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Message-ID: <20150715152817.GA16611@mail.corp.redhat.com>
Date: Wed, 15 Jul 2015 11:28:17 -0400
From: Benjamin Tissoires <benjamin.tissoires@...hat.com>
To: cpaul@...hat.com
Cc: linux-kernel@...r.kernel.org, linux-input@...r.kernel.org,
Hans de Goede <hdegoede@...hat.com>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Andreas Mohr <andi@...as.de>
Subject: Re: [PATCH v5] i8042: Add unmask_kbd_data option
On Jul 02 2015 or thereabouts, cpaul@...hat.com wrote:
> From: Stephen Chandler Paul <cpaul@...hat.com>
>
> A big problem with the current i8042 debugging option is that it outputs
> data going to and from the keyboard by default. As a result, many dmesg
> logs uploaded by users will unintentionally contain sensitive information
> such as their password, as such it's probably a good idea not to output
> data coming from the keyboard unless specifically enabled by the user.
>
> Signed-off-by: Stephen Chandler Paul <cpaul@...hat.com>
> ---
FWIW, in case you are missing my input Dmitry:
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>
Thanks everyone involved in this process!
Cheers,
Benjamin
> Changes
> * Fix incorrect option name in MODULE_PARM_DESC() (I have no idea how that
> happened in the first place)
> * Replaced the description with one of the suggestions given by Andreas
> * Rename debug_kbd to unmask_kbd_data
> * Improve description in Documentation/kernel-parameters.txt
>
> Documentation/kernel-parameters.txt | 4 ++++
> drivers/input/serio/i8042.c | 43 +++++++++++++++++++++++++++++++++----
> drivers/input/serio/i8042.h | 13 +++++++++++
> drivers/input/serio/serio.c | 4 +---
> include/linux/serio.h | 2 ++
> 5 files changed, 59 insertions(+), 7 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index ae44749..352a5f1 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -1304,6 +1304,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
> <bus_id>,<clkrate>
>
> i8042.debug [HW] Toggle i8042 debug mode
> + i8042.unmask_kbd_data
> + [HW] Enable printing of interrupt data from the KBD port
> + (disabled by default, and as a pre-condition
> + requires that i8042.debug=1 be enabled)
> i8042.direct [HW] Put keyboard port into non-translated mode
> i8042.dumbkbd [HW] Pretend that controller can only read data from
> keyboard and cannot control its state
> diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c
> index cb5ece7..e6d1529 100644
> --- a/drivers/input/serio/i8042.c
> +++ b/drivers/input/serio/i8042.c
> @@ -88,6 +88,10 @@ MODULE_PARM_DESC(nopnp, "Do not use PNP to detect controller settings");
> static bool i8042_debug;
> module_param_named(debug, i8042_debug, bool, 0600);
> MODULE_PARM_DESC(debug, "Turn i8042 debugging mode on and off");
> +
> +static bool i8042_unmask_kbd_data;
> +module_param_named(unmask_kbd_data, i8042_unmask_kbd_data, bool, 0600);
> +MODULE_PARM_DESC(unmask_kbd_data, "Unconditional enable (may reveal sensitive data) of normally sanitize-filtered kbd data traffic debug log [pre-condition: i8042.debug=1 enabled]");
> #endif
>
> static bool i8042_bypass_aux_irq_test;
> @@ -116,6 +120,7 @@ struct i8042_port {
> struct serio *serio;
> int irq;
> bool exists;
> + bool driver_bound;
> signed char mux;
> };
>
> @@ -133,6 +138,7 @@ static bool i8042_kbd_irq_registered;
> static bool i8042_aux_irq_registered;
> static unsigned char i8042_suppress_kbd_ack;
> static struct platform_device *i8042_platform_device;
> +static struct notifier_block i8042_kbd_bind_notifier_block;
>
> static irqreturn_t i8042_interrupt(int irq, void *dev_id);
> static bool (*i8042_platform_filter)(unsigned char data, unsigned char str,
> @@ -528,10 +534,10 @@ static irqreturn_t i8042_interrupt(int irq, void *dev_id)
> port = &i8042_ports[port_no];
> serio = port->exists ? port->serio : NULL;
>
> - dbg("%02x <- i8042 (interrupt, %d, %d%s%s)\n",
