From 895ac1376d5abcb94ca1b70a595579f253237790 Mon Sep 17 00:00:00 2001
From: Eugene Syromiatnikov <esyr@redhat.com>
Date: Mon, 7 Jan 2019 16:22:29 +0100
Subject: [PATCH] ptp: check that rsv field is zero in struct
ptp_sys_offset_extended
Otherwise it is impossible to use it for something else, as it will break
userspace that puts garbage there.
The same check should be done in other structures, but the fact that
data in reserved fields is ignored is already part of the kernel ABI.
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/ptp/ptp_chardev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 797fab33bb98..7cbea796652a 100644
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -224,7 +224,8 @@ long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
extoff = NULL;
break;
}
- if (extoff->n_samples > PTP_MAX_SAMPLES) {
+ if (extoff->n_samples > PTP_MAX_SAMPLES
+ || extoff->rsv[0] || extoff->rsv[1] || extoff->rsv[2]) {
err = -EINVAL;
break;
}