[Intel-gfx] [PATCH] drm/i915/gvt: Fix out-of-bounds buffer write into opregion->signature[]

[Zhenyu Wang]

On 2017.11.21 10:19:21 +0000, Chris Wilson wrote:
> Quoting Zhenyu Wang (2017-11-21 03:19:51)
> > On 2017.11.20 21:15:16 +0000, Chris Wilson wrote:
> > > sparse spots
> > > 
> > > drivers/gpu/drm/i915/gvt/opregion.c:234 alloc_and_init_virt_opregion() error: memcpy() 'header->signature' too small (16 vs 17)
> > > 
> > > as gvt is indeed trying to memcpy a string longer than the signature[].
> > > 
> > > Fixes: b2d6ef70614e ("drm/i915/gvt: Let each vgpu has separate opregion memory")
> > > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > > Cc: Xiong Zhang <xiong.y.zhang at intel.com>
> > > Cc: Zhenyu Wang <zhenyuw at linux.intel.com>
> > > Cc: Zhi Wang <zhi.a.wang at intel.com>
> > > Cc: intel-gvt-dev at lists.freedesktop.org
> > > ---
> > >  drivers/gpu/drm/i915/gvt/opregion.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/gvt/opregion.c b/drivers/gpu/drm/i915/gvt/opregion.c
> > > index 80720e59723a..3cf4c6f18152 100644
> > > --- a/drivers/gpu/drm/i915/gvt/opregion.c
> > > +++ b/drivers/gpu/drm/i915/gvt/opregion.c
> > > @@ -232,7 +232,7 @@ static int alloc_and_init_virt_opregion(struct intel_vgpu *vgpu)
> > >       buf = (u8 *)vgpu_opregion(vgpu)->va;
> > >       header = (struct opregion_header *)buf;
> > >       memcpy(header->signature, OPREGION_SIGNATURE,
> > > -                     sizeof(OPREGION_SIGNATURE));
> > > +                     sizeof(OPREGION_SIGNATURE) - 1);
> > >       header->size = 0x8;
> > >       header->opregion_ver = 0x02000000;
> > >       header->mboxes = MBOX_VBT;
> > > -- 
> > 
> > applied this, thanks!
> 
> It's not the best patch; after sleep I think you want
> 
> static const char opregion_signature[16] = "IntelFooBar";
> 
> memcpy(header->signature, opregion_signature, sizeof(opregion_signature));

yeah, I applied below one instead. Thanks.

From ea26c96d59b27e878fe61e8ef0fed840d2281a2f Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris at chris-wilson.co.uk>
Date: Mon, 4 Dec 2017 11:23:44 +0800
Subject: [PATCH] drm/i915/gvt: Fix out-of-bounds buffer write into opregion->signature[]

sparse spots

drivers/gpu/drm/i915/gvt/opregion.c:234 alloc_and_init_virt_opregion() error: memcpy() 'header->signature' too small (16 vs 17)

as gvt is indeed trying to memcpy a string longer than the signature[].

Fixes: b2d6ef70614e ("drm/i915/gvt: Let each vgpu has separate opregion memory")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Xiong Zhang <xiong.y.zhang at intel.com>
Cc: Zhenyu Wang <zhenyuw at linux.intel.com>
Cc: Zhi Wang <zhi.a.wang at intel.com>
Cc: intel-gvt-dev at lists.freedesktop.org
Signed-off-by: Zhenyu Wang <zhenyuw at linux.intel.com>
---
 drivers/gpu/drm/i915/gvt/opregion.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/opregion.c b/drivers/gpu/drm/i915/gvt/opregion.c
index 80720e59723a..bf8e5c49a64a 100644
--- a/drivers/gpu/drm/i915/gvt/opregion.c
+++ b/drivers/gpu/drm/i915/gvt/opregion.c
@@ -218,6 +218,7 @@ static int alloc_and_init_virt_opregion(struct intel_vgpu *vgpu)
 	u8 *buf;
 	struct opregion_header *header;
 	struct vbt v;
+	const char opregion_signature[16] = OPREGION_SIGNATURE;
 
 	gvt_dbg_core("init vgpu%d opregion\n", vgpu->id);
 	vgpu_opregion(vgpu)->va = (void *)__get_free_pages(GFP_KERNEL |
@@ -231,8 +232,8 @@ static int alloc_and_init_virt_opregion(struct intel_vgpu *vgpu)
 	/* emulated opregion with VBT mailbox only */
 	buf = (u8 *)vgpu_opregion(vgpu)->va;
 	header = (struct opregion_header *)buf;
-	memcpy(header->signature, OPREGION_SIGNATURE,
-			sizeof(OPREGION_SIGNATURE));
+	memcpy(header->signature, opregion_signature,
+	       sizeof(opregion_signature));
 	header->size = 0x8;
 	header->opregion_ver = 0x02000000;
 	header->mboxes = MBOX_VBT;
-- 
2.15.0


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