Merge branch 'work.sane_pwd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull misc vfs updates from Al Viro:
 "Making sure that something like a referral point won't end up as pwd
  or root.

  The main part is the last commit (fixing mntns_install()); that one
  fixes a hard-to-hit race. The fchdir() commit is making fchdir(2) a
  bit more robust - it should be impossible to get opened files (even
  O_PATH ones) for referral points in the first place, so the existing
  checks are OK, but checking the same thing as in chdir(2) is just as
  cheap.

  The path_init() commit removes a redundant check that shouldn't have
  been there in the first place"

* 'work.sane_pwd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  make sure that mntns_install() doesn't end up with referral for root
  path_init(): don't bother with checking MAY_EXEC for LOOKUP_ROOT
  make sure that fchdir() won't accept referral points, etc.
This commit is contained in:
Linus Torvalds 2017-05-12 11:39:59 -07:00
commit 050453295f
4 changed files with 55 additions and 21 deletions

View file

@ -460,20 +460,17 @@ out:
SYSCALL_DEFINE1(fchdir, unsigned int, fd)
{
struct fd f = fdget_raw(fd);
struct inode *inode;
int error = -EBADF;
int error;
error = -EBADF;
if (!f.file)
goto out;
inode = file_inode(f.file);
error = -ENOTDIR;
if (!S_ISDIR(inode->i_mode))
if (!d_can_lookup(f.file->f_path.dentry))
goto out_putf;
error = inode_permission(inode, MAY_EXEC | MAY_CHDIR);
error = inode_permission(file_inode(f.file), MAY_EXEC | MAY_CHDIR);
if (!error)
set_fs_pwd(current->fs, &f.file->f_path);
out_putf: