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Commit ed3adb56 authored by Dan Carpenter's avatar Dan Carpenter Committed by Greg Kroah-Hartman
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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: 1246ae0b ("xen: add variable hypercall caller")
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 84c6c2af

arch/x86/include/asm/xen/hypercall.h

+3 −0
Original line number Diff line number Diff line
@@ -206,6 +206,9 @@ xen_single_call(unsigned int call, 
	__HYPERCALL_DECLS;

	__HYPERCALL_5ARG(a1, a2, a3, a4, a5);



	if (call >= PAGE_SIZE / sizeof(hypercall_page[0]))

		return -EINVAL;



	asm volatile(CALL_NOSPEC

		     : __HYPERCALL_5PARAM

		     : [thunk_target] "a" (&hypercall_page[call])