Commit 2b79bc4f authored May 11, 2009 by Jeff Mahoney Committed by Linus Torvalds May 11, 2009

dup2: Fix return value with oldfd == newfd and invalid fd



The return value of dup2 when oldfd == newfd and the fd isn't valid is
not getting properly sign extended.  We end up with 4294967287 instead
of -EBADF.

I've reproduced this on SLE11 (2.6.27.21), openSUSE Factory
(2.6.29-rc5), and Ubuntu 9.04 (2.6.28).

This patch uses a signed int for the error value so it is properly
extended.

Commit 6c5d0512 introduced this
regression.

Reported-by: Jiri Dluhos <jdluhos@novell.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent fd18de50

fs/fcntl.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -117,11 +117,13 @@ SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
		{
		if (unlikely(newfd == oldfd)) { /* corner case */
		struct files_struct *files = current->files;
		int retval = oldfd;

		rcu_read_lock();
		if (!fcheck_files(files, oldfd))
		oldfd = -EBADF;
		retval = -EBADF;
		rcu_read_unlock();
		return oldfd;
		return retval;
		}
		return sys_dup3(oldfd, newfd, 0);
		}