mirror of
https://github.com/samba-team/samba.git
synced 2025-01-12 09:18:10 +03:00
Move some access check functions that are not posix-acl specific
to a new source file of their own. Michael
This commit is contained in:
Michael Adam
parent
c61b4222d3
commit
9dd18bb534
@ -542,6 +542,7 @@ SMBD_OBJ_SRV = smbd/files.o smbd/chgpasswd.o smbd/connection.o \
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smbd/quotas.o smbd/ntquotas.o $(AFS_OBJ) smbd/msdfs.o \
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$(AFS_SETTOKEN_OBJ) smbd/aio.o smbd/statvfs.o \
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smbd/dmapi.o \
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smbd/file_access.o \
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$(MANGLE_OBJ) @VFS_STATIC@
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SMBD_OBJ_BASE = $(PARAM_WITHOUT_REG_OBJ) $(SMBD_OBJ_SRV) $(LIBSMB_OBJ) \
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239
source/smbd/file_access.c
Normal file
239
source/smbd/file_access.c
Normal file
@ -0,0 +1,239 @@
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/*
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Unix SMB/CIFS implementation.
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Check access to files based on security descriptors.
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Copyright (C) Jeremy Allison 2005-2006.
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Copyright (C) Michael Adam 2007.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "includes.h"
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extern struct current_user current_user;
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#undef DBGC_CLASS
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#define DBGC_CLASS DBGC_ACLS
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/****************************************************************************
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Helper function that gets a security descriptor by connection and
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file name.
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NOTE: This is transitional, in the sense that SMB_VFS_GET_NT_ACL really
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should *not* get a files_struct pointer but a connection_struct ptr
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(automatic by the vfs handle) and the file name and _use_ that!
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****************************************************************************/
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static NTSTATUS conn_get_nt_acl(TALLOC_CTX *mem_ctx,
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struct connection_struct *conn,
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const char *fname,
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SMB_STRUCT_STAT *psbuf,
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struct security_descriptor **psd)
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{
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NTSTATUS status;
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struct files_struct *fsp = NULL;
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struct security_descriptor *secdesc = NULL;
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size_t secdesc_size;
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if (!VALID_STAT(*psbuf)) {
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if (SMB_VFS_STAT(conn, fname, psbuf) != 0) {
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return map_nt_error_from_unix(errno);
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}
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}
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/* fake a files_struct ptr: */
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status = open_file_stat(conn, NULL, fname, psbuf, &fsp);
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/* Perhaps it is a directory */
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if (NT_STATUS_EQUAL(status, NT_STATUS_FILE_IS_A_DIRECTORY)) {
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status = open_directory(conn, NULL, fname, psbuf,
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READ_CONTROL_ACCESS,
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FILE_SHARE_READ|FILE_SHARE_WRITE,
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FILE_OPEN,
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0,
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FILE_ATTRIBUTE_DIRECTORY,
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NULL, &fsp);
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}
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if (!NT_STATUS_IS_OK(status)) {
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DEBUG(3, ("Unable to open file %s: %s\n", fname,
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nt_errstr(status)));
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return status;
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}
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secdesc_size = SMB_VFS_GET_NT_ACL(fsp, fname,
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(OWNER_SECURITY_INFORMATION |
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GROUP_SECURITY_INFORMATION |
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DACL_SECURITY_INFORMATION),
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&secdesc);
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if (secdesc_size == 0) {
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DEBUG(5, ("Unable to get NT ACL for file %s\n", fname));
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return NT_STATUS_ACCESS_DENIED;
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}
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*psd = talloc_move(mem_ctx, &secdesc);
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close_file(fsp, NORMAL_CLOSE);
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return NT_STATUS_OK;
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}
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static bool can_access_file_acl(struct connection_struct *conn,
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const char * fname, SMB_STRUCT_STAT *psbuf,
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uint32_t access_mask)
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{
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bool result;
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NTSTATUS status;
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uint32_t access_granted;
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struct security_descriptor *secdesc = NULL;
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status = conn_get_nt_acl(talloc_tos(), conn, fname, psbuf, &secdesc);
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if (!NT_STATUS_IS_OK(status)) {
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DEBUG(5, ("Could not get acl: %s\n", nt_errstr(status)));
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return false;
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}
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result = se_access_check(secdesc, current_user.nt_user_token,
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access_mask, &access_granted, &status);
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TALLOC_FREE(secdesc);
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return result;
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}
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/****************************************************************************
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Actually emulate the in-kernel access checking for delete access. We need
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this to successfully return ACCESS_DENIED on a file open for delete access.
