From d06a0d715ec1423b6c42141ab1b0ff69a3effb56 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Fri, 11 Oct 2013 09:29:43 +0200 Subject: x86: add address validity check to guest_map_l1e() Just like for guest_get_eff_l1e() this prevents accessing as page tables (and with the wrong memory attribute) internal data inside Xen happening to be mapped with 1Gb pages. Signed-off-by: Jan Beulich Reviewed-by: Andrew Cooper Acked-by: Keir Fraser --- xen/include/asm-x86/paging.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/xen/include/asm-x86/paging.h b/xen/include/asm-x86/paging.h index 105a0ca1b3..e957b2fe23 100644 --- a/xen/include/asm-x86/paging.h +++ b/xen/include/asm-x86/paging.h @@ -360,7 +360,8 @@ guest_map_l1e(struct vcpu *v, unsigned long addr, unsigned long *gl1mfn) return paging_get_hostmode(v)->guest_map_l1e(v, addr, gl1mfn); /* Find this l1e and its enclosing l1mfn in the linear map */ - if ( __copy_from_user(&l2e, + if ( !__addr_ok(addr) || + __copy_from_user(&l2e, &__linear_l2_table[l2_linear_offset(addr)], sizeof(l2_pgentry_t)) != 0 ) return NULL; -- cgit v1.2.3