From: Zhou Qingyang zhou1615@umn.edu
[ Upstream commit f5e284bb74ab296f98122673c7ecd22028b2c200 ]
In komeda_plane_add(), komeda_get_layer_fourcc_list() is assigned to formats and used in drm_universal_plane_init(). drm_universal_plane_init() passes formats to __drm_universal_plane_init(). __drm_universal_plane_init() further passes formats to memcpy() as src parameter, which could lead to an undefined behavior bug on failure of komeda_get_layer_fourcc_list().
Fix this bug by adding a check of formats.
This bug was found by a static analyzer. The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs.
Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug.
Builds with CONFIG_DRM_KOMEDA=m show no new warnings, and our static analyzer no longer warns about this code.
Fixes: 61f1c4a8ab75 ("drm/komeda: Attach komeda_dev to DRM-KMS") Signed-off-by: Zhou Qingyang zhou1615@umn.edu Signed-off-by: Liviu Dudau liviu.dudau@arm.com Link: https://lore.kernel.org/dri-devel/20211201033704.32054-1-zhou1615@umn.edu Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/arm/display/komeda/komeda_plane.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c index a5f57b38d193..bc3f42e915e9 100644 --- a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c +++ b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c @@ -264,6 +264,10 @@ static int komeda_plane_add(struct komeda_kms_dev *kms,
formats = komeda_get_layer_fourcc_list(&mdev->fmt_tbl, layer->layer_type, &n_formats); + if (!formats) { + kfree(kplane); + return -ENOMEM; + }
err = drm_universal_plane_init(&kms->base, plane, get_possible_crtcs(kms, c->pipeline),