[PATCH 5.3 121/180] ppdev: fix PPGETTIME/PPSETTIME ioctls

Greg Kroah-Hartman
2019-12-16T18:13:44Z

From: Arnd Bergmann <arnd@arndb.de>

commit 998174042da229e2cf5841f574aba4a743e69650 upstream.

Going through the uses of timeval in the user space API,
I noticed two bugs in ppdev that were introduced in the y2038
conversion:

* The range check was accidentally moved from ppsettime to
ppgettime

* On sparc64, the microseconds are in the other half of the
64-bit word.

Fix both, and mark the fix for stable backports.

Cc: stable@vger.kernel.org
Fixes: 3b9ab374a1e6 ("ppdev: convert to y2038 safe")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20191108203435.112759-8-arnd@arndb.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/char/ppdev.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -619,20 +619,27 @@ static int pp_do_ioctl(struct file *file
if (copy_from_user(time32, argp, sizeof(time32)))
return -EFAULT;

+ if ((time32[0] < 0) || (time32[1] < 0))
+ return -EINVAL;
+
return pp_set_timeout(pp->pdev, time32[0], time32[1]);

case PPSETTIME64:
if (copy_from_user(time64, argp, sizeof(time64)))
return -EFAULT;

+ if ((time64[0] < 0) || (time64[1] < 0))
+ return -EINVAL;
+
+ if (IS_ENABLED(CONFIG_SPARC64) && !in_compat_syscall())
+ time64[1] >>= 32;
+
return pp_set_timeout(pp->pdev, time64[0], time64[1]);

case PPGETTIME32:
jiffies_to_timespec64(pp->pdev->timeout, &ts);
time32[0] = ts.tv_sec;
time32[1] = ts.tv_nsec / NSEC_PER_USEC;
- if ((time32[0] < 0) || (time32[1] < 0))
- return -EINVAL;

if (copy_to_user(argp, time32, sizeof(time32)))
return -EFAULT;
@@ -643,8 +650,9 @@ static int pp_do_ioctl(struct file *file
jiffies_to_timespec64(pp->pdev->timeout, &ts);
time64[0] = ts.tv_sec;
time64[1] = ts.tv_nsec / NSEC_PER_USEC;
- if ((time64[0] < 0) || (time64[1] < 0))
- return -EINVAL;
+
+ if (IS_ENABLED(CONFIG_SPARC64) && !in_compat_syscall())
+ time64[1] <<= 32;

if (copy_to_user(argp, time64, sizeof(time64)))
return -EFAULT;