fuse: verify all ioctl retry iov elements
authorZach Brown <zab@redhat.com>
Tue, 24 Jul 2012 19:10:11 +0000 (12:10 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 26 Aug 2012 22:00:39 +0000 (15:00 -0700)
commit90f9cb724d38bf4ac4e355d19b1ee697dceea021
treec40e362d46c39e709d42f94b8a53ee35ed3cb78b
parent9ea2c02bafe276e97b592a046ac733610a6d57fd
fuse: verify all ioctl retry iov elements

commit fb6ccff667712c46b4501b920ea73a326e49626a upstream.

Commit 7572777eef78ebdee1ecb7c258c0ef94d35bad16 attempted to verify that
the total iovec from the client doesn't overflow iov_length() but it
only checked the first element.  The iovec could still overflow by
starting with a small element.  The obvious fix is to check all the
elements.

The overflow case doesn't look dangerous to the kernel as the copy is
limited by the length after the overflow.  This fix restores the
intention of returning an error instead of successfully copying less
than the iovec represented.

I found this by code inspection.  I built it but don't have a test case.
I'm cc:ing stable because the initial commit did as well.

Signed-off-by: Zach Brown <zab@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fs/fuse/file.c