[Intel-wired-lan] [PATCH net v2] i40e: fix PTP pins verification

[Andrii Staikov]

Fix PTP pins verification not to contain tainted arguments. As a new PTP
pins configuration is provided by a user, it may contain tainted
arguments that are out of bounds for the list of possible values that can
lead to a potential security threat. Change pin's state name from 'invalid'
to 'empty' for more clarification.

Fixes: 1050713026a0 ("i40e: add support for PTP external synchronization clock")
Signed-off-by: Andrii Staikov <andrii.staikov at intel.com>
---
v2: Updating the commit message to fit the 75 characters limit.
---
 drivers/net/ethernet/intel/i40e/i40e_ptp.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_ptp.c b/drivers/net/ethernet/intel/i40e/i40e_ptp.c
index c37abbb3cd06..78e7c705cd89 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ptp.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ptp.c
@@ -49,7 +49,7 @@ static struct ptp_pin_desc sdp_desc[] = {
 
 enum i40e_ptp_gpio_pin_state {
 	end = -2,
-	invalid,
+	empty,
 	off,
 	in_A,
 	in_B,
@@ -1078,11 +1078,19 @@ static int i40e_ptp_set_pins(struct i40e_pf *pf,
 	else if (pin_caps == CAN_DO_PINS)
 		return 0;
 
-	if (pins->sdp3_2 == invalid)
+	if ((pins->sdp3_2 < empty || pins->sdp3_2 > out_B) ||
+	    (pins->sdp3_3 < empty || pins->sdp3_3 > out_B) ||
+	    (pins->gpio_4 < empty || pins->gpio_4 > out_B)) {
+		dev_warn(&pf->pdev->dev,
+			 "The provided PTP configuration set contains meaningless values that may potentially pose a safety threat.\n");
+		return -EPERM;
+	}
+
+	if (pins->sdp3_2 == empty)
 		pins->sdp3_2 = pf->ptp_pins->sdp3_2;
-	if (pins->sdp3_3 == invalid)
+	if (pins->sdp3_3 == empty)
 		pins->sdp3_3 = pf->ptp_pins->sdp3_3;
-	if (pins->gpio_4 == invalid)
+	if (pins->gpio_4 == empty)
 		pins->gpio_4 = pf->ptp_pins->gpio_4;
 	while (i40e_ptp_pin_led_allowed_states[i].sdp3_2 != end) {
 		if (pins->sdp3_2 == i40e_ptp_pin_led_allowed_states[i].sdp3_2 &&
-- 
2.25.1