xen: Prevent buffer overflow in privcmd ioctl
authorDan Carpenter <dan.carpenter@oracle.com>
Thu, 4 Apr 2019 15:12:17 +0000 (18:12 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 17 Apr 2019 06:37:54 +0000 (08:37 +0200)
commit4f0b27cf8a73e8dbc35347891202929b0d202ba0
treee7b418586872240cee5d0dc6408277d373718e5a
parent6ed78eba4b5474add9c534f25f0dfdfd5a8df38d
xen: Prevent buffer overflow in privcmd ioctl

commit 42d8644bd77dd2d747e004e367cb0c895a606f39 upstream.

The "call" variable comes from the user in privcmd_ioctl_hypercall().
It's an offset into the hypercall_page[] which has (PAGE_SIZE / 32)
elements.  We need to put an upper bound on it to prevent an out of
bounds access.

Cc: stable@vger.kernel.org
Fixes: 1246ae0bb992 ("xen: add variable hypercall caller")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/include/asm/xen/hypercall.h