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 <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Gleb Natapov 2010-02-25 12:43:08 +02:00 committed by Avi Kivity
parent d6ab1ed446
commit 254d4d48a5

View file

@ -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));