[PATCH] arm: mvebu: Espressobin: Disallow forwarding packets between wan and lan ports

[Stefan Roese]

On 17.08.20 16:36, Pali Rohár wrote:
> By default Topaz switch on Espressobin board forwards packets between all
> ethernet ports, including CPU (port 0), wan (port 1) and lan (ports 2,3).
> 
> This default U-Boot setup is unsuitable for using Espressobin as router as
> it opens security hole in forwarding all packets between wan and lan ports.
> E.g. dhcp packets from wan network leaks to lan network during small time
> window until U-Boot boots Linux kernel which loads network drivers which
> disallows forwarding between wan and lan.
> 
> This patch fixes above problem. For Espressobin board prior putting Topaz
> switch into forwarding mode, Topaz switch is reconfigured to allow
> forwarding packets from wan and lan ports only to CPU port. This ensures
> that packets from wan port are not forwarded to lan ports and vice-versa.
> Packets from CPU port are still forwarded to all other ports, so U-Boot
> network boot works with any ethernet port as before.
> 
> This problem was already discussed on Espressobin forum [1] and on
> Marvell's github issue tracker [2]. As a workaround people on Espressobin
> forum patched U-Boot to completely disable lan ports on Topaz switch which
> prevented forwarding packets. That workaround had an issue that U-Boot was
> unable to netboot via lan ports anymore. Change in this patch does not have
> such issue.
> 
> [1] - https://web.archive.org/web/20191231164238/http://espressobin.net/forums/topic/boot-behavior-of-the-switch-and-security/
> [2] - https://github.com/MarvellEmbeddedProcessors/u-boot-marvell/issues/18
> 
> Signed-off-by: Pali Rohár <pali at kernel.org>

Reviewed-by: Stefan Roese <sr at denx.de>

Thanks,
Stefan

> ---
>   board/Marvell/mvebu_armada-37xx/board.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/board/Marvell/mvebu_armada-37xx/board.c b/board/Marvell/mvebu_armada-37xx/board.c
> index 9bea1986d4..031de318c6 100644
> --- a/board/Marvell/mvebu_armada-37xx/board.c
> +++ b/board/Marvell/mvebu_armada-37xx/board.c
> @@ -37,20 +37,21 @@ DECLARE_GLOBAL_DATA_PTR;
>    #define SW_SMI_CMD_REG_ADDR_OFF	0
>    #define SW_SMI_CMD_DEV_ADDR_OFF	5
>    #define SW_SMI_CMD_SMI_OP_OFF		10
>    #define SW_SMI_CMD_SMI_MODE_OFF	12
>    #define SW_SMI_CMD_SMI_BUSY_OFF	15
>   
>   /* Single-chip mode */
>   /* Switch Port Registers */
>   #define MVEBU_SW_LINK_CTRL_REG		(1)
>   #define MVEBU_SW_PORT_CTRL_REG		(4)
> +#define MVEBU_SW_PORT_BASE_VLAN		(6)
>   
>   /* Global 2 Registers */
>   #define MVEBU_G2_SMI_PHY_CMD_REG	(24)
>   #define MVEBU_G2_SMI_PHY_DATA_REG	(25)
>   
>   int board_early_init_f(void)
>   {
>   	return 0;
>   }
>   
> @@ -200,22 +201,30 @@ static int mii_multi_chip_mode_write(struct mii_dev *bus, int dev_smi_addr,
>   /* Bring-up board-specific network stuff */
>   int board_network_enable(struct mii_dev *bus)
>   {
>   	if (!of_machine_is_compatible("marvell,armada-3720-espressobin"))
>   		return 0;
>   
>   	/*
>   	 * FIXME: remove this code once Topaz driver gets available
>   	 * A3720 Community Board Only
>   	 * Configure Topaz switch (88E6341)
> +	 * Restrict output to ports 1,2,3 only from port 0 (CPU)
>   	 * Set port 0,1,2,3 to forwarding Mode (through Switch Port registers)
>   	 */
> +	mii_multi_chip_mode_write(bus, 1, MVEBU_PORT_CTRL_SMI_ADDR(1),
> +				  MVEBU_SW_PORT_BASE_VLAN, BIT(0));
> +	mii_multi_chip_mode_write(bus, 1, MVEBU_PORT_CTRL_SMI_ADDR(2),
> +				  MVEBU_SW_PORT_BASE_VLAN, BIT(0));
> +	mii_multi_chip_mode_write(bus, 1, MVEBU_PORT_CTRL_SMI_ADDR(3),
> +				  MVEBU_SW_PORT_BASE_VLAN, BIT(0));
> +
>   	mii_multi_chip_mode_write(bus, 1, MVEBU_PORT_CTRL_SMI_ADDR(0),
>   				  MVEBU_SW_PORT_CTRL_REG, 0x7f);
>   	mii_multi_chip_mode_write(bus, 1, MVEBU_PORT_CTRL_SMI_ADDR(1),
>   				  MVEBU_SW_PORT_CTRL_REG, 0x7f);
>   	mii_multi_chip_mode_write(bus, 1, MVEBU_PORT_CTRL_SMI_ADDR(2),
>   				  MVEBU_SW_PORT_CTRL_REG, 0x7f);
>   	mii_multi_chip_mode_write(bus, 1, MVEBU_PORT_CTRL_SMI_ADDR(3),
>   				  MVEBU_SW_PORT_CTRL_REG, 0x7f);
>   
>   	/* RGMII Delay on Port 0 (CPU port), force link to 1000Mbps */
> 


Viele Grüße,
Stefan

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