xen: apply XSA-{182/183/184}

Sponsored by:	Citrix Systems R&D
PR:		211482

3 files changed, 181 insertions, 2 deletions

diff --git a/emulators/xen-kernel/Makefile b/emulators/xen-kernel/Makefile
index 9fa6bbb0a952..20d9a53ee3b4 100644
--- a/emulators/xen-kernel/Makefile
+++ b/emulators/xen-kernel/Makefile
@@ -3,7 +3,7 @@
 PORTNAME=	xen
 PKGNAMESUFFIX=	-kernel
 PORTVERSION=	4.7.0
-PORTREVISION=   2
+PORTREVISION=   3
 CATEGORIES=	emulators
 MASTER_SITES=	http://bits.xensource.com/oss-xen/release/${PORTVERSION}/
 
@@ -39,7 +39,9 @@ PLIST_FILES=	/boot/xen \
 		/boot/xen.4th
 EXTRA_PATCHES=	${FILESDIR}/0001-xen-logdirty-prevent-preemption-if-finished.patch:-p1 \
 		${FILESDIR}/0002-xen-rework-paging_log_dirty_op-to-work-with-hvm-gues.patch:-p1 \
-		${FILESDIR}/kconf_arch.patch:-p1
+		${FILESDIR}/kconf_arch.patch:-p1 \
+		${FILESDIR}/xsa182-unstable.patch:-p1 \
+		${FILESDIR}/xsa183-unstable.patch:-p1
 
