2011-03-02 16:16:37

by Petr Holasek

[permalink] [raw]
Subject: [PATCH] sysctl: some input constraints checks were added for /proc/sys/vm directory

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 <[email protected]>
---
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;
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


2011-03-03 01:47:14

by Dave Young

[permalink] [raw]
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 <[email protected]> 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 <[email protected]>
> ---
>  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 <[email protected]>

>        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
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2011-03-04 11:14:53

by Petr Holasek

[permalink] [raw]
Subject: Re: [PATCH] sysctl: some input constraints checks were added for /proc/sys/vm directory

----- Original Message -----
> From: "Petr Holasek" <[email protected]>
> To: [email protected]
> Cc: [email protected], "Petr Holasek" <[email protected]>, "Alexander Viro" <[email protected]>, "Andrew
> Morton" <[email protected]>, "Ingo Molnar" <[email protected]>, "Dave Young" <[email protected]>, "David
> Miller" <[email protected]>, "Don Zickus" <[email protected]>, [email protected]
> Sent: Wednesday, March 2, 2011 5:16:14 PM
> Subject: [PATCH] sysctl: some input constraints checks were added for /proc/sys/vm directory
> 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 <[email protected]>
> ---
> 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;
> 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
>
> --
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Apologize for the space/tabs mess, thanks to Dave Young for the warning,
corrected version here:

---
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;
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

2011-03-09 00:52:48

by Andrew Morton

[permalink] [raw]
Subject: Re: [PATCH] sysctl: some input constraints checks were added for /proc/sys/vm directory

On Wed, 2 Mar 2011 17:16:14 +0100
Petr Holasek <[email protected]> wrote:

> There were added boundaries of allowed input ranges for: dirty_expire_centisecs,
> drop_caches, overcommit_memory, page-cluster and panic_on_oom.
>
> ...
>

Well.. It's a non-back-compatible userspace interface change.

Yes, it's unlikely that any userspace was doing, for example, "echo 7 >
/proc/sys/vm/drop_caches". But if it was, we just broke it.