Commit 332a2e12 authored Jul 07, 2012 by Linus Torvalds

vfs: make O_PATH file descriptors usable for 'fchdir()'



We already use them for openat() and friends, but fchdir() also wants to
be able to use O_PATH file descriptors.  This should make it comparable
to the O_SEARCH of Solaris.  In particular, O_PATH allows you to access
(not-quite-open) a directory you don't have read persmission to, only
execute permission.

Noticed during development of multithread support for ksh93.

Reported-by: ольга крыжановская <olga.kryzhanovska@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org    # O_PATH introduced in 3.0+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent cd6407fe

fs/open.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -397,10 +397,10 @@ SYSCALL_DEFINE1(fchdir, unsigned int, fd)
		{
		struct file *file;
		struct inode *inode;
		int error;
		int error, fput_needed;

		error = -EBADF;
		file = fget(fd);
		file = fget_raw_light(fd, &fput_needed);
		if (!file)
		goto out;

		@@ -414,7 +414,7 @@ SYSCALL_DEFINE1(fchdir, unsigned int, fd)
		if (!error)
		set_fs_pwd(current->fs, &file->f_path);
		out_putf:
		fput(file);
		fput_light(file, fput_needed);
		out:
		return error;
		}