=?y?q?=5B=20119/187=5D=20vfs=3A=20make=20O=5FPATH=20file=20descriptors=20usable=20for=20fchdir=28=29?=

Greg Kroah-Hartman
2012-07-12T22:43:01Z

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From: Greg KH <gregkh@linuxfoundation.org>

3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Linus Torvalds <torvalds@linux-foundation.org>

commit 332a2e1244bd08b9e3ecd378028513396a004a24 upstream.

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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/open.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/fs/open.c
+++ b/fs/open.c
@@ -396,10 +396,10 @@ 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;

@@ -413,7 +413,7 @@ 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;
}