Re: [PATCH][next] dm ioctl: rate limit a couple of ioctl based error messages

[Mikulas Patocka <mpatocka@redhat.com>]

Hi

I'd like to ask - have you experienced these errors? What was the process 
that triggered them? Was it some robot that tests syscalls with random 
parameters?

Mikulas


On Thu, 24 Oct 2024, Colin Ian King wrote:

> It is possible to spam the kernel log with a misbehaving user process that
> is passing incorrect dm ioctls to /dev/mapper/control. Use a rate limit
> on these error messages to reduce the noise.
> 
> Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
> ---
>  drivers/md/dm-ioctl.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
> index f299ff393a6a..d42eac944eb5 100644
> --- a/drivers/md/dm-ioctl.c
> +++ b/drivers/md/dm-ioctl.c
> @@ -1912,7 +1912,7 @@ static int check_version(unsigned int cmd, struct dm_ioctl __user *user,
>  
>  	if ((kernel_params->version[0] != DM_VERSION_MAJOR) ||
>  	    (kernel_params->version[1] > DM_VERSION_MINOR)) {
> -		DMERR("ioctl interface mismatch: kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
> +		DMERR_LIMIT("ioctl interface mismatch: kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
>  		      DM_VERSION_MAJOR, DM_VERSION_MINOR,
>  		      DM_VERSION_PATCHLEVEL,
>  		      kernel_params->version[0],
> @@ -1961,7 +1961,7 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
>  
>  	if (unlikely(param_kernel->data_size < minimum_data_size) ||
>  	    unlikely(param_kernel->data_size > DM_MAX_TARGETS * DM_MAX_TARGET_PARAMS)) {
> -		DMERR("Invalid data size in the ioctl structure: %u",
> +		DMERR_LIMIT("Invalid data size in the ioctl structure: %u",
>  		      param_kernel->data_size);
>  		return -EINVAL;
>  	}
> -- 
> 2.39.5
>