* [PATCH] mm/damon: Adjust the size of kbuf array to avoid overflow
@ 2021-10-13 11:48 Xin Hao
2021-10-13 14:02 ` SeongJae Park
0 siblings, 1 reply; 2+ messages in thread
From: Xin Hao @ 2021-10-13 11:48 UTC (permalink / raw)
To: sjpark; +Cc: xhao, akpm, linux-mm, linux-kernel
In order to avoid the 'count' size space of kbuf array is
used up, but a "\0" is still added.
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
---
mm/damon/dbgfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index faee070977d8..20c61eed54af 100644
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -247,7 +247,7 @@ static ssize_t dbgfs_kdamond_pid_read(struct file *file,
char *kbuf;
ssize_t len;
- kbuf = kmalloc(count, GFP_KERNEL);
+ kbuf = kmalloc(count + 1, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
--
2.31.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] mm/damon: Adjust the size of kbuf array to avoid overflow
2021-10-13 11:48 [PATCH] mm/damon: Adjust the size of kbuf array to avoid overflow Xin Hao
@ 2021-10-13 14:02 ` SeongJae Park
0 siblings, 0 replies; 2+ messages in thread
From: SeongJae Park @ 2021-10-13 14:02 UTC (permalink / raw)
To: Xin Hao; +Cc: sjpark, akpm, linux-mm, linux-kernel
Hi Xin,
On Wed, 13 Oct 2021 19:48:54 +0800 Xin Hao <xhao@linux.alibaba.com> wrote:
> In order to avoid the 'count' size space of kbuf array is
> used up, but a "\0" is still added.
Thank you for this patch! :)
But... I unsure how this can cause a buffer overflow, as 'kbuf' is accessed by
only size-specified functions, namely 'scnprintf()' and
'simple_read_from_buffer()'.
If I'm missing something, please feel free to let me know.
Thanks,
SJ
>
> Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
> ---
> mm/damon/dbgfs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
> index faee070977d8..20c61eed54af 100644
> --- a/mm/damon/dbgfs.c
> +++ b/mm/damon/dbgfs.c
> @@ -247,7 +247,7 @@ static ssize_t dbgfs_kdamond_pid_read(struct file *file,
> char *kbuf;
> ssize_t len;
>
> - kbuf = kmalloc(count, GFP_KERNEL);
> + kbuf = kmalloc(count + 1, GFP_KERNEL);
> if (!kbuf)
> return -ENOMEM;
>
> --
> 2.31.0
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-10-13 14:02 ` SeongJae Park
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