From 3281e0ef0cab247e5dcd4537b4fc7145d666ca4c Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sat, 25 Mar 2006 03:06:35 -0800
Subject: [PATCH] --- yaml --- r: 23501 b: refs/heads/master c:
 7d99b7d634d81bb372e03e4561c80430aa4cfac2 h: refs/heads/master i:   23499:
 6b7e8b10122884f7152f3490102400a378cc1036 v: v3

---
 [refs]                                        |  2 +-
 .../feature-removal-schedule.txt              | 12 ++++
 trunk/kernel/itimer.c                         | 66 +++++++++++++++++++
 3 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 1895eff3d1b7..2e51a684279e 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c08b8a49100715b20e6f7c997e992428b5e06078
+refs/heads/master: 7d99b7d634d81bb372e03e4561c80430aa4cfac2
diff --git a/trunk/Documentation/feature-removal-schedule.txt b/trunk/Documentation/feature-removal-schedule.txt
index 21272e4b4a5c..495858b236b6 100644
--- a/trunk/Documentation/feature-removal-schedule.txt
+++ b/trunk/Documentation/feature-removal-schedule.txt
@@ -176,6 +176,18 @@ Who:	Richard Knutsson <ricknu-0@student.ltu.se> and Greg Kroah-Hartman <gregkh@s
 
 ---------------------------
 
+What:	Usage of invalid timevals in setitimer
+When:	March 2007
+Why:	POSIX requires to validate timevals in the setitimer call. This
+	was never done by Linux. The invalid (e.g. negative timevals) were
+	silently converted to more or less random timeouts and intervals.
+	Until the removal a per boot limited number of warnings is printed
+	and the timevals are sanitized.
+
+Who:	Thomas Gleixner <tglx@linutronix.de>
+
+---------------------------
+
 What:	I2C interface of the it87 driver
 When:	January 2007
 Why:	The ISA interface is faster and should be always available. The I2C
diff --git a/trunk/kernel/itimer.c b/trunk/kernel/itimer.c
index a2dc375927d8..680e6b70c872 100644
--- a/trunk/kernel/itimer.c
+++ b/trunk/kernel/itimer.c
@@ -143,6 +143,60 @@ int it_real_fn(void *data)
 	return HRTIMER_NORESTART;
 }
 
+/*
+ * We do not care about correctness. We just sanitize the values so
+ * the ktime_t operations which expect normalized values do not
+ * break. This converts negative values to long timeouts similar to
+ * the code in kernel versions < 2.6.16
+ *
+ * Print a limited number of warning messages when an invalid timeval
+ * is detected.
+ */
+static void fixup_timeval(struct timeval *tv, int interval)
+{
+	static int warnlimit = 10;
+	unsigned long tmp;
+
+	if (warnlimit > 0) {
+		warnlimit--;
+		printk(KERN_WARNING
+		       "setitimer: %s (pid = %d) provided "
+		       "invalid timeval %s: tv_sec = %ld tv_usec = %ld\n",
+		       current->comm, current->pid,
+		       interval ? "it_interval" : "it_value",
+		       tv->tv_sec, (long) tv->tv_usec);
+	}
+
+	tmp = tv->tv_usec;
+	if (tmp >= USEC_PER_SEC) {
+		tv->tv_usec = tmp % USEC_PER_SEC;
+		tv->tv_sec += tmp / USEC_PER_SEC;
+	}
+
+	tmp = tv->tv_sec;
+	if (tmp > LONG_MAX)
+		tv->tv_sec = LONG_MAX;
+}
+
+/*
+ * Returns true if the timeval is in canonical form
+ */
+#define timeval_valid(t) \
+	(((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
+
+/*
+ * Check for invalid timevals, sanitize them and print a limited
+ * number of warnings.
+ */
+static void check_itimerval(struct itimerval *value) {
+
+	if (unlikely(!timeval_valid(&value->it_value)))
+		fixup_timeval(&value->it_value, 0);
+
+	if (unlikely(!timeval_valid(&value->it_interval)))
+		fixup_timeval(&value->it_interval, 1);
+}
+
 int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
 {
 	struct task_struct *tsk = current;
@@ -150,6 +204,18 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
 	ktime_t expires;
 	cputime_t cval, cinterval, nval, ninterval;
 
+	/*
+	 * Validate the timevals in value.
+	 *
+	 * Note: Although the spec requires that invalid values shall
+	 * return -EINVAL, we just fixup the value and print a limited
+	 * number of warnings in order not to break users of this
+	 * historical misfeature.
+	 *
+	 * Scheduled for replacement in March 2007
+	 */
+	check_itimerval(value);
+
 	switch (which) {
 	case ITIMER_REAL:
 again: