I'll try using another mail client like Mutt later. :) Regards, Zheng Wang Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> 于2022年9月17日周六 17:07写道： > > On Fri, Sep 16, 2022 at 11:54:42PM +0800, Zheng Hacker wrote: > > >From afe79848cb74cc8e45ab426d13fa2394c87e0422 Mon Sep 17 00:00:00 2001 > > From: xmzyshypnc <1002992920@xxxxxx> > > Date: Fri, 16 Sep 2022 23:48:23 +0800 > > Subject: [PATCH] drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry > > > > There is a double-free security bug in split_2MB_gtt_entry. > > > > Here is a calling chain : > > ppgtt_populate_spt->ppgtt_populate_shadow_entry->split_2MB_gtt_entry. > > > > If intel_gvt_dma_map_guest_page failed, it will call > > ppgtt_invalidate_spt, which will finally call ppgtt_free_spt and > > kfree(spt). But the caller does not notice that, and it will call > > ppgtt_free_spt again in error path. > > > > Fix this by only freeing spt in ppgtt_invalidate_spt in good case. > > > > Signed-off-by: Zheng Wang <hackerzheng666@xxxxxxxxx> > > --- > > drivers/gpu/drm/i915/gvt/gtt.c | 16 +++++++++------- > > 1 file changed, 9 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c > > index ce0eb03709c3..550519f0acca 100644 > > --- a/drivers/gpu/drm/i915/gvt/gtt.c > > +++ b/drivers/gpu/drm/i915/gvt/gtt.c > > @@ -959,7 +959,7 @@ static inline int ppgtt_put_spt(struct > > intel_vgpu_ppgtt_spt *spt) > > return atomic_dec_return(&spt->refcount); > > } > > > > -static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt); > > +static int ppgtt_invalidate_spt(struct intel_vgpu_ppgtt_spt *spt, int > > is_error); > > > > static int ppgtt_invalidate_spt_by_shadow_entry(struct intel_vgpu *vgpu, > > struct intel_gvt_gtt_entry *e) > > @@ -995,7 +995,7 @@ static int > > ppgtt_invalidate_spt_by_shadow_entry(struct intel_vgpu *vgpu, > > Still line-wrapped and whitespace broken :( >
