lkml.org 
[lkml]   [2018]   [Dec]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] proc/sysctl: fix return error for proc_doulongvec_minmax
Date
If the number of input parameters is less than the total
parameters, an EINVAL error will be returned.

e.g.
We use proc_doulongvec_minmax to pass up to two parameters
with kern_table.

{
.procname = "monitor_signals",
.data = &monitor_sigs,
.maxlen = 2*sizeof(unsigned long),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},

Reproduce:
When passing two parameters, it's work normal. But passing
only one parameter, an error "Invalid argument"(EINVAL) is
returned.

[root@cl150 ~]# echo 1 2 > /proc/sys/kernel/monitor_signals
[root@cl150 ~]# cat /proc/sys/kernel/monitor_signals
1 2
[root@cl150 ~]# echo 3 > /proc/sys/kernel/monitor_signals
-bash: echo: write error: Invalid argument
[root@cl150 ~]# echo $?
1
[root@cl150 ~]# cat /proc/sys/kernel/monitor_signals
3 2
[root@cl150 ~]#

The following is the result after apply this patch. No error
is returned when the number of input parameters is less than
the total parameters.

[root@cl150 ~]# echo 1 2 > /proc/sys/kernel/monitor_signals
[root@cl150 ~]# cat /proc/sys/kernel/monitor_signals
1 2
[root@cl150 ~]# echo 3 > /proc/sys/kernel/monitor_signals
[root@cl150 ~]# echo $?
0
[root@cl150 ~]# cat /proc/sys/kernel/monitor_signals
3 2
[root@cl150 ~]#

There are three processing functions dealing with digital parameters,
__do_proc_dointvec/__do_proc_douintvec/__do_proc_doulongvec_minmax.

This patch deals with __do_proc_doulongvec_minmax, just as
__do_proc_dointvec does, adding a check for parameters 'left'. In
__do_proc_douintvec, its code implementation explicitly does not
support multiple inputs.

static int __do_proc_douintvec(...){
...
/*
* Arrays are not supported, keep this simple. *Do not* add
* support for them.
*/
if (vleft != 1) {
*lenp = 0;
return -EINVAL;
}
...
}

So, just __do_proc_doulongvec_minmax has the problem. And most use of
proc_doulongvec_minmax/proc_doulongvec_ms_jiffies_minmax just have one
parameter.

Signed-off-by: Cheng Lin <cheng.lin130@zte.com.cn>
---
kernel/sysctl.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 5fc724e..9ee261f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2779,6 +2779,8 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int
bool neg;

left -= proc_skip_spaces(&p);
+ if (!left)
+ break;

err = proc_get_long(&p, &left, &val, &neg,
proc_wspace_sep,
--
1.8.3.1
\
 
 \ /
  Last update: 2018-12-06 08:33    [W:0.048 / U:0.564 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site