linux/fs/cifs/dir.c
Linus Torvalds 7d6beb71da idmapped-mounts-v5.12
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Merge tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

Pull idmapped mounts from Christian Brauner:
 "This introduces idmapped mounts which has been in the making for some
  time. Simply put, different mounts can expose the same file or
  directory with different ownership. This initial implementation comes
  with ports for fat, ext4 and with Christoph's port for xfs with more
  filesystems being actively worked on by independent people and
  maintainers.

  Idmapping mounts handle a wide range of long standing use-cases. Here
  are just a few:

   - Idmapped mounts make it possible to easily share files between
     multiple users or multiple machines especially in complex
     scenarios. For example, idmapped mounts will be used in the
     implementation of portable home directories in
     systemd-homed.service(8) where they allow users to move their home
     directory to an external storage device and use it on multiple
     computers where they are assigned different uids and gids. This
     effectively makes it possible to assign random uids and gids at
     login time.

   - It is possible to share files from the host with unprivileged
     containers without having to change ownership permanently through
     chown(2).

   - It is possible to idmap a container's rootfs and without having to
     mangle every file. For example, Chromebooks use it to share the
     user's Download folder with their unprivileged containers in their
     Linux subsystem.

   - It is possible to share files between containers with
     non-overlapping idmappings.

   - Filesystem that lack a proper concept of ownership such as fat can
     use idmapped mounts to implement discretionary access (DAC)
     permission checking.

   - They allow users to efficiently changing ownership on a per-mount
     basis without having to (recursively) chown(2) all files. In
     contrast to chown (2) changing ownership of large sets of files is
     instantenous with idmapped mounts. This is especially useful when
     ownership of a whole root filesystem of a virtual machine or
     container is changed. With idmapped mounts a single syscall
     mount_setattr syscall will be sufficient to change the ownership of
     all files.

   - Idmapped mounts always take the current ownership into account as
     idmappings specify what a given uid or gid is supposed to be mapped
     to. This contrasts with the chown(2) syscall which cannot by itself
     take the current ownership of the files it changes into account. It
     simply changes the ownership to the specified uid and gid. This is
     especially problematic when recursively chown(2)ing a large set of
     files which is commong with the aforementioned portable home
     directory and container and vm scenario.

   - Idmapped mounts allow to change ownership locally, restricting it
     to specific mounts, and temporarily as the ownership changes only
     apply as long as the mount exists.

  Several userspace projects have either already put up patches and
  pull-requests for this feature or will do so should you decide to pull
  this:

   - systemd: In a wide variety of scenarios but especially right away
     in their implementation of portable home directories.

         https://systemd.io/HOME_DIRECTORY/

   - container runtimes: containerd, runC, LXD:To share data between
     host and unprivileged containers, unprivileged and privileged
     containers, etc. The pull request for idmapped mounts support in
     containerd, the default Kubernetes runtime is already up for quite
     a while now: https://github.com/containerd/containerd/pull/4734

   - The virtio-fs developers and several users have expressed interest
     in using this feature with virtual machines once virtio-fs is
     ported.

   - ChromeOS: Sharing host-directories with unprivileged containers.

  I've tightly synced with all those projects and all of those listed
  here have also expressed their need/desire for this feature on the
  mailing list. For more info on how people use this there's a bunch of
  talks about this too. Here's just two recent ones:

      https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf
      https://fosdem.org/2021/schedule/event/containers_idmap/

  This comes with an extensive xfstests suite covering both ext4 and
  xfs:

      https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts

  It covers truncation, creation, opening, xattrs, vfscaps, setid
  execution, setgid inheritance and more both with idmapped and
  non-idmapped mounts. It already helped to discover an unrelated xfs
  setgid inheritance bug which has since been fixed in mainline. It will
  be sent for inclusion with the xfstests project should you decide to
  merge this.

  In order to support per-mount idmappings vfsmounts are marked with
  user namespaces. The idmapping of the user namespace will be used to
  map the ids of vfs objects when they are accessed through that mount.
  By default all vfsmounts are marked with the initial user namespace.
  The initial user namespace is used to indicate that a mount is not
  idmapped. All operations behave as before and this is verified in the
  testsuite.

  Based on prior discussions we want to attach the whole user namespace
  and not just a dedicated idmapping struct. This allows us to reuse all
  the helpers that already exist for dealing with idmappings instead of
  introducing a whole new range of helpers. In addition, if we decide in
  the future that we are confident enough to enable unprivileged users
  to setup idmapped mounts the permission checking can take into account
  whether the caller is privileged in the user namespace the mount is
  currently marked with.

