lib/file-has-acl.c

   1 /* Test whether a file has a nontrivial ACL.  -*- coding: utf-8 -*-
   2
   3    Copyright (C) 2002-2003, 2005-2018 Free Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.
  17
  18    Written by Paul Eggert, Andreas Grünbacher, and Bruno Haible.  */
  19
  20 /* Without this pragma, gcc 4.7.0 20120126 may suggest that the
  21    file_has_acl function might be candidate for attribute 'const'  */
  22 #if (__GNUC__ == 4 && 6 <= __GNUC_MINOR__) || 4 < __GNUC__
  23 # pragma GCC diagnostic ignored "-Wsuggest-attribute=const"
  24 #endif
  25
  26 #include <config.h>
  27
  28 #include "acl.h"
  29
  30 #include "acl-internal.h"
  31
  32 #if GETXATTR_WITH_POSIX_ACLS
  33 # include <sys/xattr.h>
  34 # include <linux/xattr.h>
  35 #endif
  36
  37 /* Return 1 if NAME has a nontrivial access control list,
  38    0 if ACLs are not supported, or if NAME has no or only a base ACL,
  39    and -1 (setting errno) on error.  Note callers can determine
  40    if ACLs are not supported as errno is set in that case also.
  41    SB must be set to the stat buffer of NAME,
  42    obtained through stat() or lstat().  */
  43
  44 int
  45 file_has_acl (char const *name, struct stat const *sb)
  46 {
  47 #if USE_ACL
  48   if (! S_ISLNK (sb->st_mode))
  49     {
  50
  51 # if GETXATTR_WITH_POSIX_ACLS
  52
  53       ssize_t ret;
  54
  55       ret = getxattr (name, XATTR_NAME_POSIX_ACL_ACCESS, NULL, 0);
  56       if (ret < 0 && errno == ENODATA)
  57         ret = 0;
  58       else if (ret > 0)
  59         return 1;
  60
  61       if (ret == 0 && S_ISDIR (sb->st_mode))
  62         {
  63           ret = getxattr (name, XATTR_NAME_POSIX_ACL_DEFAULT, NULL, 0);
  64           if (ret < 0 && errno == ENODATA)
  65             ret = 0;
  66           else if (ret > 0)
  67             return 1;
  68         }
  69
  70       if (ret < 0)
  71         return - acl_errno_valid (errno);
  72       return ret;
  73
  74 # elif HAVE_ACL_GET_FILE
  75
  76       /* POSIX 1003.1e (draft 17 -- abandoned) specific version.  */
  77       /* Linux, FreeBSD, Mac OS X, IRIX, Tru64, Cygwin >= 2.5 */
  78       int ret;
  79
  80       if (HAVE_ACL_EXTENDED_FILE) /* Linux */
  81         {
  82           /* On Linux, acl_extended_file is an optimized function: It only
  83              makes two calls to getxattr(), one for ACL_TYPE_ACCESS, one for
  84              ACL_TYPE_DEFAULT.  */
  85           ret = acl_extended_file (name);
  86         }
  87       else /* FreeBSD, Mac OS X, IRIX, Tru64, Cygwin >= 2.5 */
  88         {
  89 #  if HAVE_ACL_TYPE_EXTENDED /* Mac OS X */
  90           /* On Mac OS X, acl_get_file (name, ACL_TYPE_ACCESS)
  91              and acl_get_file (name, ACL_TYPE_DEFAULT)
  92              always return NULL / EINVAL.  There is no point in making
  93              these two useless calls.  The real ACL is retrieved through
  94              acl_get_file (name, ACL_TYPE_EXTENDED).  */
  95           acl_t acl = acl_get_file (name, ACL_TYPE_EXTENDED);
  96           if (acl)
  97             {
  98               ret = acl_extended_nontrivial (acl);
  99               acl_free (acl);
 100             }
 101           else
 102             ret = -1;
 103 #  else /* FreeBSD, IRIX, Tru64, Cygwin >= 2.5 */
 104           acl_t acl = acl_get_file (name, ACL_TYPE_ACCESS);
 105           if (acl)
 106             {
 107               int saved_errno;
 108
 109               ret = acl_access_nontrivial (acl);
 110               saved_errno = errno;
 111               acl_free (acl);
 112               errno = saved_errno;
 113 #   if HAVE_ACL_FREE_TEXT /* Tru64 */
 114               /* On OSF/1, acl_get_file (name, ACL_TYPE_DEFAULT) always
 115                  returns NULL with errno not set.  There is no point in
 116                  making this call.  */
 117 #   else /* FreeBSD, IRIX, Cygwin >= 2.5 */
 118               /* On Linux, FreeBSD, IRIX, acl_get_file (name, ACL_TYPE_ACCESS)
 119                  and acl_get_file (name, ACL_TYPE_DEFAULT) on a directory
 120                  either both succeed or both fail; it depends on the
 121                  file system.  Therefore there is no point in making the second
 122                  call if the first one already failed.  */
 123               if (ret == 0 && S_ISDIR (sb->st_mode))
