/*
Unix SMB/CIFS implementation.
Check access to files based on security descriptors.
Copyright (C) Jeremy Allison 2005-2006.
Copyright (C) Michael Adam 2007.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
#include "includes.h"
#undef DBGC_CLASS
#define DBGC_CLASS DBGC_ACLS
/**
* Security descriptor / NT Token level access check function.
*/
bool can_access_file_acl(struct connection_struct *conn,
const char * fname,
uint32_t access_mask)
{
NTSTATUS status;
uint32_t access_granted;
struct security_descriptor *secdesc = NULL;
status = SMB_VFS_GET_NT_ACL(conn, fname,
(OWNER_SECURITY_INFORMATION |
GROUP_SECURITY_INFORMATION |
DACL_SECURITY_INFORMATION),
&secdesc);
if (!NT_STATUS_IS_OK(status)) {
DEBUG(5, ("Could not get acl: %s\n", nt_errstr(status)));
return false;
}
status = se_access_check(secdesc, conn->server_info->ptok,
access_mask, &access_granted);
TALLOC_FREE(secdesc);
return NT_STATUS_IS_OK(status);
}
/****************************************************************************
Actually emulate the in-kernel access checking for delete access. We need
this to successfully return ACCESS_DENIED on a file open for delete access.
****************************************************************************/
bool can_delete_file_in_directory(connection_struct *conn, const char *fname)
{
SMB_STRUCT_STAT sbuf;
TALLOC_CTX *ctx = talloc_tos();
char *dname = NULL;
if (!CAN_WRITE(conn)) {
return False;
}
/* Get the parent directory permission mask and owners. */
if (!parent_dirname(ctx, fname, &dname, NULL)) {
return False;
}
if(SMB_VFS_STAT(conn, dname, &sbuf) != 0) {
return False;
}
/* fast paths first */
if (!S_ISDIR(sbuf.st_mode)) {
return False;
}
if (conn->server_info->utok.uid == 0 || conn->admin_user) {
/* I'm sorry sir, I didn't know you were root... */
return True;
}
#ifdef S_ISVTX
/* sticky bit means delete only by owner or root. */
if (sbuf.st_mode & S_ISVTX) {
SMB_STRUCT_STAT sbuf_file;
if(SMB_VFS_STAT(conn, fname, &sbuf_file) != 0) {
if (errno == ENOENT) {
/* If the file doesn't already exist then
* yes we'll be able to delete it. */
return True;
}
return False;
}
/*
* Patch from SATOH Fumiyasu
* for bug #3348. Don't assume owning sticky bit
* directory means write access allowed.
*/
if (conn->server_info->utok.uid != sbuf_file.st_uid) {
return False;
}
}
#endif
/* now for ACL checks */
/*
* There's two ways to get the permission to delete a file: First by
* having the DELETE bit on the file itself and second if that does
* not help, by the DELETE_CHILD bit on the containing directory.
*
* Here we only check the directory permissions, we will
* check the file DELETE permission separately.
*/
return can_access_file_acl(conn, dname, FILE_DELETE_CHILD);
}
/****************************************************************************
Actually emulate the in-kernel access checking for read/write access. We need
this to successfully check for ability to write for dos filetimes.
Note this doesn't take into account share write permissions.
****************************************************************************/
bool can_access_file_data(connection_struct *conn, const char *fname, SMB_STRUCT_STAT *psbuf, uint32 access_mask)
{
if (!(access_mask & (FILE_READ_DATA|FILE_WRITE_DATA))) {
return False;
}
access_mask &= (FILE_READ_DATA|FILE_WRITE_DATA);
/* some fast paths first */
DEBUG(10,("can_access_file_data: requesting 0x%x on file %s\n",
(unsigned int)access_mask, fname ));
if (conn->server_info->utok.uid == 0 || conn->admin_user) {
/* I'm sorry sir, I didn't know you were root... */
return True;
}
if (!VALID_STAT(*psbuf)) {
/* Get the file permission mask and owners. */
if(SMB_VFS_STAT(conn, fname, psbuf) != 0) {
return False;
}
}
/* Check primary owner access. */
if (conn->server_info->utok.uid == psbuf->st_uid) {
switch (access_mask) {
case FILE_READ_DATA:
return (psbuf->st_mode & S_IRUSR) ? True : False;
case FILE_WRITE_DATA:
return (psbuf->st_mode & S_IWUSR) ? True : False;
default: /* FILE_READ_DATA|FILE_WRITE_DATA */
if ((psbuf->st_mode & (S_IWUSR|S_IRUSR)) == (S_IWUSR|S_IRUSR)) {
return True;
} else {
return False;
}
}
}
/* now for ACL checks */
return can_access_file_acl(conn, fname, access_mask);
}
/****************************************************************************
Userspace check for write access.
Note this doesn't take into account share write permissions.
****************************************************************************/
bool can_write_to_file(connection_struct *conn, const char *fname, SMB_STRUCT_STAT *psbuf)
{
return can_access_file_data(conn, fname, psbuf, FILE_WRITE_DATA);
}
/****************************************************************************
Check for an existing default Windows ACL on a directory.
****************************************************************************/
bool directory_has_default_acl(connection_struct *conn, const char *fname)
{
/* returns talloced off tos. */
struct security_descriptor *secdesc = NULL;
unsigned int i;
NTSTATUS status = SMB_VFS_GET_NT_ACL(conn, fname,
DACL_SECURITY_INFORMATION, &secdesc);
if (!NT_STATUS_IS_OK(status) || secdesc == NULL) {
return false;
}
for (i = 0; i < secdesc->dacl->num_aces; i++) {
struct security_ace *psa = &secdesc->dacl->aces[i];
if (psa->flags & (SEC_ACE_FLAG_OBJECT_INHERIT|
SEC_ACE_FLAG_CONTAINER_INHERIT)) {
TALLOC_FREE(secdesc);
return true;
}
}
TALLOC_FREE(secdesc);
return false;
}