 unixmode |= tmp;
 229         }
 230
 231         /* if we previously had any w bits set then leave them alone
 232                 whilst adding in the new w bits, if the new mode is not rdonly */
 233         if (!IS_DOS_READONLY(dosmode)) {
 234                 unixmode |= (st->st_mode & (S_IWUSR|S_IWGRP|S_IWOTH));
 235         }
 236
 237         if ((ret = vfs_chmod(conn,fname,unixmode)) == 0)
 238                 return 0;
 239
 240         if((errno != EPERM) && (errno != EACCES))
 241                 return -1;
 242
 243         if(!lp_dos_filemode(SNUM(conn)))
 244                 return -1;
 245
 246         /* We want DOS semantics, ie allow non owner with write permission to change the
 247                 bits on a file. Just like file_utime below.
 248         */
 249
 250         /* Check if we have write access. */
 251         if (CAN_WRITE(conn)) {
 252                 /*
 253                  * We need to open the file with write access whilst
 254                  * still in our current user context. This ensures we
 255                  * are not violating security in doing the fchmod.
 256                  * This file open does *not* break any oplocks we are
 257                  * holding. We need to review this.... may need to
 258                  * break batch oplocks open by others. JRA.
 259                  */
 260                 files_struct *fsp = open_file_fchmod(conn,fname,st);
 261                 if (!fsp)
 262                         return -1;
 263                 become_root();
 264                 ret = conn->vfs_ops.fchmod(fsp, fsp->fd, unixmode);
 265                 unbecome_root();
 266                 close_file_fchmod(fsp);
 267         }
 268
 269         return( ret );
 270 }
 271
 272
 273 /*******************************************************************
 274 Wrapper around dos_utime that possibly allows DOS semantics rather
 275 than POSIX.
 276 *******************************************************************/
 277 int file_utime(connection_struct *conn, char *fname, struct utimbuf *times)
 278 {
 279   extern struct current_user current_user;
 280   SMB_STRUCT_STAT sb;
 281   int ret = -1;
 282
 283   errno = 0;
 284
 285   if(conn->vfs_ops.utime(conn,fname, times) == 0)
 286     return 0;
 287
 288   if((errno != EPERM) && (errno != EACCES))
 289     return -1;
 290
 291   if(!lp_dos_filetimes(SNUM(conn)))
 292     return -1;
 293
 294   /* We have permission (given by the Samba admin) to
 295      break POSIX semantics and allow a user to change
 296      the time on a file they don't own but can write to
 297      (as DOS does).
 298    */
 299
 300   if(vfs_stat(conn,fname,&sb) != 0)
 301     return -1;
 302
 303   /* Check if we have write access. */
 304   if (CAN_WRITE(conn)) {
 305           if (((sb.st_mode & S_IWOTH) ||
 306                conn->admin_user ||
 307                ((sb.st_mode & S_IWUSR) && current_user.uid==sb.st_uid) ||
 308                ((sb.st_mode & S_IWGRP) &&
 309                 in_group(sb.st_gid,current_user.gid,
 310                          current_user.ngroups,current_user.groups)))) {
 311                   /* We are allowed to become root and change the filetime. */
 312                   become_root();
 313                   ret = conn->vfs_ops.utime(conn,fname, times);
 314                   unbecome_root();
 315           }
 316   }
 317
 318   return ret;
 319 }
 320
 321 /*******************************************************************
 322 Change a filetime - possibly allowing DOS semantics.
 323 *******************************************************************/
 324 BOOL set_filetime(connection_struct *conn, char *fname, time_t mtime)
 325 {
 326   struct utimbuf times;
 327
 328   if (null_mtime(mtime)) return(True);
 329
 330   times.modtime = times.actime = mtime;
 331
 332   if (file_utime(conn, fname, &times)) {
 333     DEBUG(4,("set_filetime(%s) failed: %s\n",fname,strerror(errno)));
 334     return False;
 335   }
 336
 337   return(True);
 338 }