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 X-Spam-Level: X-Spam-Status: No, score=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 27DF5C433E1 for ; Fri, 21 Aug 2020 05:40:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 034C720724 for ; Fri, 21 Aug 2020 05:40:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597988434; bh=zRCjuahUes6jERrX4goHO80ytxWyRaqKLIhIomFNSjg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=dSyNhovD3KzAKBBRCZYFa+U+1/JuSlkwVGK20233okB6a+I0ds6O4WO9Kxx7NzsfS 0KAiGpy1iwifM6HATrOQ5jjG2S1IvDIJu+e6t0LeTjKF6VDMi8yS2GeCJheuZTOErZ TZtxx4Fn+3WMOvgF5924QUP0UGA1ClbXHAb86tqg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726813AbgHUFkb (ORCPT ); Fri, 21 Aug 2020 01:40:31 -0400 Received: from mail-wm1-f66.google.com ([209.85.128.66]:39523 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726002AbgHUFk2 (ORCPT ); Fri, 21 Aug 2020 01:40:28 -0400 Received: by mail-wm1-f66.google.com with SMTP id g75so626716wme.4 for ; Thu, 20 Aug 2020 22:40:27 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=GYy21gsBobrfE+n697gXaTEDTqhXl3ZvlItxvgDKUpg=; b=FxlrkUB/rGQMiwWReE7tiuSH2pDuN2H8yLnmV4+g5CTbN32NcU6zruJfczSeHiDlzT VNsFJFiqUTZi3FZNVOIx7rQCq2TmsGsEuo+wOzCE0GFd7qC2/lspUEp3dNW8xsNInR6U oBYh0uoIGYn6sLARp0iiypWgVG16gNLPW6vDbeb0jNLF0qKPBYQsT9x8G2qrQFe+lhvw qf5WciCiyjsMe15FA70O73XjkRNVqXiTTiYfsfqcIBw/jAc9pJlVnJDntPSqT6MHi3hz HCWwQpk1PrjQy+wGa5jZU7a6JdkUMrdKrsSfHWyKu/t5Xb3RRKvfUY/J5/nyQS3uc793 mokQ== X-Gm-Message-State: AOAM532TPuVhf58e+0J64dPRtEU9uUJwKJnQbSpriaLiq7gg6zcX+3C0 xZB98R6J7qWXsPpkP5PFJUg= X-Google-Smtp-Source: ABdhPJyKwq7JDwgNVczIaowypJVZ0FDSzLrM9VMY1YsL5y6vs+Zgx/KETjQQwLwGckNGQ1ngq5R/uQ== X-Received: by 2002:a1c:ab06:: with SMTP id u6mr1228329wme.172.1597988426324; Thu, 20 Aug 2020 22:40:26 -0700 (PDT) Received: from kozik-lap ([194.230.155.216]) by smtp.googlemail.com with ESMTPSA id s20sm2220457wmh.21.2020.08.20.22.40.24 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Thu, 20 Aug 2020 22:40:25 -0700 (PDT) Date: Fri, 21 Aug 2020 07:40:23 +0200 From: Krzysztof Kozlowski To: Markus Mayer Cc: Florian Fainelli , Colin Ian King , BCM Kernel Feedback , Linux ARM Kernel , Linux Kernel Subject: Re: [PATCH] memory: brcmstb_dpfe: fix array index out of bounds Message-ID: <20200821054023.GA3906@kozik-lap> References: <20200821010333.20436-1-mmayer@broadcom.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200821010333.20436-1-mmayer@broadcom.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 20, 2020 at 06:03:33PM -0700, Markus Mayer wrote: > We would overrun the error_text array if we hit a TIMEOUT condition, > because we were using the error code "ETIMEDOUT" (which is 110) as an > array index. > > We fix the problem by correcting the array index and by providing a > function to retrieve error messages rather than accessing the array > directly. The function includes a bounds check that prevents the array > from being overrun. > > Signed-off-by: Markus Mayer > --- > > This patch was prepared in response to https://lkml.org/lkml/2020/8/18/505. > > drivers/memory/brcmstb_dpfe.c | 23 ++++++++++++++++------- > 1 file changed, 16 insertions(+), 7 deletions(-) > > diff --git a/drivers/memory/brcmstb_dpfe.c b/drivers/memory/brcmstb_dpfe.c > index 81abc4a98a27..a986a849f58e 100644 > --- a/drivers/memory/brcmstb_dpfe.c > +++ b/drivers/memory/brcmstb_dpfe.c > @@ -190,11 +190,6 @@ struct brcmstb_dpfe_priv { > struct mutex lock; > }; > > -static const char * const error_text[] = { > - "Success", "Header code incorrect", "Unknown command or argument", > - "Incorrect checksum", "Malformed command", "Timed out", > -}; > - > /* > * Forward declaration of our sysfs attribute functions, so we can declare the > * attribute data structures early. > @@ -307,6 +302,20 @@ static const struct dpfe_api dpfe_api_v3 = { > }, > }; > > +static const char * const get_error_text(unsigned int i) The pointer itself is returned by value and you cannot return a const value. I mean, you can but it does not have an effect. Only pointed memory should be const (const const char*). Best regards, Krzysztof > +{ > + static const char * const error_text[] = { > + "Success", "Header code incorrect", > + "Unknown command or argument", "Incorrect checksum", > + "Malformed command", "Timed out", "Unknown error", > + }; > + > + if (unlikely(i >= ARRAY_SIZE(error_text))) > + i = ARRAY_SIZE(error_text) - 1; > + > + return error_text[i]; > +} > + > static bool is_dcpu_enabled(struct brcmstb_dpfe_priv *priv) > { > u32 val; > @@ -446,7 +455,7 @@ static int __send_command(struct brcmstb_dpfe_priv *priv, unsigned int cmd, > } > if (resp != 0) { > mutex_unlock(&priv->lock); > - return -ETIMEDOUT; > + return -ffs(DCPU_RET_ERR_TIMEDOUT); > } > > /* Compute checksum over the message */ > @@ -695,7 +704,7 @@ static ssize_t generic_show(unsigned int command, u32 response[], > > ret = __send_command(priv, command, response); > if (ret < 0) > - return sprintf(buf, "ERROR: %s\n", error_text[-ret]); > + return sprintf(buf, "ERROR: %s\n", get_error_text(-ret)); > > return 0; > } > -- > 2.17.1 >