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authorJohn Stultz <john.stultz@linaro.org>2012-08-08 15:36:20 -0400
committerBen Hutchings <ben@decadent.org.uk>2012-09-19 15:04:59 +0100
commit8dd006cdafa7c955f6f4c66d25564d90aa29af1d (patch)
tree69075d430b9fd89bb133875bc420452b40fa7651 /kernel
parent6293b62174d4bb3594c7d41276a3c35755101aba (diff)
time: Improve sanity checking of timekeeping inputs
This is a -stable backport of 4e8b14526ca7fb046a81c94002c1c43b6fdf0e9b Unexpected behavior could occur if the time is set to a value large enough to overflow a 64bit ktime_t (which is something larger then the year 2262). Also unexpected behavior could occur if large negative offsets are injected via adjtimex. So this patch improves the sanity check timekeeping inputs by improving the timespec_valid() check, and then makes better use of timespec_valid() to make sure we don't set the time to an invalid negative value or one that overflows ktime_t. Note: This does not protect from setting the time close to overflowing ktime_t and then letting natural accumulation cause the overflow. Reported-by: CAI Qian <caiqian@redhat.com> Reported-by: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Zhouping Liu <zliu@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/1344454580-17031-1-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linux Kernel <linux-kernel@vger.kernel.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/time/timekeeping.c26
1 files changed, 24 insertions, 2 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 03e67d458b8f..36440c88fa87 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -382,7 +382,7 @@ int do_settimeofday(const struct timespec *tv)
struct timespec ts_delta;
unsigned long flags;
- if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
+ if (!timespec_valid(tv))
return -EINVAL;
write_seqlock_irqsave(&xtime_lock, flags);
@@ -417,6 +417,8 @@ EXPORT_SYMBOL(do_settimeofday);
int timekeeping_inject_offset(struct timespec *ts)
{
unsigned long flags;
+ struct timespec tmp;
+ int ret = 0;
if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
@@ -425,9 +427,16 @@ int timekeeping_inject_offset(struct timespec *ts)
timekeeping_forward_now();
+ tmp = timespec_add(xtime, *ts);
+ if (!timespec_valid(&tmp)) {
+ ret = -EINVAL;
+ goto error;
+ }
+
xtime = timespec_add(xtime, *ts);
wall_to_monotonic = timespec_sub(wall_to_monotonic, *ts);
+error: /* even if we error out, we forwarded the time, so call update */
timekeeping_update(true);
write_sequnlock_irqrestore(&xtime_lock, flags);
@@ -435,7 +444,7 @@ int timekeeping_inject_offset(struct timespec *ts)
/* signal hrtimers about time change */
clock_was_set();
- return 0;
+ return ret;
}
EXPORT_SYMBOL(timekeeping_inject_offset);
@@ -582,7 +591,20 @@ void __init timekeeping_init(void)
struct timespec now, boot;
read_persistent_clock(&now);
+ if (!timespec_valid(&now)) {
+ pr_warn("WARNING: Persistent clock returned invalid value!\n"
+ " Check your CMOS/BIOS settings.\n");
+ now.tv_sec = 0;
+ now.tv_nsec = 0;
+ }
+
read_boot_clock(&boot);
+ if (!timespec_valid(&boot)) {
+ pr_warn("WARNING: Boot clock returned invalid value!\n"
+ " Check your CMOS/BIOS settings.\n");
+ boot.tv_sec = 0;
+ boot.tv_nsec = 0;
+ }
write_seqlock_irqsave(&xtime_lock, flags);