From patchwork Wed Nov 23 10:52:13 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liviu Dudau X-Patchwork-Id: 9442923 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 0098D600BA for ; Wed, 23 Nov 2016 10:52:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 11244203B9 for ; Wed, 23 Nov 2016 10:52:27 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 03BAB2236A; Wed, 23 Nov 2016 10:52:27 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 6D65E203B9 for ; Wed, 23 Nov 2016 10:52:26 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7A8F86E0CF; Wed, 23 Nov 2016 10:52:25 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from cam-smtp0.cambridge.arm.com (fw-tnat.cambridge.arm.com [217.140.96.140]) by gabe.freedesktop.org (Postfix) with ESMTPS id E52AC6E0CF for ; Wed, 23 Nov 2016 10:52:23 +0000 (UTC) Received: from e106497-lin.cambridge.arm.com (e106497-lin.cambridge.arm.com [10.2.131.185]) by cam-smtp0.cambridge.arm.com (8.13.8/8.13.8) with ESMTP id uANAqDeO011363; Wed, 23 Nov 2016 10:52:14 GMT From: Liviu Dudau To: Eric Engestrom Subject: [PATCH v2] drm: check for NULL parameter in exported drm_get_format_name() function. Date: Wed, 23 Nov 2016 10:52:13 +0000 Message-Id: <20161123105213.27674-1-Liviu.Dudau@arm.com> X-Mailer: git-send-email 2.10.2 In-Reply-To: References: Cc: Daniel Vetter , LKML , DRI devel , Jani Nikula X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP drm_get_format_name() de-references the buf parameter without checking if the pointer was not NULL. Given that the function is EXPORT-ed, lets sanitise the parameters before proceeding. v2: Use BUG_ON() to annoy users that did not pass valid parameters to function. Fixes: b3c11ac267d461d3d5 ("drm: move allocation out of drm_get_format_name()) Cc: Eric Engestrom Cc: Rob Clark Cc: Jani Nikula Cc: Daniel Vetter Signed-off-by: Liviu Dudau --- I still think sanity checking the parameters of an exported function is worth doing, even if the way one triggers the NULL pointer crash is priviledged. Not a big fan of the verbosity of BUG_ON() and would rather silently reject NULL buf pointer, but that is a matter of taste. drivers/gpu/drm/drm_fourcc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c index 90d2cc8..6d80239 100644 --- a/drivers/gpu/drm/drm_fourcc.c +++ b/drivers/gpu/drm/drm_fourcc.c @@ -85,6 +85,8 @@ EXPORT_SYMBOL(drm_mode_legacy_fb_format); */ const char *drm_get_format_name(uint32_t format, struct drm_format_name_buf *buf) { + BUG_ON(!buf); + snprintf(buf->str, sizeof(buf->str), "%c%c%c%c %s-endian (0x%08x)", printable_char(format & 0xff),