Commit 254d4d48 authored by Gleb Natapov's avatar Gleb Natapov Committed by Avi Kivity
Browse files

KVM: fix segment_base() error checking 



fix segment_base() to properly check for null segment selector and
avoid accessing NULL pointer if ldt selector in null.

Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent d6ab1ed4

arch/x86/kvm/x86.c

+3 −1
Original line number Diff line number Diff line
@@ -230,7 +230,7 @@ unsigned long segment_base(u16 selector) 
	unsigned long table_base;

	unsigned long v;



	if (selector == 0)

	if (!(selector & ~3))

		return 0;



	native_store_gdt(&gdt);
@@ -239,6 +239,8 @@ unsigned long segment_base(u16 selector) 
	if (selector & 4) {           /* from ldt */

		u16 ldt_selector = kvm_read_ldt();



		if (!(ldt_selector & ~3))

			return 0;

		table_base = segment_base(ldt_selector);

	}

	d = (struct desc_struct *)(table_base + (selector & ~7));