  The user namespace the mount will be marked with can be specified by
  passing a file descriptor refering to the user namespace as an
  argument to the new mount_setattr() syscall together with the new
  MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
  of extensibility.

  The following conditions must be met in order to create an idmapped
  mount:

   - The caller must currently have the CAP_SYS_ADMIN capability in the
     user namespace the underlying filesystem has been mounted in.

   - The underlying filesystem must support idmapped mounts.

   - The mount must not already be idmapped. This also implies that the
     idmapping of a mount cannot be altered once it has been idmapped.

   - The mount must be a detached/anonymous mount, i.e. it must have
     been created by calling open_tree() with the OPEN_TREE_CLONE flag
     and it must not already have been visible in the filesystem.

  The last two points guarantee easier semantics for userspace and the
  kernel and make the implementation significantly simpler.

  By default vfsmounts are marked with the initial user namespace and no
  behavioral or performance changes are observed.

  The manpage with a detailed description can be found here:

      1d7b902e28

  In order to support idmapped mounts, filesystems need to be changed
  and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The
  patches to convert individual filesystem are not very large or
  complicated overall as can be seen from the included fat, ext4, and
  xfs ports. Patches for other filesystems are actively worked on and
  will be sent out separately. The xfstestsuite can be used to verify
  that port has been done correctly.

  The mount_setattr() syscall is motivated independent of the idmapped
  mounts patches and it's been around since July 2019. One of the most
  valuable features of the new mount api is the ability to perform
  mounts based on file descriptors only.

  Together with the lookup restrictions available in the openat2()
  RESOLVE_* flag namespace which we added in v5.6 this is the first time
  we are close to hardened and race-free (e.g. symlinks) mounting and
  path resolution.

  While userspace has started porting to the new mount api to mount
  proper filesystems and create new bind-mounts it is currently not
  possible to change mount options of an already existing bind mount in
  the new mount api since the mount_setattr() syscall is missing.

  With the addition of the mount_setattr() syscall we remove this last
  restriction and userspace can now fully port to the new mount api,
  covering every use-case the old mount api could. We also add the
  crucial ability to recursively change mount options for a whole mount
  tree, both removing and adding mount options at the same time. This
  syscall has been requested multiple times by various people and
  projects.

  There is a simple tool available at

      https://github.com/brauner/mount-idmapped

  that allows to create idmapped mounts so people can play with this
  patch series. I'll add support for the regular mount binary should you
  decide to pull this in the following weeks:

  Here's an example to a simple idmapped mount of another user's home
  directory:

	u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt

	u1001@f2-vm:/$ ls -al /home/ubuntu/
	total 28
	drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 .
	drwxr-xr-x 4 root   root   4096 Oct 28 04:00 ..
	-rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history
	-rw-r--r-- 1 ubuntu ubuntu  220 Feb 25  2020 .bash_logout
	-rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25  2020 .bashrc
	-rw-r--r-- 1 ubuntu ubuntu  807 Feb 25  2020 .profile
	-rw-r--r-- 1 ubuntu ubuntu    0 Oct 16 16:11 .sudo_as_admin_successful
	-rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo

	u1001@f2-vm:/$ ls -al /mnt/
	total 28
	drwxr-xr-x  2 u1001 u1001 4096 Oct 28 22:07 .
	drwxr-xr-x 29 root  root  4096 Oct 28 22:01 ..
	-rw-------  1 u1001 u1001 3154 Oct 28 22:12 .bash_history
	-rw-r--r--  1 u1001 u1001  220 Feb 25  2020 .bash_logout
	-rw-r--r--  1 u1001 u1001 3771 Feb 25  2020 .bashrc
	-rw-r--r--  1 u1001 u1001  807 Feb 25  2020 .profile
	-rw-r--r--  1 u1001 u1001    0 Oct 16 16:11 .sudo_as_admin_successful
	-rw-------  1 u1001 u1001 1144 Oct 28 00:43 .viminfo

	u1001@f2-vm:/$ touch /mnt/my-file

	u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file

	u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file

	u1001@f2-vm:/$ ls -al /mnt/my-file
	-rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file

	u1001@f2-vm:/$ ls -al /home/ubuntu/my-file
	-rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file

	u1001@f2-vm:/$ getfacl /mnt/my-file
	getfacl: Removing leading '/' from absolute path names
	# file: mnt/my-file
	# owner: u1001
	# group: u1001
	user::rw-
	user:u1001:rwx
	group::rw-
	mask::rwx
	other::r--

	u1001@f2-vm:/$ getfacl /home/ubuntu/my-file
	getfacl: Removing leading '/' from absolute path names
	# file: home/ubuntu/my-file
	# owner: ubuntu
	# group: ubuntu
	user::rw-
	user:ubuntu:rwx
	group::rw-
	mask::rwx
	other::r--"

* tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits)
  xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl
  xfs: support idmapped mounts
  ext4: support idmapped mounts
  fat: handle idmapped mounts
  tests: add mount_setattr() selftests
  fs: introduce MOUNT_ATTR_IDMAP
  fs: add mount_setattr()
  fs: add attr_flags_to_mnt_flags helper
  fs: split out functions to hold writers
  namespace: only take read lock in do_reconfigure_mnt()
  mount: make {lock,unlock}_mount_hash() static
  namespace: take lock_mount_hash() directly when changing flags
  nfs: do not export idmapped mounts
  overlayfs: do not mount on top of idmapped mounts
  ecryptfs: do not mount on top of idmapped mounts
  ima: handle idmapped mounts
  apparmor: handle idmapped mounts
  fs: make helpers idmap mount aware
  exec: handle idmapped mounts
  would_dump: handle idmapped mounts
  ...
2021-02-23 13:39:45 -08:00

897 lines
23 KiB
C

/*
* fs/cifs/dir.c
*
* vfs operations that deal with dentries
*
* Copyright (C) International Business Machines Corp., 2002,2009
* Author(s): Steve French (sfrench@us.ibm.com)
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/file.h>
#include "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#include "cifs_unicode.h"
#include "fs_context.h"
static void
renew_parental_timestamps(struct dentry *direntry)
{
/* BB check if there is a way to get the kernel to do this or if we
really need this */
do {
cifs_set_time(direntry, jiffies);
direntry = direntry->d_parent;
} while (!IS_ROOT(direntry));
}
char *
cifs_build_path_to_root(struct smb3_fs_context *ctx, struct cifs_sb_info *cifs_sb,
struct cifs_tcon *tcon, int add_treename)
{
int pplen = ctx->prepath ? strlen(ctx->prepath) + 1 : 0;
int dfsplen;
char *full_path = NULL;
/* if no prefix path, simply set path to the root of share to "" */
if (pplen == 0) {
full_path = kzalloc(1, GFP_KERNEL);
return full_path;
}
if (add_treename)
dfsplen = strnlen(tcon->treeName, MAX_TREE_SIZE + 1);
else
dfsplen = 0;
full_path = kmalloc(dfsplen + pplen + 1, GFP_KERNEL);
if (full_path == NULL)
return full_path;
if (dfsplen)
memcpy(full_path, tcon->treeName, dfsplen);
full_path[dfsplen] = CIFS_DIR_SEP(cifs_sb);
memcpy(full_path + dfsplen + 1, ctx->prepath, pplen);
convert_delimiter(full_path, CIFS_DIR_SEP(cifs_sb));
return full_path;
}
/* Note: caller must free return buffer */
char *
build_path_from_dentry(struct dentry *direntry)
{
struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
bool prefix = tcon->Flags & SMB_SHARE_IS_IN_DFS;
return build_path_from_dentry_optional_prefix(direntry,
prefix);
}
char *
build_path_from_dentry_optional_prefix(struct dentry *direntry, bool prefix)
{
struct dentry *temp;
int namelen;
int dfsplen;
int pplen = 0;
char *full_path;
char dirsep;
struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
unsigned seq;
dirsep = CIFS_DIR_SEP(cifs_sb);
if (prefix)
dfsplen = strnlen(tcon->treeName, MAX_TREE_SIZE + 1);
else
dfsplen = 0;
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH)
pplen = cifs_sb->prepath ? strlen(cifs_sb->prepath) + 1 : 0;
cifs_bp_rename_retry:
namelen = dfsplen + pplen;
seq = read_seqbegin(&rename_lock);
rcu_read_lock();
for (temp = direntry; !IS_ROOT(temp);) {
namelen += (1 + temp->d_name.len);
temp = temp->d_parent;
if (temp == NULL) {
cifs_dbg(VFS, "corrupt dentry\n");
rcu_read_unlock();
return NULL;
}
}
rcu_read_unlock();
full_path = kmalloc(namelen+1, GFP_ATOMIC);
if (full_path == NULL)
return full_path;
full_path[namelen] = 0; /* trailing null */
rcu_read_lock();
for (temp = direntry; !IS_ROOT(temp);) {
spin_lock(&temp->d_lock);
namelen -= 1 + temp->d_name.len;
if (namelen < 0) {
spin_unlock(&temp->d_lock);
