linux-kernel - Re: [PATCH] sysctl: some input constraints checks were added for /proc/sys/vm directory

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Message-ID: <AANLkTim5k4zaqVR3EEua1YRF5z4F8nRhDxr61cvg0=6x@mail.gmail.com>
Date:	Thu, 3 Mar 2011 09:47:12 +0800
From:	Dave Young <hidave.darkstar@...il.com>
To:	Petr Holasek <pholasek@...hat.com>
Cc:	linux-kernel@...r.kernel.org, anton@...hat.com,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>,
	David Miller <davem@...emloft.net>,
	Don Zickus <dzickus@...hat.com>, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH] sysctl: some input constraints checks were added for
 /proc/sys/vm directory

On Thu, Mar 3, 2011 at 12:16 AM, Petr Holasek <pholasek@...hat.com> wrote:
> There were added boundaries of allowed input ranges for: dirty_expire_centisecs,
> drop_caches, overcommit_memory, page-cluster and panic_on_oom.
>
> Signed-off-by: Petr Holasek <pholasek@...hat.com>
> ---
>  fs/drop_caches.c |    6 +++++-
>  kernel/sysctl.c  |   17 +++++++++++++----
>  2 files changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/fs/drop_caches.c b/fs/drop_caches.c
> index 2195c21..8e61858 100644
> --- a/fs/drop_caches.c
> +++ b/fs/drop_caches.c
> @@ -45,7 +45,11 @@ static void drop_slab(void)
>  int drop_caches_sysctl_handler(ctl_table *table, int write,
>        void __user *buffer, size_t *length, loff_t *ppos)
>  {
> -       proc_dointvec_minmax(table, write, buffer, length, ppos);
> +       int ret;
> +
> +       ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
> +       if (ret)
> +           return ret;

s/space/tab, otherwise Acked-by: Dave Young <hidave.darkstar@...il.com>

>        if (write) {
>                if (sysctl_drop_caches & 1)
>                        iterate_supers(drop_pagecache_sb, NULL);
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index 0f1bd83..e0a4d50 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -117,6 +117,7 @@ static int neg_one = -1;
>  static int zero;
>  static int __maybe_unused one = 1;
>  static int __maybe_unused two = 2;
> +static int __maybe_unused three = 3;
>  static unsigned long one_ul = 1;
>  static int one_hundred = 100;
>  #ifdef CONFIG_PRINTK
> @@ -978,14 +979,18 @@ static struct ctl_table vm_table[] = {
>                .data           = &sysctl_overcommit_memory,
>                .maxlen         = sizeof(sysctl_overcommit_memory),
>                .mode           = 0644,
> -               .proc_handler   = proc_dointvec,
> +               .proc_handler   = proc_dointvec_minmax,
> +               .extra1         = &zero,
> +               .extra2         = &two,
>        },
>        {
>                .procname       = "panic_on_oom",
>                .data           = &sysctl_panic_on_oom,
>                .maxlen         = sizeof(sysctl_panic_on_oom),
>                .mode           = 0644,
> -               .proc_handler   = proc_dointvec,
> +               .proc_handler   = proc_dointvec_minmax,
> +               .extra1         = &zero,
> +               .extra2         = &two,
>        },
>        {
>                .procname       = "oom_kill_allocating_task",
> @@ -1013,7 +1018,8 @@ static struct ctl_table vm_table[] = {
>                .data           = &page_cluster,
>                .maxlen         = sizeof(int),
>                .mode           = 0644,
> -               .proc_handler   = proc_dointvec,
> +               .proc_handler   = proc_dointvec_minmax,
> +               .extra1         = &zero,
>        },
>        {
>                .procname       = "dirty_background_ratio",
> @@ -1061,7 +1067,8 @@ static struct ctl_table vm_table[] = {
>                .data           = &dirty_expire_interval,
>                .maxlen         = sizeof(dirty_expire_interval),
>                .mode           = 0644,
> -               .proc_handler   = proc_dointvec,
> +               .proc_handler   = proc_dointvec_minmax,
> +               .extra1         = &zero,
>        },
>        {
>                .procname       = "nr_pdflush_threads",
> @@ -1137,6 +1144,8 @@ static struct ctl_table vm_table[] = {
>                .maxlen         = sizeof(int),
>                .mode           = 0644,
>                .proc_handler   = drop_caches_sysctl_handler,
> +               .extra1         = &one,
> +               .extra2         = &three,
>        },
>  #ifdef CONFIG_COMPACTION
>        {
> --
> 1.7.1
>
>



-- 
Regards
dave