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| author | Konrad Gräfe <k.graefe@gateware.de> | 2023-05-05 17:36:40 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-05-30 14:42:13 +0300 |
| commit | f7fd2e97f1a92c4d1b7b9adffe77c434efbc8033 (patch) | |
| tree | dce4f739207d2308e0f5f379f12074257de20ceb | |
| parent | 19935fc1ed222d781e9e768b1e34865c7624e824 (diff) | |
| download | linux-f7fd2e97f1a92c4d1b7b9adffe77c434efbc8033.tar.xz | |
usb: gadget: u_ether: Fix host MAC address case
[ Upstream commit 3c0f4f09c063e143822393d99cb2b19a85451c07 ]
The CDC-ECM specification [1] requires to send the host MAC address as
an uppercase hexadecimal string in chapter "5.4 Ethernet Networking
Functional Descriptor":
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.
[1]: https://www.usb.org/document-library/class-definitions-communication-devices-12, file ECM120.pdf
Fixes: bcd4a1c40bee ("usb: gadget: u_ether: construct with default values and add setters/getters")
Cc: stable@vger.kernel.org
Signed-off-by: Konrad Gräfe <k.graefe@gateware.de>
Link: https://lore.kernel.org/r/20230505143640.443014-1-k.graefe@gateware.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/usb/gadget/function/u_ether.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/usb/gadget/function/u_ether.c b/drivers/usb/gadget/function/u_ether.c index 561a090ced6d..7d9a551c47f9 100644 --- a/drivers/usb/gadget/function/u_ether.c +++ b/drivers/usb/gadget/function/u_ether.c @@ -17,6 +17,7 @@ #include <linux/etherdevice.h> #include <linux/ethtool.h> #include <linux/if_vlan.h> +#include <linux/string_helpers.h> #include <linux/usb/composite.h> #include "u_ether.h" @@ -940,6 +941,8 @@ 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); + string_upper(host_addr, host_addr); + return strlen(host_addr); } EXPORT_SYMBOL_GPL(gether_get_host_addr_cdc); |