Re: [PATCH v2 4/4] param: convert some "on"/"off" users to strtobool

From: Kees Cook
Date: Thu Feb 04 2016 - 21:12:21 EST

On Thu, Feb 4, 2016 at 4:11 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> On Thu, Feb 4, 2016 at 3:04 PM, Andy Shevchenko
> <andy.shevchenko@xxxxxxxxx> wrote:
>> On Thu, Feb 4, 2016 at 11:00 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>>> This changes several users of manual "on"/"off" parsing to use strtobool.
>>> (Which means they will now parse y/n/1/0 meaningfully too.)
>>>
>>
>> I like this change, but can you carefully check the acceptance of the
>> returned value?
>> Briefly I saw 1 or 0 as okay in different places.
>
> Maybe I missed something, but I think this is actually a bug fix. The
> two cases are early_param and __setup:
>
> For early_param, the functions are called when walking the command
> line in do_early_param via parse_args in parse_early_options. Any
> non-zero return values produce a warning (in do_early_param not
> parse_args). So this is a bug fix, since the function I touched would
> (almost) always return 0, even with bad values (i.e. fixes unreported
> bad arguments):
>
> early_param early_parse_stp always 0
> early_param early_parse_topology always 0
> early_param parse_gart_mem always 0 unless !p (then -EINVAL)
>
> For __setup, these are handled by obsolete_checksetup via
> unknown_bootoption via parse_args in start_kernel, as a way to merge
> __setup calls that should really be in param (i.e. non-early __setup).
> Return values are bubbled up into parse_args and hit:
>
> default:
> pr_err("%s: `%s' invalid for parameter `%s'\n",
> doing, val ?: "", param);
> break;
>
> So this is also a bug fix, since these __setup functions returned inverted
> values or always failed:
>
> __setup rtasmsgs_setup always 1
> __setup setup_cede_offline 1 on success, otherwise 0
> __setup setup_hrtimer_hres 1 on success, otherwise 0
> __setup setup_tick_nohz 1 on success, otherwise 0
>
> So if you specified any of these, they would trigger a bogus "invalid
> parameter" report.
>
> I will double-check...

I am wrong! __setup functions (as handled by unknown_bootoption) need
to return 1, or they end up in the init environment. I will send a
fix...