 124                 {
 125                   acl = acl_get_file (name, ACL_TYPE_DEFAULT);
 126                   if (acl)
 127                     {
 128 #    ifdef __CYGWIN__ /* Cygwin >= 2.5 */
 129                       ret = acl_access_nontrivial (acl);
 130                       saved_errno = errno;
 131                       acl_free (acl);
 132                       errno = saved_errno;
 133 #    else
 134                       ret = (0 < acl_entries (acl));
 135                       acl_free (acl);
 136 #    endif
 137                     }
 138                   else
 139                     ret = -1;
 140                 }
 141 #   endif
 142             }
 143           else
 144             ret = -1;
 145 #  endif
 146         }
 147       if (ret < 0)
 148         return - acl_errno_valid (errno);
 149       return ret;
 150
 151 # elif HAVE_FACL && defined GETACL /* Solaris, Cygwin < 2.5, not HP-UX */
 152
 153 #  if defined ACL_NO_TRIVIAL
 154
 155       /* Solaris 10 (newer version), which has additional API declared in
 156          <sys/acl.h> (acl_t) and implemented in libsec (acl_set, acl_trivial,
 157          acl_fromtext, ...).  */
 158       return acl_trivial (name);
 159
 160 #  else /* Solaris, Cygwin, general case */
 161
 162       /* Solaris 2.5 through Solaris 10, Cygwin, and contemporaneous versions
 163          of Unixware.  The acl() call returns the access and default ACL both
 164          at once.  */
 165       {
 166         /* Initially, try to read the entries into a stack-allocated buffer.
 167            Use malloc if it does not fit.  */
 168         enum
 169           {
 170             alloc_init = 4000 / sizeof (aclent_t), /* >= 3 */
 171             alloc_max = MIN (INT_MAX, SIZE_MAX / sizeof (aclent_t))
 172           };
 173         aclent_t buf[alloc_init];
 174         size_t alloc = alloc_init;
 175         aclent_t *entries = buf;
 176         aclent_t *malloced = NULL;
 177         int count;
 178
 179         for (;;)
 180           {
 181             count = acl (name, GETACL, alloc, entries);
 182             if (count < 0 && errno == ENOSPC)
 183               {
 184                 /* Increase the size of the buffer.  */
 185                 free (malloced);
 186                 if (alloc > alloc_max / 2)
 187                   {
 188                     errno = ENOMEM;
 189                     return -1;
 190                   }
 191                 alloc = 2 * alloc; /* <= alloc_max */
 192                 entries = malloced =
 193                   (aclent_t *) malloc (alloc * sizeof (aclent_t));
 194                 if (entries == NULL)
 195                   {
 196                     errno = ENOMEM;
 197                     return -1;
 198                   }
 199                 continue;
 200               }
 201             break;
 202           }
 203         if (count < 0)
 204           {
 205             if (errno == ENOSYS || errno == ENOTSUP)
 206               ;
 207             else
 208               {
 209                 int saved_errno = errno;
 210                 free (malloced);
 211                 errno = saved_errno;
 212                 return -1;
 213               }
 214           }
 215         else if (count == 0)
 216           ;
 217         else
 218           {
 219             /* Don't use MIN_ACL_ENTRIES:  It's set to 4 on Cygwin, but Cygwin
 220                returns only 3 entries for files with no ACL.  But this is safe:
 221                If there are more than 4 entries, there cannot be only the
 222                "user::", "group::", "other:", and "mask:" entries.  */
 223             if (count > 4)
 224               {
 225                 free (malloced);
 226                 return 1;
 227               }
 228
 229             if (acl_nontrivial (count, entries))
 230               {
 231                 free (malloced);
 232                 return 1;
 233               }
 234           }
 235         free (malloced);
 236       }
 237
 238 #   ifdef ACE_GETACL
 239       /* Solaris also has a different variant of ACLs, used in ZFS and NFSv4
 240          file systems (whereas the other ones are used in UFS file systems).  */
 241       {
 242         /* Initially, try to read the entries into a stack-allocated buffer.
