To rename a file in SMB2 we open it with the DELETE access and do a
special SetInfo on it. If the handle is missing the DELETE bit the
server will fail the SetInfo with STATUS_ACCESS_DENIED.
We currently try to reuse any existing opened handle we have with
cifs_get_writable_path(). That function looks for handles with WRITE
access but doesn't check for DELETE, making rename() fail if it finds
a handle to reuse. Simple reproducer below.
To select handles with the DELETE bit, this patch adds a flag argument
to cifs_get_writable_path() and find_writable_file() and the existing
'bool fsuid_only' argument is converted to a flag.
The cifsFileInfo struct only stores the UNIX open mode but not the
original SMB access flags. Since the DELETE bit is not mapped in that
mode, this patch stores the access mask in cifs_fid on file open,
which is accessible from cifsFileInfo.
Simple reproducer:
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#define E(s) perror(s), exit(1)
int main(int argc, char *argv[])
{
int fd, ret;
if (argc != 3) {
fprintf(stderr, "Usage: %s A B\n"
"create&open A in write mode, "
"rename A to B, close A\n", argv[0]);
return 0;
}
fd = openat(AT_FDCWD, argv[1], O_WRONLY|O_CREAT|O_SYNC, 0666);
if (fd == -1) E("openat()");
ret = rename(argv[1], argv[2]);
if (ret) E("rename()");
ret = close(fd);
if (ret) E("close()");
return ret;
}
$ gcc -o bugrename bugrename.c
$ ./bugrename /mnt/a /mnt/b
rename(): Permission denied
Fixes:
8de9e86c67ba ("cifs: create a helper to find a writeable handle by path name")
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
__u64 volatile_fid; /* volatile file id for smb2 */
__u8 lease_key[SMB2_LEASE_KEY_SIZE]; /* lease key for smb2 */
__u8 create_guid[16];
+ __u32 access;
struct cifs_pending_open *pending_open;
unsigned int epoch;
#ifdef CONFIG_CIFS_DEBUG2
return false;
}
+
+/* cifs_get_writable_file() flags */
+#define FIND_WR_ANY 0
+#define FIND_WR_FSUID_ONLY 1
+#define FIND_WR_WITH_DELETE 2
+
#define MID_FREE 0
#define MID_REQUEST_ALLOCATED 1
#define MID_REQUEST_SUBMITTED 2
extern bool is_size_safe_to_change(struct cifsInodeInfo *, __u64 eof);
extern void cifs_update_eof(struct cifsInodeInfo *cifsi, loff_t offset,
unsigned int bytes_written);
-extern struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *, bool);
+extern struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *, int);
extern int cifs_get_writable_file(struct cifsInodeInfo *cifs_inode,
- bool fsuid_only,
+ int flags,
struct cifsFileInfo **ret_file);
extern int cifs_get_writable_path(struct cifs_tcon *tcon, const char *name,
+ int flags,
struct cifsFileInfo **ret_file);
extern struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *, bool);
extern int cifs_get_readable_path(struct cifs_tcon *tcon, const char *name,
*oplock = rsp->OplockLevel;
/* cifs fid stays in le */
oparms->fid->netfid = rsp->Fid;
+ oparms->fid->access = desired_access;
/* Let caller know file was created so we can set the mode. */
/* Do we care about the CreateAction in any other cases? */
wdata2->tailsz = tailsz;
wdata2->bytes = cur_len;
- rc = cifs_get_writable_file(CIFS_I(inode), false,
+ rc = cifs_get_writable_file(CIFS_I(inode), FIND_WR_ANY,
&wdata2->cfile);
if (!wdata2->cfile) {
cifs_dbg(VFS, "No writable handle to retry writepages rc=%d\n",
/* Return -EBADF if no handle is found and general rc otherwise */
int
-cifs_get_writable_file(struct cifsInodeInfo *cifs_inode, bool fsuid_only,
+cifs_get_writable_file(struct cifsInodeInfo *cifs_inode, int flags,
struct cifsFileInfo **ret_file)
{
struct cifsFileInfo *open_file, *inv_file = NULL;
bool any_available = false;
int rc = -EBADF;
unsigned int refind = 0;
-
+ bool fsuid_only = flags & FIND_WR_FSUID_ONLY;
+ bool with_delete = flags & FIND_WR_WITH_DELETE;
*ret_file = NULL;
/*
continue;
if (fsuid_only && !uid_eq(open_file->uid, current_fsuid()))
continue;
+ if (with_delete && !(open_file->fid.access & DELETE))
+ continue;
