2021-12-20 09:14:54

by Baokun Li

Subject: [PATCH -next V2] sysctl: returns -EINVAL when a negative value is passed to proc_doulongvec_minmax

When we pass a negative value to the proc_doulongvec_minmax() function,
the function returns 0, but the corresponding interface value does not
change.

we can easily reproduce this problem with the following commands:
`cd /proc/sys/fs/epoll`
`echo -1 > max_user_watches; echo $?; cat max_user_watches`

This function requires a non-negative number to be passed in, so when
a negative number is passed in, -EINVAL is returned.

Reported-by: Hulk Robot <[email protected]>
Signed-off-by: Baokun Li <[email protected]>
---
V1->V2:
Modify the judgment position.

kernel/sysctl.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 7f07b058b180..4211e39a5fd3 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1147,10 +1147,11 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table,
err = proc_get_long(&p, &left, &val, &neg,
proc_wspace_sep,
sizeof(proc_wspace_sep), NULL);
- if (err)
+ if (err || neg) {
+ err = -EINVAL;
break;
- if (neg)
- continue;
+ }
+
val = convmul * val / convdiv;
if ((min && val < *min) || (max && val > *max)) {
err = -EINVAL;
--
2.31.1

2021-12-20 19:17:39

by Luis Chamberlain

Subject: Re: [PATCH -next V2] sysctl: returns -EINVAL when a negative value is passed to proc_doulongvec_minmax

On Mon, Dec 20, 2021 at 05:26:27PM +0800, Baokun Li wrote:
> When we pass a negative value to the proc_doulongvec_minmax() function,
> the function returns 0, but the corresponding interface value does not
> change.
>
> we can easily reproduce this problem with the following commands:
> `cd /proc/sys/fs/epoll`
> `echo -1 > max_user_watches; echo $?; cat max_user_watches`
>
> This function requires a non-negative number to be passed in, so when
> a negative number is passed in, -EINVAL is returned.
>
> Reported-by: Hulk Robot <[email protected]>
> Signed-off-by: Baokun Li <[email protected]>

Acked-by: Luis Chamberlain <[email protected]>

Luis

2021-12-21 01:21:14

by Baokun Li

Subject: Re: [PATCH -next V2] sysctl: returns -EINVAL when a negative value is passed to proc_doulongvec_minmax

在 2021/12/21 3:17, Luis Chamberlain 写道:
> On Mon, Dec 20, 2021 at 05:26:27PM +0800, Baokun Li wrote:
>> When we pass a negative value to the proc_doulongvec_minmax() function,
>> the function returns 0, but the corresponding interface value does not
>> change.
>>
>> we can easily reproduce this problem with the following commands:
>> `cd /proc/sys/fs/epoll`
>> `echo -1 > max_user_watches; echo $?; cat max_user_watches`
>>
>> This function requires a non-negative number to be passed in, so when
>> a negative number is passed in, -EINVAL is returned.
>>
>> Reported-by: Hulk Robot <[email protected]>
>> Signed-off-by: Baokun Li <[email protected]>
> Acked-by: Luis Chamberlain <[email protected]>
>
> Luis
> .

Thank you for your Ack.

--
With Best Regards,
Baokun Li