 243            Use malloc if it does not fit.  */
 244         enum
 245           {
 246             alloc_init = 4000 / sizeof (ace_t), /* >= 3 */
 247             alloc_max = MIN (INT_MAX, SIZE_MAX / sizeof (ace_t))
 248           };
 249         ace_t buf[alloc_init];
 250         size_t alloc = alloc_init;
 251         ace_t *entries = buf;
 252         ace_t *malloced = NULL;
 253         int count;
 254
 255         for (;;)
 256           {
 257             count = acl (name, ACE_GETACL, alloc, entries);
 258             if (count < 0 && errno == ENOSPC)
 259               {
 260                 /* Increase the size of the buffer.  */
 261                 free (malloced);
 262                 if (alloc > alloc_max / 2)
 263                   {
 264                     errno = ENOMEM;
 265                     return -1;
 266                   }
 267                 alloc = 2 * alloc; /* <= alloc_max */
 268                 entries = malloced = (ace_t *) malloc (alloc * sizeof (ace_t));
 269                 if (entries == NULL)
 270                   {
 271                     errno = ENOMEM;
 272                     return -1;
 273                   }
 274                 continue;
 275               }
 276             break;
 277           }
 278         if (count < 0)
 279           {
 280             if (errno == ENOSYS || errno == EINVAL)
 281               ;
 282             else
 283               {
 284                 int saved_errno = errno;
 285                 free (malloced);
 286                 errno = saved_errno;
 287                 return -1;
 288               }
 289           }
 290         else if (count == 0)
 291           ;
 292         else
 293           {
 294             /* In the old (original Solaris 10) convention:
 295                If there are more than 3 entries, there cannot be only the
 296                ACE_OWNER, ACE_GROUP, ACE_OTHER entries.
 297                In the newer Solaris 10 and Solaris 11 convention:
 298                If there are more than 6 entries, there cannot be only the
 299                ACE_OWNER, ACE_GROUP, ACE_EVERYONE entries, each once with
 300                NEW_ACE_ACCESS_ALLOWED_ACE_TYPE and once with
 301                NEW_ACE_ACCESS_DENIED_ACE_TYPE.  */
 302             if (count > 6)
 303               {
 304                 free (malloced);
 305                 return 1;
 306               }
 307
 308             if (acl_ace_nontrivial (count, entries))
 309               {
 310                 free (malloced);
 311                 return 1;
 312               }
 313           }
 314         free (malloced);
 315       }
 316 #   endif
 317
 318       return 0;
 319 #  endif
 320
 321 # elif HAVE_GETACL /* HP-UX */
 322
 323       {
 324         struct acl_entry entries[NACLENTRIES];
 325         int count;
 326
 327         count = getacl (name, NACLENTRIES, entries);
 328
 329         if (count < 0)
 330           {
 331             /* ENOSYS is seen on newer HP-UX versions.
 332                EOPNOTSUPP is typically seen on NFS mounts.
 333                ENOTSUP was seen on Quantum StorNext file systems (cvfs).  */
 334             if (errno == ENOSYS || errno == EOPNOTSUPP || errno == ENOTSUP)
 335               ;
 336             else
 337               return -1;
 338           }
 339         else if (count == 0)
 340           return 0;
 341         else /* count > 0 */
 342           {
 343             if (count > NACLENTRIES)
 344               /* If NACLENTRIES cannot be trusted, use dynamic memory
 345                  allocation.  */
 346               abort ();
 347
 348             /* If there are more than 3 entries, there cannot be only the
 349                (uid,%), (%,gid), (%,%) entries.  */
 350             if (count > 3)
 351               return 1;
 352
 353             {
 354               struct stat statbuf;
 355
 356               if (stat (name, &statbuf) < 0)
 357                 return -1;
 358
 359               return acl_nontrivial (count, entries);
 360             }
 361           }
 362       }
 363
 364 #  if HAVE_ACLV_H /* HP-UX >= 11.11 */
 365
 366       {
 367         struct acl entries[NACLVENTRIES];
 368         int count;
 369
 370         count = acl ((char *) name, ACL_GET, NACLVENTRIES, entries);
 371
 372         if (count < 0)
 373           {
 374             /* EOPNOTSUPP is seen on NFS in HP-UX 11.11, 11.23.
