[Xen-changelog] [xen stable-4.5] xen/arm: vgic-v2: Don't crash the hypervisor if the SGI target mode is invalid

[patchbot@xxxxxxx]

commit 1e753b62a178afbd48a23dc4cb451c59bb0caf34
Author:     Julien Grall <julien.grall@xxxxxxxxxx>
AuthorDate: Fri Jan 23 14:15:07 2015 +0000
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Wed Feb 18 10:28:14 2015 +0000

    xen/arm: vgic-v2: Don't crash the hypervisor if the SGI target mode is 
invalid
    
    The GICv2 spec reserved the value 0b11 for GICD_SGIR.TargetListFilter.
    
    Even if it's an invalid value, a malicious guest could write this value
    and threfore crash the hypervisor.
    
    Replace the BUG() by logging the error and inject a data abort to the guest.
    
    This was introduced by commit ea37fd21110b6fbcf9257f814076a243d3873cb7
    "xen/arm: split vgic driver into generic and vgic-v2 driver".
    
    This is CVE-2015-0268 / XSA-117.
    
    Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 xen/arch/arm/vgic-v2.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/xen/arch/arm/vgic-v2.c b/xen/arch/arm/vgic-v2.c
index 477f05a..eb4c90b 100644
--- a/xen/arch/arm/vgic-v2.c
+++ b/xen/arch/arm/vgic-v2.c
@@ -255,7 +255,10 @@ static int vgic_v2_to_sgi(struct vcpu *v, register_t sgir)
         sgi_mode = SGI_TARGET_SELF;
         break;
     default:
-        BUG();
+        printk(XENLOG_G_DEBUG
+               "%pv: vGICD: unhandled GICD_SGIR write %"PRIregister" with 
wrong mode\n",
+               v, sgir);
+        return 0;
     }
 
     return vgic_to_sgi(v, sgir, sgi_mode, virq, vcpu_mask);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.5

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