[xen] Lock order reversal between page_alloc_lock and mm_rwlock, Hypercalls exposed to privilege rings 1 a

[myoung]

commit 14cd6e1a74ae36fe7ee6edc1cd3209ae8bc2cdf8
Author: Michael Young <m.a.young at durham.ac.uk>
Date:   Tue Nov 26 21:15:20 2013 +0000

    Lock order reversal between page_alloc_lock and mm_rwlock,
    Hypercalls exposed to privilege rings 1 and 2 of HVM guests

 xen.spec                 |   12 +++++++++++-
 xsa74-4.3-unstable.patch |   41 +++++++++++++++++++++++++++++++++++++++++
 xsa76.patch              |   19 +++++++++++++++++++
 3 files changed, 71 insertions(+), 1 deletions(-)
---
diff --git a/xen.spec b/xen.spec
index dac8a31..6f87417 100644
--- a/xen.spec
+++ b/xen.spec
@@ -46,7 +46,7 @@
 Summary: Xen is a virtual machine monitor
 Name:    xen
 Version: 4.3.1
-Release: 3%{?dist}
+Release: 4%{?dist}
 Group:   Development/Libraries
 License: GPLv2+ and LGPLv2+ and BSD
 URL:     http://xen.org/
@@ -101,6 +101,8 @@ Patch21: xen.64.bit.hyp.on.ix86.patch
 Patch22: xsa73-4.3-unstable.patch
 Patch23: xsa75-4.3-unstable.patch
 Patch24: xsa78.patch
+Patch25: xsa74-4.3-unstable.patch
+Patch26: xsa76.patch
 
 Patch100: xen-configure-xend.patch
 
@@ -284,6 +286,8 @@ manage Xen virtual machines.
 %patch22 -p1
 %patch23 -p1
 %patch24 -p1
+%patch25 -p1
+%patch26 -p1
 
 %patch100 -p1
 
@@ -816,6 +820,12 @@ rm -rf %{buildroot}
 %endif
 
 %changelog
+* Tue Nov 26 2013 Michael Young <m.a.young at durham.ac.uk> - 4.3.1-4
+- Lock order reversal between page_alloc_lock and mm_rwlock
+    [XSA-74, CVE-2013-4553] (#1034925)
+- Hypercalls exposed to privilege rings 1 and 2 of HVM guests
+    [XSA-76, CVE-2013-4554] (#1034923)
+
 * Thu Nov 21 2013 Michael Young <m.a.young at durham.ac.uk> - 4.3.1-3
 - Insufficient TLB flushing in VT-d (iommu) code
     [XSA-78, CVE-2013-6375] (#1033149)
diff --git a/xsa74-4.3-unstable.patch b/xsa74-4.3-unstable.patch
new file mode 100644
index 0000000..4c9c27c
--- /dev/null
+++ b/xsa74-4.3-unstable.patch
@@ -0,0 +1,41 @@
+x86: restrict XEN_DOMCTL_getmemlist
+
+Coverity ID 1055652
+
+(See the code comment.)
+
+This is CVE-2013-4553 / XSA-74.
+
+Signed-off-by: Jan Beulich <jbeulich at suse.com>
+Reviewed-by: Andrew Cooper <andrew.cooper3 at citrix.com>
+Reviewed-by: Tim Deegan <tim at xen.org>
+
+--- a/xen/arch/x86/domctl.c
++++ b/xen/arch/x86/domctl.c
+@@ -329,6 +329,26 @@ long arch_do_domctl(
+             break;
+         }
+ 
++        /*
++         * XSA-74: This sub-hypercall is broken in several ways:
++         * - lock order inversion (p2m locks inside page_alloc_lock)
++         * - no preemption on huge max_pfns input
++         * - not (re-)checking d->is_dying with page_alloc_lock held
++         * - not honoring start_pfn input (which libxc also doesn't set)
++         * Additionally it is rather useless, as the result is stale by the
++         * time the caller gets to look at it.
++         * As it only has a single, non-production consumer (xen-mceinj),
++         * rather than trying to fix it we restrict it for the time being.
++         */
++        if ( /* No nested locks inside copy_to_guest_offset(). */
++             paging_mode_external(current->domain) ||
++             /* Arbitrary limit capping processing time. */
++             max_pfns > GB(4) / PAGE_SIZE )
++        {
++            ret = -EOPNOTSUPP;
++            break;
++        }
++
+         spin_lock(&d->page_alloc_lock);
+ 
+         ret = i = 0;
diff --git a/xsa76.patch b/xsa76.patch
new file mode 100644
index 0000000..54e4325
--- /dev/null
+++ b/xsa76.patch
@@ -0,0 +1,19 @@
+x86/HVM: only allow ring 0 guest code to make hypercalls
+
+Anything else would allow for privilege escalation.
+
+This is CVE-2013-4554 / XSA-76.
+
+Signed-off-by: Jan Beulich <jbeulich at suse.com>
+
+--- a/xen/arch/x86/hvm/hvm.c
++++ b/xen/arch/x86/hvm/hvm.c
+@@ -3359,7 +3359,7 @@ int hvm_do_hypercall(struct cpu_user_reg
+     case 4:
+     case 2:
+         hvm_get_segment_register(curr, x86_seg_ss, &sreg);
+-        if ( unlikely(sreg.attr.fields.dpl == 3) )
++        if ( unlikely(sreg.attr.fields.dpl) )
+         {
+     default:
+             regs->eax = -EPERM;