break;
} else {
full_path[namelen] = dirsep;
strncpy(full_path + namelen + 1, temp->d_name.name,
temp->d_name.len);
cifs_dbg(FYI, "name: %s\n", full_path + namelen);
}
spin_unlock(&temp->d_lock);
temp = temp->d_parent;
if (temp == NULL) {
cifs_dbg(VFS, "corrupt dentry\n");
rcu_read_unlock();
kfree(full_path);
return NULL;
}
}
rcu_read_unlock();
if (namelen != dfsplen + pplen || read_seqretry(&rename_lock, seq)) {
cifs_dbg(FYI, "did not end path lookup where expected. namelen=%ddfsplen=%d\n",
namelen, dfsplen);
/* presumably this is only possible if racing with a rename
of one of the parent directories (we can not lock the dentries
above us to prevent this, but retrying should be harmless) */
kfree(full_path);
goto cifs_bp_rename_retry;
}
/* DIR_SEP already set for byte 0 / vs \ but not for
subsequent slashes in prepath which currently must
be entered the right way - not sure if there is an alternative
since the '\' is a valid posix character so we can not switch
those safely to '/' if any are found in the middle of the prepath */
/* BB test paths to Windows with '/' in the midst of prepath */
if (pplen) {
int i;
cifs_dbg(FYI, "using cifs_sb prepath <%s>\n", cifs_sb->prepath);
memcpy(full_path+dfsplen+1, cifs_sb->prepath, pplen-1);
full_path[dfsplen] = dirsep;
for (i = 0; i < pplen-1; i++)
if (full_path[dfsplen+1+i] == '/')
full_path[dfsplen+1+i] = CIFS_DIR_SEP(cifs_sb);
}
if (dfsplen) {
strncpy(full_path, tcon->treeName, dfsplen);
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) {
int i;
for (i = 0; i < dfsplen; i++) {
if (full_path[i] == '\\')
full_path[i] = '/';
}
}
}
return full_path;
}
/*
* Don't allow path components longer than the server max.
* Don't allow the separator character in a path component.
* The VFS will not allow "/", but "\" is allowed by posix.
*/
static int
check_name(struct dentry *direntry, struct cifs_tcon *tcon)
{
struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
int i;
if (unlikely(tcon->fsAttrInfo.MaxPathNameComponentLength &&
direntry->d_name.len >
le32_to_cpu(tcon->fsAttrInfo.MaxPathNameComponentLength)))
return -ENAMETOOLONG;
if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)) {
for (i = 0; i < direntry->d_name.len; i++) {
if (direntry->d_name.name[i] == '\\') {
cifs_dbg(FYI, "Invalid file name\n");
return -EINVAL;
}
}
}
return 0;
}
/* Inode operations in similar order to how they appear in Linux file fs.h */
static int
cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
struct tcon_link *tlink, unsigned oflags, umode_t mode,
__u32 *oplock, struct cifs_fid *fid)
{
int rc = -ENOENT;
int create_options = CREATE_NOT_DIR;
int desired_access;
struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
struct cifs_tcon *tcon = tlink_tcon(tlink);
char *full_path = NULL;
FILE_ALL_INFO *buf = NULL;
struct inode *newinode = NULL;
int disposition;
struct TCP_Server_Info *server = tcon->ses->server;
struct cifs_open_parms oparms;
*oplock = 0;
if (tcon->ses->server->oplocks)
*oplock = REQ_OPLOCK;
full_path = build_path_from_dentry(direntry);
if (!full_path)
return -ENOMEM;
if (tcon->unix_ext && cap_unix(tcon->ses) && !tcon->broken_posix_open &&
(CIFS_UNIX_POSIX_PATH_OPS_CAP &
le64_to_cpu(tcon->fsUnixInfo.Capability))) {
rc = cifs_posix_open(full_path, &newinode, inode->i_sb, mode,
oflags, oplock, &fid->netfid, xid);
switch (rc) {
case 0:
if (newinode == NULL) {
/* query inode info */
goto cifs_create_get_file_info;
}
if (S_ISDIR(newinode->i_mode)) {
CIFSSMBClose(xid, tcon, fid->netfid);
iput(newinode);
rc = -EISDIR;
goto out;
}
if (!S_ISREG(newinode->i_mode)) {
/*
* The server may allow us to open things like
* FIFOs, but the client isn't set up to deal
