source/modules/vfs_acl_xattr.c

   1 /*
   2  * Store Windows ACLs in xattrs.
   3  *
   4  * Copyright (C) Volker Lendecke, 2008
   5  * Copyright (C) Jeremy Allison, 2008
   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 3 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, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 /* NOTE: This is an experimental module, not yet finished. JRA. */
  22
  23 #include "includes.h"
  24 #include "librpc/gen_ndr/xattr.h"
  25 #include "librpc/gen_ndr/ndr_xattr.h"
  26
  27 #undef DBGC_CLASS
  28 #define DBGC_CLASS DBGC_VFS
  29
  30 static NTSTATUS parse_acl_blob(const DATA_BLOB *pblob,
  31                                 const struct timespec cts,
  32                                 uint32 security_info,
  33                                 struct security_descriptor **ppdesc)
  34 {
  35         TALLOC_CTX *ctx = talloc_tos();
  36         struct xattr_NTACL xacl;
  37         enum ndr_err_code ndr_err;
  38         size_t sd_size;
  39         struct timespec ts;
  40
  41         ndr_err = ndr_pull_struct_blob(pblob, ctx, &xacl,
  42                         (ndr_pull_flags_fn_t)ndr_pull_xattr_NTACL);
  43
  44         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
  45                 DEBUG(5, ("parse_acl_blob: ndr_pull_xattr_NTACL failed: %s\n",
  46                         ndr_errstr(ndr_err)));
  47                 return ndr_map_error2ntstatus(ndr_err);;
  48         }
  49
  50         if (xacl.version != 2) {
  51                 return NT_STATUS_REVISION_MISMATCH;
  52         }
  53
  54         /*
  55          * Check that the ctime timestamp is ealier
  56          * than the stored timestamp.
  57          */
  58
  59         ts = nt_time_to_unix_timespec(&xacl.info.sd_ts->last_changed);
  60
  61         if (timespec_compare(&cts, &ts) > 0) {
  62                 DEBUG(5, ("parse_acl_blob: stored ACL out of date.\n"));
  63                 return NT_STATUS_EA_CORRUPT_ERROR;
  64         }
  65
  66         *ppdesc = make_sec_desc(ctx, SEC_DESC_REVISION, SEC_DESC_SELF_RELATIVE,
  67                         (security_info & OWNER_SECURITY_INFORMATION)
  68                         ? xacl.info.sd_ts->sd->owner_sid : NULL,
  69                         (security_info & GROUP_SECURITY_INFORMATION)
  70                         ? xacl.info.sd_ts->sd->group_sid : NULL,
  71                         (security_info & SACL_SECURITY_INFORMATION)
  72                         ? xacl.info.sd_ts->sd->sacl : NULL,
  73                         (security_info & DACL_SECURITY_INFORMATION)
  74                         ? xacl.info.sd_ts->sd->dacl : NULL,
  75                         &sd_size);
  76
  77         TALLOC_FREE(xacl.info.sd);
  78
  79         return (*ppdesc != NULL) ? NT_STATUS_OK : NT_STATUS_NO_MEMORY;
  80 }
  81
  82 static NTSTATUS get_acl_blob(TALLOC_CTX *ctx,
  83                         vfs_handle_struct *handle,
  84                         files_struct *fsp,
  85                         const char *name,
  86                         DATA_BLOB *pblob)
  87 {
  88         size_t size = 1024;
  89         uint8_t *val = NULL;
  90         uint8_t *tmp;
  91         ssize_t sizeret;
  92         int saved_errno;
  93
  94         ZERO_STRUCTP(pblob);
  95
  96   again:
  97
  98         tmp = TALLOC_REALLOC_ARRAY(ctx, val, uint8_t, size);
  99         if (tmp == NULL) {
 100                 TALLOC_FREE(val);
 101                 return NT_STATUS_NO_MEMORY;
 102         }
 103         val = tmp;
 104
 105         become_root();
 106         if (fsp) {
 107                 sizeret = SMB_VFS_FGETXATTR(fsp, XATTR_NTACL_NAME, val, size);
 108         } else {
 109                 sizeret = SMB_VFS_GETXATTR(handle->conn, name,
 110                                         XATTR_NTACL_NAME, val, size);
 111         }
 112         if (sizeret == -1) {
 113                 saved_errno = errno;
 114         }
 115         unbecome_root();
 116
 117         /* Max ACL size is 65536 bytes. */
 118         if (sizeret == -1) {
 119                 errno = saved_errno;
 120                 if ((errno == ERANGE) && (size != 65536)) {
 121                         /* Too small, try again. */
 122                         size = 65536;
 123                         goto again;
