Support resetting device on attach

Makefile

@@ -5,6 +5,8 @@ install-vm:
 	install qubes-rpc/qubes.USB $(DESTDIR)/etc/qubes-rpc
 	install -d $(DESTDIR)/usr/lib/qubes
 	install src/usb-* $(DESTDIR)/usr/lib/qubes
+	install -d $(DESTDIR)/usr/lib/udev/rules.d
+	install src/*.rules $(DESTDIR)/usr/lib/udev/rules.d
 	install -d $(DESTDIR)/etc/qubes/suspend-pre.d
 	ln -s ../../../usr/lib/qubes/usb-detach-all \
 		$(DESTDIR)/etc/qubes/suspend-pre.d/usb-detach-all.sh

rpm_spec/qubes-usb-proxy.spec.in

@@ -31,6 +31,8 @@ make install-vm DESTDIR=${RPM_BUILD_ROOT}
 /usr/lib/qubes/usb-import
 /usr/lib/qubes/usb-export
 /usr/lib/qubes/usb-detach-all
+/usr/lib/qubes/usb-reset
+/usr/lib/udev/rules.d/80-qubes-usb-reset.rules
 
 %changelog
 @CHANGELOG@

src/80-qubes-usb-reset.rules

@@ -0,0 +1,3 @@
+# Nitrokey 3 Bootloader, requires reset on attach
+# See https://github.com/QubesOS/qubes-issues/issues/8953
+SUBSYSTEM=="usb", ENV{ID_VENDOR_ID}=="20a0", ENV{ID_MODEL_ID}=="42dd", ENV{QUBES_USB_RESET}="1"

src/usb-export

@@ -93,14 +93,32 @@ modprobe usbip-host
 # Request that both IN and OUT be handled on a single (stdin) socket
 kill -USR1 "$QREXEC_AGENT_PID" || exit 1
 
+attach_to_usbip=true
 # Unbind the device from the driver
 if [ -d "$devpath/driver" ]; then
-    printf %s "$busid" > "$devpath/driver/unbind" || exit 1
+    old_driver=$(readlink -f "$devpath/driver")
+    if [ "$old_driver" != "$SYS_USBIP_HOST" ]; then
+        printf %s "$busid" > "$devpath/driver/unbind" || exit 1
+    else
+        attach_to_usbip=
+    fi
 fi
 
 # Bind to the usbip-host driver
 printf 'add %s' "$busid" > "$SYS_USBIP_HOST/match_busid" || exit 1
-echo "$busid" > "$SYS_USBIP_HOST/bind" || exit 1
+if [ -n "$attach_to_usbip" ]; then
+    echo "$busid" > "$SYS_USBIP_HOST/bind" || exit 1
+
+    # optionally reset the device to clear any state from previous driver
+    reset_on_attach=$(udevadm info --query=property \
+        --value --property=QUBES_USB_RESET --path="$devpath")
+    if [ -f /run/qubes-service/usb-reset-on-attach ]; then
+        reset_on_attach=1
+    fi
+    if [ -n "$reset_on_attach" ]; then
+        /usr/lib/qubes/usb-reset "$devpath"
+    fi
+fi
 
 # One more safety check - make sure the device is available
 read status < "$devpath/usbip_status"

src/usb-reset

@@ -0,0 +1,25 @@
+#!/usr/bin/python3
+
+import sys
+import os
+import fcntl
+from pathlib import Path
+
+# from /usr/include/linux/usbdevice_fs.h
+# _IO('U', 20)
+USBDEVFS_RESET = 0x5514
+
+def main():
+    if len(sys.argv) != 2:
+        print("Usage: usb-reset sysfs-devpath", file=sys.stderr())
+        exit(2)
+    devpath = sys.argv[1]
+    uevent = (Path(devpath) / "uevent").read_text()
+    devname = [line.partition("=")[2]
+               for line in uevent.splitlines()
+               if line.startswith("DEVNAME=")][0]
+    with (Path("/dev") / devname).open("w") as dev_f:
+        fcntl.ioctl(dev_f, USBDEVFS_RESET, 0)
+
+if __name__ == "__main__":
+    main()