* with that. If it's not a regular file, just
* close it and proceed as if it were a normal
* lookup.
*/
CIFSSMBClose(xid, tcon, fid->netfid);
goto cifs_create_get_file_info;
}
/* success, no need to query */
goto cifs_create_set_dentry;
case -ENOENT:
goto cifs_create_get_file_info;
case -EIO:
case -EINVAL:
/*
* EIO could indicate that (posix open) operation is not
* supported, despite what server claimed in capability
* negotiation.
*
* POSIX open in samba versions 3.3.1 and earlier could
* incorrectly fail with invalid parameter.
*/
tcon->broken_posix_open = true;
break;
case -EREMOTE:
case -EOPNOTSUPP:
/*
* EREMOTE indicates DFS junction, which is not handled
* in posix open. If either that or op not supported
* returned, follow the normal lookup.
*/
break;
default:
goto out;
}
/*
* fallthrough to retry, using older open call, this is case
* where server does not support this SMB level, and falsely
* claims capability (also get here for DFS case which should be
* rare for path not covered on files)
*/
}
desired_access = 0;
if (OPEN_FMODE(oflags) & FMODE_READ)
desired_access |= GENERIC_READ; /* is this too little? */
if (OPEN_FMODE(oflags) & FMODE_WRITE)
desired_access |= GENERIC_WRITE;
disposition = FILE_OVERWRITE_IF;
if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
disposition = FILE_CREATE;
else if ((oflags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
disposition = FILE_OVERWRITE_IF;
else if ((oflags & O_CREAT) == O_CREAT)
disposition = FILE_OPEN_IF;
else
cifs_dbg(FYI, "Create flag not set in create function\n");
/*
* BB add processing to set equivalent of mode - e.g. via CreateX with
* ACLs
*/
if (!server->ops->open) {
rc = -ENOSYS;
goto out;
}
buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
if (buf == NULL) {
rc = -ENOMEM;
goto out;
}
/*
* if we're not using unix extensions, see if we need to set
* ATTR_READONLY on the create call
*/
if (!tcon->unix_ext && (mode & S_IWUGO) == 0)
create_options |= CREATE_OPTION_READONLY;
oparms.tcon = tcon;
oparms.cifs_sb = cifs_sb;
oparms.desired_access = desired_access;
oparms.create_options = cifs_create_options(cifs_sb, create_options);
oparms.disposition = disposition;
oparms.path = full_path;
oparms.fid = fid;
oparms.reconnect = false;
oparms.mode = mode;
rc = server->ops->open(xid, &oparms, oplock, buf);
if (rc) {
cifs_dbg(FYI, "cifs_create returned 0x%x\n", rc);
goto out;
}
/*
* If Open reported that we actually created a file then we now have to
* set the mode if possible.
*/
if ((tcon->unix_ext) && (*oplock & CIFS_CREATE_ACTION)) {
struct cifs_unix_set_info_args args = {
.mode = mode,
.ctime = NO_CHANGE_64,
.atime = NO_CHANGE_64,
.mtime = NO_CHANGE_64,
.device = 0,
};
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
args.uid = current_fsuid();
if (inode->i_mode & S_ISGID)
args.gid = inode->i_gid;
else
args.gid = current_fsgid();
} else {
args.uid = INVALID_UID; /* no change */
args.gid = INVALID_GID; /* no change */
}
CIFSSMBUnixSetFileInfo(xid, tcon, &args, fid->netfid,
current->tgid);
} else {
/*
* BB implement mode setting via Windows security
* descriptors e.g.
*/
/* CIFSSMBWinSetPerms(xid,tcon,path,mode,-1,-1,nls);*/
/* Could set r/o dos attribute if mode & 0222 == 0 */
}
cifs_create_get_file_info:
/* server might mask mode so we have to query for it */
if (tcon->unix_ext)
rc = cifs_get_inode_info_unix(&newinode, full_path, inode->i_sb,
xid);
else {
/* TODO: Add support for calling POSIX query info here, but passing in fid */
rc = cifs_get_inode_info(&newinode, full_path, buf, inode->i_sb,
xid, fid);
if (newinode) {
if (server->ops->set_lease_key)
server->ops->set_lease_key(newinode, fid);
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DYNPERM)
