[PATCH v2] net: phy: fix phy_get_internal_delay accessing an empty array

[PATCH v2] net: phy: fix phy_get_internal_delay accessing an empty array

[Kévin L'hôpital]

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>
---
V1 -> V2: Fixed Signed-off-by tags

 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 3611ea64875e..3ad9bbf65cbe 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -2959,7 +2959,7 @@ 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]) {
-- 
2.34.1

Re: [PATCH v2] net: phy: fix phy_get_internal_delay accessing an empty array

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Thu,  7 Mar 2024 12:19:06 +0100 you wrote:
> 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.
> 
> [...]

Here is the summary with links:
  - [v2] net: phy: fix phy_get_internal_delay accessing an empty array
    https://git.kernel.org/netdev/net/c/4469c0c5b14a

You are awesome, thank you!
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