pre-fill structures for certain HYPERVISOR_xen_version sub-ops

... avoiding to pass hypervisor stack contents back to the caller
through space unused by the respective strings.

This is CVE-2015-2045 / XSA-122.

Signed-off-by: Aaron Adams <Aaron.Adams@nccgroup.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
master commit: fe2e079f642effb3d24a6e1a7096ef26e691d93e
master date: 2015-03-05 13:35:54 +0100

diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index c915bbcb65acdbecc85c2d5053928fe9a5abc8f6..fe3ccb5cba429cb5a16b6efaf5ba5622b86a7dda 100644 (file)
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -216,6 +216,8 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE(void) arg)
     case XENVER_extraversion:
     {
         xen_extraversion_t extraversion;
+
+        memset(extraversion, 0, sizeof(extraversion));
         safe_strcpy(extraversion, xen_extra_version());
         if ( copy_to_guest(arg, extraversion, ARRAY_SIZE(extraversion)) )
             return -EFAULT;
@@ -225,6 +227,8 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE(void) arg)
     case XENVER_compile_info:
     {
         struct xen_compile_info info;
+
+        memset(&info, 0, sizeof(info));
         safe_strcpy(info.compiler,       xen_compiler());
         safe_strcpy(info.compile_by,     xen_compile_by());
         safe_strcpy(info.compile_domain, xen_compile_domain());
@@ -260,6 +264,8 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE(void) arg)
     case XENVER_changeset:
     {
         xen_changeset_info_t chgset;
+
+        memset(chgset, 0, sizeof(chgset));
         safe_strcpy(chgset, xen_changeset());
         if ( copy_to_guest(arg, chgset, ARRAY_SIZE(chgset)) )
             return -EFAULT;