Re: [PATCH] /proc/sysrq-trigger: accept multiple keys at once

Greg Kroah-Hartman
2023-11-13T18:33:54Z

On Mon, Nov 13, 2023 at 07:22:19PM +0100, Tomas Mudrunka wrote:
> Just for convenience.
> This way we can do:
> `echo reisub > /proc/sysrq-trigger`
> Instead of:
> `for i in r e i s u b; do echo "$i" > /proc/sysrq-trigger; done;`
>
> Signed-off-by: Tomas Mudrunka <tomas.mudrunka@gmail.com>
> ---
> drivers/tty/sysrq.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
> index 6b4a28bcf..bc5a679f6 100644
> --- a/drivers/tty/sysrq.c
> +++ b/drivers/tty/sysrq.c
> @@ -1154,10 +1154,12 @@ EXPORT_SYMBOL(unregister_sysrq_key);
> static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf,
> size_t count, loff_t *ppos)
> {
> - if (count) {
> + size_t i;
> +
> + for (i = 0; i < count; i++) {
> char c;
>
> - if (get_user(c, buf))
> + if (get_user(c, buf+i))

What did you just break where people would send a string and only relied
on the first character being checked? This might not be ok to do.

Also, no documentation update?

thanks,

greg k-h