newinode->i_mode = mode;
if ((*oplock & CIFS_CREATE_ACTION) &&
(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID)) {
newinode->i_uid = current_fsuid();
if (inode->i_mode & S_ISGID)
newinode->i_gid = inode->i_gid;
else
newinode->i_gid = current_fsgid();
}
}
}
cifs_create_set_dentry:
if (rc != 0) {
cifs_dbg(FYI, "Create worked, get_inode_info failed rc = %d\n",
rc);
goto out_err;
}
if (S_ISDIR(newinode->i_mode)) {
rc = -EISDIR;
goto out_err;
}
d_drop(direntry);
d_add(direntry, newinode);
out:
kfree(buf);
kfree(full_path);
return rc;
out_err:
if (server->ops->close)
server->ops->close(xid, tcon, fid);
if (newinode)
iput(newinode);
goto out;
}
int
cifs_atomic_open(struct inode *inode, struct dentry *direntry,
struct file *file, unsigned oflags, umode_t mode)
{
int rc;
unsigned int xid;
struct tcon_link *tlink;
struct cifs_tcon *tcon;
struct TCP_Server_Info *server;
struct cifs_fid fid;
struct cifs_pending_open open;
__u32 oplock;
struct cifsFileInfo *file_info;
/*
* Posix open is only called (at lookup time) for file create now. For
* opens (rather than creates), because we do not know if it is a file
* or directory yet, and current Samba no longer allows us to do posix
* open on dirs, we could end up wasting an open call on what turns out
* to be a dir. For file opens, we wait to call posix open till
* cifs_open. It could be added to atomic_open in the future but the
* performance tradeoff of the extra network request when EISDIR or
* EACCES is returned would have to be weighed against the 50% reduction
* in network traffic in the other paths.
*/
if (!(oflags & O_CREAT)) {
struct dentry *res;
/*
* Check for hashed negative dentry. We have already revalidated
* the dentry and it is fine. No need to perform another lookup.
*/
if (!d_in_lookup(direntry))
return -ENOENT;
res = cifs_lookup(inode, direntry, 0);
if (IS_ERR(res))
return PTR_ERR(res);
return finish_no_open(file, res);
}
xid = get_xid();
cifs_dbg(FYI, "parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
inode, direntry, direntry);
tlink = cifs_sb_tlink(CIFS_SB(inode->i_sb));
if (IS_ERR(tlink)) {
rc = PTR_ERR(tlink);
goto out_free_xid;
}
tcon = tlink_tcon(tlink);
rc = check_name(direntry, tcon);
if (rc)
goto out;
server = tcon->ses->server;
if (server->ops->new_lease_key)
server->ops->new_lease_key(&fid);
cifs_add_pending_open(&fid, tlink, &open);
rc = cifs_do_create(inode, direntry, xid, tlink, oflags, mode,
&oplock, &fid);
if (rc) {
cifs_del_pending_open(&open);
goto out;
}
if ((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
file->f_mode |= FMODE_CREATED;
rc = finish_open(file, direntry, generic_file_open);
if (rc) {
if (server->ops->close)
server->ops->close(xid, tcon, &fid);
cifs_del_pending_open(&open);
goto out;
}
if (file->f_flags & O_DIRECT &&
CIFS_SB(inode->i_sb)->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) {
if (CIFS_SB(inode->i_sb)->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
file->f_op = &cifs_file_direct_nobrl_ops;
else
file->f_op = &cifs_file_direct_ops;
}
file_info = cifs_new_fileinfo(&fid, file, tlink, oplock);
if (file_info == NULL) {
if (server->ops->close)
server->ops->close(xid, tcon, &fid);
cifs_del_pending_open(&open);
rc = -ENOMEM;
}
out:
cifs_put_tlink(tlink);
out_free_xid:
free_xid(xid);
return rc;
}
int cifs_create(struct user_namespace *mnt_userns, struct inode *inode,
struct dentry *direntry, umode_t mode, bool excl)
{
int rc;
unsigned int xid = get_xid();
/*
* BB below access is probably too much for mknod to request
* but we have to do query and setpathinfo so requesting
* less could fail (unless we want to request getatr and setatr
