1. 05 Nov, 2014 3 commits
    • Nadav Amit's avatar
      KVM: x86: Handle errors when RIP is set during far jumps · b8ba339d
      Nadav Amit authored
      commit d1442d85 upstream.
      
      Far jmp/call/ret may fault while loading a new RIP.  Currently KVM does not
      handle this case, and may result in failed vm-entry once the assignment is
      done.  The tricky part of doing so is that loading the new CS affects the
      VMCS/VMCB state, so if we fail during loading the new RIP, we are left in
      unconsistent state.  Therefore, this patch saves on 64-bit the old CS
      descriptor and restores it if loading RIP failed.
      
      This fixes CVE-2014-3647.
      Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      [ kamal: backport to 3.13-stable: context; __long_segment_descriptor args ]
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      b8ba339d
    • Paolo Bonzini's avatar
      KVM: x86: use new CS.RPL as CPL during task switch · 208f481f
      Paolo Bonzini authored
      commit 2356aaeb upstream.
      
      During task switch, all of CS.DPL, CS.RPL, SS.DPL must match (in addition
      to all the other requirements) and will be the new CPL.  So far this
      worked by carefully setting the CS selector and flag before doing the
      task switch; setting CS.selector will already change the CPL.
      
      However, this will not work once we get the CPL from SS.DPL, because
      then you will have to set the full segment descriptor cache to change
      the CPL.  ctxt->ops->cpl(ctxt) will then return the old CPL during the
      task switch, and the check that SS.DPL == CPL will fail.
      
      Temporarily assume that the CPL comes from CS.RPL during task switch
      to a protected-mode task.  This is the same approach used in QEMU's
      emulation code, which (until version 2.0) manually tracks the CPL.
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      [ kamal: 3.13-stable prereq for
        d1442d85 KVM: x86: Handle errors when RIP is set during far jumps ]
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      208f481f
    • Quentin Casasnovas's avatar
      kvm: fix excessive pages un-pinning in kvm_iommu_map error path. · 6f74f650
      Quentin Casasnovas authored
      commit 3d32e4db upstream.
      
      The third parameter of kvm_unpin_pages() when called from
      kvm_iommu_map_pages() is wrong, it should be the number of pages to un-pin
      and not the page size.
      
      This error was facilitated with an inconsistent API: kvm_pin_pages() takes
      a size, but kvn_unpin_pages() takes a number of pages, so fix the problem
      by matching the two.
      
      This was introduced by commit 350b8bdd ("kvm: iommu: fix the third parameter
      of kvm_iommu_put_pages (CVE-2014-3601)"), which fixes the lack of
      un-pinning for pages intended to be un-pinned (i.e. memory leak) but
      unfortunately potentially aggravated the number of pages we un-pin that
      should have stayed pinned. As far as I understand though, the same
      practical mitigations apply.
      
      This issue was found during review of Red Hat 6.6 patches to prepare
      Ksplice rebootless updates.
      
      Thanks to Vegard for his time on a late Friday evening to help me in
      understanding this code.
      
      Fixes: 350b8bdd ("kvm: iommu: fix the third parameter of... (CVE-2014-3601)")
      Signed-off-by: default avatarQuentin Casasnovas <quentin.casasnovas@oracle.com>
      Signed-off-by: default avatarVegard Nossum <vegard.nossum@oracle.com>
      Signed-off-by: default avatarJamie Iles <jamie.iles@oracle.com>
      Reviewed-by: default avatarSasha Levin <sasha.levin@oracle.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      6f74f650
  2. 31 Oct, 2014 37 commits