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****************************************************************************/
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bool can_delete_file_in_directory(connection_struct *conn, const char *fname)
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{
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SMB_STRUCT_STAT sbuf;
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TALLOC_CTX *ctx = talloc_tos();
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char *dname = NULL;
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if (!CAN_WRITE(conn)) {
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return False;
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}
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/* Get the parent directory permission mask and owners. */
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if (!parent_dirname_talloc(ctx,
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fname,
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&dname,
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NULL)) {
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return False;
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}
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if(SMB_VFS_STAT(conn, dname, &sbuf) != 0) {
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return False;
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}
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/* fast paths first */
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if (!S_ISDIR(sbuf.st_mode)) {
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return False;
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}
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if (current_user.ut.uid == 0 || conn->admin_user) {
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/* I'm sorry sir, I didn't know you were root... */
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return True;
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}
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/* Check primary owner write access. */
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if (current_user.ut.uid == sbuf.st_uid) {
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return (sbuf.st_mode & S_IWUSR) ? True : False;
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}
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#ifdef S_ISVTX
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/* sticky bit means delete only by owner or root. */
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if (sbuf.st_mode & S_ISVTX) {
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SMB_STRUCT_STAT sbuf_file;
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if(SMB_VFS_STAT(conn, fname, &sbuf_file) != 0) {
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if (errno == ENOENT) {
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/* If the file doesn't already exist then
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* yes we'll be able to delete it. */
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return True;
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}
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return False;
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}
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/*
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* Patch from SATOH Fumiyasu <fumiyas@miraclelinux.com>
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* for bug #3348. Don't assume owning sticky bit
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* directory means write access allowed.
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*/
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if (current_user.ut.uid != sbuf_file.st_uid) {
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return False;
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}
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}
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#endif
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/* now for ACL checks */
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return can_access_file_acl(conn, dname, &sbuf, FILE_WRITE_DATA);
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}
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/****************************************************************************
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Actually emulate the in-kernel access checking for read/write access. We need
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this to successfully check for ability to write for dos filetimes.
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Note this doesn't take into account share write permissions.
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****************************************************************************/
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bool can_access_file(connection_struct *conn, const char *fname, SMB_STRUCT_STAT *psbuf, uint32 access_mask)
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{
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if (!(access_mask & (FILE_READ_DATA|FILE_WRITE_DATA))) {
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return False;
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}
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access_mask &= (FILE_READ_DATA|FILE_WRITE_DATA);
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/* some fast paths first */
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DEBUG(10,("can_access_file: requesting 0x%x on file %s\n",
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(unsigned int)access_mask, fname ));
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if (current_user.ut.uid == 0 || conn->admin_user) {
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/* I'm sorry sir, I didn't know you were root... */
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return True;
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}
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if (!VALID_STAT(*psbuf)) {
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/* Get the file permission mask and owners. */
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if(SMB_VFS_STAT(conn, fname, psbuf) != 0) {
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return False;
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}
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}
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/* Check primary owner access. */
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if (current_user.ut.uid == psbuf->st_uid) {
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switch (access_mask) {
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case FILE_READ_DATA:
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return (psbuf->st_mode & S_IRUSR) ? True : False;
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case FILE_WRITE_DATA:
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return (psbuf->st_mode & S_IWUSR) ? True : False;
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default: /* FILE_READ_DATA|FILE_WRITE_DATA */
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if ((psbuf->st_mode & (S_IWUSR|S_IRUSR)) == (S_IWUSR|S_IRUSR)) {
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return True;
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} else {
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return False;
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}
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}
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}
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/* now for ACL checks */
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return can_access_file_acl(conn, fname, psbuf, access_mask);
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}
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/****************************************************************************
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Userspace check for write access.
