[PATCH] rtc subsystem: add capability checks
Centralize CAP_SYS_XXX checks to avoid duplicate code and missing checks in
the drivers.
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 413c7d5..5396bee 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -69,6 +69,7 @@
rtc->id = id;
rtc->ops = ops;
rtc->owner = owner;
+ rtc->max_user_freq = 64;
rtc->class_dev.dev = dev;
rtc->class_dev.class = rtc_class;
rtc->class_dev.release = rtc_device_release;
diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
index 07387c9..61a5825 100644
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -214,6 +214,28 @@
struct rtc_wkalrm alarm;
void __user *uarg = (void __user *) arg;
+ /* check that the calles has appropriate permissions
+ * for certain ioctls. doing this check here is useful
+ * to avoid duplicate code in each driver.
+ */
+ switch (cmd) {
+ case RTC_EPOCH_SET:
+ case RTC_SET_TIME:
+ if (!capable(CAP_SYS_TIME))
+ return -EACCES;
+ break;
+
+ case RTC_IRQP_SET:
+ if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE))
+ return -EACCES;
+ break;
+
+ case RTC_PIE_ON:
+ if (!capable(CAP_SYS_RESOURCE))
+ return -EACCES;
+ break;
+ }
+
/* avoid conflicting IRQ users */
if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) {
spin_lock(&rtc->irq_task_lock);
@@ -272,9 +294,6 @@
break;
case RTC_SET_TIME:
- if (!capable(CAP_SYS_TIME))
- return -EACCES;
-
if (copy_from_user(&tm, uarg, sizeof(tm)))
return -EFAULT;
@@ -290,10 +309,6 @@
err = -EINVAL;
break;
}
- if (!capable(CAP_SYS_TIME)) {
- err = -EACCES;
- break;
- }
rtc_epoch = arg;
err = 0;
#endif
diff --git a/drivers/rtc/rtc-sa1100.c b/drivers/rtc/rtc-sa1100.c
index a997529..ab486fb 100644
--- a/drivers/rtc/rtc-sa1100.c
+++ b/drivers/rtc/rtc-sa1100.c
@@ -229,8 +229,6 @@
spin_unlock_irq(&sa1100_rtc_lock);
return 0;
case RTC_PIE_ON:
- if ((rtc_freq > 64) && !capable(CAP_SYS_RESOURCE))
- return -EACCES;
spin_lock_irq(&sa1100_rtc_lock);
OSMR1 = TIMER_FREQ/rtc_freq + OSCR;
OIER |= OIER_E1;
@@ -242,8 +240,6 @@
case RTC_IRQP_SET:
if (arg < 1 || arg > TIMER_FREQ)
return -EINVAL;
- if ((arg > 64) && (!capable(CAP_SYS_RESOURCE)))
- return -EACCES;
rtc_freq = arg;
return 0;
}
diff --git a/drivers/rtc/rtc-vr41xx.c b/drivers/rtc/rtc-vr41xx.c
index 277596c..33e0292 100644
--- a/drivers/rtc/rtc-vr41xx.c
+++ b/drivers/rtc/rtc-vr41xx.c
@@ -81,7 +81,6 @@
#define RTC_FREQUENCY 32768
#define MAX_PERIODIC_RATE 6553
-#define MAX_USER_PERIODIC_RATE 64
static void __iomem *rtc1_base;
static void __iomem *rtc2_base;
@@ -240,9 +239,6 @@
if (arg > MAX_PERIODIC_RATE)
return -EINVAL;
- if (arg > MAX_USER_PERIODIC_RATE && capable(CAP_SYS_RESOURCE) == 0)
- return -EACCES;
-
periodic_frequency = arg;
count = RTC_FREQUENCY;
@@ -263,10 +259,6 @@
/* Doesn't support before 1900 */
if (arg < 1900)
return -EINVAL;
-
- if (capable(CAP_SYS_TIME) == 0)
- return -EACCES;
-
epoch = arg;
break;
default:
diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index 4331076..c12cbc1 100644
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -155,6 +155,7 @@
struct rtc_task *irq_task;
spinlock_t irq_task_lock;
int irq_freq;
+ int max_user_freq;
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
struct work_struct uie_task;
struct timer_list uie_timer;