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=-11.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 4F59CC388F9 for ; Fri, 23 Oct 2020 21:15:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C7BC321D6C for ; Fri, 23 Oct 2020 21:15:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Sij1l/Cq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755634AbgJWVPP (ORCPT ); Fri, 23 Oct 2020 17:15:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36402 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755437AbgJWVPP (ORCPT ); Fri, 23 Oct 2020 17:15:15 -0400 Received: from mail-oo1-xc44.google.com (mail-oo1-xc44.google.com [IPv6:2607:f8b0:4864:20::c44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 81E8FC0613CE; Fri, 23 Oct 2020 14:15:13 -0700 (PDT) Received: by mail-oo1-xc44.google.com with SMTP id c10so784815oon.6; Fri, 23 Oct 2020 14:15:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=nivdWhdjmwmXXwWHH0ujQVWH0+nRhW8NuKzonNv+j1Y=; b=Sij1l/CqiTFRKBk7oTI7YI3Wde5ahXr9pIMx1G9Bh07aGz0ILDt3qsS6/wvWUctinH lKStq+GsY/+DD9uZ+2ehw1hTFMuxN3ZYsF5TB4l+28sYCUhISPh/nuXaqdCeG0HeN1mk unQ3+EbscXJ1JvcTy6zG0tH95F2c0Pt3WN4mWEqMrO+Q3PLO+FSB4Mw6wgTDU4tvwLNd OVYZbBsEaUAJUa+eMueM5jCl2i8m0jAT6mgsLPKsOPzp9LiYN2PsacSQPdfxUhVDXHQW jPpNBoX6/65ALKg+CQDhTQ+5Rg+mfEKqmGLlXk3MkZtggf4r0Qw3BB6BvyjgAgfou2e2 ixQw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=nivdWhdjmwmXXwWHH0ujQVWH0+nRhW8NuKzonNv+j1Y=; b=KLTckBLqYfM8C52dDMZBYMWpVhSoTvynXx/p66kNRiay4wwNlC1cNdb7pZzuN7+UTj GSybebtFxUwd9dO/9QtGALHft/UszdL9MWjKho3OunLJPc+EnG3rvVYHdC1QH97ucEeo IuiPZK0ojEEpwe0dW2+gDEdh7vUMXB5rZ+n/rq9KPYlZzEovvCRhca0Gw5e5t4hivpzy O6MlomlI3tFCmfC+QqI1McWLJbjOVnukv/xQKrglRbUnPUHl8MGaEpwOyySSj/ztQhS9 258jSmRvC+MPZvb0poHCJJ2dvI36qvtLfbOUK7zFWwWYZciUms4CyUk8GHa2VTRdBYrp HFTg== X-Gm-Message-State: AOAM533NpngbhrqaIAywgDRM2el2j+RsVr9nl7Tu+vqdPTkNWkD2c+Gk NrQfGBmJf7lNvjo3BI+Ckdw= X-Google-Smtp-Source: ABdhPJyx8/AIk2GXr4LnL3eC8AaqYs7ZGiY4RA1M47NbVijdt4f6plFj+1eEm5f3JsZXXITs4ezBYQ== X-Received: by 2002:a4a:c218:: with SMTP id z24mr3415385oop.9.1603487711408; Fri, 23 Oct 2020 14:15:11 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id b13sm775194oib.4.2020.10.23.14.15.10 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Fri, 23 Oct 2020 14:15:11 -0700 (PDT) Sender: Guenter Roeck Date: Fri, 23 Oct 2020 14:15:09 -0700 From: Guenter Roeck To: Dan Carpenter Cc: Ugur Usug , Jean Delvare , linux-hwmon@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH] hwmon: (pmbus/max20730) use scnprintf() instead of snprintf() Message-ID: <20201023211509.GA28238@roeck-us.net> References: <20201022070824.GC2817762@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201022070824.GC2817762@mwanda> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org On Thu, Oct 22, 2020 at 10:08:24AM +0300, Dan Carpenter wrote: > The snprintf() function returns the number of characters which would > have been printed if there were enough space, but the scnprintf() > returns the number of characters which were actually printed. If the > buffer is not large enough, then using snprintf() would result in a > read overflow and an information leak. > > Fixes: 8910c0bd533d ("hwmon: (pmbus/max20730) add device monitoring via debugfs") > Signed-off-by: Dan Carpenter Applied. Thanks, Guenter > --- > drivers/hwmon/pmbus/max20730.c | 26 +++++++++++++------------- > 1 file changed, 13 insertions(+), 13 deletions(-) > > diff --git a/drivers/hwmon/pmbus/max20730.c b/drivers/hwmon/pmbus/max20730.c > index 57923d72490c..be83b98411c7 100644 > --- a/drivers/hwmon/pmbus/max20730.c > +++ b/drivers/hwmon/pmbus/max20730.c > @@ -122,8 +122,8 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, > switch (idx) { > case MAX20730_DEBUGFS_VOUT_MIN: > ret = VOLT_FROM_REG(data->mfr_voutmin * 10000); > - len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d.