queue posix-timers-sanitize-overrun-handling.patch for 4.9

Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/queue-4.9/posix-timers-sanitize-overrun-handling.patch b/queue-4.9/posix-timers-sanitize-overrun-handling.patch
new file mode 100644 (file)
index 0000000..9ce6c09
--- /dev/null
+++ b/queue-4.9/posix-timers-sanitize-overrun-handling.patch
@@ -0,0 +1,152 @@
+From 1e33008fa94dcb8179b616d00e92cbb3fbcceb1c Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 1 Nov 2018 13:02:38 -0700
+Subject: posix-timers: Sanitize overrun handling
+
+[ Upstream commit 78c9c4dfbf8c04883941445a195276bb4bb92c76 ]
+
+The posix timer overrun handling is broken because the forwarding functions
+can return a huge number of overruns which does not fit in an int. As a
+consequence timer_getoverrun(2) and siginfo::si_overrun can turn into
+random number generators.
+
+The k_clock::timer_forward() callbacks return a 64 bit value now. Make
+k_itimer::ti_overrun[_last] 64bit as well, so the kernel internal
+accounting is correct. 3Remove the temporary (int) casts.
+
+Add a helper function which clamps the overrun value returned to user space
+via timer_getoverrun(2) or siginfo::si_overrun limited to a positive value
+between 0 and INT_MAX. INT_MAX is an indicator for user space that the
+overrun value has been clamped.
+
+Reported-by: Team OWL337 <icytxw@gmail.com>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Acked-by: John Stultz <john.stultz@linaro.org>
+Cc: Peter Zijlstra <peterz@infradead.org>
+Cc: Michael Kerrisk <mtk.manpages@gmail.com>
+Link: https://lkml.kernel.org/r/20180626132705.018623573@linutronix.de
+[florian: Make patch apply to v4.9.135]
+Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
+Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sasha Levin <sashal@kernel.org>
+---
+ include/linux/posix-timers.h   |  4 ++--
+ kernel/time/posix-cpu-timers.c |  2 +-
+ kernel/time/posix-timers.c     | 29 +++++++++++++++++++----------
+ 3 files changed, 22 insertions(+), 13 deletions(-)
+
+diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
+index 62d44c176071..e4b8678183f5 100644
+--- a/include/linux/posix-timers.h
++++ b/include/linux/posix-timers.h
+@@ -65,8 +65,8 @@ struct k_itimer {
+       spinlock_t it_lock;
+       clockid_t it_clock;             /* which timer type */
+       timer_t it_id;                  /* timer id */
+-      int it_overrun;                 /* overrun on pending signal  */
+-      int it_overrun_last;            /* overrun on last delivered signal */
++      s64 it_overrun;                 /* overrun on pending signal  */
++      s64 it_overrun_last;            /* overrun on last delivered signal */
+       int it_requeue_pending;         /* waiting to requeue this timer */
+ #define REQUEUE_PENDING 1
+       int it_sigev_notify;            /* notify word of sigevent struct */
+diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
+index 39008d78927a..21a27bb73587 100644
+--- a/kernel/time/posix-cpu-timers.c
++++ b/kernel/time/posix-cpu-timers.c
+@@ -103,7 +103,7 @@ static void bump_cpu_timer(struct k_itimer *timer,
+                       continue;
+ 
+               timer->it.cpu.expires += incr;
+-              timer->it_overrun += 1 << i;
++              timer->it_overrun += 1LL << i;
+               delta -= incr;
+       }
+ }
+diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
+index fc7c37ad90a0..0e6ed2e7d066 100644
+--- a/kernel/time/posix-timers.c
++++ b/kernel/time/posix-timers.c
+@@ -355,6 +355,17 @@ static __init int init_posix_timers(void)
+ 
+ __initcall(init_posix_timers);
+ 
++/*
++ * The siginfo si_overrun field and the return value of timer_getoverrun(2)
