[Xen-changelog] [xen stable-4.4] domctl: don't allow a toolstack domain to call domain_pause() on itself

[patchbot@xxxxxxx]

commit 6b09a29ced2e7fc449a39f513e1d8c2b10d2af6d
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Wed Apr 1 10:10:31 2015 +0100
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Wed Apr 1 10:14:42 2015 +0100

    domctl: don't allow a toolstack domain to call domain_pause() on itself
    
    These DOMCTL subops were accidentally declared safe for disaggregation
    in the wake of XSA-77.
    
    This is XSA-127 / CVE-2015-2751.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 xen/arch/x86/domctl.c |    8 ++++++++
 xen/common/domctl.c   |    6 ++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index ea76a4f..f01771d 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -960,6 +960,10 @@ long arch_do_domctl(
     {
         xen_guest_tsc_info_t info;
 
+        ret = -EINVAL;
+        if ( d == current->domain ) /* no domain_pause() */
+            break;
+
         domain_pause(d);
         tsc_get_info(d, &info.tsc_mode,
                         &info.elapsed_nsec,
@@ -975,6 +979,10 @@ long arch_do_domctl(
 
     case XEN_DOMCTL_settscinfo:
     {
+        ret = -EINVAL;
+        if ( d == current->domain ) /* no domain_pause() */
+            break;
+
         domain_pause(d);
         tsc_set_info(d, domctl->u.tsc_info.info.tsc_mode,
                      domctl->u.tsc_info.info.elapsed_nsec,
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 49e2c23..0e7ad3d 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -396,8 +396,10 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
u_domctl)
 
     case XEN_DOMCTL_resumedomain:
     {
-        domain_resume(d);
-        ret = 0;
+        if ( d == current->domain ) /* no domain_pause() */
+            ret = -EINVAL;
+        else
+            domain_resume(d);
     }
     break;
 
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.4

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