%d\n", > - ret / 10000, ret % 10000); > + len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d.%d\n", > + ret / 10000, ret % 10000); > break; > case MAX20730_DEBUGFS_FREQUENCY: > val = (data->mfr_devset1 & MAX20730_MFR_DEVSET1_FSW_MASK) > @@ -141,7 +141,7 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, > ret = 800; > else > ret = 900; > - len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > + len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > break; > case MAX20730_DEBUGFS_PG_DELAY: > val = (data->mfr_devset1 & MAX20730_MFR_DEVSET1_TSTAT_MASK) > @@ -223,7 +223,7 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, > case MAX20730_DEBUGFS_OC_PROTECT_MODE: > ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_OCPM_MASK) > >> MAX20730_MFR_DEVSET2_OCPM_BIT_POS; > - len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > + len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > break; > case MAX20730_DEBUGFS_SS_TIMING: > val = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_SS_MASK) > @@ -241,32 +241,32 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, > case MAX20730_DEBUGFS_IMAX: > ret = (data->mfr_devset2 & MAX20730_MFR_DEVSET2_IMAX_MASK) > >> MAX20730_MFR_DEVSET2_IMAX_BIT_POS; > - len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > + len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > break; > case MAX20730_DEBUGFS_OPERATION: > ret = i2c_smbus_read_byte_data(psu->client, PMBUS_OPERATION); > if (ret < 0) > return ret; > - len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > + len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > break; > case MAX20730_DEBUGFS_ON_OFF_CONFIG: > ret = i2c_smbus_read_byte_data(psu->client, PMBUS_ON_OFF_CONFIG); > if (ret < 0) > return ret; > - len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > + len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > break; > case MAX20730_DEBUGFS_SMBALERT_MASK: > ret = i2c_smbus_read_word_data(psu->client, > PMBUS_SMB_ALERT_MASK); > if (ret < 0) > return ret; > - len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > + len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > break; > case MAX20730_DEBUGFS_VOUT_MODE: > ret = i2c_smbus_read_byte_data(psu->client, PMBUS_VOUT_MODE); > if (ret < 0) > return ret; > - len = snprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > + len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, "%d\n", ret); > break; > case MAX20730_DEBUGFS_VOUT_COMMAND: > ret = i2c_smbus_read_word_data(psu->client, PMBUS_VOUT_COMMAND); > @@ -274,8 +274,8 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, > return ret; > > ret = VOLT_FROM_REG(ret * 10000); > - len = snprintf(tbuf, DEBUG_FS_DATA_MAX, > - "%d.%d\n", ret / 10000, ret % 10000); > + len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, > + "%d.%d\n", ret / 10000, ret % 10000); > break; > case MAX20730_DEBUGFS_VOUT_MAX: > ret = i2c_smbus_read_word_data(psu->client, PMBUS_VOUT_MAX); > @@ -283,8 +283,8 @@ static ssize_t max20730_debugfs_read(struct file *file, char __user *buf, > return ret; > > ret = VOLT_FROM_REG(ret * 10000); > - len = snprintf(tbuf, DEBUG_FS_DATA_MAX, > - "%d.%d\n", ret / 10000, ret % 10000); > + len = scnprintf(tbuf, DEBUG_FS_DATA_MAX, > + "%d.%d\n", ret / 10000, ret % 10000); > break; > default: > len = strlcpy(tbuf, "Invalid\n", DEBUG_FS_DATA_MAX);