[PATCH AUTOSEL 4.14 07/11] net: usb: pegasus: Proper error handing when setting pegasus' MAC address

Sasha Levin
2020-10-12T19:05:14Z

From: Petko Manolov <petko.manolov@konsulko.com>

[ Upstream commit f30e25a9d1b25ac8d40071c4dc2679ad0fcdc55a ]

v2:

If reading the MAC address from eeprom fail don't throw an error, use randomly
generated MAC instead. Either way the adapter will soldier on and the return
type of set_ethernet_addr() can be reverted to void.

v1:

Fix a bug in set_ethernet_addr() which does not take into account possible
errors (or partial reads) returned by its helpers. This can potentially lead to
writing random data into device's MAC address registers.

Signed-off-by: Petko Manolov <petko.manolov@konsulko.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/usb/pegasus.c | 35 +++++++++++++++++++++++++++--------
1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/drivers/net/usb/pegasus.c b/drivers/net/usb/pegasus.c
index 5435c34dfcc76..a7db3f6fa6498 100644
--- a/drivers/net/usb/pegasus.c
+++ b/drivers/net/usb/pegasus.c
@@ -362,28 +362,47 @@ fail:
}
#endif /* PEGASUS_WRITE_EEPROM */

-static inline void get_node_id(pegasus_t *pegasus, __u8 *id)
+static inline int get_node_id(pegasus_t *pegasus, u8 *id)
{
- int i;
- __u16 w16;
+ int i, ret;
+ u16 w16;

for (i = 0; i < 3; i++) {
- read_eprom_word(pegasus, i, &w16);
+ ret = read_eprom_word(pegasus, i, &w16);
+ if (ret < 0)
+ return ret;
((__le16 *) id)[i] = cpu_to_le16(w16);
}
+
+ return 0;
}

static void set_ethernet_addr(pegasus_t *pegasus)
{
- __u8 node_id[6];
+ int ret;
+ u8 node_id[6];

if (pegasus->features & PEGASUS_II) {
- get_registers(pegasus, 0x10, sizeof(node_id), node_id);
+ ret = get_registers(pegasus, 0x10, sizeof(node_id), node_id);
+ if (ret < 0)
+ goto err;
} else {
- get_node_id(pegasus, node_id);
- set_registers(pegasus, EthID, sizeof(node_id), node_id);
+ ret = get_node_id(pegasus, node_id);
+ if (ret < 0)
+ goto err;
+ ret = set_registers(pegasus, EthID, sizeof(node_id), node_id);
+ if (ret < 0)
+ goto err;
}
+
memcpy(pegasus->net->dev_addr, node_id, sizeof(node_id));
+
+ return;
+err:
+ eth_hw_addr_random(pegasus->net);
+ dev_info(&pegasus->intf->dev, "software assigned MAC address.\n");
+
+ return;
}

static inline int reset_mac(pegasus_t *pegasus)
--
2.25.1