 
 .include <bsd.port.options.mk>
diff --git a/emulators/xen-kernel/files/xsa182-unstable.patch b/emulators/xen-kernel/files/xsa182-unstable.patch
new file mode 100644
index 000000000000..3e40e8a5300f
--- /dev/null
+++ b/emulators/xen-kernel/files/xsa182-unstable.patch
@@ -0,0 +1,102 @@
+From 00593655e231ed5ea20704120037026e33b83fbb Mon Sep 17 00:00:00 2001
+From: Andrew Cooper <andrew.cooper3@citrix.com>
+Date: Mon, 11 Jul 2016 14:32:03 +0100
+Subject: [PATCH] x86/pv: Remove unsafe bits from the mod_l?_entry() fastpath
+
+All changes in writeability and cacheability must go through full
+re-validation.
+
+Rework the logic as a whitelist, to make it clearer to follow.
+
+This is XSA-182
+
+Reported-by: Jérémie Boutoille <jboutoille@ext.quarkslab.com>
+Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
+Reviewed-by: Tim Deegan <tim@xen.org>
+---
+ xen/arch/x86/mm.c          | 28 ++++++++++++++++------------
+ xen/include/asm-x86/page.h |  1 +
+ 2 files changed, 17 insertions(+), 12 deletions(-)
+
+diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
+index dbcf6cb..56ca19f 100644
+--- a/xen/arch/x86/mm.c
++++ b/xen/arch/x86/mm.c
+@@ -1852,6 +1852,14 @@ static inline int update_intpte(intpte_t *p,
+                   _t ## e_get_intpte(_o), _t ## e_get_intpte(_n),   \
+                   (_m), (_v), (_ad))
+ 
++/*
++ * PTE flags that a guest may change without re-validating the PTE.
++ * All other bits affect translation, caching, or Xen's safety.
++ */
++#define FASTPATH_FLAG_WHITELIST                                     \
++    (_PAGE_NX_BIT | _PAGE_AVAIL_HIGH | _PAGE_AVAIL | _PAGE_GLOBAL | \
++     _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_USER)
++
+ /* Update the L1 entry at pl1e to new value nl1e. */
+ static int mod_l1_entry(l1_pgentry_t *pl1e, l1_pgentry_t nl1e,
+                         unsigned long gl1mfn, int preserve_ad,
+@@ -1891,9 +1899,8 @@ static int mod_l1_entry(l1_pgentry_t *pl1e, l1_pgentry_t nl1e,
+             nl1e = l1e_from_pfn(page_to_mfn(page), l1e_get_flags(nl1e));
+         }
+ 
+-        /* Fast path for identical mapping, r/w, presence, and cachability. */
+-        if ( !l1e_has_changed(ol1e, nl1e,
+-                              PAGE_CACHE_ATTRS | _PAGE_RW | _PAGE_PRESENT) )
++        /* Fast path for sufficiently-similar mappings. */
++        if ( !l1e_has_changed(ol1e, nl1e, ~FASTPATH_FLAG_WHITELIST) )
+         {
+             adjust_guest_l1e(nl1e, pt_dom);
+             rc = UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, pt_vcpu,
+@@ -1970,11 +1977,8 @@ static int mod_l2_entry(l2_pgentry_t *pl2e,
+             return -EINVAL;
+         }
+ 
+-        /* Fast path for identical mapping and presence. */
+-        if ( !l2e_has_changed(ol2e, nl2e,
+-                              unlikely(opt_allow_superpage)
+-                              ? _PAGE_PSE | _PAGE_RW | _PAGE_PRESENT
+-                              : _PAGE_PRESENT) )
++        /* Fast path for sufficiently-similar mappings. */
++        if ( !l2e_has_changed(ol2e, nl2e, ~FASTPATH_FLAG_WHITELIST) )
+         {
+             adjust_guest_l2e(nl2e, d);
+             if ( UPDATE_ENTRY(l2, pl2e, ol2e, nl2e, pfn, vcpu, preserve_ad) )
+@@ -2039,8 +2043,8 @@ static int mod_l3_entry(l3_pgentry_t *pl3e,
+             return -EINVAL;
+         }
+ 
+-        /* Fast path for identical mapping and presence. */
+-        if ( !l3e_has_changed(ol3e, nl3e, _PAGE_PRESENT) )
++        /* Fast path for sufficiently-similar mappings. */
++        if ( !l3e_has_changed(ol3e, nl3e, ~FASTPATH_FLAG_WHITELIST) )
+         {
+             adjust_guest_l3e(nl3e, d);
+             rc = UPDATE_ENTRY(l3, pl3e, ol3e, nl3e, pfn, vcpu, preserve_ad);
+@@ -2103,8 +2107,8 @@ static int mod_l4_entry(l4_pgentry_t *pl4e,
+             return -EINVAL;
+         }
+ 
+-        /* Fast path for identical mapping and presence. */