 124                 }
 125
 126                 /* Real error - exit here. */
 127                 TALLOC_FREE(val);
 128                 return map_nt_error_from_unix(errno);
 129         }
 130
 131         pblob->data = val;
 132         pblob->length = sizeret;
 133         return NT_STATUS_OK;
 134 }
 135
 136 static int mkdir_acl_xattr(vfs_handle_struct *handle,  const char *path, mode_t mode)
 137 {
 138         return SMB_VFS_NEXT_MKDIR(handle, path, mode);
 139 }
 140
 141 static int rmdir_acl_xattr(vfs_handle_struct *handle,  const char *path)
 142 {
 143         return SMB_VFS_NEXT_RMDIR(handle, path);
 144 }
 145
 146 static int open_acl_xattr(vfs_handle_struct *handle,  const char *fname, files_struct *fsp, int flags, mode_t mode)
 147 {
 148         return SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode);
 149 }
 150
 151 static int unlink_acl_xattr(vfs_handle_struct *handle,  const char *fname)
 152 {
 153         return SMB_VFS_NEXT_UNLINK(handle, fname);
 154 }
 155
 156 static NTSTATUS get_nt_acl_xattr_internal(vfs_handle_struct *handle,
 157                                         files_struct *fsp,
 158                                         const char *name,
 159                                         uint32 security_info,
 160                                         SEC_DESC **ppdesc)
 161 {
 162         TALLOC_CTX *ctx = talloc_tos();
 163         DATA_BLOB blob;
 164         SMB_STRUCT_STAT sbuf;
 165         NTSTATUS status;
 166
 167         if (fsp && name == NULL) {
 168                 name = fsp->fsp_name;
 169         }
 170
 171         DEBUG(10, ("get_nt_acl_xattr_internal: name=%s\n", name));
 172
 173         status = get_acl_blob(ctx, handle, fsp, name, &blob);
 174         if (!NT_STATUS_IS_OK(status)) {
 175                 DEBUG(10, ("get_acl_blob returned %s\n", nt_errstr(status)));
 176                 return status;
 177         }
 178
 179         if (fsp && fsp->fh->fd != -1) {
 180                 if (SMB_VFS_FSTAT(fsp, &sbuf) == -1) {
 181                         return map_nt_error_from_unix(errno);
 182                 }
 183         } else {
 184                 if (SMB_VFS_STAT(handle->conn, name, &sbuf) == -1) {
 185                         return map_nt_error_from_unix(errno);
 186                 }
 187         }
 188
 189         status = parse_acl_blob(&blob, get_ctimespec(&sbuf),
 190                         security_info, ppdesc);
 191         if (!NT_STATUS_IS_OK(status)) {
 192                 DEBUG(10, ("parse_acl_blob returned %s\n",
 193                                 nt_errstr(status)));
 194                 return status;
 195         }
 196
 197         TALLOC_FREE(blob.data);
 198         return status;
 199 }
 200
 201 static NTSTATUS fget_nt_acl_xattr(vfs_handle_struct *handle, files_struct *fsp,
 202         uint32 security_info, SEC_DESC **ppdesc)
 203 {
 204         NTSTATUS status = get_nt_acl_xattr_internal(handle, fsp,
 205                                 NULL, security_info, ppdesc);
 206         if (NT_STATUS_IS_OK(status)) {
 207                 return NT_STATUS_OK;
 208         }
 209         return SMB_VFS_NEXT_FGET_NT_ACL(handle, fsp,
 210                         security_info, ppdesc);
 211 }
 212
 213 static NTSTATUS get_nt_acl_xattr(vfs_handle_struct *handle,
 214         const char *name, uint32 security_info, SEC_DESC **ppdesc)
 215 {
 216         NTSTATUS status = get_nt_acl_xattr_internal(handle, NULL,
 217                                 name, security_info, ppdesc);
 218         if (NT_STATUS_IS_OK(status)) {
 219                 return NT_STATUS_OK;
 220         }
 221         return SMB_VFS_NEXT_GET_NT_ACL(handle, name,
 222                         security_info, ppdesc);
 223 }
 224
 225 static NTSTATUS create_acl_blob(SEC_DESC *psd, DATA_BLOB *pblob)
 226 {
 227         struct xattr_NTACL xacl;
 228         struct security_descriptor_timestamp sd_ts;
 229         enum ndr_err_code ndr_err;
 230         TALLOC_CTX *ctx = talloc_tos();
 231         struct timespec curr = timespec_current();
 232
 233         ZERO_STRUCT(xacl);
 234         ZERO_STRUCT(sd_ts);
 235
 236         /* Horrid hack as setting an xattr changes the ctime
 237          * on Linux. This gives a race of 1 second during
 238          * which we would not see a POSIX ACL set.
