From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6908FC77B73 for ; Mon, 1 May 2023 03:14:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232941AbjEADOT (ORCPT ); Sun, 30 Apr 2023 23:14:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232713AbjEADMa (ORCPT ); Sun, 30 Apr 2023 23:12:30 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0D83B1988; Sun, 30 Apr 2023 20:04:43 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E990A616FF; Mon, 1 May 2023 03:04:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21CD7C4339B; Mon, 1 May 2023 03:04:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1682910278; bh=0IuqPKYtoTumQGNmGhHYe/+Xf+xvrNDgDjfU4fCgdqk=; h=From:To:Cc:Subject:Date:From; b=FK38VIhxDu0yEK9UwYYr6+apSbVwxKxJw7QLU94spNBT03I00HhkHU0A5Qjl+MvRX aGyu6EZMhF0kAcZy35oCx6bclEkJYjixzCZWtoxQYRl+wkegZCjcLqH4H3Kv4S59FL lY4mAbAm/ETNxmuEGZz/hhOwNNVeAcfgSJouex9KT6yEPKB3n0gNYQnSTCyguIKXh0 52rTp5xqvZ7HGz89r4QVAkczitzcr6aQwjX83+GXmBC/V9whapimm1bZCcImlaKENZ sLP0R0J9QKErIXxJB2eS3TsdSRHFOtqHhtalk9/uAa+DkkSxAEAX82KefcjLDQvW2J ZPHpo3uLgKrHA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jani Nikula , Iaroslav Boliukin , Dmitry Osipenko , Sasha Levin , maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, daniel@ffwll.ch, dri-devel@lists.freedesktop.org Subject: [PATCH AUTOSEL 5.15 01/17] drm/displayid: add displayid_get_header() and check bounds better Date: Sun, 30 Apr 2023 23:04:18 -0400 Message-Id: <20230501030435.3254695-1-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jani Nikula [ Upstream commit 5bacecc3c56131c31f18b23d366f2184328fd9cf ] Add a helper to get a pointer to struct displayid_header. To be pedantic, add buffer overflow checks to not touch the base if that itself would overflow. Cc: Iaroslav Boliukin Cc: Dmitry Osipenko Signed-off-by: Jani Nikula Tested-by: Dmitry Osipenko Reviewed-by: Dmitry Osipenko Signed-off-by: Dmitry Osipenko Link: https://patchwork.freedesktop.org/patch/msgid/4a03b3a5132642d3cdb6d4c2641422955a917292.1676580180.git.jani.nikula@intel.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_displayid.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_displayid.c b/drivers/gpu/drm/drm_displayid.c index 32da557b960fd..82b7f0bb44097 100644 --- a/drivers/gpu/drm/drm_displayid.c +++ b/drivers/gpu/drm/drm_displayid.c @@ -7,13 +7,28 @@ #include #include +static const struct displayid_header * +displayid_get_header(const u8 *displayid, int length, int index) +{ + const struct displayid_header *base; + + if (sizeof(*base) > length - index) + return ERR_PTR(-EINVAL); + + base = (const struct displayid_header *)&displayid[index]; + + return base; +} + static int validate_displayid(const u8 *displayid, int length, int idx) { int i, dispid_length; u8 csum = 0; const struct displayid_header *base; - base = (const struct displayid_header *)&displayid[idx]; + base = displayid_get_header(displayid, length, idx); + if (IS_ERR(base)) + return PTR_ERR(base); DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n", base->rev, base->bytes, base->prod_id, base->ext_count); -- 2.39.2