* [PATCH] sched/fair: Null terminate buffer when updating tunable_scaling
@ 2021-09-27 11:46 Mel Gorman
2021-09-27 16:50 ` Vincent Guittot
2021-10-01 12:10 ` [tip: sched/urgent] " tip-bot2 for Mel Gorman
0 siblings, 2 replies; 3+ messages in thread
From: Mel Gorman @ 2021-09-27 11:46 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Mike Galbraith, Ingo Molnar, Valentin Schneider, Vincent Guittot,
LKML
This patch null-terminates the temporary buffer in sched_scaling_write()
so kstrtouint() does not return failure and checks the value is valid.
Before
$ cat /sys/kernel/debug/sched/tunable_scaling
1
$ echo 0 > /sys/kernel/debug/sched/tunable_scaling
-bash: echo: write error: Invalid argument
$ cat /sys/kernel/debug/sched/tunable_scaling
1
After
$ cat /sys/kernel/debug/sched/tunable_scaling
1
$ echo 0 > /sys/kernel/debug/sched/tunable_scaling
$ cat /sys/kernel/debug/sched/tunable_scaling
0
$ echo 3 > /sys/kernel/debug/sched/tunable_scaling
-bash: echo: write error: Invalid argument
Fixes: 8a99b6833c88 ("sched: Move SCHED_DEBUG sysctl to debugfs")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
kernel/sched/debug.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 49716228efb4..17a653b67006 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -173,16 +173,22 @@ static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[16];
+ unsigned int scaling;
if (cnt > 15)
cnt = 15;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
+ buf[cnt] = '\0';
- if (kstrtouint(buf, 10, &sysctl_sched_tunable_scaling))
+ if (kstrtouint(buf, 10, &scaling))
return -EINVAL;
+ if (scaling >= SCHED_TUNABLESCALING_END)
+ return -EINVAL;
+
+ sysctl_sched_tunable_scaling = scaling;
if (sched_update_scaling())
return -EINVAL;
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] sched/fair: Null terminate buffer when updating tunable_scaling
2021-09-27 11:46 [PATCH] sched/fair: Null terminate buffer when updating tunable_scaling Mel Gorman
@ 2021-09-27 16:50 ` Vincent Guittot
2021-10-01 12:10 ` [tip: sched/urgent] " tip-bot2 for Mel Gorman
1 sibling, 0 replies; 3+ messages in thread
From: Vincent Guittot @ 2021-09-27 16:50 UTC (permalink / raw)
To: Mel Gorman
Cc: Peter Zijlstra, Mike Galbraith, Ingo Molnar, Valentin Schneider,
LKML
On Mon, 27 Sept 2021 at 13:46, Mel Gorman <mgorman@techsingularity.net> wrote:
>
> This patch null-terminates the temporary buffer in sched_scaling_write()
> so kstrtouint() does not return failure and checks the value is valid.
>
> Before
> $ cat /sys/kernel/debug/sched/tunable_scaling
> 1
> $ echo 0 > /sys/kernel/debug/sched/tunable_scaling
> -bash: echo: write error: Invalid argument
> $ cat /sys/kernel/debug/sched/tunable_scaling
> 1
>
> After
> $ cat /sys/kernel/debug/sched/tunable_scaling
> 1
> $ echo 0 > /sys/kernel/debug/sched/tunable_scaling
> $ cat /sys/kernel/debug/sched/tunable_scaling
> 0
> $ echo 3 > /sys/kernel/debug/sched/tunable_scaling
> -bash: echo: write error: Invalid argument
>
> Fixes: 8a99b6833c88 ("sched: Move SCHED_DEBUG sysctl to debugfs")
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
> kernel/sched/debug.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index 49716228efb4..17a653b67006 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -173,16 +173,22 @@ static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf,
> size_t cnt, loff_t *ppos)
> {
> char buf[16];
> + unsigned int scaling;
>
> if (cnt > 15)
> cnt = 15;
>
> if (copy_from_user(&buf, ubuf, cnt))
> return -EFAULT;
> + buf[cnt] = '\0';
>
> - if (kstrtouint(buf, 10, &sysctl_sched_tunable_scaling))
> + if (kstrtouint(buf, 10, &scaling))
> return -EINVAL;
>
> + if (scaling >= SCHED_TUNABLESCALING_END)
> + return -EINVAL;
> +
> + sysctl_sched_tunable_scaling = scaling;
> if (sched_update_scaling())
> return -EINVAL;
>
^ permalink raw reply [flat|nested] 3+ messages in thread* [tip: sched/urgent] sched/fair: Null terminate buffer when updating tunable_scaling
2021-09-27 11:46 [PATCH] sched/fair: Null terminate buffer when updating tunable_scaling Mel Gorman
2021-09-27 16:50 ` Vincent Guittot
@ 2021-10-01 12:10 ` tip-bot2 for Mel Gorman
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot2 for Mel Gorman @ 2021-10-01 12:10 UTC (permalink / raw)
To: linux-tip-commits
Cc: Mel Gorman, Peter Zijlstra (Intel), Vincent Guittot, x86,
linux-kernel
The following commit has been merged into the sched/urgent branch of tip:
Commit-ID: 703066188f63d66cc6b9d678e5b5ef1213c5938e
Gitweb: https://git.kernel.org/tip/703066188f63d66cc6b9d678e5b5ef1213c5938e
Author: Mel Gorman <mgorman@techsingularity.net>
AuthorDate: Mon, 27 Sep 2021 12:46:35 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 01 Oct 2021 13:57:57 +02:00
sched/fair: Null terminate buffer when updating tunable_scaling
This patch null-terminates the temporary buffer in sched_scaling_write()
so kstrtouint() does not return failure and checks the value is valid.
Before:
$ cat /sys/kernel/debug/sched/tunable_scaling
1
$ echo 0 > /sys/kernel/debug/sched/tunable_scaling
-bash: echo: write error: Invalid argument
$ cat /sys/kernel/debug/sched/tunable_scaling
1
After:
$ cat /sys/kernel/debug/sched/tunable_scaling
1
$ echo 0 > /sys/kernel/debug/sched/tunable_scaling
$ cat /sys/kernel/debug/sched/tunable_scaling
0
$ echo 3 > /sys/kernel/debug/sched/tunable_scaling
-bash: echo: write error: Invalid argument
Fixes: 8a99b6833c88 ("sched: Move SCHED_DEBUG sysctl to debugfs")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20210927114635.GH3959@techsingularity.net
---
kernel/sched/debug.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 4971622..17a653b 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -173,16 +173,22 @@ static ssize_t sched_scaling_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[16];
+ unsigned int scaling;
if (cnt > 15)
cnt = 15;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
+ buf[cnt] = '\0';
- if (kstrtouint(buf, 10, &sysctl_sched_tunable_scaling))
+ if (kstrtouint(buf, 10, &scaling))
return -EINVAL;
+ if (scaling >= SCHED_TUNABLESCALING_END)
+ return -EINVAL;
+
+ sysctl_sched_tunable_scaling = scaling;
if (sched_update_scaling())
return -EINVAL;
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2021-09-27 11:46 [PATCH] sched/fair: Null terminate buffer when updating tunable_scaling Mel Gorman
2021-09-27 16:50 ` Vincent Guittot
2021-10-01 12:10 ` [tip: sched/urgent] " tip-bot2 for Mel Gorman
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