[PATCH] sys_stime needs a compat function

I realized that the best way to get the sys_time/sys_stime problem fixed is
to make sys_time 64 bit safe by using "time_t *" instead of "int *" and to
introduce two proper compat functions compat_sys_time and compat_sys_stime.

The prototype change of sys_time is transparent for 32 bit architectures
because both "int" and "time_t" are 32 bit.  For 64 bit the type change
would be wrong but luckily no 64 bit architecture uses sys_time/sys_stime
in 64 bit mode.  The patch makes the following change:

ia64     : Remove sys32_time, use compat_sys_time and
           add (!!) compat_sys_stime to compat syscall table.
mips     : Use compat_sys_time/compat_sys_stime in 32 bit syscall table.
           Add #ifdef magic to compile sys_time/sys_stime and
           compat_sys_time/compat_sys_stime only if needed.
parisc   : Remove sys32_time, use compat_sys_time and compat_sys_stime.
ppc64    : remove sys32_time, ppc64_sys32_stime and ppc64_sys_stime.
           Use common compat_sys_time, compat_sys_stime and sys_stime.
s390     : Use compat_sys_stime. Add #ifdef magic to compile
           sys_time/sys_stime and compat_sys_time/compat_sys_stime only
           if needed.
sparc64  : Use compat_sys_time/compat_Sys_stime in 32 bit syscall table.
um       : Remove um_time and um_stime. Use common functions sys_time and
           sys_stime. This adds a CAP_SYS_TIME check to UMs stime call.
x86_64   : Remove sys32_time. Use compat_sys_time and compat_sys_stime
           in 32 bit syscall table.

The original stime bug is fixed for mips, parisc, s390, sparc64 and
x86_64. Can the arch-maintainers please take a look at this?

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

Convert compat_time_t to time_t in 32 bit emulation for sys_stime and
consolidate all the different implementation of sys_time, sys_stime and
their 32-bit emulation parts.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 42 insertions, 4 deletions

diff --git a/kernel/compat.c b/kernel/compat.c
index 672310635347a0..48fc40aec71210 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -20,6 +20,7 @@
 #include <linux/futex.h>	/* for FUTEX_WAIT */
 #include <linux/syscalls.h>
 #include <linux/unistd.h>
+#include <linux/security.h>
 
 #include <asm/uaccess.h>
 
@@ -680,3 +681,42 @@ long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
 
 	return 0;
 }
+
+#ifdef __ARCH_WANT_COMPAT_SYS_TIME
+
+/* compat_time_t is a 32 bit "long" and needs to get converted. */
+
+asmlinkage long compat_sys_time(compat_time_t __user * tloc)
+{
+	compat_time_t i;
+	struct timeval tv;
+
+	do_gettimeofday(&tv);
+	i = tv.tv_sec;
+
+	if (tloc) {
+		if (put_user(i,tloc))
+			i = -EFAULT;
+	}
+	return i;
+}
+
+asmlinkage long compat_sys_stime(compat_time_t __user *tptr)
+{
+	struct timespec tv;
+	int err;
+
+	if (get_user(tv.tv_sec, tptr))
+		return -EFAULT;
+
+	tv.tv_nsec = 0;
+
+	err = security_settime(&tv, NULL);
+	if (err)
+		return err;
+
+	do_settimeofday(&tv);
+	return 0;
+}
+
+#endif /* __ARCH_WANT_COMPAT_SYS_TIME */
diff --git a/kernel/time.c b/kernel/time.c
index b6d01cf709c49b..5ceab525f203f0 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -52,12 +52,10 @@ EXPORT_SYMBOL(sys_tz);
  * sys_gettimeofday().  Is this for backwards compatibility?  If so,
  * why not move it into the appropriate arch directory (for those
  * architectures that need it).
- *
- * XXX This function is NOT 64-bit clean!
  */
-asmlinkage long sys_time(int __user * tloc)
+asmlinkage long sys_time(time_t __user * tloc)
 {
-	int i;
+	time_t i;
 	struct timeval tv;
 
 	do_gettimeofday(&tv);