+-        if ( !l4e_has_changed(ol4e, nl4e, _PAGE_PRESENT) )
++        /* Fast path for sufficiently-similar mappings. */
++        if ( !l4e_has_changed(ol4e, nl4e, ~FASTPATH_FLAG_WHITELIST) )
+         {
+             adjust_guest_l4e(nl4e, d);
+             rc = UPDATE_ENTRY(l4, pl4e, ol4e, nl4e, pfn, vcpu, preserve_ad);
+diff --git a/xen/include/asm-x86/page.h b/xen/include/asm-x86/page.h
+index 224852a..4ae387f 100644
+--- a/xen/include/asm-x86/page.h
++++ b/xen/include/asm-x86/page.h
+@@ -313,6 +313,7 @@ void efi_update_l4_pgtable(unsigned int l4idx, l4_pgentry_t);
+ #define _PAGE_AVAIL2   _AC(0x800,U)
+ #define _PAGE_AVAIL    _AC(0xE00,U)
+ #define _PAGE_PSE_PAT  _AC(0x1000,U)
++#define _PAGE_AVAIL_HIGH (_AC(0x7ff, U) << 12)
+ #define _PAGE_NX       (cpu_has_nx ? _PAGE_NX_BIT : 0)
+ /* non-architectural flags */
+ #define _PAGE_PAGED   0x2000U
+-- 
+2.1.4
+
diff --git a/emulators/xen-kernel/files/xsa183-unstable.patch b/emulators/xen-kernel/files/xsa183-unstable.patch
new file mode 100644
index 000000000000..573c530112c2
--- /dev/null
+++ b/emulators/xen-kernel/files/xsa183-unstable.patch
@@ -0,0 +1,75 @@
+From 2fd4f34058fb5f87fbd80978dbd2cb458aff565d Mon Sep 17 00:00:00 2001
+From: Andrew Cooper <andrew.cooper3@citrix.com>
+Date: Wed, 15 Jun 2016 18:32:14 +0100
+Subject: [PATCH] x86/entry: Avoid SMAP violation in
+ compat_create_bounce_frame()
+
+A 32bit guest kernel might be running on user mappings.
+compat_create_bounce_frame() must whitelist its guest accesses to avoid
+risking a SMAP violation.
+
+For both variants of create_bounce_frame(), re-blacklist user accesses if
+execution exits via an exception table redirection.
+
+This is XSA-183 / CVE-2016-6259
+
+Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
+Reviewed-by: George Dunlap <george.dunlap@citrix.com>
+Reviewed-by: Jan Beulich <jbeulich@suse.com>
+---
+v2:
+ * Include CLAC on the exit paths from compat_create_bounce_frame which occur
+   from faults attempting to load %fs
+ * Reposition ASM_STAC to avoid breaking the macro-op fusion of test/jz
+---
+ xen/arch/x86/x86_64/compat/entry.S | 3 +++
+ xen/arch/x86/x86_64/entry.S        | 2 ++
+ 2 files changed, 5 insertions(+)
+
+diff --git a/xen/arch/x86/x86_64/compat/entry.S b/xen/arch/x86/x86_64/compat/entry.S
+index 7f02afd..e80c53c 100644
+--- a/xen/arch/x86/x86_64/compat/entry.S
++++ b/xen/arch/x86/x86_64/compat/entry.S
+@@ -318,6 +318,7 @@ ENTRY(compat_int80_direct_trap)
+ compat_create_bounce_frame:
+         ASSERT_INTERRUPTS_ENABLED
+         mov   %fs,%edi
++        ASM_STAC
+         testb $2,UREGS_cs+8(%rsp)
+         jz    1f
+         /* Push new frame at registered guest-OS stack base. */
+@@ -364,6 +365,7 @@ compat_create_bounce_frame:
+         movl  TRAPBOUNCE_error_code(%rdx),%eax
+ .Lft8:  movl  %eax,%fs:(%rsi)           # ERROR CODE
+ 1:
++        ASM_CLAC
+         /* Rewrite our stack frame and return to guest-OS mode. */
+         /* IA32 Ref. Vol. 3: TF, VM, RF and NT flags are cleared on trap. */
+         andl  $~(X86_EFLAGS_VM|X86_EFLAGS_RF|\
+@@ -403,6 +405,7 @@ compat_crash_page_fault_4:
+         addl  $4,%esi
+ compat_crash_page_fault:
+ .Lft14: mov   %edi,%fs
++        ASM_CLAC
+         movl  %esi,%edi
+         call  show_page_walk
+         jmp   dom_crash_sync_extable
+diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
+index ad8c64c..f7178cd 100644
+--- a/xen/arch/x86/x86_64/entry.S
++++ b/xen/arch/x86/x86_64/entry.S
+@@ -420,9 +420,11 @@ domain_crash_page_fault_16:
+ domain_crash_page_fault_8:
+         addq  $8,%rsi
+ domain_crash_page_fault:
++        ASM_CLAC
+         movq  %rsi,%rdi
+         call  show_page_walk
+ ENTRY(dom_crash_sync_extable)
++        ASM_CLAC
+         # Get out of the guest-save area of the stack.
+         GET_STACK_END(ax)
+         leaq  STACK_CPUINFO_FIELD(guest_cpu_user_regs)(%rax),%rsp
+-- 
+2.1.4
+