[PATCH AUTOSEL 4.20 036/304] ptp: check gettime64 return code in PTP_SYS_OFFSET ioctl

[Sasha Levin]

From: Miroslav Lichvar <mlich...@redhat.com>

[ Upstream commit 83d0bdc7390b890905634186baaa294475cd6a06 ]

If a gettime64 call fails, return the error and avoid copying data back
to user.

Cc: Richard Cochran <richardcoch...@gmail.com>
Cc: Jacob Keller <jacob.e.kel...@intel.com>
Signed-off-by: Miroslav Lichvar <mlich...@redhat.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/ptp/ptp_chardev.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 2012551d93e0..796eeffdf93b 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -228,7 +228,9 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, 
unsigned long arg)
                        pct->sec = ts.tv_sec;
                        pct->nsec = ts.tv_nsec;
                        pct++;
-                       ptp->info->gettime64(ptp->info, &ts);
+                       err = ptp->info->gettime64(ptp->info, &ts);
+                       if (err)
+                               goto out;
                        pct->sec = ts.tv_sec;
                        pct->nsec = ts.tv_nsec;
                        pct++;
@@ -281,6 +283,7 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, 
unsigned long arg)
                break;
        }
 
+out:
        kfree(sysoff);
        return err;
 }
-- 
2.19.1