> - data, port_no, irq,
> - dfl & SERIO_PARITY ? ", bad parity" : "",
> - dfl & SERIO_TIMEOUT ? ", timeout" : "");
> + filter_dbg(port->driver_bound, data, "<- i8042 (interrupt, %d, %d%s%s)\n",
> + port_no, irq,
> + dfl & SERIO_PARITY ? ", bad parity" : "",
> + dfl & SERIO_TIMEOUT ? ", timeout" : "");
>
> filtered = i8042_filter(data, str, serio);
>
> @@ -1438,6 +1444,29 @@ static int __init i8042_setup_kbd(void)
> return error;
> }
>
> +static int i8042_kbd_bind_notifier(struct notifier_block *nb,
> + unsigned long action, void *data)
> +{
> + struct device *dev = data;
> + struct serio *serio = to_serio_port(dev);
> + struct i8042_port *port = serio->port_data;
> +
> + if (serio != i8042_ports[I8042_KBD_PORT_NO].serio)
> + return 0;
> +
> + switch (action) {
> + case BUS_NOTIFY_BOUND_DRIVER:
> + port->driver_bound = true;
> + break;
> +
> + case BUS_NOTIFY_UNBOUND_DRIVER:
> + port->driver_bound = false;
> + break;
> + }
> +
> + return 0;
> +}
> +
> static int __init i8042_probe(struct platform_device *dev)
> {
> int error;
> @@ -1507,6 +1536,10 @@ static struct platform_driver i8042_driver = {
> .shutdown = i8042_shutdown,
> };
>
> +static struct notifier_block i8042_kbd_bind_notifier_block = {
> + .notifier_call = i8042_kbd_bind_notifier,
> +};
> +
> static int __init i8042_init(void)
> {
> struct platform_device *pdev;
> @@ -1528,6 +1561,7 @@ static int __init i8042_init(void)
> goto err_platform_exit;
> }
>
> + bus_register_notifier(&serio_bus, &i8042_kbd_bind_notifier_block);
> panic_blink = i8042_panic_blink;
>
> return 0;
> @@ -1543,6 +1577,7 @@ static void __exit i8042_exit(void)
> platform_driver_unregister(&i8042_driver);
> i8042_platform_exit();
>
> + bus_unregister_notifier(&serio_bus, &i8042_kbd_bind_notifier_block);
> panic_blink = NULL;
> }
>
> diff --git a/drivers/input/serio/i8042.h b/drivers/input/serio/i8042.h
> index fc080be..1db0a40 100644
> --- a/drivers/input/serio/i8042.h
> +++ b/drivers/input/serio/i8042.h
> @@ -73,6 +73,17 @@ static unsigned long i8042_start_time;
> printk(KERN_DEBUG KBUILD_MODNAME ": [%d] " format, \
> (int) (jiffies - i8042_start_time), ##arg); \
> } while (0)
> +
> +#define filter_dbg(filter, data, format, args...) \
> + do { \
> + if (!i8042_debug) \
> + break; \
> + \
> + if (!filter || i8042_unmask_kbd_data) \
> + dbg("%02x " format, data, ##args); \
> + else \
> + dbg("** " format, ##args); \
> + } while (0)
> #else
> #define dbg_init() do { } while (0)
> #define dbg(format, arg...) \
> @@ -80,6 +91,8 @@ static unsigned long i8042_start_time;
> if (0) \
> printk(KERN_DEBUG pr_fmt(format), ##arg); \
> } while (0)
> +
> +#define filter_dbg(filter, data, format, args...) do { } while (0)
> #endif
>
> #endif /* _I8042_H */
> diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
> index a05a517..63422d2 100644
> --- a/drivers/input/serio/serio.c
> +++ b/drivers/input/serio/serio.c
> @@ -49,8 +49,6 @@ static DEFINE_MUTEX(serio_mutex);
>
> static LIST_HEAD(serio_list);
>
> -static struct bus_type serio_bus;
> -
> static void serio_add_port(struct serio *serio);
> static int serio_reconnect_port(struct serio *serio);
> static void serio_disconnect_port(struct serio *serio);
> @@ -1017,7 +1015,7 @@ irqreturn_t serio_interrupt(struct serio *serio,
> }
> EXPORT_SYMBOL(serio_interrupt);
>
> -static struct bus_type serio_bus = {
> +struct bus_type serio_bus = {
> .name = "serio",
> .drv_groups = serio_driver_groups,
> .match = serio_bus_match,
> diff --git a/include/linux/serio.h b/include/linux/serio.h
> index 9f779c7..df4ab5d 100644
> --- a/include/linux/serio.h
> +++ b/include/linux/serio.h
> @@ -18,6 +18,8 @@
> #include <linux/mod_devicetable.h>
> #include <uapi/linux/serio.h>
>
> +extern struct bus_type serio_bus;
> +
> struct serio {
> void *port_data;
>
> --
> 2.4.3
>
--
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