From patchwork Wed May 4 15:14:41 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kieran Bingham X-Patchwork-Id: 618496 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3r0M8k6Bdkz9sf6 for ; Thu, 5 May 2016 01:17:10 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753227AbcEDPPJ (ORCPT ); Wed, 4 May 2016 11:15:09 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:34944 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752701AbcEDPPI (ORCPT ); Wed, 4 May 2016 11:15:08 -0400 Received: by mail-wm0-f66.google.com with SMTP id e201so10854230wme.2; Wed, 04 May 2016 08:15:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=Y5f16/6Cvwy2Pvm24wcywMn6hlIqxDJ8IWS0V6FjNkA=; b=BcWkwcu5q7cvhOJm7kKUpCLSKbWNWtbNnXaEa1B3L8l8ZgH0Oj2Fm8Zf3oeI1BPMyD aDz8/hZch8pCwnjCvmcE+6HbaGx+IFFB0mPBIXbP+t9paS9butO2UphYrBK/piTMO5es iv/zDon1GVAoc7O/RQgHjbay05SV498P/eP4zJHRUOsgHz0MkB+bbdlWK8QEeV6k9FQZ r1WlyVM3WVomAL+MoGLVyH+L6v9bBydjUj80BQQHlMpmYk3FBZbY2Sr2XOXdgLKH7MAI C41Yz6P3d8MBiYK1UbRhSP1dezoiOynlk53dF11mXezSDWrQ9hHSKHiSW4BVp5mLtI3R T7Cw== X-Gm-Message-State: AOPr4FX0nlL3toBwl+gNKnOeMSH793hXlV+fMv9J8CjAPlnDCRlKJtCrkN1yQS9bfexvDw== X-Received: by 10.194.96.10 with SMTP id do10mr9051873wjb.132.1462374906655; Wed, 04 May 2016 08:15:06 -0700 (PDT) Received: from CookieMonster.cookiemonster.local (cpc87017-aztw30-2-0-cust65.18-1.cable.virginm.net. [92.232.232.66]) by smtp.gmail.com with ESMTPSA id u187sm5497613wmu.21.2016.05.04.08.15.05 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 04 May 2016 08:15:05 -0700 (PDT) From: Kieran Bingham To: Wolfram Sang , Lee Jones , javier@osg.samsung.com Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, grant.likely@linaro.org, sameo@linux.intel.com, Kieran Bingham Subject: [PATCHv5 1/8] i2c: Add pointer dereference protection to i2c_match_id() Date: Wed, 4 May 2016 16:14:41 +0100 Message-Id: <1462374888-22888-2-git-send-email-kieran@bingham.xyz> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1462374888-22888-1-git-send-email-kieran@bingham.xyz> References: <1462374888-22888-1-git-send-email-kieran@bingham.xyz> Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Lee Jones Here we're providing dereference protection for i2c_match_id(), which saves us having to do it each time it's called. We're also stripping out the (now) needless checks in i2c_device_match(). This patch paves the way for other, similar code trimming. Acked-by: Grant Likely Signed-off-by: Lee Jones Signed-off-by: Kieran Bingham Tested-by: Kieran Bingham Reviewed-by: Javier Martinez Canillas Tested-by: Javier Martinez Canillas --- drivers/i2c/i2c-core.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index e584d88ee337..e980c8257676 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -493,6 +493,9 @@ static inline int acpi_i2c_install_space_handler(struct i2c_adapter *adapter) static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id, const struct i2c_client *client) { + if (!(id && client)) + return NULL; + while (id->name[0]) { if (strcmp(client->name, id->name) == 0) return id; @@ -506,8 +509,6 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv) struct i2c_client *client = i2c_verify_client(dev); struct i2c_driver *driver; - if (!client) - return 0; /* Attempt an OF style match */ if (of_driver_match_device(dev, drv)) @@ -518,9 +519,10 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv) return 1; driver = to_i2c_driver(drv); - /* match on an id table if there is one */ - if (driver->id_table) - return i2c_match_id(driver->id_table, client) != NULL; + + /* Finally an I2C match */ + if (i2c_match_id(driver->id_table, client)) + return 1; return 0; }