[PATCH] usb: gadget: u_ether: Fix host MAC address case

[PATCH] usb: gadget: u_ether: Fix host MAC address case

[Konrad Gräfe]

[-- Attachment #1.1.1: Type: text/plain, Size: 876 bytes --]


As the CDC-ECM specification states the host MAC address must be sent to
the host as an uppercase hexadecimal string:
     The Unicode character is chosen from the set of values 30h through
     39h and 41h through 46h (0-9 and A-F).

However, snprintf(.., "%pm", ..) generates a lowercase MAC address
string. While most host drivers are tolerant to this, UsbNcm.sys on
Windows 10 is not. Instead it uses a different MAC address with all
bytes set to zero including and after the first byte containing a
lowercase letter. On Windows 11 Microsoft fixed it, but apparently they
did not backport the fix.

This change fixes the issue by upper-casing the MAC to comply with the
specification.

Signed-off-by: Konrad Gräfe <k.graefe@gateware.de>
---
  drivers/usb/gadget/function/u_ether.c | 10 +++++++++-
  1 file changed, 9 insertions(+), 1 deletion(-)



[-- Attachment #1.1.2: 0001-usb-gadget-u_ether-Fix-host-MAC-address-case.patch --]
[-- Type: text/x-patch, Size: 812 bytes --]

diff --git drivers/usb/gadget/function/u_ether.c drivers/usb/gadget/function/u_ether.c
index 6956ad8ba8dd..49d29b04ef93 100644
--- drivers/usb/gadget/function/u_ether.c
+++ drivers/usb/gadget/function/u_ether.c
@@ -958,6 +958,7 @@ EXPORT_SYMBOL_GPL(gether_get_host_addr);
 int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
 {
 	struct eth_dev *dev;
+	int i, slen;
 
 	if (len < 13)
 		return -EINVAL;
@@ -965,7 +966,14 @@ int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
 	dev = netdev_priv(net);
 	snprintf(host_addr, len, "%pm", dev->host_mac);
 
-	return strlen(host_addr);
+
+	slen = strlen(host_addr);
+
+	for(i = 0; i < slen; i++) {
+		host_addr[i] = toupper(host_addr[i]);
+	}
+
+	return slen;
 }
 EXPORT_SYMBOL_GPL(gether_get_host_addr_cdc);
 


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 840 bytes --]

Re: [PATCH] usb: gadget: u_ether: Fix host MAC address case

[Greg KH]

On Tue, Apr 25, 2023 at 02:58:53PM +0200, Konrad Gräfe wrote:
> 
> As the CDC-ECM specification states the host MAC address must be sent to
> the host as an uppercase hexadecimal string:
>     The Unicode character is chosen from the set of values 30h through
>     39h and 41h through 46h (0-9 and A-F).
> 
> However, snprintf(.., "%pm", ..) generates a lowercase MAC address
> string. While most host drivers are tolerant to this, UsbNcm.sys on
> Windows 10 is not. Instead it uses a different MAC address with all
> bytes set to zero including and after the first byte containing a
> lowercase letter. On Windows 11 Microsoft fixed it, but apparently they
> did not backport the fix.
> 
> This change fixes the issue by upper-casing the MAC to comply with the
> specification.
> 
> Signed-off-by: Konrad Gräfe <k.graefe@gateware.de>
> ---
>  drivers/usb/gadget/function/u_ether.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> 

> diff --git drivers/usb/gadget/function/u_ether.c drivers/usb/gadget/function/u_ether.c
> index 6956ad8ba8dd..49d29b04ef93 100644
> --- drivers/usb/gadget/function/u_ether.c
> +++ drivers/usb/gadget/function/u_ether.c
> @@ -958,6 +958,7 @@ EXPORT_SYMBOL_GPL(gether_get_host_addr);
>  int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
>  {
>  	struct eth_dev *dev;
> +	int i, slen;
>  
>  	if (len < 13)
>  		return -EINVAL;
> @@ -965,7 +966,14 @@ int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
>  	dev = netdev_priv(net);
>  	snprintf(host_addr, len, "%pm", dev->host_mac);
>  
> -	return strlen(host_addr);
> +
> +	slen = strlen(host_addr);
> +
> +	for(i = 0; i < slen; i++) {
> +		host_addr[i] = toupper(host_addr[i]);
> +	}
> +
> +	return slen;
>  }
>  EXPORT_SYMBOL_GPL(gether_get_host_addr_cdc);
>  
> 



Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- Your patch contains warnings and/or errors noticed by the
  scripts/checkpatch.pl tool.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
from other developers.

thanks,

greg k-h's patch email bot

[PATCH] usb: gadget: u_ether: Fix host MAC address case

[Konrad Gräfe]

[-- Attachment #1: Type: text/plain, Size: 851 bytes --]


As the CDC-ECM specification states the host MAC address must be sent to
the host as an uppercase hexadecimal string:
     The Unicode character is chosen from the set of values 30h through
     39h and 41h through 46h (0-9 and A-F).

However, snprintf(.., "%pm", ..) generates a lowercase MAC address
string. While most host drivers are tolerant to this, UsbNcm.sys on
Windows 10 is not. Instead it uses a different MAC address with all
bytes set to zero including and after the first byte containing a
lowercase letter. On Windows 11 Microsoft fixed it, but apparently they
did not backport the fix.

This change fixes the issue by upper-casing the MAC to comply with the
specification.

Signed-off-by: Konrad Gräfe <k.graefe@gateware.de>
---
  drivers/usb/gadget/function/u_ether.c | 9 ++++++++-
  1 file changed, 8 insertions(+), 1 deletion(-)


[-- Attachment #2: 0001-usb-gadget-u_ether-Fix-host-MAC-address-case.patch --]
[-- Type: text/x-patch, Size: 815 bytes --]

diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c
index 6956ad8ba8dd..250734e090fc 100644
--- a/drivers/usb/gadget/function/u_ether.c
+++ b/drivers/usb/gadget/function/u_ether.c
@@ -958,6 +958,7 @@ EXPORT_SYMBOL_GPL(gether_get_host_addr);
 int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
 {
 	struct eth_dev *dev;
+	int i, slen;
 
 	if (len < 13)
 		return -EINVAL;
@@ -965,7 +966,13 @@ int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
 	dev = netdev_priv(net);
 	snprintf(host_addr, len, "%pm", dev->host_mac);
 
-	return strlen(host_addr);
+
+	slen = strlen(host_addr);
+
+	for (i = 0; i < slen; i++)
+		host_addr[i] = toupper(host_addr[i]);
+
+	return slen;
 }
 EXPORT_SYMBOL_GPL(gether_get_host_addr_cdc);
 

Re: [PATCH] usb: gadget: u_ether: Fix host MAC address case

[Greg KH]

On Tue, Apr 25, 2023 at 03:15:08PM +0200, Konrad Gräfe wrote:
> 
> As the CDC-ECM specification states the host MAC address must be sent to
> the host as an uppercase hexadecimal string:
>     The Unicode character is chosen from the set of values 30h through
>     39h and 41h through 46h (0-9 and A-F).
> 
> However, snprintf(.., "%pm", ..) generates a lowercase MAC address
> string. While most host drivers are tolerant to this, UsbNcm.sys on
> Windows 10 is not. Instead it uses a different MAC address with all
> bytes set to zero including and after the first byte containing a
> lowercase letter. On Windows 11 Microsoft fixed it, but apparently they
> did not backport the fix.
> 
> This change fixes the issue by upper-casing the MAC to comply with the
> specification.
> 
> Signed-off-by: Konrad Gräfe <k.graefe@gateware.de>
> ---
>  drivers/usb/gadget/function/u_ether.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 

> diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c
> index 6956ad8ba8dd..250734e090fc 100644
> --- a/drivers/usb/gadget/function/u_ether.c
> +++ b/drivers/usb/gadget/function/u_ether.c
> @@ -958,6 +958,7 @@ EXPORT_SYMBOL_GPL(gether_get_host_addr);
>  int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
>  {
>  	struct eth_dev *dev;
> +	int i, slen;
>  
>  	if (len < 13)
>  		return -EINVAL;
> @@ -965,7 +966,13 @@ int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
>  	dev = netdev_priv(net);
>  	snprintf(host_addr, len, "%pm", dev->host_mac);
>  
> -	return strlen(host_addr);
> +
> +	slen = strlen(host_addr);
> +
> +	for (i = 0; i < slen; i++)
> +		host_addr[i] = toupper(host_addr[i]);
> +
> +	return slen;
>  }
>  EXPORT_SYMBOL_GPL(gether_get_host_addr_cdc);
>  
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- This looks like a new version of a previously submitted patch, but you
  did not list below the --- line any changes from the previous version.
  Please read the section entitled "The canonical patch format" in the
  kernel file, Documentation/process/submitting-patches.rst for what
  needs to be done here to properly describe this.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
from other developers.

thanks,

greg k-h's patch email bot

[PATCH] usb: gadget: u_ether: Fix host MAC address case

[Konrad Gräfe]

[-- Attachment #1: Type: text/plain, Size: 891 bytes --]


As the CDC-ECM specification states the host MAC address must be sent to
the host as an uppercase hexadecimal string:
     The Unicode character is chosen from the set of values 30h through
     39h and 41h through 46h (0-9 and A-F).

However, snprintf(.., "%pm", ..) generates a lowercase MAC address
string. While most host drivers are tolerant to this, UsbNcm.sys on
Windows 10 is not. Instead it uses a different MAC address with all
bytes set to zero including and after the first byte containing a
lowercase letter. On Windows 11 Microsoft fixed it, but apparently they
did not backport the fix.

This change fixes the issue by upper-casing the MAC to comply with the
specification.

Signed-off-by: Konrad Gräfe <k.graefe@gateware.de>
---
V1 -> V2: Fixed checkpatch.pl warnings

  drivers/usb/gadget/function/u_ether.c | 9 ++++++++-
  1 file changed, 8 insertions(+), 1 deletion(-)


[-- Attachment #2: 0001-usb-gadget-u_ether-Fix-host-MAC-address-case.patch --]
[-- Type: text/x-patch, Size: 815 bytes --]

diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c
index 6956ad8ba8dd..250734e090fc 100644
--- a/drivers/usb/gadget/function/u_ether.c
+++ b/drivers/usb/gadget/function/u_ether.c
@@ -958,6 +958,7 @@ EXPORT_SYMBOL_GPL(gether_get_host_addr);
 int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
 {
 	struct eth_dev *dev;
+	int i, slen;
 
 	if (len < 13)
 		return -EINVAL;
@@ -965,7 +966,13 @@ int gether_get_host_addr_cdc(struct net_device *net, char *host_addr, int len)
 	dev = netdev_priv(net);
 	snprintf(host_addr, len, "%pm", dev->host_mac);
 
-	return strlen(host_addr);
+
+	slen = strlen(host_addr);
+
+	for (i = 0; i < slen; i++)
+		host_addr[i] = toupper(host_addr[i]);
+
+	return slen;
 }
 EXPORT_SYMBOL_GPL(gether_get_host_addr_cdc);
 

Re: [PATCH] usb: gadget: u_ether: Fix host MAC address case

[Quentin Schulz]

Hi Konrad,

On 4/26/23 12:17, Konrad Gräfe wrote:
> 
> As the CDC-ECM specification states the host MAC address must be sent to
> the host as an uppercase hexadecimal string:
>      The Unicode character is chosen from the set of values 30h through
>      39h and 41h through 46h (0-9 and A-F).
> 
> However, snprintf(.., "%pm", ..) generates a lowercase MAC address
> string. While most host drivers are tolerant to this, UsbNcm.sys on
> Windows 10 is not. Instead it uses a different MAC address with all
> bytes set to zero including and after the first byte containing a
> lowercase letter. On Windows 11 Microsoft fixed it, but apparently they
> did not backport the fix.
> 
> This change fixes the issue by upper-casing the MAC to comply with the
> specification.
> 
> Signed-off-by: Konrad Gräfe <k.graefe@gateware.de>
> ---
> V1 -> V2: Fixed checkpatch.pl warnings
> 

