Input: i8042 - add unmask_kbd_data option

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@redhat.com>
Reviewed-by: Andreas Mohr <andim2@users.sf.net>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index bfcb1a6..fd0f7cd 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1274,6 +1274,10 @@ 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..c9c98f0 100644 (file)
--- 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_UNBIND_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 (file)
--- 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..8f82897 100644 (file)
--- 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,
@@ -1029,6 +1027,7 @@ static struct bus_type serio_bus = {
        .pm             = &serio_pm_ops,
 #endif
 };
+EXPORT_SYMBOL(serio_bus);
 
 static int __init serio_init(void)
 {

diff --git a/include/linux/serio.h b/include/linux/serio.h
index 9f779c7..df4ab5d 100644 (file)
--- 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;