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* [PATCH] net: usb: pegasus: Proper error handing when setting pegasus' MAC address
@ 2020-09-29 11:40 Petko Manolov
  2020-10-02  1:42 ` David Miller
  0 siblings, 1 reply; 4+ messages in thread
From: Petko Manolov @ 2020-09-29 11:40 UTC (permalink / raw)
  To: netdev; +Cc: davem, Petko Manolov

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>
---
 drivers/net/usb/pegasus.c | 35 ++++++++++++++++++++++++++---------
 1 file changed, 26 insertions(+), 9 deletions(-)

diff --git a/drivers/net/usb/pegasus.c b/drivers/net/usb/pegasus.c
index e92cb51a2c77..25855f976c1b 100644
--- a/drivers/net/usb/pegasus.c
+++ b/drivers/net/usb/pegasus.c
@@ -360,28 +360,45 @@ static int write_eprom_word(pegasus_t *pegasus, __u8 index, __u16 data)
 }
 #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)
+static int 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 0;
+err:
+	dev_err(&pegasus->intf->dev, "device's MAC address not set.\n");
+	return ret;
 }
 
 static inline int reset_mac(pegasus_t *pegasus)
-- 
2.28.0


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: [PATCH] net: usb: pegasus: Proper error handing when setting pegasus' MAC address
  2020-09-29 11:40 [PATCH] net: usb: pegasus: Proper error handing when setting pegasus' MAC address Petko Manolov
@ 2020-10-02  1:42 ` David Miller
  2020-10-02  7:56   ` [PATCH v2] " Petko Manolov
  2020-10-02  7:57   ` [PATCH] " Petko Manolov
  0 siblings, 2 replies; 4+ messages in thread
From: David Miller @ 2020-10-02  1:42 UTC (permalink / raw)
  To: petko.manolov; +Cc: netdev

From: Petko Manolov <petko.manolov@konsulko.com>
Date: Tue, 29 Sep 2020 14:40:39 +0300

> -static void set_ethernet_addr(pegasus_t *pegasus)
> +static int set_ethernet_addr(pegasus_t *pegasus)
>  {

You change this to return an 'int' but no callers were updated to check it.

Furthermore, failure to probe a MAC address can be resolved by
choosing a random MAC address.  This handling is preferrable because
it allows the interface to still come up successfully.

^ permalink raw reply	[flat|nested] 4+ messages in thread
* [PATCH v2] net: usb: pegasus: Proper error handing when setting pegasus' MAC address
  2020-10-02  1:42 ` David Miller
@ 2020-10-02  7:56   ` Petko Manolov
  2020-10-02  7:57   ` [PATCH] " Petko Manolov
  1 sibling, 0 replies; 4+ messages in thread
From: Petko Manolov @ 2020-10-02  7:56 UTC (permalink / raw)
  To: netdev; +Cc: davem, Petko Manolov

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>
---
 drivers/net/usb/pegasus.c | 34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/drivers/net/usb/pegasus.c b/drivers/net/usb/pegasus.c
index e92cb51a2c77..39b78d8fcc79 100644
--- a/drivers/net/usb/pegasus.c
+++ b/drivers/net/usb/pegasus.c
@@ -360,28 +360,47 @@ static int write_eprom_word(pegasus_t *pegasus, __u8 index, __u16 data)
 }
 #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)
-- 
2.28.0


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: [PATCH] net: usb: pegasus: Proper error handing when setting pegasus' MAC address
  2020-10-02  1:42 ` David Miller
  2020-10-02  7:56   ` [PATCH v2] " Petko Manolov
@ 2020-10-02  7:57   ` Petko Manolov
  1 sibling, 0 replies; 4+ messages in thread
From: Petko Manolov @ 2020-10-02  7:57 UTC (permalink / raw)
  To: David Miller; +Cc: netdev

On 20-10-01 18:42:18, David Miller wrote:
> From: Petko Manolov <petko.manolov@konsulko.com>
> Date: Tue, 29 Sep 2020 14:40:39 +0300
> 
> > -static void set_ethernet_addr(pegasus_t *pegasus)
> > +static int set_ethernet_addr(pegasus_t *pegasus)
> >  {
> 
> You change this to return an 'int' but no callers were updated to check it.
> 
> Furthermore, failure to probe a MAC address can be resolved by choosing a 
> random MAC address.  This handling is preferrable because it allows the 
> interface to still come up successfully.

Thanks for looking into this.  V2 already sent.

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-10-02  7:57 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-29 11:40 [PATCH] net: usb: pegasus: Proper error handing when setting pegasus' MAC address Petko Manolov
2020-10-02  1:42 ` David Miller
2020-10-02  7:56   ` [PATCH v2] " Petko Manolov
2020-10-02  7:57   ` [PATCH] " Petko Manolov

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