Subject: [PATCH AUTOSEL 5.4 09/26] net: bmac: Fix read of MAC address from ROM

From: Sasha Levin <[email-masked]>
Date: Thu, 28 May 2020 07:56:37 -0400

From: Jeremy Kerr <[email-masked]>

[ Upstream commit ef01cee2ee1b369c57a936166483d40942bcc3e3 ]

In bmac_get_station_address, We're reading two bytes at a time from ROM,
but we do that six times, resulting in 12 bytes of read & writes. This
means we will write off the end of the six-byte destination buffer.

This change fixes the for-loop to only read/write six bytes.

Based on a proposed fix from Finn Thain <[email-masked]>.

Signed-off-by: Jeremy Kerr <[email-masked]>
Reported-by: Stan Johnson <[email-masked]>
Tested-by: Stan Johnson <[email-masked]>
Reported-by: Finn Thain <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 drivers/net/ethernet/apple/bmac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/apple/bmac.c b/drivers/net/ethernet/apple/bmac.c
index a58185b1d8bf..3e3711b60d01 100644
--- a/drivers/net/ethernet/apple/bmac.c
+++ b/drivers/net/ethernet/apple/bmac.c
@@ -1182,7 +1182,7 @@ bmac_get_station_address(struct net_device *dev, unsigned char *ea)
 	int i;
 	unsigned short data;
 
-	for (i = 0; i < 6; i++)
+	for (i = 0; i < 3; i++)
 		{
 			reset_and_select_srom(dev);
 			data = read_srom(dev, i + EnetAddressOffset/2, SROMAddressBits);
-- 
2.25.1