source/smbd/dosmode.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    dos mode handling functions
   4    Copyright (C) Andrew Tridgell 1992-1998
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 #include "includes.h"
  22
  23 /****************************************************************************
  24  Change a dos mode to a unix mode.
  25     Base permission for files:
  26          if inheriting
  27            apply read/write bits from parent directory.
  28          else
  29            everybody gets read bit set
  30          dos readonly is represented in unix by removing everyone's write bit
  31          dos archive is represented in unix by the user's execute bit
  32          dos system is represented in unix by the group's execute bit
  33          dos hidden is represented in unix by the other's execute bit
  34          if !inheriting {
  35            Then apply create mask,
  36            then add force bits.
  37          }
  38     Base permission for directories:
  39          dos directory is represented in unix by unix's dir bit and the exec bit
  40          if !inheriting {
  41            Then apply create mask,
  42            then add force bits.
  43          }
  44 ****************************************************************************/
  45
  46 mode_t unix_mode(connection_struct *conn, int dosmode, const char *fname)
  47 {
  48         mode_t result = (S_IRUSR | S_IRGRP | S_IROTH | S_IWUSR | S_IWGRP | S_IWOTH);
  49         mode_t dir_mode = 0; /* Mode of the parent directory if inheriting. */
  50
  51         if (!lp_store_dos_attributes(SNUM(conn)) && IS_DOS_READONLY(dosmode)) {
  52                 result &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
  53         }
  54
  55         if (fname && lp_inherit_perms(SNUM(conn))) {
  56                 char *dname;
  57                 SMB_STRUCT_STAT sbuf;
  58
  59                 dname = parent_dirname(fname);
  60                 DEBUG(2,("unix_mode(%s) inheriting from %s\n",fname,dname));
  61                 if (SMB_VFS_STAT(conn,dname,&sbuf) != 0) {
  62                         DEBUG(4,("unix_mode(%s) failed, [dir %s]: %s\n",fname,dname,strerror(errno)));
  63                         return(0);      /* *** shouldn't happen! *** */
  64                 }
  65
  66                 /* Save for later - but explicitly remove setuid bit for safety. */
  67                 dir_mode = sbuf.st_mode & ~S_ISUID;
  68                 DEBUG(2,("unix_mode(%s) inherit mode %o\n",fname,(int)dir_mode));
  69                 /* Clear "result" */
  70                 result = 0;
  71         }
  72
  73         if (IS_DOS_DIR(dosmode)) {
  74                 /* We never make directories read only for the owner as under DOS a user
  75                 can always create a file in a read-only directory. */
  76                 result |= (S_IFDIR | S_IWUSR);
  77
  78                 if (dir_mode) {
  79                         /* Inherit mode of parent directory. */
  80                         result |= dir_mode;
  81                 } else {
  82                         /* Provisionally add all 'x' bits */
  83                         result |= (S_IXUSR | S_IXGRP | S_IXOTH);
  84
  85                         /* Apply directory mask */
  86                         result &= lp_dir_mask(SNUM(conn));
  87                         /* Add in force bits */
  88                         result |= lp_force_dir_mode(SNUM(conn));
  89                 }
  90         } else {
  91                 if (lp_map_archive(SNUM(conn)) && IS_DOS_ARCHIVE(dosmode))
  92                         result |= S_IXUSR;
  93
  94                 if (lp_map_system(SNUM(conn)) && IS_DOS_SYSTEM(dosmode))
  95                         result |= S_IXGRP;
  96
  97                 if (lp_map_hidden(SNUM(conn)) && IS_DOS_HIDDEN(dosmode))
  98                         result |= S_IXOTH;
  99
 100                 if (dir_mode) {
 101                         /* Inherit 666 component of parent directory mode */
 102                         result |= dir_mode & (S_IRUSR | S_IRGRP | S_IROTH | S_IWUSR | S_IWGRP | S_IWOTH);
 103                 } else {
 104                         /* Apply mode mask */
 105                         result &= lp_create_mask(SNUM(conn));
 106                         /* Add in force bits */
 107                         result |= lp_force_create_mode(SNUM(conn));
 108                 }
 109         }
 110
 111         DEBUG(3,("unix_mode(%s) returning 0%o\n",fname,(int)result ));
 112         return(result);
 113 }
 114
 115 /****************************************************************************
