CVE-2016-3960 / XSA-173
Bug #1581420 reported by
Philipp Hahn
This bug affects 1 person
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
xen (Ubuntu) |
Fix Released
|
Medium
|
Unassigned | ||
Precise |
Fix Released
|
Medium
|
Unassigned | ||
Trusty |
Fix Released
|
Medium
|
Unassigned | ||
Wily |
Fix Released
|
Medium
|
Unassigned | ||
Xenial |
Fix Released
|
Medium
|
Unassigned |
Bug Description
<http://
x86 shadow pagetables: address width overflow
CVE References
Changed in xen (Ubuntu Precise): | |
status: | New → In Progress |
importance: | Undecided → Medium |
assignee: | nobody → Stefan Bader (smb) |
To post a comment you must log in.
xen-4.3 dropped support for x86-32 bit. walk_tables_ 2_levels' : c:146:30: error: '_PAGE_INVALID_BIT' undeclared (first use in this function) return- type]
As such compilation fails for 4.1 on i386::
> guest_walk.c: In function 'mandatory_flags':
> guest_walk.c:66:40: error: '_PAGE_INVALID_BIT' undeclared (first use in this function)
> guest_walk.c:66:40: note: each undeclared identifier is reported only once for each function it appears in
> guest_walk.c: In function 'guest_
> guest_walk.
> guest_walk.c: In function 'mandatory_flags':
> guest_walk.c:67:1: error: control reaches end of non-void function [-Werror=
Define _PAGE_INVALID_BIT for x86-32 too, for which support was dropped in xen-4.3:
diff --git a/xen/include/ asm-x86/ x86_32/ page.h b/xen/include/ asm-x86/ x86_32/ page.h asm-x86/ x86_32/ page.h asm-x86/ x86_32/ page.h _NOCACHE;
: BASE_DISALLOW_MASK)
index ca6988c..a2cd306 100644
--- a/xen/include/
+++ b/xen/include/
@@ -135,6 +135,12 @@ extern unsigned int PAGE_HYPERVISOR
#define L3_DISALLOW_MASK 0xFFFFF1FEU /* must-be-zero */
+/*
+ * Bit 24 of a 24-bit flag mask! This is not any bit of a real pte,
+ * and is only used for signalling in variables that contain flags.
+ */
+#define _PAGE_INVALID_BIT (1U<<24)
+
#endif /* __X86_32_PAGE_H__ */
/*
Waiting on confirmation from xen-devel that using bit 24 on x86-32 is okay.