timerfd: Make timerfd_settime() time namespace aware

timerfd_settime() accepts an absolute value of the expiration time if
TFD_TIMER_ABSTIME is specified. This value is in the task's time namespace
and has to be converted to the host's time namespace.

Co-developed-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20191112012724.250792-14-dima@arista.com

diff --git a/fs/timerfd.c b/fs/timerfd.c
index ac7f59a..c5509d2 100644 (file)
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -26,6 +26,7 @@
 #include <linux/syscalls.h>
 #include <linux/compat.h>
 #include <linux/rcupdate.h>
+#include <linux/time_namespace.h>
 
 struct timerfd_ctx {
        union {
@@ -196,6 +197,8 @@ static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
        }
 
        if (texp != 0) {
+               if (flags & TFD_TIMER_ABSTIME)
+                       texp = timens_ktime_to_host(clockid, texp);
                if (isalarm(ctx)) {
                        if (flags & TFD_TIMER_ABSTIME)
                                alarm_start(&ctx->t.alarm, texp);