-Kees

>
> -Kees
>
>>
>>
>>> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
>>> Acked-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
>>> Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
>>> Cc: x86@xxxxxxxxxx
>>> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
>>> Cc: linux-s390@xxxxxxxxxxxxxxx
>>> ---
>>> arch/powerpc/kernel/rtasd.c | 9 ++-------
>>> arch/powerpc/platforms/pseries/hotplug-cpu.c | 10 ++--------
>>> arch/s390/kernel/time.c | 8 ++------
>>> arch/s390/kernel/topology.c | 7 ++-----
>>> arch/x86/kernel/aperture_64.c | 12 ++----------
>>> include/linux/tick.h | 2 +-
>>> kernel/time/hrtimer.c | 10 ++--------
>>> kernel/time/tick-sched.c | 10 ++--------
>>> 8 files changed, 15 insertions(+), 53 deletions(-)
>>>
>>> diff --git a/arch/powerpc/kernel/rtasd.c b/arch/powerpc/kernel/rtasd.c
>>> index 5a2c049c1c61..567ed5a2f43a 100644
>>> --- a/arch/powerpc/kernel/rtasd.c
>>> +++ b/arch/powerpc/kernel/rtasd.c
>>> @@ -49,7 +49,7 @@ static unsigned int rtas_error_log_buffer_max;
>>> static unsigned int event_scan;
>>> static unsigned int rtas_event_scan_rate;
>>>
>>> -static int full_rtas_msgs = 0;
>>> +static bool full_rtas_msgs;
>>>
>>> /* Stop logging to nvram after first fatal error */
>>> static int logging_enabled; /* Until we initialize everything,
>>> @@ -592,11 +592,6 @@ __setup("surveillance=", surveillance_setup);
>>>
>>> static int __init rtasmsgs_setup(char *str)
>>> {
>>> - if (strcmp(str, "on") == 0)
>>> - full_rtas_msgs = 1;
>>> - else if (strcmp(str, "off") == 0)
>>> - full_rtas_msgs = 0;
>>> -
>>> - return 1;
>>> + return kstrtobool(str, 0, &full_rtas_msgs);
>>> }
>>> __setup("rtasmsgs=", rtasmsgs_setup);
>>> diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
>>> index 32274f72fe3f..b9787cae4108 100644
>>> --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
>>> +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
>>> @@ -47,20 +47,14 @@ static DEFINE_PER_CPU(enum cpu_state_vals, current_state) = CPU_STATE_OFFLINE;
>>>
>>> static enum cpu_state_vals default_offline_state = CPU_STATE_OFFLINE;
>>>
>>> -static int cede_offline_enabled __read_mostly = 1;
>>> +static bool cede_offline_enabled __read_mostly = true;
>>>
>>> /*
>>> * Enable/disable cede_offline when available.
>>> */
>>> static int __init setup_cede_offline(char *str)
>>> {
>>> - if (!strcmp(str, "off"))
>>> - cede_offline_enabled = 0;
>>> - else if (!strcmp(str, "on"))
>>> - cede_offline_enabled = 1;
>>> - else
>>> - return 0;
>>> - return 1;
>>> + return kstrtobool(str, 0, &cede_offline_enabled);
>>> }
>>>
>>> __setup("cede_offline=", setup_cede_offline);
>>> diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
>>> index 99f84ac31307..dff6ce1b84b2 100644
>>> --- a/arch/s390/kernel/time.c
>>> +++ b/arch/s390/kernel/time.c
>>> @@ -1433,7 +1433,7 @@ device_initcall(etr_init_sysfs);
>>> /*
>>> * Server Time Protocol (STP) code.
>>> */
>>> -static int stp_online;
>>> +static bool stp_online;
>>> static struct stp_sstpi stp_info;
>>> static void *stp_page;
>>>
>>> @@ -1444,11 +1444,7 @@ static struct timer_list stp_timer;
>>>
>>> static int __init early_parse_stp(char *p)
>>> {
>>> - if (strncmp(p, "off", 3) == 0)
>>> - stp_online = 0;
>>> - else if (strncmp(p, "on", 2) == 0)
>>> - stp_online = 1;
>>> - return 0;
>>> + return kstrtobool(p, 0, &stp_online);
>>> }
>>> early_param("stp", early_parse_stp);
>>>
>>> diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
>>> index 40b8102fdadb..5d8a80651f61 100644
>>> --- a/arch/s390/kernel/topology.c
>>> +++ b/arch/s390/kernel/topology.c
>>> @@ -37,7 +37,7 @@ static void set_topology_timer(void);
>>> static void topology_work_fn(struct work_struct *work);
