From: Sasha Levin Date: Thu, 8 Nov 2018 15:47:01 +0000 (-0500) Subject: queue posix-timers-sanitize-overrun-handling.patch for 4.9 X-Git-Tag: v3.18.125~11^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=010ddd4dc865cddebb1db38d17fc164d57909017;p=thirdparty%2Fkernel%2Fstable-queue.git queue posix-timers-sanitize-overrun-handling.patch for 4.9 Signed-off-by: Sasha Levin --- 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 index 00000000000..9ce6c092b8f --- /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 +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 +Signed-off-by: Thomas Gleixner +Acked-by: John Stultz +Cc: Peter Zijlstra +Cc: Michael Kerrisk +Link: https://lkml.kernel.org/r/20180626132705.018623573@linutronix.de +[florian: Make patch apply to v4.9.135] +Signed-off-by: Florian Fainelli +Reviewed-by: Thomas Gleixner +Signed-off-by: Sasha Levin +--- + 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 2843df59d89..cc8167f7790 100644 --- 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