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Note this doesn't take into account share write permissions.
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****************************************************************************/
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bool can_write_to_file(connection_struct *conn, const char *fname, SMB_STRUCT_STAT *psbuf)
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{
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return can_access_file(conn, fname, psbuf, FILE_WRITE_DATA);
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}
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@ -4125,218 +4125,6 @@ bool set_unix_posix_acl(connection_struct *conn, files_struct *fsp, const char *
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return True;
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}
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/****************************************************************************
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Helper function that gets a security descriptor by connection and
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file name.
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NOTE: This is transitional, in the sense that SMB_VFS_GET_NT_ACL really
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should *not* get a files_struct pointer but a connection_struct ptr
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(automatic by the vfs handle) and the file name and _use_ that!
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****************************************************************************/
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static NTSTATUS conn_get_nt_acl(TALLOC_CTX *mem_ctx,
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struct connection_struct *conn,
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const char *fname,
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SMB_STRUCT_STAT *psbuf,
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struct security_descriptor **psd)
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{
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NTSTATUS status;
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struct files_struct *fsp = NULL;
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struct security_descriptor *secdesc = NULL;
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size_t secdesc_size;
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if (!VALID_STAT(*psbuf)) {
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if (SMB_VFS_STAT(conn, fname, psbuf) != 0) {
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return map_nt_error_from_unix(errno);
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}
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}
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/* fake a files_struct ptr: */
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status = open_file_stat(conn, NULL, fname, psbuf, &fsp);
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/* Perhaps it is a directory */
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if (NT_STATUS_EQUAL(status, NT_STATUS_FILE_IS_A_DIRECTORY)) {
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status = open_directory(conn, NULL, fname, psbuf,
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READ_CONTROL_ACCESS,
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FILE_SHARE_READ|FILE_SHARE_WRITE,
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FILE_OPEN,
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0,
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FILE_ATTRIBUTE_DIRECTORY,
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NULL, &fsp);
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}
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if (!NT_STATUS_IS_OK(status)) {
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DEBUG(3, ("Unable to open file %s: %s\n", fname,
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nt_errstr(status)));
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return status;
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}
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secdesc_size = SMB_VFS_GET_NT_ACL(fsp, fname,
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(OWNER_SECURITY_INFORMATION |
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GROUP_SECURITY_INFORMATION |
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DACL_SECURITY_INFORMATION),
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&secdesc);
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if (secdesc_size == 0) {
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DEBUG(5, ("Unable to get NT ACL for file %s\n", fname));
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return NT_STATUS_ACCESS_DENIED;
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}
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*psd = talloc_move(mem_ctx, &secdesc);
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close_file(fsp, NORMAL_CLOSE);
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return NT_STATUS_OK;
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}
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static bool can_access_file_acl(struct connection_struct *conn,
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const char * fname, SMB_STRUCT_STAT *psbuf,
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uint32_t access_mask)
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{
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bool result;
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NTSTATUS status;
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uint32_t access_granted;
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struct security_descriptor *secdesc = NULL;
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status = conn_get_nt_acl(talloc_tos(), conn, fname, psbuf, &secdesc);
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if (!NT_STATUS_IS_OK(status)) {
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DEBUG(5, ("Could not get acl: %s\n", nt_errstr(status)));
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return false;
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}
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result = se_access_check(secdesc, current_user.nt_user_token,
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access_mask, &access_granted, &status);
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TALLOC_FREE(secdesc);
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return result;
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}
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/****************************************************************************
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Actually emulate the in-kernel access checking for delete access. We need
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this to successfully return ACCESS_DENIED on a file open for delete access.
