* [PATCH] printk: drop redundant devkmsg_log_str memsets
@ 2018-01-19 4:39 Sergey Senozhatsky
2018-01-19 14:17 ` Steven Rostedt
2018-01-22 9:54 ` Petr Mladek
0 siblings, 2 replies; 5+ messages in thread
From: Sergey Senozhatsky @ 2018-01-19 4:39 UTC (permalink / raw)
To: Petr Mladek, Steven Rostedt; +Cc: linux-kernel, Sergey Senozhatsky
We copy in null terminated strings "on" and "off", no
need to zero out devkmsg_log_str in control_devkmsg().
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
kernel/printk/printk.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index d70927c384f3..9faddcfd3994 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -136,13 +136,10 @@ static int __init control_devkmsg(char *str)
/*
* Set sysctl string accordingly:
*/
- if (devkmsg_log == DEVKMSG_LOG_MASK_ON) {
- memset(devkmsg_log_str, 0, DEVKMSG_STR_MAX_SIZE);
- strncpy(devkmsg_log_str, "on", 2);
- } else if (devkmsg_log == DEVKMSG_LOG_MASK_OFF) {
- memset(devkmsg_log_str, 0, DEVKMSG_STR_MAX_SIZE);
- strncpy(devkmsg_log_str, "off", 3);
- }
+ if (devkmsg_log == DEVKMSG_LOG_MASK_ON)
+ strcpy(devkmsg_log_str, "on");
+ else if (devkmsg_log == DEVKMSG_LOG_MASK_OFF)
+ strcpy(devkmsg_log_str, "off");
/* else "ratelimit" which is set by default. */
/*
--
2.16.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] printk: drop redundant devkmsg_log_str memsets
2018-01-19 4:39 [PATCH] printk: drop redundant devkmsg_log_str memsets Sergey Senozhatsky
@ 2018-01-19 14:17 ` Steven Rostedt
2018-01-20 6:05 ` Sergey Senozhatsky
2018-01-22 9:54 ` Petr Mladek
1 sibling, 1 reply; 5+ messages in thread
From: Steven Rostedt @ 2018-01-19 14:17 UTC (permalink / raw)
To: Sergey Senozhatsky; +Cc: Petr Mladek, linux-kernel, Sergey Senozhatsky
On Fri, 19 Jan 2018 13:39:01 +0900
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> wrote:
> We copy in null terminated strings "on" and "off", no
> need to zero out devkmsg_log_str in control_devkmsg().
>
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> ---
> kernel/printk/printk.c | 11 ++++-------
> 1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index d70927c384f3..9faddcfd3994 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -136,13 +136,10 @@ static int __init control_devkmsg(char *str)
> /*
> * Set sysctl string accordingly:
> */
> - if (devkmsg_log == DEVKMSG_LOG_MASK_ON) {
> - memset(devkmsg_log_str, 0, DEVKMSG_STR_MAX_SIZE);
> - strncpy(devkmsg_log_str, "on", 2);
> - } else if (devkmsg_log == DEVKMSG_LOG_MASK_OFF) {
> - memset(devkmsg_log_str, 0, DEVKMSG_STR_MAX_SIZE);
> - strncpy(devkmsg_log_str, "off", 3);
> - }
> + if (devkmsg_log == DEVKMSG_LOG_MASK_ON)
> + strcpy(devkmsg_log_str, "on");
> + else if (devkmsg_log == DEVKMSG_LOG_MASK_OFF)
> + strcpy(devkmsg_log_str, "off");
> /* else "ratelimit" which is set by default. */
>
> /*
Yep, and even the sysctl checks for the terminating nul string, so
there's no leaks of any kind.
Tested by adding: printk.devkmsg=on and running:
$ hexdump -C /proc/sys/kernel/printk_devkmsg
00000000 6f 6e 0a |on.|
00000003
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
-- Steve
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] printk: drop redundant devkmsg_log_str memsets
2018-01-19 14:17 ` Steven Rostedt
@ 2018-01-20 6:05 ` Sergey Senozhatsky
0 siblings, 0 replies; 5+ messages in thread
From: Sergey Senozhatsky @ 2018-01-20 6:05 UTC (permalink / raw)
To: Steven Rostedt
Cc: Sergey Senozhatsky, Petr Mladek, linux-kernel, Sergey Senozhatsky
On (01/19/18 09:17), Steven Rostedt wrote:
> Yep, and even the sysctl checks for the terminating nul string, so
> there's no leaks of any kind.
>
> Tested by adding: printk.devkmsg=on and running:
>
> $ hexdump -C /proc/sys/kernel/printk_devkmsg
> 00000000 6f 6e 0a |on.|
> 00000003
>
>
> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
thanks.
-ss
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] printk: drop redundant devkmsg_log_str memsets
2018-01-19 4:39 [PATCH] printk: drop redundant devkmsg_log_str memsets Sergey Senozhatsky
2018-01-19 14:17 ` Steven Rostedt
@ 2018-01-22 9:54 ` Petr Mladek
2018-01-22 9:59 ` Sergey Senozhatsky
1 sibling, 1 reply; 5+ messages in thread
From: Petr Mladek @ 2018-01-22 9:54 UTC (permalink / raw)
To: Sergey Senozhatsky; +Cc: Steven Rostedt, linux-kernel, Sergey Senozhatsky
On Fri 2018-01-19 13:39:01, Sergey Senozhatsky wrote:
> We copy in null terminated strings "on" and "off", no
> need to zero out devkmsg_log_str in control_devkmsg().
>
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Great catch!
Reviewed-by: Petr Mladek <pmladek@suse.com>
I have pushed this into for-4.16 branch in printk.git, see
https://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk.git/commit/?h=for-4.16&id=6fd78a1a99c9580da49ee8f951fdce9846256375
Best Regards,
Petr
^ permalink raw reply [flat|nested] 5+ messages in thread
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2018-01-19 4:39 [PATCH] printk: drop redundant devkmsg_log_str memsets Sergey Senozhatsky
2018-01-19 14:17 ` Steven Rostedt
2018-01-20 6:05 ` Sergey Senozhatsky
2018-01-22 9:54 ` Petr Mladek
2018-01-22 9:59 ` Sergey Senozhatsky
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