itimers: Move compat itimer syscalls to native ones

get rid of set_fs(), sanitize compat copyin/copyout.

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/20170607084241.28657-12-viro@ZenIV.linux.org.uk

diff --git a/include/linux/compat.h b/include/linux/compat.h
index ecb8dd261d3674aef841099fe2e06080a5427641..425563c7647b3d2fb08764c0f3e6e3e8e5bd2368 100644 (file)
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -94,6 +94,10 @@ struct compat_itimerval {
        struct compat_timeval   it_value;
 };
 
+struct itimerval;
+int get_compat_itimerval(struct itimerval *, const struct compat_itimerval __user *);
+int put_compat_itimerval(struct compat_itimerval __user *, const struct itimerval *);
+
 struct compat_tms {
        compat_clock_t          tms_utime;
        compat_clock_t          tms_stime;

diff --git a/kernel/compat.c b/kernel/compat.c
index 1fb8cf7e691ebb3cd06b113ffb068a861b00ecb0..c349417d2c40e07850cc45d4d8148818b11ec2d8 100644 (file)
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -217,65 +217,28 @@ int compat_convert_timespec(struct timespec __user **kts,
        return 0;
 }
 
-static inline long get_compat_itimerval(struct itimerval *o,
-               struct compat_itimerval __user *i)
+int get_compat_itimerval(struct itimerval *o, const struct compat_itimerval __user *i)
 {
-       return (!access_ok(VERIFY_READ, i, sizeof(*i)) ||
-               (__get_user(o->it_interval.tv_sec, &i->it_interval.tv_sec) |
-                __get_user(o->it_interval.tv_usec, &i->it_interval.tv_usec) |
-                __get_user(o->it_value.tv_sec, &i->it_value.tv_sec) |
-                __get_user(o->it_value.tv_usec, &i->it_value.tv_usec)));
-}
-
-static inline long put_compat_itimerval(struct compat_itimerval __user *o,
-               struct itimerval *i)
-{
-       return (!access_ok(VERIFY_WRITE, o, sizeof(*o)) ||
-               (__put_user(i->it_interval.tv_sec, &o->it_interval.tv_sec) |
-                __put_user(i->it_interval.tv_usec, &o->it_interval.tv_usec) |
-                __put_user(i->it_value.tv_sec, &o->it_value.tv_sec) |
-                __put_user(i->it_value.tv_usec, &o->it_value.tv_usec)));
-}
-
-asmlinkage long sys_ni_posix_timers(void);
-
-COMPAT_SYSCALL_DEFINE2(getitimer, int, which,
-               struct compat_itimerval __user *, it)
-{
-       struct itimerval kit;
-       int error;
-
-       if (!IS_ENABLED(CONFIG_POSIX_TIMERS))
-               return sys_ni_posix_timers();
+       struct compat_itimerval v32;
 
-       error = do_getitimer(which, &kit);
-       if (!error && put_compat_itimerval(it, &kit))
-               error = -EFAULT;
-       return error;
+       if (copy_from_user(&v32, i, sizeof(struct compat_itimerval)))
+               return -EFAULT;
+       o->it_interval.tv_sec = v32.it_interval.tv_sec;
+       o->it_interval.tv_usec = v32.it_interval.tv_usec;
+       o->it_value.tv_sec = v32.it_value.tv_sec;
+       o->it_value.tv_usec = v32.it_value.tv_usec;
+       return 0;
 }
 
-COMPAT_SYSCALL_DEFINE3(setitimer, int, which,
-               struct compat_itimerval __user *, in,
-               struct compat_itimerval __user *, out)
+int put_compat_itimerval(struct compat_itimerval __user *o, const struct itimerval *i)
 {
-       struct itimerval kin, kout;
-       int error;
+       struct compat_itimerval v32;
 
-       if (!IS_ENABLED(CONFIG_POSIX_TIMERS))
-               return sys_ni_posix_timers();
-
-       if (in) {
-               if (get_compat_itimerval(&kin, in))
-                       return -EFAULT;
-       } else
-               memset(&kin, 0, sizeof(kin));
-
-       error = do_setitimer(which, &kin, out ? &kout : NULL);
-       if (error || !out)
-               return error;
-       if (put_compat_itimerval(out, &kout))
-               return -EFAULT;
-       return 0;
+       v32.it_interval.tv_sec = i->it_interval.tv_sec;
+       v32.it_interval.tv_usec = i->it_interval.tv_usec;
+       v32.it_value.tv_sec = i->it_value.tv_sec;
+       v32.it_value.tv_usec = i->it_value.tv_usec;
+       return copy_to_user(o, &v32, sizeof(struct compat_itimerval)) ? -EFAULT : 0;
 }
 
 static compat_clock_t clock_t_to_compat_clock_t(clock_t x)

diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c
index 087d6a1279b833124d6359017687c4fff0cd88ca..9dd7ff5e445a6c5e4b2522fb50b8126caa6b3cff 100644 (file)
--- a/kernel/time/itimer.c
+++ b/kernel/time/itimer.c
@@ -15,6 +15,7 @@
 #include <linux/posix-timers.h>
 #include <linux/hrtimer.h>
 #include <trace/events/timer.h>
+#include <linux/compat.h>
 
 #include <linux/uaccess.h>
 
@@ -116,6 +117,19 @@ SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value)
        return error;
 }
 
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE2(getitimer, int, which,
+                      struct compat_itimerval __user *, it)
+{
+       struct itimerval kit;
+       int error = do_getitimer(which, &kit);
+
+       if (!error && put_compat_itimerval(it, &kit))
+               error = -EFAULT;
+       return error;
+}
+#endif
+
 
 /*
  * The timer is automagically restarted, when interval != 0
@@ -294,3 +308,27 @@ SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
                return -EFAULT;
        return 0;
 }
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE3(setitimer, int, which,
+                      struct compat_itimerval __user *, in,
+                      struct compat_itimerval __user *, out)
+{
+       struct itimerval kin, kout;
+       int error;
+
+       if (in) {
+               if (get_compat_itimerval(&kin, in))
+                       return -EFAULT;
+       } else {
+               memset(&kin, 0, sizeof(kin));
+       }
+
+       error = do_setitimer(which, &kin, out ? &kout : NULL);
+       if (error || !out)
+               return error;
+       if (put_compat_itimerval(out, &kout))
+               return -EFAULT;
+       return 0;
+}
+#endif

diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index f4a1962d1729072a59e2a52f7a6da4d8df04cabd..7f88517461e828ad9697d43abc99fcfe22d776f3 100644 (file)
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -44,6 +44,8 @@ SYS_NI(alarm);
 COMPAT_SYS_NI(clock_adjtime);
 COMPAT_SYS_NI(timer_settime);
 COMPAT_SYS_NI(timer_gettime);
+COMPAT_SYS_NI(getitimer);
+COMPAT_SYS_NI(setitimer);
 
 /*
  * We preserve minimal support for CLOCK_REALTIME and CLOCK_MONOTONIC