When sending a new version, please use the -v option of git format-patch 
to add the v2 prefix in the [PATCH] header, see 
https://lore.kernel.org/lkml/20230417065005.24967-1-yu.tu@amlogic.com/ 
(here a v7).

c.f. 
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#the-canonical-patch-format

Additionally, please use scripts/get_maintainer.pl on your patch to know 
who to put in the recipient list, here you're missing 
linux-kernel@vger.kernel.org which is always added. If I'm not mistaken, 
it's basically used for archival purposes but also so people don't have 
to subscribe or search through all mailing list to know what's going on 
globally in the kernel community.

>   drivers/usb/gadget/function/u_ether.c | 9 ++++++++-
>   1 file changed, 8 insertions(+), 1 deletion(-)
> 

The patch should be the mail body and not attached, git send-email 
should be able to get you through the hoops. I've seen 
https://git-send-email.io/ mentioned in various places so maybe that 
could help you get started.
See 
https://lore.kernel.org/lkml/20230417065005.24967-2-yu.tu@amlogic.com/ 
and yours: 
https://lore.kernel.org/all/f147dabd-5c39-31c2-0ff0-f72745d7cd3f@gateware.de/

In yours, you can see
"""
[-- Attachment #1.1.2: 
0001-usb-gadget-u_ether-Fix-host-MAC-address-case.patch --]
[-- Type: text/x-patch, Size: 812 bytes --]
"""
this is not good.

The point of the mailing list patch submission process is to allow 
in-line review, people will typically comment in-line directly, see 
https://lore.kernel.org/lkml/20230426111358.xh3gbhlvxj46ggi5@CAB-WSD-L081021/ 
for example. Adding the patch as an attachment doesn't allow this review 
process to happen. There also are a few robots applying patches directly 
from the various mailing lists and running some build tests 
automatically, I am not sure they are developed with patch as an 
attachment in mind.

c.f. 
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#no-mime-no-links-no-compression-no-attachments-just-plain-text

For the "i'm not so sure" part of my mail now.
I don't know if this matches stable backport policy but I believe it 
could/should. So maybe add:
"""
Cc: stable@vger.kernel.org
"""
before your Signed-off-by, c.f. 
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html

I think you should add:
"""
Fixes: bcd4a1c40bee ("usb: gadget: u_ether: construct with default 
values and add setters/getters")
"""
since (I believe) this is fixing an issue introduced in that commit.
c.f. 
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#using-reported-by-tested-by-reviewed-by-suggested-by-and-fixes 
and 
https://www.kernel.org/doc/html/latest/process/submitting-patches.html#describe-your-changes

Cheers,
Quentin

Re: [PATCH] usb: gadget: u_ether: Fix host MAC address case

[Greg KH]

On Wed, Apr 26, 2023 at 12:17:53PM +0200, Konrad Gräfe wrote:
> 
> As the CDC-ECM specification states the host MAC address must be sent to
> the host as an uppercase hexadecimal string:
>     The Unicode character is chosen from the set of values 30h through
>     39h and 41h through 46h (0-9 and A-F).
> 
> However, snprintf(.., "%pm", ..) generates a lowercase MAC address
> string. While most host drivers are tolerant to this, UsbNcm.sys on
> Windows 10 is not. Instead it uses a different MAC address with all
> bytes set to zero including and after the first byte containing a
> lowercase letter. On Windows 11 Microsoft fixed it, but apparently they
> did not backport the fix.
> 
> This change fixes the issue by upper-casing the MAC to comply with the
> specification.
> 
> Signed-off-by: Konrad Gräfe <k.graefe@gateware.de>
> ---
> V1 -> V2: Fixed checkpatch.pl warnings

There is no "v2" in the subject line, so our tools will get confused and
have no idea this is a newer patch.

Please fix up and send a v3?

>  	snprintf(host_addr, len, "%pm", dev->host_mac);

Is there no option to print a mac address with all uppercase?  If not,
why not add that instead as it's needed here and maybe other places,
right?

thanks,

greg k-h