From 416529374b4793ba2d2e97e736d108a2e0f3ef07 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 1 Feb 2008 20:35:31 +0300 Subject: [PATCH] hrtimer: fix *rmtp/restarts handling in compat_sys_nanosleep() Spotted by Pavel Emelyanov and Alexey Dobriyan. compat_sys_nanosleep() implicitly uses hrtimer_nanosleep_restart(), this can't work. Make a suitable compat_nanosleep_restart() helper. Introduced by commit c70878b4e0b6cf8d2f1e46319e48e821ef4a8aba hrtimer: hook compat_sys_nanosleep up to high res timer code Also, set ->addr_limit = KERNEL_DS before doing hrtimer_nanosleep(), this func was changed by the previous patch and now takes the "__user *" parameter. Thanks to Ingo Molnar for fixing the bug in this patch. Signed-off-by: Oleg Nesterov Cc: Andrew Morton Cc: Alexey Dobriyan Cc: Pavel Emelyanov Cc: Peter Zijlstra Cc: Toyo Abe Signed-off-by: Thomas Gleixner --- kernel/compat.c | 44 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 40 insertions(+), 4 deletions(-) diff --git a/kernel/compat.c b/kernel/compat.c index 42a1ed4b61b1..f2a297504287 100644 --- a/kernel/compat.c +++ b/kernel/compat.c @@ -40,10 +40,36 @@ int put_compat_timespec(const struct timespec *ts, struct compat_timespec __user __put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0; } +static long compat_nanosleep_restart(struct restart_block *restart) +{ + struct compat_timespec __user *rmtp; + struct timespec rmt; + mm_segment_t oldfs; + long ret; + + rmtp = (struct compat_timespec __user *)(restart->arg1); + restart->arg1 = (unsigned long)&rmt; + oldfs = get_fs(); + set_fs(KERNEL_DS); + ret = hrtimer_nanosleep_restart(restart); + set_fs(oldfs); + + if (ret) { + restart->fn = compat_nanosleep_restart; + restart->arg1 = (unsigned long)rmtp; + + if (rmtp && put_compat_timespec(&rmt, rmtp)) + return -EFAULT; + } + + return ret; +} + asmlinkage long compat_sys_nanosleep(struct compat_timespec __user *rqtp, struct compat_timespec __user *rmtp) { struct timespec tu, rmt; + mm_segment_t oldfs; long ret; if (get_compat_timespec(&tu, rqtp)) @@ -52,11 +78,21 @@ asmlinkage long compat_sys_nanosleep(struct compat_timespec __user *rqtp, if (!timespec_valid(&tu)) return -EINVAL; - ret = hrtimer_nanosleep(&tu, rmtp ? &rmt : NULL, HRTIMER_MODE_REL, - CLOCK_MONOTONIC); + oldfs = get_fs(); + set_fs(KERNEL_DS); + ret = hrtimer_nanosleep(&tu, + rmtp ? (struct timespec __user *)&rmt : NULL, + HRTIMER_MODE_REL, CLOCK_MONOTONIC); + set_fs(oldfs); + + if (ret) { + struct restart_block *restart + = ¤t_thread_info()->restart_block; + + restart->fn = compat_nanosleep_restart; + restart->arg1 = (unsigned long)rmtp; - if (ret && rmtp) { - if (put_compat_timespec(&rmt, rmtp)) + if (rmtp && put_compat_timespec(&rmt, rmtp)) return -EFAULT; } -- 2.20.1