Re: [PATCH 07/12] Input: sysrq: mv sysrq into drivers/tty/sysrq.c

Kees Cook
2025-05-09T17:10:36Z

On Fri, May 09, 2025 at 02:54:11PM +0200, Joel Granados wrote:
> Move both sysrq ctl_table and supported sysrq_sysctl_handler helper
> function into drivers/tty/sysrq.c. Replaced the __do_proc_dointvec in
> helper function with do_proc_dointvec as the former is local to
> kernel/sysctl.c.

nit: do_proc_dointvec_minmax

>
> This is part of a greater effort to move ctl tables into their
> respective subsystems which will reduce the merge conflicts in
> kernel/sysctl.c.
>
> Signed-off-by: Joel Granados <joel.granados@kernel.org>

But yes, this looks correct.

Reviewed-by: Kees Cook <kees@kernel.org>

-Kees

> ---
> drivers/tty/sysrq.c | 38 ++++++++++++++++++++++++++++++++++++++
> kernel/sysctl.c | 30 ------------------------------
> 2 files changed, 38 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
> index 6853c4660e7c2586487fea83c12f0b7780db1ee1..8a304189749f3e33af48141a1aba5e456616c7de 100644
> --- a/drivers/tty/sysrq.c
> +++ b/drivers/tty/sysrq.c
> @@ -1119,6 +1119,44 @@ int sysrq_toggle_support(int enable_mask)
> }
> EXPORT_SYMBOL_GPL(sysrq_toggle_support);
>
> +static int sysrq_sysctl_handler(const struct ctl_table *table, int write,
> + void *buffer, size_t *lenp, loff_t *ppos)
> +{
> + int tmp, ret;
> + struct ctl_table t = *table;
> +
> + tmp = sysrq_mask();
> + t.data = &tmp;
> +
> + ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
> +
> + if (ret || !write)
> + return ret;
> +
> + if (write)
> + sysrq_toggle_support(tmp);
> +
> + return 0;
> +}
> +
> +static const struct ctl_table sysrq_sysctl_table[] = {
> + {
> + .procname = "sysrq",
> + .data = NULL,
> + .maxlen = sizeof(int),
> + .mode = 0644,
> + .proc_handler = sysrq_sysctl_handler,
> + },
> +};
> +
> +static int __init init_sysrq_sysctl(void)
> +{
> + register_sysctl_init("kernel", sysrq_sysctl_table);
> + return 0;
> +}
> +
> +subsys_initcall(init_sysrq_sysctl);
> +
> static int __sysrq_swap_key_ops(u8 key, const struct sysrq_key_op *insert_op_p,
> const struct sysrq_key_op *remove_op_p)
> {
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index febf328054aa5a7b2462a256598f86f5ded87c90..ebcc7d75acd9fecbf3c10f31480c3cb6960cb53e 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -31,7 +31,6 @@
> #include <linux/kernel.h>
> #include <linux/kobject.h>
> #include <linux/net.h>
> -#include <linux/sysrq.h>
> #include <linux/highuid.h>
> #include <linux/writeback.h>
> #include <linux/ratelimit.h>
> @@ -964,26 +963,6 @@ int proc_dou8vec_minmax(const struct ctl_table *table, int write,
> }
> EXPORT_SYMBOL_GPL(proc_dou8vec_minmax);
>
> -#ifdef CONFIG_MAGIC_SYSRQ
> -static int sysrq_sysctl_handler(const struct ctl_table *table, int write,
> - void *buffer, size_t *lenp, loff_t *ppos)
> -{
> - int tmp, ret;
> -
> - tmp = sysrq_mask();
> -
> - ret = __do_proc_dointvec(&tmp, table, write, buffer,
> - lenp, ppos, NULL, NULL);
> - if (ret || !write)
> - return ret;
> -
> - if (write)
> - sysrq_toggle_support(tmp);
> -
> - return 0;
> -}
> -#endif
> -
> static int __do_proc_doulongvec_minmax(void *data,
> const struct ctl_table *table, int write,
> void *buffer, size_t *lenp, loff_t *ppos,
> @@ -1612,15 +1591,6 @@ static const struct ctl_table kern_table[] = {
> .proc_handler = proc_dostring,
> },
> #endif
> -#ifdef CONFIG_MAGIC_SYSRQ
> - {
> - .procname = "sysrq",
> - .data = NULL,
> - .maxlen = sizeof (int),
> - .mode = 0644,
> - .proc_handler = sysrq_sysctl_handler,
> - },
> -#endif
> #ifdef CONFIG_PROC_SYSCTL
> {
> .procname = "cad_pid",
>
> --
> 2.47.2
>
>

--
Kees Cook