* permissions (only). At least for POSIX we do not have to
* request so much.
*/
unsigned oflags = O_EXCL | O_CREAT | O_RDWR;
struct tcon_link *tlink;
struct cifs_tcon *tcon;
struct TCP_Server_Info *server;
struct cifs_fid fid;
__u32 oplock;
cifs_dbg(FYI, "cifs_create parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
inode, direntry, direntry);
tlink = cifs_sb_tlink(CIFS_SB(inode->i_sb));
rc = PTR_ERR(tlink);
if (IS_ERR(tlink))
goto out_free_xid;
tcon = tlink_tcon(tlink);
server = tcon->ses->server;
if (server->ops->new_lease_key)
server->ops->new_lease_key(&fid);
rc = cifs_do_create(inode, direntry, xid, tlink, oflags, mode,
&oplock, &fid);
if (!rc && server->ops->close)
server->ops->close(xid, tcon, &fid);
cifs_put_tlink(tlink);
out_free_xid:
free_xid(xid);
return rc;
}
int cifs_mknod(struct user_namespace *mnt_userns, struct inode *inode,
struct dentry *direntry, umode_t mode, dev_t device_number)
{
int rc = -EPERM;
unsigned int xid;
struct cifs_sb_info *cifs_sb;
struct tcon_link *tlink;
struct cifs_tcon *tcon;
char *full_path = NULL;
if (!old_valid_dev(device_number))
return -EINVAL;
cifs_sb = CIFS_SB(inode->i_sb);
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
return PTR_ERR(tlink);
tcon = tlink_tcon(tlink);
xid = get_xid();
full_path = build_path_from_dentry(direntry);
if (full_path == NULL) {
rc = -ENOMEM;
goto mknod_out;
}
rc = tcon->ses->server->ops->make_node(xid, inode, direntry, tcon,
full_path, mode,
device_number);
mknod_out:
kfree(full_path);
free_xid(xid);
cifs_put_tlink(tlink);
return rc;
}
struct dentry *
cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
unsigned int flags)
{
unsigned int xid;
int rc = 0; /* to get around spurious gcc warning, set to zero here */
struct cifs_sb_info *cifs_sb;
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
struct inode *newInode = NULL;
char *full_path = NULL;
xid = get_xid();
cifs_dbg(FYI, "parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
parent_dir_inode, direntry, direntry);
/* check whether path exists */
cifs_sb = CIFS_SB(parent_dir_inode->i_sb);
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink)) {
free_xid(xid);
return ERR_CAST(tlink);
}
pTcon = tlink_tcon(tlink);
rc = check_name(direntry, pTcon);
if (unlikely(rc)) {
cifs_put_tlink(tlink);
free_xid(xid);
return ERR_PTR(rc);
}
/* can not grab the rename sem here since it would
deadlock in the cases (beginning of sys_rename itself)
in which we already have the sb rename sem */
full_path = build_path_from_dentry(direntry);
if (full_path == NULL) {
cifs_put_tlink(tlink);
free_xid(xid);
return ERR_PTR(-ENOMEM);
}
if (d_really_is_positive(direntry)) {
cifs_dbg(FYI, "non-NULL inode in lookup\n");
} else {
cifs_dbg(FYI, "NULL inode in lookup\n");
}
cifs_dbg(FYI, "Full path: %s inode = 0x%p\n",
full_path, d_inode(direntry));
if (pTcon->posix_extensions)
rc = smb311_posix_get_inode_info(&newInode, full_path, parent_dir_inode->i_sb, xid);
else if (pTcon->unix_ext) {
rc = cifs_get_inode_info_unix(&newInode, full_path,
parent_dir_inode->i_sb, xid);
} else {
rc = cifs_get_inode_info(&newInode, full_path, NULL,
parent_dir_inode->i_sb, xid, NULL);
}
if (rc == 0) {
/* since paths are not looked up by component - the parent
directories are presumed to be good here */
renew_parental_timestamps(direntry);
} else if (rc == -ENOENT) {
cifs_set_time(direntry, jiffies);
newInode = NULL;
} else {
if (rc != -EACCES) {
cifs_dbg(FYI, "Unexpected lookup error %d\n", rc);
/* We special case check for Access Denied - since that
is a common return code */
}
newInode = ERR_PTR(rc);
}
kfree(full_path);
cifs_put_tlink(tlink);
free_xid(xid);
return d_splice_alias(newInode, direntry);
}
static int
