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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 87D19C10F11 for ; Wed, 24 Apr 2019 04:05:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A12E218D3 for ; Wed, 24 Apr 2019 04:05:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726310AbfDXEFA (ORCPT ); Wed, 24 Apr 2019 00:05:00 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:48014 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725440AbfDXEE7 (ORCPT ); Wed, 24 Apr 2019 00:04:59 -0400 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 5571CFDBECB2FABFF52E; Wed, 24 Apr 2019 12:04:57 +0800 (CST) Received: from [127.0.0.1] (10.184.225.177) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.439.0; Wed, 24 Apr 2019 12:04:47 +0800 Subject: Re: [PATCH next] sysctl: add proc_dointvec_jiffies_minmax to limit the min/max write value From: Zhiqiang Liu To: , , , , , , , CC: , , "Zhoukang (A)" References: <032e024f-2b1b-a980-1b53-d903bc8db297@huawei.com> Message-ID: <3e421384-a9cb-e534-3370-953c56883516@huawei.com> Date: Wed, 24 Apr 2019 12:04:17 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 In-Reply-To: <032e024f-2b1b-a980-1b53-d903bc8db297@huawei.com> Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.184.225.177] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Friendly ping... > From: Zhiqiang Liu > > In proc_dointvec_jiffies func, the write value is only checked > whether it is larger than INT_MAX. If the write value is less > than zero, it can also be successfully writen in the data. > > However, in some scenarios, users would adopt the data to > set timers or check whether time is expired. Generally, the data > will be cast to an unsigned type variable, then the negative data > becomes a very large unsigned value, which leads to long waits > or other unpredictable problems. > > Here, we add a new func, proc_dointvec_jiffies_minmax, to limit the > min/max write value, which is similar to the proc_dointvec_minmax func. > > Signed-off-by: Zhiqiang Liu > Reported-by: Qiang Ning > Reviewed-by: Jie Liu > --- > include/linux/sysctl.h | 2 ++ > kernel/sysctl.c | 44 +++++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 45 insertions(+), 1 deletion(-) > > diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h > index b769ecf..8bde8a0 100644 > --- a/include/linux/sysctl.h > +++ b/include/linux/sysctl.h > @@ -53,6 +53,8 @@ extern int proc_douintvec_minmax(struct ctl_table *table, int write, > loff_t *ppos); > extern int proc_dointvec_jiffies(struct ctl_table *, int, > void __user *, size_t *, loff_t *); > +extern int proc_dointvec_jiffies_minmax(struct ctl_table *, int, > + void __user *, size_t *, loff_t *); > extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int, > void __user *, size_t *, loff_t *); > extern int proc_dointvec_ms_jiffies(struct ctl_table *, int, > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index c9ec050..8e1eb59 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -2967,10 +2967,15 @@ static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp, > int *valp, > int write, void *data) > { > + struct do_proc_dointvec_minmax_conv_param *param = data; > + > if (write) { > if (*lvalp > INT_MAX / HZ) > return 1; > *valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ); > + if ((param->min && (*param->min)*HZ > *valp) || > + (param->max && (*param->max)*HZ < *valp)) > + return -EINVAL; > } else { > int val = *valp; > unsigned long lval; > @@ -3053,7 +3058,37 @@ int proc_dointvec_jiffies(struct ctl_table *table, int write, > void __user *buffer, size_t *lenp, loff_t *ppos) > { > return do_proc_dointvec(table,write,buffer,lenp,ppos, > - do_proc_dointvec_jiffies_conv,NULL); > + do_proc_dointvec_jiffies_conv, NULL); > +} > + > +/** > + * proc_dointvec_jiffies_minmax - read a vector of integers as seconds with min/max values > + * @table: the sysctl table > + * @write: %TRUE if this is a write to the sysctl file > + * @buffer: the user buffer > + * @lenp: the size of the user buffer > + * @ppos: file position > + * > + * Reads/writes up to table->maxlen/sizeof(unsigned int) integer > + * values from/to the user buffer, treated as an ASCII string. > + * The values read are assumed to be in seconds, and are converted into > + * jiffies. > + * > + * This routine will ensure the values are within the range specified by > + * table->extra1 (min) and table->extra2 (max). > + * > + * Returns 0 on success or -EINVAL on write when the range check fails. > + */ > +int proc_dointvec_jiffies_minmax(struct ctl_table *table, int write, > + void __user *buffer, size_t *lenp, loff_t *ppos) > +{ > + struct do_proc_dointvec_minmax_conv_param param = { > + .min = (int *) table->extra1, > + .max = (int *) table->extra2, > + }; > + > + return do_proc_dointvec(table, write, buffer, lenp, ppos, > + do_proc_dointvec_jiffies_conv, ¶m); > } > > /** > @@ -3301,6 +3336,12 @@ int proc_dointvec_jiffies(struct ctl_table *table, int write, > return -ENOSYS; > } > > +int proc_dointvec_jiffies_minmax(struct ctl_table *table, int write, > + void __user *buffer, size_t *lenp, loff_t *ppos) > +{ > + return -ENOSYS; > +} > + > int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write, > void __user *buffer, size_t *lenp, loff_t *ppos) > { > @@ -3359,6 +3400,7 @@ static int proc_dointvec_minmax_bpf_stats(struct ctl_table *table, int write, > EXPORT_SYMBOL(proc_dointvec); > EXPORT_SYMBOL(proc_douintvec); > EXPORT_SYMBOL(proc_dointvec_jiffies); > +EXPORT_SYMBOL(proc_dointvec_jiffies_minmax); > EXPORT_SYMBOL(proc_dointvec_minmax); > EXPORT_SYMBOL_GPL(proc_douintvec_minmax); > EXPORT_SYMBOL(proc_dointvec_userhz_jiffies); >