++ * are of type int. Clamp the overrun value to INT_MAX
++ */
++static inline int timer_overrun_to_int(struct k_itimer *timr, int baseval)
++{
++      s64 sum = timr->it_overrun_last + (s64)baseval;
++
++      return sum > (s64)INT_MAX ? INT_MAX : (int)sum;
++}
++
+ static void schedule_next_timer(struct k_itimer *timr)
+ {
+       struct hrtimer *timer = &timr->it.real.timer;
+@@ -362,12 +373,11 @@ static void schedule_next_timer(struct k_itimer *timr)
+       if (timr->it.real.interval.tv64 == 0)
+               return;
+ 
+-      timr->it_overrun += (unsigned int) hrtimer_forward(timer,
+-                                              timer->base->get_time(),
+-                                              timr->it.real.interval);
++      timr->it_overrun += hrtimer_forward(timer, timer->base->get_time(),
++                                          timr->it.real.interval);
+ 
+       timr->it_overrun_last = timr->it_overrun;
+-      timr->it_overrun = -1;
++      timr->it_overrun = -1LL;
+       ++timr->it_requeue_pending;
+       hrtimer_restart(timer);
+ }
+@@ -396,7 +406,7 @@ void do_schedule_next_timer(struct siginfo *info)
+               else
+                       schedule_next_timer(timr);
+ 
+-              info->si_overrun += timr->it_overrun_last;
++              info->si_overrun = timer_overrun_to_int(timr, info->si_overrun);
+       }
+ 
+       if (timr)
+@@ -491,8 +501,7 @@ static enum hrtimer_restart posix_timer_fn(struct hrtimer *timer)
+                                       now = ktime_add(now, kj);
+                       }
+ #endif
+-                      timr->it_overrun += (unsigned int)
+-                              hrtimer_forward(timer, now,
++                      timr->it_overrun += hrtimer_forward(timer, now,
+                                               timr->it.real.interval);
+                       ret = HRTIMER_RESTART;
+                       ++timr->it_requeue_pending;
+@@ -633,7 +642,7 @@ SYSCALL_DEFINE3(timer_create, const clockid_t, which_clock,
+       it_id_set = IT_ID_SET;
+       new_timer->it_id = (timer_t) new_timer_id;
+       new_timer->it_clock = which_clock;
+-      new_timer->it_overrun = -1;
++      new_timer->it_overrun = -1LL;
+ 
+       if (timer_event_spec) {
+               if (copy_from_user(&event, timer_event_spec, sizeof (event))) {
+@@ -762,7 +771,7 @@ common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
+        */
+       if (iv.tv64 && (timr->it_requeue_pending & REQUEUE_PENDING ||
+                       timr->it_sigev_notify == SIGEV_NONE))
+-              timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv);
++              timr->it_overrun += hrtimer_forward(timer, now, iv);
+ 
+       remaining = __hrtimer_expires_remaining_adjusted(timer, now);
+       /* Return 0 only, when the timer is expired and not pending */
+@@ -824,7 +833,7 @@ SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id)
+       if (!timr)
+               return -EINVAL;
+ 
+-      overrun = timr->it_overrun_last;
++      overrun = timer_overrun_to_int(timr, 0);
+       unlock_timer(timr, flags);
+ 
+       return overrun;
+-- 
+2.17.1
+

diff --git a/queue-4.9/series b/queue-4.9/series
index 2843df59d89165526881936200cb53ad876eebbd..cc8167f7790b7fe065ea70dd3909e1f3baa5d5cd 100644 (file)
--- a/queue-4.9/series
+++ b/queue-4.9/series
@@ -156,3 +156,4 @@ ahci-don-t-ignore-result-code-of-ahci_reset_controll.patch
 gpio-mxs-get-rid-of-external-api-call.patch
 xfs-truncate-transaction-does-not-modify-the-inobt.patch
 net-fs_enet-do-not-call-phy_stop-in-interrupts.patch
+posix-timers-sanitize-overrun-handling.patch