cifs_d_revalidate(struct dentry *direntry, unsigned int flags)
{
struct inode *inode;
int rc;
if (flags & LOOKUP_RCU)
return -ECHILD;
if (d_really_is_positive(direntry)) {
inode = d_inode(direntry);
if ((flags & LOOKUP_REVAL) && !CIFS_CACHE_READ(CIFS_I(inode)))
CIFS_I(inode)->time = 0; /* force reval */
rc = cifs_revalidate_dentry(direntry);
if (rc) {
cifs_dbg(FYI, "cifs_revalidate_dentry failed with rc=%d", rc);
switch (rc) {
case -ENOENT:
case -ESTALE:
/*
* Those errors mean the dentry is invalid
* (file was deleted or recreated)
*/
return 0;
default:
/*
* Otherwise some unexpected error happened
* report it as-is to VFS layer
*/
return rc;
}
}
else {
/*
* If the inode wasn't known to be a dfs entry when
* the dentry was instantiated, such as when created
* via ->readdir(), it needs to be set now since the
* attributes will have been updated by
* cifs_revalidate_dentry().
*/
if (IS_AUTOMOUNT(inode) &&
!(direntry->d_flags & DCACHE_NEED_AUTOMOUNT)) {
spin_lock(&direntry->d_lock);
direntry->d_flags |= DCACHE_NEED_AUTOMOUNT;
spin_unlock(&direntry->d_lock);
}
return 1;
}
}
/*
* This may be nfsd (or something), anyway, we can't see the
* intent of this. So, since this can be for creation, drop it.
*/
if (!flags)
return 0;
/*
* Drop the negative dentry, in order to make sure to use the
* case sensitive name which is specified by user if this is
* for creation.
*/
if (flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
return 0;
if (time_after(jiffies, cifs_get_time(direntry) + HZ) || !lookupCacheEnabled)
return 0;
return 1;
}
/* static int cifs_d_delete(struct dentry *direntry)
{
int rc = 0;
cifs_dbg(FYI, "In cifs d_delete, name = %pd\n", direntry);
return rc;
} */
const struct dentry_operations cifs_dentry_ops = {
.d_revalidate = cifs_d_revalidate,
.d_automount = cifs_dfs_d_automount,
/* d_delete: cifs_d_delete, */ /* not needed except for debugging */
};
static int cifs_ci_hash(const struct dentry *dentry, struct qstr *q)
{
struct nls_table *codepage = CIFS_SB(dentry->d_sb)->local_nls;
unsigned long hash;
wchar_t c;
int i, charlen;
hash = init_name_hash(dentry);
for (i = 0; i < q->len; i += charlen) {
charlen = codepage->char2uni(&q->name[i], q->len - i, &c);
/* error out if we can't convert the character */
if (unlikely(charlen < 0))
return charlen;
hash = partial_name_hash(cifs_toupper(c), hash);
}
q->hash = end_name_hash(hash);
return 0;
}
static int cifs_ci_compare(const struct dentry *dentry,
unsigned int len, const char *str, const struct qstr *name)
{
struct nls_table *codepage = CIFS_SB(dentry->d_sb)->local_nls;
wchar_t c1, c2;
int i, l1, l2;
/*
* We make the assumption here that uppercase characters in the local
* codepage are always the same length as their lowercase counterparts.
*
* If that's ever not the case, then this will fail to match it.
*/
if (name->len != len)
return 1;
for (i = 0; i < len; i += l1) {
/* Convert characters in both strings to UTF-16. */
l1 = codepage->char2uni(&str[i], len - i, &c1);
l2 = codepage->char2uni(&name->name[i], name->len - i, &c2);
/*
* If we can't convert either character, just declare it to
* be 1 byte long and compare the original byte.
*/
if (unlikely(l1 < 0 && l2 < 0)) {
if (str[i] != name->name[i])
return 1;
l1 = 1;
continue;
}
/*
* Here, we again ass|u|me that upper/lowercase versions of
* a character are the same length in the local NLS.
*/
if (l1 != l2)
return 1;
/* Now compare uppercase versions of these characters */
if (cifs_toupper(c1) != cifs_toupper(c2))
return 1;
}
return 0;
}
const struct dentry_operations cifs_ci_dentry_ops = {
.d_revalidate = cifs_d_revalidate,
.d_hash = cifs_ci_hash,
.d_compare = cifs_ci_compare,
.d_automount = cifs_dfs_d_automount,
};