ntp: Move adjtimex related compat syscalls to native counterparts

Get rid of set_fs() mess and sanitize compat_{get,put}_timex(),
while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170607084241.28657-9-viro@ZenIV.linux.org.uk

3 files changed, 52 insertions, 1 deletions

diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index 749b76f2d757..954d1d8ff9e6 100644
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -28,6 +28,7 @@ asmlinkage long sys_ni_posix_timers(void)
 }
 
 #define SYS_NI(name)  SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers)
+#define COMPAT_SYS_NI(name)  SYSCALL_ALIAS(compat_sys_##name, sys_ni_posix_timers)
 
 SYS_NI(timer_create);
 SYS_NI(timer_gettime);
@@ -40,6 +41,7 @@ SYS_NI(setitimer);
 #ifdef __ARCH_WANT_SYS_ALARM
 SYS_NI(alarm);
 #endif
+COMPAT_SYS_NI(clock_adjtime);
 
 /*
  * We preserve minimal support for CLOCK_REALTIME and CLOCK_MONOTONIC
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index ea4a463436bf..b1b6d52d6425 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -1018,6 +1018,33 @@ SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
         return err;
 }
 
+#ifdef CONFIG_COMPAT
+
+COMPAT_SYSCALL_DEFINE2(clock_adjtime, clockid_t, which_clock,
+                       struct compat_timex __user *, utp)
+{
+        const struct k_clock *kc = clockid_to_kclock(which_clock);
+        struct timex ktx;
+        int err;
+
+        if (!kc)
+                return -EINVAL;
+        if (!kc->clock_adj)
+                return -EOPNOTSUPP;
+
+        err = compat_get_timex(&ktx, utp);
+        if (err)
+                return err;
+
+        err = kc->clock_adj(which_clock, &ktx);
+
+        if (err >= 0)
+                err = compat_put_timex(utp, &ktx);
+
+        return err;
+}
+#endif
+
 SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
                 struct timespec __user *, tp)
 {
diff --git a/kernel/time/time.c b/kernel/time/time.c
index 49c73c6ed648..400662f16c5a 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -39,6 +39,7 @@
 #include <linux/ptrace.h>
 
 #include <linux/uaccess.h>
+#include <linux/compat.h>
 #include <asm/unistd.h>
 
 #include <generated/timeconst.h>
@@ -224,12 +225,33 @@ SYSCALL_DEFINE1(adjtimex, struct timex __user *, txc_p)
          * structure. But bear in mind that the structures
          * may change
          */
-        if(copy_from_user(&txc, txc_p, sizeof(struct timex)))
+        if (copy_from_user(&txc, txc_p, sizeof(struct timex)))
                 return -EFAULT;
         ret = do_adjtimex(&txc);
         return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret;
 }
 
+#ifdef CONFIG_COMPAT
+
+COMPAT_SYSCALL_DEFINE1(adjtimex, struct compat_timex __user *, utp)
+{
+        struct timex txc;
+        int err, ret;
+
+        err = compat_get_timex(&txc, utp);
+        if (err)
+                return err;
+
+        ret = do_adjtimex(&txc);
+
+        err = compat_put_timex(utp, &txc);
+        if (err)
+                return err;
+
+        return ret;
+}
+#endif
+
 /*
  * Convert jiffies to milliseconds and back.
  *