On Wed, Jun 08, 2022 at 10:50:39AM +0300, Jani Nikula wrote:
> Unfortunately, there are still plenty of interfaces around that require
> a struct edid pointer, and it's impossible to change them all at
> once. Add an accessor to the raw EDID data to help the transition.
>
> While there are no such cases now, be defensive against raw EDID
> extension count indicating bigger EDID than is actually allocated.
>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_edid.c | 26 ++++++++++++++++++++++++++
> include/drm/drm_edid.h | 1 +
> 2 files changed, 27 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 952724788963..4e788c5cbf25 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -2333,6 +2333,32 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
> }
> EXPORT_SYMBOL_GPL(drm_do_get_edid);
>
> +/**
> + * drm_edid_raw - Get a pointer to the raw EDID data.
> + * @drm_edid: drm_edid container
> + *
> + * Get a pointer to the raw EDID data.
> + *
> + * This is for transition only. Avoid using this like the plague.
> + *
> + * Return: Pointer to raw EDID data.
> + */
> +const struct edid *drm_edid_raw(const struct drm_edid *drm_edid)
> +{
> + if (!drm_edid || !drm_edid->size)
> + return NULL;
> +
> + /*
> + * Do not return pointers where relying on EDID extension count would
> + * lead to buffer overflow.
> + */
> + if (WARN_ON(edid_size(drm_edid->edid) > drm_edid->size))
> + return NULL;
> +
> + return drm_edid->edid;
> +}
> +EXPORT_SYMBOL(drm_edid_raw);
> +
> /* Allocate struct drm_edid container *without* duplicating the edid data */
> static const struct drm_edid *_drm_edid_alloc(const void *edid, size_t size)
> {
> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
> index aeb2fa95bc04..2181977ae683 100644
> --- a/include/drm/drm_edid.h
> +++ b/include/drm/drm_edid.h
> @@ -597,6 +597,7 @@ drm_display_mode_from_cea_vic(struct drm_device *dev,
> const struct drm_edid *drm_edid_alloc(const void *edid, size_t size);
> const struct drm_edid *drm_edid_dup(const struct drm_edid *drm_edid);
> void drm_edid_free(const struct drm_edid *drm_edid);
> +const struct edid *drm_edid_raw(const struct drm_edid *drm_edid);
> const struct drm_edid *drm_edid_read(struct drm_connector *connector);
> const struct drm_edid *drm_edid_read_ddc(struct drm_connector *connector,
> struct i2c_adapter *adapter);
> --
> 2.30.2
--
Ville Syrjälä
Intel
