From: Cheng Lin <cheng.lin130@xxxxxxxxxx>
Subject: proc/sysctl: fix return error for proc_doulongvec_minmax()
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.
Link: http://lkml.kernel.org/r/1544081775-15720-1-git-send-email-cheng.lin130@xxxxxxxxxx
Signed-off-by: Cheng Lin <cheng.lin130@xxxxxxxxxx>
Acked-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/sysctl.c | 2 ++
1 file changed, 2 insertions(+)
--- a/kernel/sysctl.c~proc-sysctl-fix-return-error-for-proc_doulongvec_minmax
+++ a/kernel/sysctl.c
@@ -2787,6 +2787,8 @@ static int __do_proc_doulongvec_minmax(v
bool neg;
left -= proc_skip_spaces(&p);
+ if (!left)
+ break;
err = proc_get_long(&p, &left, &val, &neg,
proc_wspace_sep,
_
