Messages in this thread Patch in this message | | | From | Zheng Hacker <> | Date | Mon, 5 Sep 2022 15:46:09 +0800 | Subject | Re: [PATCH] drm/i915/gvt: fix double-free bug in split_2MB_gtt_entry. |
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I rewrote the letter. Hope it works.
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 returning the result of ppgtt_invalidate_spt to split_2MB_gtt_entry.
Signed-off-by: Zheng Wang
--- drivers/gpu/drm/i915/gvt/gtt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c index ce0eb03709c3..9f14fded8c0c 100644 --- a/drivers/gpu/drm/i915/gvt/gtt.c +++ b/drivers/gpu/drm/i915/gvt/gtt.c @@ -1215,7 +1215,7 @@ static int split_2MB_gtt_entry(struct intel_vgpu *vgpu, ret = intel_gvt_dma_map_guest_page(vgpu, start_gfn + sub_index, PAGE_SIZE, &dma_addr); if (ret) { - ppgtt_invalidate_spt(spt); + ret = ppgtt_invalidate_spt(spt); return ret; } sub_se.val64 = se->val64; -- 2.25.1
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