From cdcd6aef9db5797995d4153ea19fdf56d189f0e4 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <mripard@kernel.org>
Date: Tue, 24 Oct 2023 12:56:40 +0200
Subject: [PATCH] drm/vc4: tests: Fix UAF in the mock helpers
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The VC4 mock helpers allocate the CRTC, encoders and connectors using a
call to kunit_kzalloc(), but the DRM device they are attache to survives
for longer than the test itself which leads to use-after-frees reported
by KASAN.

Switch to drmm_kzalloc to tie the lifetime of these objects to the main
DRM device.

Fixes: f759f5b53f1c ("drm/vc4: tests: Introduce a mocking infrastructure")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Closes: https://lore.kernel.org/all/CA+G9fYvJA2HGqzR9LGgq63v0SKaUejHAE6f7+z9cwWN-ourJ_g@mail.gmail.com/
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Reviewed-by: MaĆ­ra Canal <mcanal@igalia.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231024105640.352752-1-mripard@kernel.org
---
 drivers/gpu/drm/vc4/tests/vc4_mock_crtc.c   | 2 +-
 drivers/gpu/drm/vc4/tests/vc4_mock_output.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vc4/tests/vc4_mock_crtc.c b/drivers/gpu/drm/vc4/tests/vc4_mock_crtc.c
index 5d12d7beef0eb..ade3309ae042f 100644
--- a/drivers/gpu/drm/vc4/tests/vc4_mock_crtc.c
+++ b/drivers/gpu/drm/vc4/tests/vc4_mock_crtc.c
@@ -26,7 +26,7 @@ struct vc4_dummy_crtc *vc4_mock_pv(struct kunit *test,
 	struct vc4_crtc *vc4_crtc;
 	int ret;
 
-	dummy_crtc = kunit_kzalloc(test, sizeof(*dummy_crtc), GFP_KERNEL);
+	dummy_crtc = drmm_kzalloc(drm, sizeof(*dummy_crtc), GFP_KERNEL);
 	KUNIT_ASSERT_NOT_NULL(test, dummy_crtc);
 
 	vc4_crtc = &dummy_crtc->crtc;
diff --git a/drivers/gpu/drm/vc4/tests/vc4_mock_output.c b/drivers/gpu/drm/vc4/tests/vc4_mock_output.c
index 6e11fcc9ef45e..e70d7c3076acf 100644
--- a/drivers/gpu/drm/vc4/tests/vc4_mock_output.c
+++ b/drivers/gpu/drm/vc4/tests/vc4_mock_output.c
@@ -32,7 +32,7 @@ struct vc4_dummy_output *vc4_dummy_output(struct kunit *test,
 	struct drm_encoder *enc;
 	int ret;
 
-	dummy_output = kunit_kzalloc(test, sizeof(*dummy_output), GFP_KERNEL);
+	dummy_output = drmm_kzalloc(drm, sizeof(*dummy_output), GFP_KERNEL);
 	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dummy_output);
 	dummy_output->encoder.type = vc4_encoder_type;
 
-- 
GitLab