net: phy: fix phy_get_internal_delay accessing an empty array

[ Upstream commit 4469c0c5b14a0919f5965c7ceac96b523eb57b79 ]

The phy_get_internal_delay function could try to access to an empty
array in the case that the driver is calling phy_get_internal_delay
without defining delay_values and rx-internal-delay-ps or
tx-internal-delay-ps is defined to 0 in the device-tree.
This will lead to "unable to handle kernel NULL pointer dereference at
virtual address 0". To avoid this kernel oops, the test should be delay
>= 0. As there is already delay < 0 test just before, the test could
only be size == 0.

Fixes: 92252eec913b ("net: phy: Add a helper to return the index for of the internal delay")
Co-developed-by: Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@savoirfairelinux.com>
Signed-off-by: Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@savoirfairelinux.com>
Signed-off-by: Kévin L'hôpital <kevin.lhopital@savoirfairelinux.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 095d16ceafcf83a877173faa3d8f89948f300592..8654e05ddc4153df2448a277a23d7ba06c7ae04b 100644 (file)
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -2769,7 +2769,7 @@ s32 phy_get_internal_delay(struct phy_device *phydev, struct device *dev,
        if (delay < 0)
                return delay;
 
-       if (delay && size == 0)
+       if (size == 0)
                return delay;
 
        if (delay < delay_values[0] || delay > delay_values[size - 1]) {