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****************************************************************************/
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bool can_delete_file_in_directory(connection_struct *conn, const char *fname)
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{
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SMB_STRUCT_STAT sbuf;
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TALLOC_CTX *ctx = talloc_tos();
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char *dname = NULL;
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if (!CAN_WRITE(conn)) {
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return False;
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}
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/* Get the parent directory permission mask and owners. */
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if (!parent_dirname_talloc(ctx,
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fname,
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&dname,
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NULL)) {
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return False;
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}
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if(SMB_VFS_STAT(conn, dname, &sbuf) != 0) {
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return False;
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}
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/* fast paths first */
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if (!S_ISDIR(sbuf.st_mode)) {
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return False;
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}
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if (current_user.ut.uid == 0 || conn->admin_user) {
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/* I'm sorry sir, I didn't know you were root... */
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return True;
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}
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/* Check primary owner write access. */
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if (current_user.ut.uid == sbuf.st_uid) {
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return (sbuf.st_mode & S_IWUSR) ? True : False;
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}
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#ifdef S_ISVTX
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/* sticky bit means delete only by owner or root. */
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if (sbuf.st_mode & S_ISVTX) {
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SMB_STRUCT_STAT sbuf_file;
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if(SMB_VFS_STAT(conn, fname, &sbuf_file) != 0) {
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if (errno == ENOENT) {
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/* If the file doesn't already exist then
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* yes we'll be able to delete it. */
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return True;
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}
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return False;
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}
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/*
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* Patch from SATOH Fumiyasu <fumiyas@miraclelinux.com>
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* for bug #3348. Don't assume owning sticky bit
|
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* directory means write access allowed.
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*/
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if (current_user.ut.uid != sbuf_file.st_uid) {
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return False;
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}
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}
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#endif
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/* now for ACL checks */
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return can_access_file_acl(conn, dname, &sbuf, FILE_WRITE_DATA);
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}
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|
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/****************************************************************************
|
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Actually emulate the in-kernel access checking for read/write access. We need
|
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this to successfully check for ability to write for dos filetimes.
|
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Note this doesn't take into account share write permissions.
|
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****************************************************************************/
|
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|
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bool can_access_file(connection_struct *conn, const char *fname, SMB_STRUCT_STAT *psbuf, uint32 access_mask)
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{
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if (!(access_mask & (FILE_READ_DATA|FILE_WRITE_DATA))) {
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return False;
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}
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access_mask &= (FILE_READ_DATA|FILE_WRITE_DATA);
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/* some fast paths first */
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DEBUG(10,("can_access_file: requesting 0x%x on file %s\n",
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(unsigned int)access_mask, fname ));
|
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if (current_user.ut.uid == 0 || conn->admin_user) {
|
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/* I'm sorry sir, I didn't know you were root... */
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return True;
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}
|
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if (!VALID_STAT(*psbuf)) {
|
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/* Get the file permission mask and owners. */
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if(SMB_VFS_STAT(conn, fname, psbuf) != 0) {
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return False;
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}
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}
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/* Check primary owner access. */
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if (current_user.ut.uid == psbuf->st_uid) {
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switch (access_mask) {
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case FILE_READ_DATA:
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return (psbuf->st_mode & S_IRUSR) ? True : False;
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case FILE_WRITE_DATA:
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return (psbuf->st_mode & S_IWUSR) ? True : False;
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default: /* FILE_READ_DATA|FILE_WRITE_DATA */
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if ((psbuf->st_mode & (S_IWUSR|S_IRUSR)) == (S_IWUSR|S_IRUSR)) {
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return True;
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} else {
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return False;
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}
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}
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}
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/* now for ACL checks */
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return can_access_file_acl(conn, fname, psbuf, access_mask);
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}
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/****************************************************************************
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Userspace check for write access.
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Note this doesn't take into account share write permissions.
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****************************************************************************/
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bool can_write_to_file(connection_struct *conn, const char *fname, SMB_STRUCT_STAT *psbuf)
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{
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return can_access_file(conn, fname, psbuf, FILE_WRITE_DATA);
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}
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/********************************************************************
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Pull the NT ACL from a file on disk or the OpenEventlog() access
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check. Caller is responsible for freeing the returned security
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