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 --- 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 d63d83800a8a..dd3f17e970dd 100644 --- a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c +++ b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c @@ -265,6 +265,10 @@ 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) { + err = -ENOMEM; + goto cleanup; + }
err = drm_universal_plane_init(&kms->base, plane, get_possible_crtcs(kms, c->pipeline),
Hi Zhou,
On Tue, Nov 30, 2021 at 10:23:01PM +0800, Zhou Qingyang wrote:
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.
If multiple researchers have cross-reviewed the bug how many have reviewed the fix? I'm asking because there is a problem with the fix ....
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
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 d63d83800a8a..dd3f17e970dd 100644 --- a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c +++ b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c @@ -265,6 +265,10 @@ 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) {
err = -ENOMEM;goto cleanup;
If you go to cleanup here it is too early, as the plane variable has not been initialised by the drm_universal_plane_init(), so komeda_plane_destroy() will crash. The correct fix here is to free the kplane allocation and then return -ENOMEM.
}
err = drm_universal_plane_init(&kms->base, plane, get_possible_crtcs(kms, c->pipeline),
-- 2.25.1
Best regards, Liviu
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 --- Changes in v2 - Use kfree and return instead of using 'goto'
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 d63d83800a8a..aa193c58f4bf 100644 --- a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c +++ b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c @@ -265,6 +265,10 @@ 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),
On Wed, Dec 01, 2021 at 11:37:03AM +0800, Zhou Qingyang wrote:
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
Thanks for the fix!
Reviewed-by: Liviu Dudau liviu.dudau@arm.com
Best regards, Liviu
Changes in v2
- Use kfree and return instead of using 'goto'
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 d63d83800a8a..aa193c58f4bf 100644 --- a/drivers/gpu/drm/arm/display/komeda/komeda_plane.c +++ b/drivers/gpu/drm/arm/display/komeda/komeda_plane.c @@ -265,6 +265,10 @@ 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),
-- 2.25.1
dri-devel@lists.freedesktop.org
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Liviu Dudau -
Zhou Qingyang