Commit 1c5c12ee authored by Tao Ren's avatar Tao Ren Committed by David S. Miller
Browse files

net/ncsi: handle overflow when incrementing mac address 



Previously BMC's MAC address is calculated by simply adding 1 to the
last byte of network controller's MAC address, and it produces incorrect
result when network controller's MAC address ends with 0xFF.

The problem can be fixed by calling eth_addr_inc() function to increment
MAC address; besides, the MAC address is also validated before assigning
to BMC.

Fixes: cb10c7c0 ("net/ncsi: Add NCSI Broadcom OEM command")
Signed-off-by: default avatarTao Ren <taoren@fb.com>
Acked-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: default avatarSamuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ffbf9870

include/linux/etherdevice.h

+12 −0
Original line number Diff line number Diff line
@@ -448,6 +448,18 @@ static inline void eth_addr_dec(u8 *addr) 
	u64_to_ether_addr(u, addr);

}



/**

 * eth_addr_inc() - Increment the given MAC address.

 * @addr: Pointer to a six-byte array containing Ethernet address to increment.

 */

static inline void eth_addr_inc(u8 *addr)

{

	u64 u = ether_addr_to_u64(addr);



	u++;

	u64_to_ether_addr(u, addr);

}



/**

 * is_etherdev_addr - Tell if given Ethernet address belongs to the device.

 * @dev: Pointer to a device structure

net/ncsi/ncsi-rsp.c

+5 −1
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/netdevice.h>

#include <linux/etherdevice.h>

#include <linux/skbuff.h>



#include <net/ncsi.h>
@@ -667,7 +668,10 @@ static int ncsi_rsp_handler_oem_bcm_gma(struct ncsi_request *nr) 
	ndev->priv_flags |= IFF_LIVE_ADDR_CHANGE;

	memcpy(saddr.sa_data, &rsp->data[BCM_MAC_ADDR_OFFSET], ETH_ALEN);

	/* Increase mac address by 1 for BMC's address */

	saddr.sa_data[ETH_ALEN - 1]++;

	eth_addr_inc((u8 *)saddr.sa_data);

	if (!is_valid_ether_addr((const u8 *)saddr.sa_data))

		return -ENXIO;



	ret = ops->ndo_set_mac_address(ndev, &saddr);

	if (ret < 0)

		netdev_warn(ndev, "NCSI: 'Writing mac address to device failed\n");

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