 375                EINVAL is seen on NFS in HP-UX 11.31.  */
 376             if (errno == ENOSYS || errno == EOPNOTSUPP || errno == EINVAL)
 377               ;
 378             else
 379               return -1;
 380           }
 381         else if (count == 0)
 382           return 0;
 383         else /* count > 0 */
 384           {
 385             if (count > NACLVENTRIES)
 386               /* If NACLVENTRIES cannot be trusted, use dynamic memory
 387                  allocation.  */
 388               abort ();
 389
 390             /* If there are more than 4 entries, there cannot be only the
 391                four base ACL entries.  */
 392             if (count > 4)
 393               return 1;
 394
 395             return aclv_nontrivial (count, entries);
 396           }
 397       }
 398
 399 #  endif
 400
 401 # elif HAVE_ACLX_GET && defined ACL_AIX_WIP /* AIX */
 402
 403       acl_type_t type;
 404       char aclbuf[1024];
 405       void *acl = aclbuf;
 406       size_t aclsize = sizeof (aclbuf);
 407       mode_t mode;
 408
 409       for (;;)
 410         {
 411           /* The docs say that type being 0 is equivalent to ACL_ANY, but it
 412              is not true, in AIX 5.3.  */
 413           type.u64 = ACL_ANY;
 414           if (aclx_get (name, 0, &type, aclbuf, &aclsize, &mode) >= 0)
 415             break;
 416           if (errno == ENOSYS)
 417             return 0;
 418           if (errno != ENOSPC)
 419             {
 420               if (acl != aclbuf)
 421                 {
 422                   int saved_errno = errno;
 423                   free (acl);
 424                   errno = saved_errno;
 425                 }
 426               return -1;
 427             }
 428           aclsize = 2 * aclsize;
 429           if (acl != aclbuf)
 430             free (acl);
 431           acl = malloc (aclsize);
 432           if (acl == NULL)
 433             {
 434               errno = ENOMEM;
 435               return -1;
 436             }
 437         }
 438
 439       if (type.u64 == ACL_AIXC)
 440         {
 441           int result = acl_nontrivial ((struct acl *) acl);
 442           if (acl != aclbuf)
 443             free (acl);
 444           return result;
 445         }
 446       else if (type.u64 == ACL_NFS4)
 447         {
 448           int result = acl_nfs4_nontrivial ((nfs4_acl_int_t *) acl);
 449           if (acl != aclbuf)
 450             free (acl);
 451           return result;
 452         }
 453       else
 454         {
 455           /* A newer type of ACL has been introduced in the system.
 456              We should better support it.  */
 457           if (acl != aclbuf)
 458             free (acl);
 459           errno = EINVAL;
 460           return -1;
 461         }
 462
 463 # elif HAVE_STATACL /* older AIX */
 464
 465       union { struct acl a; char room[4096]; } u;
 466
 467       if (statacl ((char *) name, STX_NORMAL, &u.a, sizeof (u)) < 0)
 468         return -1;
 469
 470       return acl_nontrivial (&u.a);
 471
 472 # elif HAVE_ACLSORT /* NonStop Kernel */
 473
 474       {
 475         struct acl entries[NACLENTRIES];
 476         int count;
 477
 478         count = acl ((char *) name, ACL_GET, NACLENTRIES, entries);
 479
 480         if (count < 0)
 481           {
 482             if (errno == ENOSYS || errno == ENOTSUP)
 483               ;
 484             else
 485               return -1;
 486           }
 487         else if (count == 0)
 488           return 0;
 489         else /* count > 0 */
 490           {
 491             if (count > NACLENTRIES)
 492               /* If NACLENTRIES cannot be trusted, use dynamic memory
 493                  allocation.  */
 494               abort ();
 495
 496             /* If there are more than 4 entries, there cannot be only the
 497                four base ACL entries.  */
 498             if (count > 4)
 499               return 1;
 500
 501             return acl_nontrivial (count, entries);
 502           }
 503       }
 504
 505 # endif
 506     }
 507 #endif
 508
 509   return 0;
 510 }