Commit 42d8644b authored Apr 04, 2019 by Dan Carpenter Committed by Juergen Gross Apr 05, 2019

xen: Prevent buffer overflow in privcmd ioctl



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: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

parent ad94dc3a

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])

Admin message