From 254d4d48a56925622a5592ad590a738735b66135 Mon Sep 17 00:00:00 2001 From: Gleb Natapov Date: Thu, 25 Feb 2010 12:43:08 +0200 Subject: [PATCH] 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: Gleb Natapov Signed-off-by: Avi Kivity --- arch/x86/kvm/x86.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e07b243055f8..814e72a02eff 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -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)); -- 2.45.2