 116  Change a unix mode to a dos mode.
 117 ****************************************************************************/
 118
 119 uint32 dos_mode_from_sbuf(connection_struct *conn, SMB_STRUCT_STAT *sbuf)
 120 {
 121         int result = 0;
 122
 123         if ((sbuf->st_mode & S_IWUSR) == 0)
 124                 result |= aRONLY;
 125
 126         if (MAP_ARCHIVE(conn) && ((sbuf->st_mode & S_IXUSR) != 0))
 127                 result |= aARCH;
 128
 129         if (MAP_SYSTEM(conn) && ((sbuf->st_mode & S_IXGRP) != 0))
 130                 result |= aSYSTEM;
 131
 132         if (MAP_HIDDEN(conn) && ((sbuf->st_mode & S_IXOTH) != 0))
 133                 result |= aHIDDEN;
 134
 135         if (S_ISDIR(sbuf->st_mode))
 136                 result = aDIR | (result & aRONLY);
 137
 138 #if defined (HAVE_STAT_ST_BLOCKS) && defined (HAVE_STAT_ST_BLKSIZE)
 139         if (sbuf->st_size > sbuf->st_blocks * (SMB_OFF_T)sbuf->st_blksize) {
 140                 result |= FILE_ATTRIBUTE_SPARSE;
 141         }
 142 #endif
 143
 144 #ifdef S_ISLNK
 145 #if LINKS_READ_ONLY
 146         if (S_ISLNK(sbuf->st_mode) && S_ISDIR(sbuf->st_mode))
 147                 result |= aRONLY;
 148 #endif
 149 #endif
 150
 151         DEBUG(8,("dos_mode_from_sbuf returning "));
 152
 153         if (result & aHIDDEN) DEBUG(8, ("h"));
 154         if (result & aRONLY ) DEBUG(8, ("r"));
 155         if (result & aSYSTEM) DEBUG(8, ("s"));
 156         if (result & aDIR   ) DEBUG(8, ("d"));
 157         if (result & aARCH  ) DEBUG(8, ("a"));
 158
 159         DEBUG(8,("\n"));
 160         return result;
 161 }
 162
 163 /****************************************************************************
 164  Get DOS attributes from an EA.
 165 ****************************************************************************/
 166
 167 static BOOL get_ea_dos_attribute(connection_struct *conn, const char *path,SMB_STRUCT_STAT *sbuf, uint32 *pattr)
 168 {
 169         ssize_t sizeret;
 170         fstring attrstr;
 171         unsigned int dosattr;
 172
 173         if (!lp_store_dos_attributes(SNUM(conn))) {
 174                 return False;
 175         }
 176
 177         *pattr = 0;
 178
 179         sizeret = SMB_VFS_GETXATTR(conn, path, SAMBA_XATTR_DOS_ATTRIB, attrstr, sizeof(attrstr));
 180         if (sizeret == -1) {
 181 #if defined(ENOTSUP) && defined(ENOATTR)
 182                 if ((errno != ENOTSUP) && (errno != ENOATTR) && (errno != EACCES)) {
 183                         DEBUG(1,("get_ea_dos_attributes: Cannot get attribute from EA on file %s: Error = %s\n",
 184                                 path, strerror(errno) ));
 185                 }
 186 #endif
 187                 return False;
 188         }
 189         /* Null terminate string. */
 190         attrstr[sizeret] = 0;
 191         DEBUG(10,("get_ea_dos_attribute: %s attrstr = %s\n", path, attrstr));
 192
 193         if (sizeret < 2 || attrstr[0] != '0' || attrstr[1] != 'x' ||
 194                         sscanf(attrstr, "%x", &dosattr) != 1) {
 195                 DEBUG(1,("get_ea_dos_attributes: Badly formed DOSATTRIB on file %s - %s\n", path, attrstr));
 196                 return False;
 197         }
 198
 199         if (S_ISDIR(sbuf->st_mode)) {
 200                 dosattr |= aDIR;
 201         }
 202         *pattr = (uint32)(dosattr & SAMBA_ATTRIBUTES_MASK);
 203
 204         DEBUG(8,("get_ea_dos_attribute returning (0x%x)", dosattr));
 205
 206         if (dosattr & aHIDDEN) DEBUG(8, ("h"));
 207         if (dosattr & aRONLY ) DEBUG(8, ("r"));
 208         if (dosattr & aSYSTEM) DEBUG(8, ("s"));
 209         if (dosattr & aDIR   ) DEBUG(8, ("d"));
 210         if (dosattr & aARCH  ) DEBUG(8, ("a"));
 211
 212         DEBUG(8,("\n"));
 213
 214         return True;
 215 }
 216
 217 /****************************************************************************
 218  Set DOS attributes in an EA.
 219 ****************************************************************************/
 220
 221 static BOOL set_ea_dos_attribute(connection_struct *conn, const char *path, SMB_STRUCT_STAT *sbuf, uint32 dosmode)
 222 {
 223         fstring attrstr;
 224         files_struct *fsp = NULL;
 225         BOOL ret = False;
 226
 227         snprintf(attrstr, sizeof(attrstr)-1, "0x%x", dosmode & SAMBA_ATTRIBUTES_MASK);
 228         if (SMB_VFS_SETXATTR(conn, path, SAMBA_XATTR_DOS_ATTRIB, attrstr, strlen(attrstr), 0) == -1) {
 229                 if((errno != EPERM) && (errno != EACCES)) {
 230                         return False;
 231                 }
 232
 233                 /* We want DOS semantics, ie allow non owner with write permission to change the
 234                         bits on a file. Just like file_utime below.
