diff options
Diffstat (limited to 'emulators/xen-kernel/files/xsa227.patch')
| -rw-r--r-- | emulators/xen-kernel/files/xsa227.patch | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/emulators/xen-kernel/files/xsa227.patch b/emulators/xen-kernel/files/xsa227.patch new file mode 100644 index 000000000000..86aa41e2d486 --- /dev/null +++ b/emulators/xen-kernel/files/xsa227.patch @@ -0,0 +1,52 @@ +From fa7268b94f8a0a7792ee12d5b8e23a60e52a3a84 Mon Sep 17 00:00:00 2001 +From: Andrew Cooper <andrew.cooper3@citrix.com> +Date: Tue, 20 Jun 2017 19:18:54 +0100 +Subject: [PATCH] x86/grant: Disallow misaligned PTEs + +Pagetable entries must be aligned to function correctly. Disallow attempts +from the guest to have a grant PTE created at a misaligned address, which +would result in corruption of the L1 table with largely-guest-controlled +values. + +This is XSA-227 + +Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> +Reviewed-by: Jan Beulich <jbeulich@suse.com> +--- + xen/arch/x86/mm.c | 13 +++++++++++++ + 1 file changed, 13 insertions(+) + +diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c +index 97b3b4b..00f517a 100644 +--- a/xen/arch/x86/mm.c ++++ b/xen/arch/x86/mm.c +@@ -3763,6 +3763,9 @@ static int create_grant_pte_mapping( + l1_pgentry_t ol1e; + struct domain *d = v->domain; + ++ if ( !IS_ALIGNED(pte_addr, sizeof(nl1e)) ) ++ return GNTST_general_error; ++ + adjust_guest_l1e(nl1e, d); + + gmfn = pte_addr >> PAGE_SHIFT; +@@ -3819,6 +3822,16 @@ static int destroy_grant_pte_mapping( + struct page_info *page; + l1_pgentry_t ol1e; + ++ /* ++ * addr comes from Xen's active_entry tracking so isn't guest controlled, ++ * but it had still better be PTE-aligned. ++ */ ++ if ( !IS_ALIGNED(addr, sizeof(ol1e)) ) ++ { ++ ASSERT_UNREACHABLE(); ++ return GNTST_general_error; ++ } ++ + gmfn = addr >> PAGE_SHIFT; + page = get_page_from_gfn(d, gmfn, NULL, P2M_ALLOC); + +-- +2.1.4 + |