[Xen-changelog] [xen stable-4.2] nested VMX: VMLANUCH/VMRESUME emulation must check permission first thing

[patchbot@xxxxxxx]

commit b10c183d5cb230e7fd018d2a2aa286b92f6c5b91
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon Nov 11 09:18:59 2013 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Nov 11 09:18:59 2013 +0100

    nested VMX: VMLANUCH/VMRESUME emulation must check permission first thing
    
    Otherwise uninitialized data may be used, leading to crashes.
    
    This is CVE-2013-4551 / XSA-75.
    
    Reported-and-tested-by: Jeff Zimmerman <Jeff_Zimmerman@xxxxxxxxxx>
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-and-tested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    master commit: 4e87bc5b03e05123ba5c888f77969140c8ebd1bf
    master date: 2013-11-11 09:15:04 +0100
---
 xen/arch/x86/hvm/vmx/vvmx.c |   16 +++++++++-------
 1 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
index 278b50f..1b95a46 100644
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -1075,15 +1075,10 @@ int nvmx_handle_vmxoff(struct cpu_user_regs *regs)
     return X86EMUL_OKAY;
 }
 
-int nvmx_vmresume(struct vcpu *v, struct cpu_user_regs *regs)
+static int nvmx_vmresume(struct vcpu *v, struct cpu_user_regs *regs)
 {
     struct nestedvmx *nvmx = &vcpu_2_nvmx(v);
     struct nestedvcpu *nvcpu = &vcpu_nestedhvm(v);
-    int rc;
-
-    rc = vmx_inst_check_privilege(regs, 0);
-    if ( rc != X86EMUL_OKAY )
-        return rc;
 
     /* check VMCS is valid and IO BITMAP is set */
     if ( (nvcpu->nv_vvmcxaddr != VMCX_EADDR) &&
@@ -1100,6 +1095,10 @@ int nvmx_handle_vmresume(struct cpu_user_regs *regs)
 {
     int launched;
     struct vcpu *v = current;
+    int rc = vmx_inst_check_privilege(regs, 0);
+
+    if ( rc != X86EMUL_OKAY )
+        return rc;
 
     if ( vcpu_nestedhvm(v).nv_vvmcxaddr == VMCX_EADDR )
     {
@@ -1119,8 +1118,11 @@ int nvmx_handle_vmresume(struct cpu_user_regs *regs)
 int nvmx_handle_vmlaunch(struct cpu_user_regs *regs)
 {
     int launched;
-    int rc;
     struct vcpu *v = current;
+    int rc = vmx_inst_check_privilege(regs, 0);
+
+    if ( rc != X86EMUL_OKAY )
+        return rc;
 
     if ( vcpu_nestedhvm(v).nv_vvmcxaddr == VMCX_EADDR )
     {
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.2

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