 235                 */
 236
 237                 /* Check if we have write access. */
 238                 if(!CAN_WRITE(conn) || !lp_dos_filemode(SNUM(conn)))
 239                         return False;
 240
 241                 /*
 242                  * We need to open the file with write access whilst
 243                  * still in our current user context. This ensures we
 244                  * are not violating security in doing the setxattr.
 245                  */
 246
 247                 fsp = open_file_fchmod(conn,path,sbuf);
 248                 if (!fsp)
 249                         return ret;
 250                 become_root();
 251                 if (SMB_VFS_SETXATTR(conn, path, SAMBA_XATTR_DOS_ATTRIB, attrstr, strlen(attrstr), 0) == 0) {
 252                         ret = True;
 253                 }
 254                 unbecome_root();
 255                 close_file_fchmod(fsp);
 256                 return ret;
 257         }
 258         DEBUG(10,("set_ea_dos_attribute: set EA %s on file %s\n", attrstr, path));
 259         return True;
 260 }
 261
 262 /****************************************************************************
 263  Change a unix mode to a dos mode.
 264 ****************************************************************************/
 265
 266 uint32 dos_mode(connection_struct *conn, const char *path,SMB_STRUCT_STAT *sbuf)
 267 {
 268         uint32 result = 0;
 269
 270         DEBUG(8,("dos_mode: %s\n", path));
 271
 272         if (!VALID_STAT(*sbuf)) {
 273                 return 0;
 274         }
 275
 276         /* Get the DOS attributes from an EA by preference. */
 277         if (get_ea_dos_attribute(conn, path, sbuf, &result)) {
 278                 return result;
 279         }
 280
 281         result = dos_mode_from_sbuf(conn, sbuf);
 282
 283         /* Now do any modifications that depend on the path name. */
 284         /* hide files with a name starting with a . */
 285         if (lp_hide_dot_files(SNUM(conn))) {
 286                 const char *p = strrchr_m(path,'/');
 287                 if (p)
 288                         p++;
 289                 else
 290                         p = path;
 291
 292                 if (p[0] == '.' && p[1] != '.' && p[1] != 0)
 293                         result |= aHIDDEN;
 294         }
 295
 296         /* Optimization : Only call is_hidden_path if it's not already
 297            hidden. */
 298         if (!(result & aHIDDEN) && IS_HIDDEN_PATH(conn,path)) {
 299                 result |= aHIDDEN;
 300         }
 301
 302         DEBUG(8,("dos_mode returning "));
 303
 304         if (result & aHIDDEN) DEBUG(8, ("h"));
 305         if (result & aRONLY ) DEBUG(8, ("r"));
 306         if (result & aSYSTEM) DEBUG(8, ("s"));
 307         if (result & aDIR   ) DEBUG(8, ("d"));
 308         if (result & aARCH  ) DEBUG(8, ("a"));
 309
 310         DEBUG(8,("\n"));
 311
 312         return(result);
 313 }
 314
 315 /*******************************************************************
 316  chmod a file - but preserve some bits.
