Commit 42d8644b authored by Dan Carpenter's avatar Dan Carpenter Committed by Juergen Gross

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: 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>
parent ad94dc3a
......@@ -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])
......
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