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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Cc: =?UTF-8?q?K=C3=A9vin=20L=27h=C3=B4pital?= <kevin.lhopital@savoirfairelinux.com>,
	Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@savoirfairelinux.com>,
	Russell King <rmk+kernel@armlinux.org.uk>,
	"David S . Miller" <davem@davemloft.net>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 095/238] net: phy: fix phy_get_internal_delay accessing an empty array
Date: Sun, 24 Mar 2024 19:38:03 -0400
Message-ID: <20240324234027.1354210-96-sashal@kernel.org>
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From: Kévin L'hôpital <kevin.lhopital@savoirfairelinux.com>

[ 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>
---
 drivers/net/phy/phy_device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 095d16ceafcf8..8654e05ddc415 100644
--- 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]) {
-- 
2.43.0