linux-kernel - Re: [PATCH 3.7-rc8] drm: Fix possible EDID memory allocation oops

Open Source and information security mailing list archives

Message-ID: <CADnq5_PBhkw9aOcobnhupKD79YbXoBSvczTgTf3Jz+Nom3aG7w@mail.gmail.com>
Date:	Thu, 6 Dec 2012 10:41:06 -0500
From:	Alex Deucher <alexdeucher@...il.com>
To:	Tim Gardner <tim.gardner@...onical.com>
Cc:	linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH 3.7-rc8] drm: Fix possible EDID memory allocation oops

On Wed, Dec 5, 2012 at 2:00 PM, Tim Gardner <tim.gardner@...onical.com> wrote:
> The result of drm_property_create_blob() is not checked for success
> which could lead to a NULL pointer dereference.
>
> I was led to this by a smatch warning:
>
> drivers/gpu/drm/drm_crtc.c:3186 drm_mode_connector_update_edid_property() error: potential null dereference 'connector->edid_blob_ptr'.  (drm_property_create_blob returns null)
>
> drm_property_create_blob() calls kzalloc() which can return NULL.
>
> Cc: David Airlie <airlied@...ux.ie>
> Cc: dri-devel@...ts.freedesktop.org
> Cc: stable@...r.kernel.org # 3.0+
> Signed-off-by: Tim Gardner <tim.gardner@...onical.com>

Reviewed-by: Alex Deucher <alexander.deucher@....com>

> ---
>
> This bug actually exists in the original commit f453ba0460742ad027ae0c4c7d61e62817b3e7ef
> (2.6.29), but I only checked as far back as 3.0 for stable.
>
>  drivers/gpu/drm/drm_crtc.c |    4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index ef1b221..31872ba 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -3180,6 +3180,10 @@ int drm_mode_connector_update_edid_property(struct drm_connector *connector,
>         size = EDID_LENGTH * (1 + edid->extensions);
>         connector->edid_blob_ptr = drm_property_create_blob(connector->dev,
>                                                             size, edid);
> +       if (!connector->edid_blob_ptr) {
> +               pr_err("drm: Could not allocate %d edid blob bytes.\n", size);
> +               return -ENOMEM;
> +       }
>
>         ret = drm_connector_property_set_value(connector,
>                                                dev->mode_config.edid_property,
> --
> 1.7.9.5
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives