module verification failed: signature and/or required key missing - tainting kernel

[MesterJoda]

Hi @robertklep First of all, big thank you for your work. I'm loading the pl2303, loaded usbserial.ko first, but I'm getting this error in dmesg:

[  667.466419] usbcore: registered new interface driver usbserial
[  671.396572] pl2303: module verification failed: signature and/or required key missing - tainting kernel
[  671.407355] usbcore: registered new interface driver pl2303
[  671.413650] usbserial: USB Serial support registered for pl2303
[ 2154.836454] pl2303: version magic '4.4.180+ SMP mod_unload ' should be '4.4.302+ SMP mod_unload '

Running DS224+ (Linux NAS 4.4.302+ #69057 SMP Mon Nov 13 14:19:30 CST 2023 x86_64 GNU/Linux synology_geminilake_224+ )

I've tried to build the kernel sources myself, but I don't know where to clone your repo relative to the /toolkit folder. I've tried to copy sources/4.4.x directory to /toolkit/source/4.4.x but build fails with this error:

============================================================
                Start to run "Build Package"
------------------------------------------------------------
[geminilake] env PackageName=4.4.x /pkgscripts-ng/SynoBuild --geminilake -c --min-sdk 7.2 --parallel 4 4.4.x
Set cache size limit to 8.0 GB
Statistics zeroed
[INFO] projectList=4.4.x
[INFO] Start to build 4.4.x.
[SCRIPT] build script: //source/4.4.x/SynoBuildConf/build
[INFO] ======= Run build script =======
rm -rf *.o ch341.ko cp210x.ko rndis_host.ko pl2303.ko ti_usb_3410_5052.ko *.cmd
make -C /usr/local/x86_64-pc-linux-gnu/x86_64-pc-linux-gnu/sys-root/usr/lib/modules/DSM-7.2/build M=//source/4.4.x modules
make -C /usr/local/x86_64-pc-linux-gnu/x86_64-pc-linux-gnu/sys-root/usr/lib/modules/DSM-7.2/build M=//source/4.4.x modules
make -C /usr/local/x86_64-pc-linux-gnu/x86_64-pc-linux-gnu/sys-root/usr/lib/modules/DSM-7.2/build M=//source/4.4.x modules
make[1]: warning: jobserver unavailable: using -j1.  Add '+' to parent make rule.
make -C /usr/local/x86_64-pc-linux-gnu/x86_64-pc-linux-gnu/sys-root/usr/lib/modules/DSM-7.2/build M=//source/4.4.x modules
make[1]: Entering directory '/usr/local/x86_64-pc-linux-gnu/x86_64-pc-linux-gnu/sys-root/usr/lib/modules/DSM-7.2/build'
make[1]: warning: jobserver unavailable: using -j1.  Add '+' to parent make rule.
make[1]: Entering directory '/usr/local/x86_64-pc-linux-gnu/x86_64-pc-linux-gnu/sys-root/usr/lib/modules/DSM-7.2/build'
make[1]: warning: jobserver unavailable: using -j1.  Add '+' to parent make rule.
make[1]: Entering directory '/usr/local/x86_64-pc-linux-gnu/x86_64-pc-linux-gnu/sys-root/usr/lib/modules/DSM-7.2/build'
make[1]: warning: jobserver unavailable: using -j1.  Add '+' to parent make rule.
make[1]: Entering directory '/usr/local/x86_64-pc-linux-gnu/x86_64-pc-linux-gnu/sys-root/usr/lib/modules/DSM-7.2/build'
  CC [M]  //source/4.4.x/ch341.o
  CC [M]  //source/4.4.x/ch341.o
  CC [M]  //source/4.4.x/ch341.o
  CC [M]  //source/4.4.x/ch341.o
fixdep: error opening depfile: //source/4.4.x/.ch341.o.d: No such file or directory
scripts/Makefile.build:286: recipe for target '//source/4.4.x/ch341.o' failed
make[2]: *** [//source/4.4.x/ch341.o] Error 2
make[2]: *** Deleting file '//source/4.4.x/ch341.o'
Makefile:1467: recipe for target '_module_//source/4.4.x' failed
make[1]: *** [_module_//source/4.4.x] Error 2
make[1]: Leaving directory '/usr/local/x86_64-pc-linux-gnu/x86_64-pc-linux-gnu/sys-root/usr/lib/modules/DSM-7.2/build'
Makefile:8: recipe for target 'pl2303.ko' failed
make: *** [pl2303.ko] Error 2

I'm willing to try to build the module myself, but I need a bit of guidance then.

[MesterJoda]

Additional information. After trying a lot of different thing, I've managed to build the module by deleting all except pl2303 from Makefile, which looks like this:

kernel_mod = pl2303.ko

all: $(kernel_mod)

obj-m := pl2303.o

$(kernel_mod):
        make -C $(KSRC) M=$(PWD) modules

install: $(kernel_mod)
        mkdir -p $(DESTDIR)/4.4.x/ 2>/dev/null
        install $< $(DESTDIR)/4.4.x/

clean:
        rm -rf *.o $(kernel_mod) *.cmd
Makefile (END)

Funny thing is, the built pl2303.ko and one downloaded from here, the Github, are identical. What now?

[robertklep]

The "tainted kernel" message is a warning, not an error, the module should be loaded regardless.

This is on my DS918+:

# dmesg
[Mon Dec 11 15:05:54 2023] pl2303: module verification failed: signature and/or required key missing - tainting kernel
[Mon Dec 11 15:05:54 2023] usbcore: registered new interface driver pl2303
[Mon Dec 11 15:05:54 2023] usbserial: USB Serial support registered for pl2303

# lsmod | grep pl2303
pl2303                  9086  0
usbserial              22534  2 pl2303,ftdi_sio
usbcore               210297  13 etxhci_hcd,usblp,uhci_hcd,usb_storage,usbserial,ehci_hcd,ehci_pci,pl2303,usbhid,ftdi_sio,cdc_acm,xhci_hcd,xhci_pci

[MesterJoda]

Hi @robertklep Than you for the fast response. Here is my output:

lsmod | grep pl2303
pl2303                  9022  0
usbserial              22278  1 pl2303
usbcore               209065  12 uas,etxhci_hcd,usblp,uhci_hcd,usb_storage,usbserial,ehci_hcd,ehci_pci,pl2303,usbhid,xhci_hcd,xhci_pci

Is this then correct behaviour? Ifthat is the case, I'll gladly close the issue :)

[robertklep]

Looks like it loaded just fine 😅

[MesterJoda]

How could I check the tty? I'm seeing only

cat /proc/tty/driver/usbserial
usbserinfo:1.0 driver:2.0

Shouldn't I see similar to the following output:

usbserinfo:1.0 driver:2.0
0: module:ch341 name:"ch341-uart" vendor:1a86 product:7523 num_ports:1 port:0 path:usb-0000:00:1d.0-1.2

[robertklep]

No idea to be honest. Do you have a device connected with a PL2303 chip? What does lsusb -cui show?

[MesterJoda]

Yes, It's a APC Smart UPS, SU700I NET, trying to get Synology to talk to it, since it's not an USB UPS, but rather older model, serial only. I'm using USB to Serial with PL2303TA chip and made a male-female DE9 for APC custom pinout, based on this link lsusb -cui

|__usb1          1d6b:0002:0404 09  2.00  480MBit/s 0mA 1IF  (Linux 4.4.302+ xhci-hcd xHCI Host Controller 0000:00:15.0) hub
  |__1-2         1a86:55d3:0445 02  1.10   12MBit/s 138mA 2IFs ( 5677003661)
  1-2:1.0         (IF) 02:02:01 1EP  ()
  1-2:1.1         (IF) 0a:00:00 2EPs ()
  |__1-4         f400:f400:0100 00  2.00  480MBit/s 200mA 1IF  (Synology DiskStation 6500350AB181C639)
  1-4:1.0         (IF) 08:06:50 2EPs () usb-storage host2 (synoboot)

[robertklep]

Do you think the 1-2 device is your USB-to-serial device? It doesn't show a name, only a serial number(?). Does it disappear when you unplug the device?

[MesterJoda]

Yes, it disappeared. lsusb -cui

|__usb1          1d6b:0002:0404 09  2.00  480MBit/s 0mA 1IF  (Linux 4.4.302+ xhci-hcd xHCI Host Controller 0000:00:15.0) hub
  |__1-4         f400:f400:0100 00  2.00  480MBit/s 200mA 1IF  (Synology DiskStation 6500350AB181C639)
  1-4:1.0         (IF) 08:06:50 2EPs () usb-storage host2 (synoboot)

This is the device Cable Expert UAS-DB9M-02 USB to DB9M serial port converter

[robertklep]

Very strange, since its USB device id (1a86:55d3) suggests it might be using a CH341 chip (or at least in the CH family).

You can try and see if the ch341.ko driver supports it, but I doubt it since I cannot find that specific device id in any of the drivers. It might simply be too new, and Synology's kernel sources too old 😬

[MesterJoda]

Now that yu have mentioned it, I've loaded all of the modules, not just usbserial and pl2303 and I have a different output: lsusb -cui

|__usb1          1d6b:0002:0404 09  2.00  480MBit/s 0mA 1IF  (Linux 4.4.302+ xhci-hcd xHCI Host Controller 0000:00:15.0) hub
  |__1-2         1a86:55d3:0445 02  1.10   12MBit/s 138mA 2IFs ( 5677003661)
  1-2:1.0         (IF) 02:02:01 1EP  () cdc_acm tty/ttyACM0
  1-2:1.1         (IF) 0a:00:00 2EPs () cdc_acm
  |__1-4         f400:f400:0100 00  2.00  480MBit/s 200mA 1IF  (Synology DiskStation 6500350AB181C639)
  1-4:1.0         (IF) 08:06:50 2EPs () usb-storage host2 (synoboot)

[robertklep]

It's there as /dev/ttyACM0 now 😊

It didn't even need any of the drivers of this repository, since cdc_acm that still comes with DSM seems to support it.

[MesterJoda]

Thank you for your help. You are kind. Much obliged, Jovan