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From:   Arnd Bergmann <arnd@arndb.de>
To:     y2038@lists.linaro.org,
        Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
        stable@vger.kernel.org,
        Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH 7/8] ppdev: fix PPGETTIME/PPSETTIME ioctls
Date:   Fri,  8 Nov 2019 21:34:30 +0100
Message-Id: <20191108203435.112759-8-arnd@arndb.de>
In-Reply-To: <20191108203435.112759-1-arnd@arndb.de>
References: <20191108203435.112759-1-arnd@arndb.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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

diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c
index c86f18aa8985..34bb88fe0b0a 100644
--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -619,20 +619,27 @@ static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		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, unsigned int cmd, unsigned long arg)
 		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;
-- 
2.20.0