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.lin...@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