 239          */
 240         curr.tv_sec += 1;
 241
 242         xacl.version = 2;
 243         xacl.info.sd_ts = &sd_ts;
 244         xacl.info.sd_ts->sd = psd;
 245         unix_timespec_to_nt_time(&xacl.info.sd_ts->last_changed, curr);
 246
 247         ndr_err = ndr_push_struct_blob(
 248                         pblob, ctx, &xacl,
 249                         (ndr_push_flags_fn_t)ndr_push_xattr_NTACL);
 250
 251         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 252                 DEBUG(5, ("create_acl_blob: ndr_push_xattr_NTACL failed: %s\n",
 253                         ndr_errstr(ndr_err)));
 254                 return ndr_map_error2ntstatus(ndr_err);;
 255         }
 256
 257         return NT_STATUS_OK;
 258 }
 259
 260 static NTSTATUS store_acl_blob(files_struct *fsp,
 261                                 DATA_BLOB *pblob)
 262 {
 263         int ret;
 264         int saved_errno;
 265
 266         become_root();
 267         ret = SMB_VFS_FSETXATTR(fsp, XATTR_NTACL_NAME,
 268                         pblob->data, pblob->length, 0);
 269         if (ret) {
 270                 saved_errno = errno;
 271         }
 272         unbecome_root();
 273         if (ret) {
 274                 errno = saved_errno;
 275                 DEBUG(5, ("store_acl_blob: fsetxattr failed for file %s "
 276                         "with error %s\n",
 277                         fsp->fsp_name,
 278                         strerror(errno) ));
 279                 return map_nt_error_from_unix(errno);
 280         }
 281         return NT_STATUS_OK;
 282 }
 283
 284 static NTSTATUS fset_nt_acl_xattr(vfs_handle_struct *handle, files_struct *fsp,
 285         uint32 security_info_sent, SEC_DESC *psd)
 286 {
 287         NTSTATUS status;
 288         DATA_BLOB blob;
 289
 290         status = SMB_VFS_NEXT_FSET_NT_ACL(handle, fsp, security_info_sent, psd);
 291         if (!NT_STATUS_IS_OK(status)) {
 292                 return status;
 293         }
 294
 295         create_acl_blob(psd, &blob);
 296         store_acl_blob(fsp, &blob);
 297
 298         return NT_STATUS_OK;
 299 }
 300
 301 /* VFS operations structure */
 302
 303 static vfs_op_tuple skel_op_tuples[] =
 304 {
 305         {SMB_VFS_OP(mkdir_acl_xattr), SMB_VFS_OP_MKDIR, SMB_VFS_LAYER_TRANSPARENT},
 306         {SMB_VFS_OP(rmdir_acl_xattr), SMB_VFS_OP_RMDIR, SMB_VFS_LAYER_TRANSPARENT},
 307         {SMB_VFS_OP(open_acl_xattr),  SMB_VFS_OP_OPEN,  SMB_VFS_LAYER_TRANSPARENT},
 308         {SMB_VFS_OP(unlink_acl_xattr),SMB_VFS_OP_UNLINK,SMB_VFS_LAYER_TRANSPARENT},
 309
 310         /* NT File ACL operations */
 311
 312         {SMB_VFS_OP(fget_nt_acl_xattr),SMB_VFS_OP_FGET_NT_ACL,SMB_VFS_LAYER_TRANSPARENT},
 313         {SMB_VFS_OP(get_nt_acl_xattr), SMB_VFS_OP_GET_NT_ACL, SMB_VFS_LAYER_TRANSPARENT},
 314         {SMB_VFS_OP(fset_nt_acl_xattr),SMB_VFS_OP_FSET_NT_ACL,SMB_VFS_LAYER_TRANSPARENT},
 315
 316         {SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP}
 317 };
 318
 319 NTSTATUS vfs_acl_xattr_init(void)
 320 {
 321         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "acl_xattr", skel_op_tuples);
 322 }