Resent the mail for the former letter contains html text.
Regards,
Zheng Wang
Zheng Hacker <hackerzheng666@xxxxxxxxx> 于2022年9月5日周一 12:47写道：
Hello everyone,I'm Zheng Wang. I found a potential double-free bug in drivers/gpu/drm/i915/gvt/gtt.c. I haven't been replied for a long time. So I decided to send it to more relavent supporters and developers to help to solve the problem.Best regards,Zheng Wang.xmzyshypnc <1002992920@xxxxxx> 于2022年9月4日周日 20:32写道：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 <1002992920@xxxxxx>
---
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