if (OPEN_FMODE(open_file->f_flags) & FMODE_WRITE) {
if (!open_file->invalidHandle) {
/* found a good writable file */
}
struct cifsFileInfo *
-find_writable_file(struct cifsInodeInfo *cifs_inode, bool fsuid_only)
+find_writable_file(struct cifsInodeInfo *cifs_inode, int flags)
{
struct cifsFileInfo *cfile;
int rc;
- rc = cifs_get_writable_file(cifs_inode, fsuid_only, &cfile);
+ rc = cifs_get_writable_file(cifs_inode, flags, &cfile);
if (rc)
cifs_dbg(FYI, "couldn't find writable handle rc=%d", rc);
int
cifs_get_writable_path(struct cifs_tcon *tcon, const char *name,
+ int flags,
struct cifsFileInfo **ret_file)
{
struct list_head *tmp;
kfree(full_path);
cinode = CIFS_I(d_inode(cfile->dentry));
spin_unlock(&tcon->open_file_lock);
- return cifs_get_writable_file(cinode, 0, ret_file);
+ return cifs_get_writable_file(cinode, flags, ret_file);
}
spin_unlock(&tcon->open_file_lock);
if (mapping->host->i_size - offset < (loff_t)to)
to = (unsigned)(mapping->host->i_size - offset);
- rc = cifs_get_writable_file(CIFS_I(mapping->host), false, &open_file);
+ rc = cifs_get_writable_file(CIFS_I(mapping->host), FIND_WR_ANY,
+ &open_file);
if (!rc) {
bytes_written = cifs_write(open_file, open_file->pid,
write_data, to - from, &offset);
if (cfile)
cifsFileInfo_put(cfile);
- rc = cifs_get_writable_file(CIFS_I(inode), false, &cfile);
+ rc = cifs_get_writable_file(CIFS_I(inode), FIND_WR_ANY, &cfile);
/* in case of an error store it to return later */
if (rc)
* writebehind data than the SMB timeout for the SetPathInfo
* request would allow
*/
- open_file = find_writable_file(cifsInode, true);
+ open_file = find_writable_file(cifsInode, FIND_WR_FSUID_ONLY);
if (open_file) {
tcon = tlink_tcon(open_file->tlink);
server = tcon->ses->server;
args->ctime = NO_CHANGE_64;
args->device = 0;
- open_file = find_writable_file(cifsInode, true);
+ open_file = find_writable_file(cifsInode, FIND_WR_FSUID_ONLY);
if (open_file) {
u16 nfid = open_file->fid.netfid;
u32 npid = open_file->pid;
rc = 0;
if (attrs->ia_valid & ATTR_MTIME) {
- rc = cifs_get_writable_file(cifsInode, false, &wfile);
+ rc = cifs_get_writable_file(cifsInode, FIND_WR_ANY, &wfile);
if (!rc) {
tcon = tlink_tcon(wfile->tlink);
rc = tcon->ses->server->ops->flush(xid, tcon, &wfile->fid);
struct cifs_tcon *tcon;
/* if the file is already open for write, just use that fileid */
- open_file = find_writable_file(cinode, true);
+ open_file = find_writable_file(cinode, FIND_WR_FSUID_ONLY);
if (open_file) {
fid.netfid = open_file->fid.netfid;
netpid = open_file->pid;
cifs_i = CIFS_I(inode);
dosattrs = cifs_i->cifsAttrs | ATTR_READONLY;
data.Attributes = cpu_to_le32(dosattrs);
- cifs_get_writable_path(tcon, name, &cfile);
+ cifs_get_writable_path(tcon, name, FIND_WR_ANY, &cfile);
tmprc = smb2_compound_op(xid, tcon, cifs_sb, name,
FILE_WRITE_ATTRIBUTES, FILE_CREATE,
CREATE_NOT_FILE, ACL_NO_MODE,
{
struct cifsFileInfo *cfile;
- cifs_get_writable_path(tcon, from_name, &cfile);
+ cifs_get_writable_path(tcon, from_name, FIND_WR_WITH_DELETE, &cfile);
return smb2_set_path_attr(xid, tcon, from_name, to_name,
cifs_sb, DELETE, SMB2_OP_RENAME, cfile);
cfile->fid.persistent_fid = fid->persistent_fid;
cfile->fid.volatile_fid = fid->volatile_fid;
+ cfile->fid.access = fid->access;
#ifdef CONFIG_CIFS_DEBUG2
cfile->fid.mid = fid->mid;
#endif /* CIFS_DEBUG2 */
* some servers (Windows2016) will not reflect recent writes in
* QUERY_ALLOCATED_RANGES until SMB2_flush is called.
*/
- wrcfile = find_writable_file(cifsi, false);
+ wrcfile = find_writable_file(cifsi, FIND_WR_ANY);
if (wrcfile) {
filemap_write_and_wait(inode->i_mapping);
smb2_flush_file(xid, tcon, &wrcfile->fid);
atomic_inc(&tcon->num_remote_opens);
oparms->fid->persistent_fid = rsp->PersistentFileId;
oparms->fid->volatile_fid = rsp->VolatileFileId;
+ oparms->fid->access = oparms->desired_access;
#ifdef CONFIG_CIFS_DEBUG2
oparms->fid->mid = le64_to_cpu(rsp->sync_hdr.MessageId);
#endif /* CIFS_DEBUG2 */