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: cb10c7c0dfd9 ("net/ncsi: Add NCSI Broadcom OEM command")
Signed-off-by: Tao Ren <taoren@fb.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 0 deletions

diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index e2f3b21cd72a..aa8bfd6f738c 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -449,6 +449,18 @@ static inline void eth_addr_dec(u8 *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
  * @addr: Pointer to a six-byte array containing the Ethernet address