 317 ********************************************************************/
 318
 319 int file_set_dosmode(connection_struct *conn, const char *fname, uint32 dosmode, SMB_STRUCT_STAT *st)
 320 {
 321         SMB_STRUCT_STAT st1;
 322         int mask=0;
 323         mode_t tmp;
 324         mode_t unixmode;
 325         int ret = -1;
 326
 327         DEBUG(10,("file_set_dosmode: setting dos mode 0x%x on file %s\n", dosmode, fname));
 328         if (!st) {
 329                 st = &st1;
 330                 if (SMB_VFS_STAT(conn,fname,st))
 331                         return(-1);
 332         }
 333
 334         get_acl_group_bits(conn, fname, &st->st_mode);
 335
 336         if (S_ISDIR(st->st_mode))
 337                 dosmode |= aDIR;
 338         else
 339                 dosmode &= ~aDIR;
 340
 341         if (dos_mode(conn,fname,st) == dosmode)
 342                 return(0);
 343
 344         /* Store the DOS attributes in an EA by preference. */
 345         if (set_ea_dos_attribute(conn, fname, st, dosmode)) {
 346                 return 0;
 347         }
 348
 349         unixmode = unix_mode(conn,dosmode,fname);
 350
 351         /* preserve the s bits */
 352         mask |= (S_ISUID | S_ISGID);
 353
 354         /* preserve the t bit */
 355 #ifdef S_ISVTX
 356         mask |= S_ISVTX;
 357 #endif
 358
 359         /* possibly preserve the x bits */
 360         if (!MAP_ARCHIVE(conn))
 361                 mask |= S_IXUSR;
 362         if (!MAP_SYSTEM(conn))
 363                 mask |= S_IXGRP;
 364         if (!MAP_HIDDEN(conn))
 365                 mask |= S_IXOTH;
 366
 367         unixmode |= (st->st_mode & mask);
 368
 369         /* if we previously had any r bits set then leave them alone */
 370         if ((tmp = st->st_mode & (S_IRUSR|S_IRGRP|S_IROTH))) {
 371                 unixmode &= ~(S_IRUSR|S_IRGRP|S_IROTH);
 372                 unixmode |= tmp;
 373         }
 374
 375         /* if we previously had any w bits set then leave them alone
 376                 whilst adding in the new w bits, if the new mode is not rdonly */
 377         if (!IS_DOS_READONLY(dosmode)) {
 378                 unixmode |= (st->st_mode & (S_IWUSR|S_IWGRP|S_IWOTH));
 379         }
 380
 381         if ((ret = SMB_VFS_CHMOD(conn,fname,unixmode)) == 0)
 382                 return 0;
 383
 384         if((errno != EPERM) && (errno != EACCES))
 385                 return -1;
 386
 387         if(!lp_dos_filemode(SNUM(conn)))
 388                 return -1;
 389
 390         /* We want DOS semantics, ie allow non owner with write permission to change the
 391                 bits on a file. Just like file_utime below.
 392         */
 393
 394         /* Check if we have write access. */
 395         if (CAN_WRITE(conn)) {
 396                 /*
 397                  * We need to open the file with write access whilst
 398                  * still in our current user context. This ensures we
 399                  * are not violating security in doing the fchmod.
 400                  * This file open does *not* break any oplocks we are
 401                  * holding. We need to review this.... may need to
 402                  * break batch oplocks open by others. JRA.
 403                  */
 404                 files_struct *fsp = open_file_fchmod(conn,fname,st);
 405                 if (!fsp)
 406                         return -1;
 407                 become_root();
 408                 ret = SMB_VFS_FCHMOD(fsp, fsp->fd, unixmode);
 409                 unbecome_root();
 410                 close_file_fchmod(fsp);
 411         }
 412
 413         return( ret );
 414 }
 415
 416 /*******************************************************************
 417  Wrapper around dos_utime that possibly allows DOS semantics rather
 418  than POSIX.
 419 *******************************************************************/
 420
 421 int file_utime(connection_struct *conn, char *fname, struct utimbuf *times)
 422 {
 423         extern struct current_user current_user;
 424         SMB_STRUCT_STAT sb;
 425         int ret = -1;
 426
 427         errno = 0;
 428
 429         if(SMB_VFS_UTIME(conn,fname, times) == 0)
 430                 return 0;
 431
 432         if((errno != EPERM) && (errno != EACCES))
 433                 return -1;
 434
 435         if(!lp_dos_filetimes(SNUM(conn)))
 436                 return -1;
 437
 438         /* We have permission (given by the Samba admin) to
 439            break POSIX semantics and allow a user to change
 440            the time on a file they don't own but can write to
 441            (as DOS does).
 442          */
 443
 444         if(SMB_VFS_STAT(conn,fname,&sb) != 0)
 445                 return -1;
 446
 447         /* Check if we have write access. */
 448         if (CAN_WRITE(conn)) {
 449                 if (((sb.st_mode & S_IWOTH) || conn->admin_user ||
 450                         ((sb.st_mode & S_IWUSR) && current_user.uid==sb.st_uid) ||
 451                         ((sb.st_mode & S_IWGRP) &&
 452                                 in_group(sb.st_gid,current_user.gid,
 453                                         current_user.ngroups,current_user.groups)))) {
 454                         /* We are allowed to become root and change the filetime. */
 455                         become_root();
 456                         ret = SMB_VFS_UTIME(conn,fname, times);
 457                         unbecome_root();
 458                 }
 459         }
 460
 461         return ret;
 462 }
 463
 464 /*******************************************************************
 465  Change a filetime - possibly allowing DOS semantics.
 466 *******************************************************************/
 467
 468 BOOL set_filetime(connection_struct *conn, char *fname, time_t mtime)
 469 {
 470         struct utimbuf times;
 471
 472         if (null_mtime(mtime))
 473                 return(True);
 474
 475         times.modtime = times.actime = mtime;
 476
 477         if (file_utime(conn, fname, &times)) {
 478                 DEBUG(4,("set_filetime(%s) failed: %s\n",fname,strerror(errno)));
 479                 return False;
 480         }
 481
 482         return(True);
 483 }