Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_GPL inside which was used in the
   initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 786534b92f3c introduced a regression that caused listxattr to
return the POSIX ACL attribute names even though sysfs doesn't support
POSIX ACLs.  This happens because simple_xattr_list checks for NULL
i_acl / i_default_acl, but inode_init_always initializes those fields
to ACL_NOT_CACHED ((void *)-1).  For example:
    $ getfattr -m- -d /sys
    /sys: system.posix_acl_access: Operation not supported
    /sys: system.posix_acl_default: Operation not supported
Fix this in simple_xattr_list by checking if the filesystem supports POSIX ACLs.

Fixes: 786534b92f3c ("tmpfs: listxattr should include POSIX ACL xattrs")
Reported-by:  Marc Aurèle La France <tsi@tuyoix.net>
Tested-by: Marc Aurèle La France <tsi@tuyoix.net>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: stable@vger.kernel.org # v4.5+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull namespace fixes from Eric Biederman:
 "This is a set of four fairly obvious bug fixes:

   - a switch from d_find_alias to d_find_any_alias because the xattr
     code perversely takes a dentry

   - two mutex vs copy_to_user fixes from Jann Horn

   - a fix to use a sanitized size not the size userspace passed in from
     Christian Brauner"

* 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  getxattr: use correct xattr length
  sys: don't hold uts_sem while accessing userspace memory
  userns: move user access out of the mutex
  cap_inode_getsecurity: use d_find_any_alias() instead of d_find_alias()

When running in a container with a user namespace, if you call getxattr
with name = "system.posix_acl_access" and size % 8 != 4, then getxattr
silently skips the user namespace fixup that it normally does resulting in
un-fixed-up data being returned.
This is caused by posix_acl_fix_xattr_to_user() being passed the total
buffer size and not the actual size of the xattr as returned by
vfs_getxattr().
This commit passes the actual length of the xattr as returned by
vfs_getxattr() down.

A reproducer for the issue is:

  touch acl_posix

  setfacl -m user:0:rwx acl_posix

and the compile:

  #define _GNU_SOURCE
  #include <errno.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sys/types.h>
  #include <unistd.h>
  #include <attr/xattr.h>

  /* Run in user namespace with nsuid 0 mapped to uid != 0 on the host. */
  int main(int argc, void **argv)
  {
          ssize_t ret1, ret2;
          char buf1[128], buf2[132];
          int fret = EXIT_SUCCESS;
          char *file;

          if (argc < 2) {
                  fprintf(stderr,
                          "Please specify a file with "
                          "\"system.posix_acl_access\" permissions set\n");
                  _exit(EXIT_FAILURE);
          }
          file = argv[1];

          ret1 = getxattr(file, "system.posix_acl_access",
                          buf1, sizeof(buf1));
          if (ret1 < 0) {
                  fprintf(stderr, "%s - Failed to retrieve "
                                  "\"system.posix_acl_access\" "
                                  "from \"%s\"\n", strerror(errno), file);
                  _exit(EXIT_FAILURE);
          }

          ret2 = getxattr(file, "system.posix_acl_access",
                          buf2, sizeof(buf2));
          if (ret2 < 0) {
                  fprintf(stderr, "%s - Failed to retrieve "
                                  "\"system.posix_acl_access\" "
                                  "from \"%s\"\n", strerror(errno), file);
                  _exit(EXIT_FAILURE);
          }

          if (ret1 != ret2) {
                  fprintf(stderr, "The value of \"system.posix_acl_"
                                  "access\" for file \"%s\" changed "
                                  "between two successive calls\n", file);
                  _exit(EXIT_FAILURE);
          }

          for (ssize_t i = 0; i < ret2; i++) {
                  if (buf1[i] == buf2[i])
                          continue;

                  fprintf(stderr,
                          "Unexpected different in byte %zd: "
                          "%02x != %02x\n", i, buf1[i], buf2[i]);
                  fret = EXIT_FAILURE;
          }

          if (fret == EXIT_SUCCESS)
                  fprintf(stderr, "Test passed\n");
          else
                  fprintf(stderr, "Test failed\n");

          _exit(fret);
  }
and run:

  ./tester acl_posix

On a non-fixed up kernel this should return something like:

  root@c1:/# ./t
  Unexpected different in byte 16: ffffffa0 != 00
  Unexpected different in byte 17: ffffff86 != 00
  Unexpected different in byte 18: 01 != 00

and on a fixed kernel:

  root@c1:~# ./t
  Test passed

Cc: stable@vger.kernel.org
Fixes: 2f6f0654ab61 ("userns: Convert vfs posix_acl support to use kuids and kgids")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=199945
Reported-by: Colin Watson <cjwatson@ubuntu.com>
Signed-off-by: Christian Brauner <christian@brauner.io>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

This reverts commit 7c6893e3c9abf6a9676e060a1e35e5caca673d57.

Overlayfs no longer relies on the vfs for checking writability of files.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

It seems the first error assignment in if branch is redundant.

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

many years overdue...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

security_inode_getsecurity() provides the text string value
of a security attribute. It does not provide a "secctx".
The code in xattr_getsecurity() that calls security_inode_getsecurity()
and then calls security_release_secctx() happened to work because
SElinux and Smack treat the attribute and the secctx the same way.
It fails for cap_inode_getsecurity(), because that module has no
secctx that ever needs releasing. It turns out that Smack is the
one that's doing things wrong by not allocating memory when instructed
to do so by the "alloc" parameter.

The fix is simple enough. Change the security_release_secctx() to
kfree() because it isn't a secctx being returned by
security_inode_getsecurity(). Change Smack to allocate the string when
told to do so.

Note: this also fixes memory leaks for LSMs which implement
inode_getsecurity but not release_secctx, such as capabilities.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>

Pull overlayfs updates from Miklos Szeredi:
 "This fixes d_ino correctness in readdir, which brings overlayfs on par
  with normal filesystems regarding inode number semantics, as long as
  all layers are on the same filesystem.

  There are also some bug fixes, one in particular (random ioctl's
  shouldn't be able to modify lower layers) that touches some vfs code,
  but of course no-op for non-overlay fs"

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: fix false positive ESTALE on lookup
  ovl: don't allow writing ioctl on lower layer
  ovl: fix relatime for directories
  vfs: add flags to d_real()
  ovl: cleanup d_real for negative
  ovl: constant d_ino for non-merge dirs
  ovl: constant d_ino across copy up
  ovl: fix readdir error value
  ovl: check snprintf return

Problem with ioctl() is that it's a file operation, yet often used as an
inode operation (i.e. modify the inode despite the file being opened for
read-only).

mnt_want_write_file() is used by filesystems in such cases to get write
access on an arbitrary open file.

Since overlayfs lets filesystems do all file operations, including ioctl,
this can lead to mnt_want_write_file() returning OK for a lower file and
modification of that lower file.

This patch prevents modification by checking if the file is from an
overlayfs lower layer and returning EPERM in that case.

Need to introduce a mnt_want_write_file_path() variant that still does the
old thing for inode operations that can do the copy up + modification
correctly in such cases (fchown, fsetxattr, fremovexattr).

This does not address the correctness of such ioctls on overlayfs (the
correct way would be to copy up and attempt to perform ioctl on upper
file).

In theory this could be a regression.  We very much hope that nobody is
relying on such a hack in any sane setup.

While this patch meddles in VFS code, it has no effect on non-overlayfs
filesystems.

Reported-by: "zhangyi (F)" <yi.zhang@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>