>>> static struct sysinfo_15_1_x *tl_info;
>>>
>>> -static int topology_enabled = 1;
>>> +static bool topology_enabled = true;
>>> static DECLARE_WORK(topology_work, topology_work_fn);
>>>
>>> /*
>>> @@ -444,10 +444,7 @@ static const struct cpumask *cpu_book_mask(int cpu)
>>>
>>> static int __init early_parse_topology(char *p)
>>> {
>>> - if (strncmp(p, "off", 3))
>>> - return 0;
>>> - topology_enabled = 0;
>>> - return 0;
>>> + return kstrtobool(p, 0, &topology_enabled);
>>> }
>>> early_param("topology", early_parse_topology);
>>>
>>> diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
>>> index 6e85f713641d..6b423754083a 100644
>>> --- a/arch/x86/kernel/aperture_64.c
>>> +++ b/arch/x86/kernel/aperture_64.c
>>> @@ -227,19 +227,11 @@ static u32 __init search_agp_bridge(u32 *order, int *valid_agp)
>>> return 0;
>>> }
>>>
>>> -static int gart_fix_e820 __initdata = 1;
>>> +static bool gart_fix_e820 __initdata = true;
>>>
>>> static int __init parse_gart_mem(char *p)
>>> {
>>> - if (!p)
>>> - return -EINVAL;
>>> -
>>> - if (!strncmp(p, "off", 3))
>>> - gart_fix_e820 = 0;
>>> - else if (!strncmp(p, "on", 2))
>>> - gart_fix_e820 = 1;
>>> -
>>> - return 0;
>>> + return kstrtobool(p, 0, &gart_fix_e820);
>>> }
>>> early_param("gart_fix_e820", parse_gart_mem);
>>>
>>> diff --git a/include/linux/tick.h b/include/linux/tick.h
>>> index 97fd4e543846..0ecdf0e248f4 100644
>>> --- a/include/linux/tick.h
>>> +++ b/include/linux/tick.h
>>> @@ -98,7 +98,7 @@ static inline void tick_broadcast_exit(void)
>>> }
>>>
>>> #ifdef CONFIG_NO_HZ_COMMON
>>> -extern int tick_nohz_enabled;
>>> +extern bool tick_nohz_enabled;
>>> extern int tick_nohz_tick_stopped(void);
>>> extern void tick_nohz_idle_enter(void);
>>> extern void tick_nohz_idle_exit(void);
>>> diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
>>> index 435b8850dd80..456f066148d5 100644
>>> --- a/kernel/time/hrtimer.c
>>> +++ b/kernel/time/hrtimer.c
>>> @@ -515,7 +515,7 @@ static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
>>> /*
>>> * High resolution timer enabled ?
>>> */
>>> -static int hrtimer_hres_enabled __read_mostly = 1;
>>> +static bool hrtimer_hres_enabled __read_mostly = true;
>>> unsigned int hrtimer_resolution __read_mostly = LOW_RES_NSEC;
>>> EXPORT_SYMBOL_GPL(hrtimer_resolution);
>>>
>>> @@ -524,13 +524,7 @@ EXPORT_SYMBOL_GPL(hrtimer_resolution);
>>> */
>>> static int __init setup_hrtimer_hres(char *str)
>>> {
>>> - if (!strcmp(str, "off"))
>>> - hrtimer_hres_enabled = 0;
>>> - else if (!strcmp(str, "on"))
>>> - hrtimer_hres_enabled = 1;
>>> - else
>>> - return 0;
>>> - return 1;
>>> + return kstrtobool(str, 0, &hrtimer_hres_enabled);
>>> }
>>>
>>> __setup("highres=", setup_hrtimer_hres);
>>> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
>>> index 9d7a053545f5..b57f822c2069 100644
>>> --- a/kernel/time/tick-sched.c
>>> +++ b/kernel/time/tick-sched.c
>>> @@ -387,20 +387,14 @@ void __init tick_nohz_init(void)
>>> /*
>>> * NO HZ enabled ?
>>> */
>>> -int tick_nohz_enabled __read_mostly = 1;
>>> +bool tick_nohz_enabled __read_mostly = true;
>>> unsigned long tick_nohz_active __read_mostly;
>>> /*
>>> * Enable / Disable tickless mode
>>> */
>>> static int __init setup_tick_nohz(char *str)
>>> {
>>> - if (!strcmp(str, "off"))
>>> - tick_nohz_enabled = 0;
>>> - else if (!strcmp(str, "on"))
>>> - tick_nohz_enabled = 1;
>>> - else
>>> - return 0;
>>> - return 1;
>>> + return kstrtobool(str, 0, &tick_nohz_enabled);
>>> }
>>>
>>> __setup("nohz=", setup_tick_nohz);
>>> --
>>> 2.6.3
>>>
>>
>>
>>
>> --
>> With Best Regards,
>> Andy Shevchenko
>
>
>
> --
> Kees Cook
> Chrome OS & Brillo Security



--
Kees Cook
Chrome OS & Brillo Security