[PATCH v4] i8042: Add debug_kbd option

From: cpaul
Date: Fri Jun 26 2015 - 20:25:11 EST

Next message: Greg KH: "Re: [v3.16.y-ckt][v3.18.y][v3.19.y-ckt][v4.0.y][PATCH 1/1]Drivers: hv: vmbus: Add support for VMBus panic notifier handler"
Previous message: Stephen Rothwell: "Re: [PATCH] modules: elide param_lock if !CONFIG_SYSFS"
In reply to: Dmitry Torokhov: "Re: [PATCH v3] i8042: Add debug_kbd option"
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From: Stephen Chandler Paul <cpaul@xxxxxxxxxx>

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@xxxxxxxxxx>
---
Changes
* Remove #ifdefs around notifier code
* Rename i8042_port.filter_dbg to i8042.driver_bound
* Instead of checking the parent of the current device, compare serio against
i8042_ports[I8042_KBD_PORT_NO].serio
* Use a switch case instead of an if-else when checking the action in the bus
notifier
* Export serio_bus into serio.h, register the bus notifiers at module load time
as opposed to port registration time

Documentation/kernel-parameters.txt | 3 +++
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, 58 insertions(+), 7 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index ae44749..a9d2b19 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1304,6 +1304,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
<bus_id>,<clkrate>

i8042.debug [HW] Toggle i8042 debug mode
+ i8042.debug_kbd [HW] Enable printing of interrupt data from the KBD port
+ (disabled by default, 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..e29d6a4 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_debug_kbd;
+module_param_named(debug_kbd, i8042_debug_kbd, bool, 0600);
+MODULE_PARM_DESC(i8042_kbd, "Turn i8042 kbd debugging output on or off (requires i8042.debug=1)");
#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..a198f0d 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_debug_kbd) \
+ 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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Next message: Greg KH: "Re: [v3.16.y-ckt][v3.18.y][v3.19.y-ckt][v4.0.y][PATCH 1/1]Drivers: hv: vmbus: Add support for VMBus panic notifier handler"
Previous message: Stephen Rothwell: "Re: [PATCH] modules: elide param_lock if !CONFIG_SYSFS"
In reply to: Dmitry Torokhov: "Re: [PATCH v3] i8042: Add debug_kbd option"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]