How to mask the serial number exposed in /proc/cpuinfo

[Dantes]

I have serious issues with the serial number being exposed in /proc/cpuinfo.

Especially when browsers have access to this information.

 

Afaik, its u-boot who passed this information on to Linux.

Any idea how to mask this from Linux?

 

Your help is appreciated

[Dantes]

Well I tried the following, but it did "not" work unfortunately

 

apt install device-tree-compiler

 

then converted the nanopi-r6c device tree from dtb to dts

 

dtc -I dtb -O dts -o rk3588s-nanopi-r6c.dtb rk3588s-nanopi-r6c.dts

 

Inserted a  serial-number
 

/dts-v1/;

/ {
    compatible = "friendlyelec,nanopi-r6c\0rockchip,rk3588";
    interrupt-parent = <0x01>;
    #address-cells = <0x02>;
    #size-cells = <0x02>;
    model = "FriendlyElec NanoPi R6C";
    serial-number = "0000000000000000"

 

then converted the nanopi-r6c device tree from dts to dtb

 

dtc -I dts -O dtb -o rk3588s-nanopi-r6c.dts rk3588s-nanopi-r6c.dtb

 

renamed the original .bak and copied the new file into /boot/dtb:
 

sudo mv /boot/dtb/rockchip/rk3588s-nanopi-r6c.dtb /boot/dtb/rockchip/rk3588s-nanopi-r6c.dtb.bak
sudo cp rk3588s-nanopi-r6c.dtb /boot/dtb/rockchip/rk3588s-nanopi-r6c.dtb

 

/proc/cpuinfo and /sys/firmware/devicetree/base/serial-number still show the original serial. Maybe someone smarter can pick this up

 

 

 

 

Edited June 10, 2023 by Dantes

[Dantes]

I found out that OpenWRT does not have this (at least the mj82 build), so I asked there if we could be enlightened: https://forum.openwrt.org/t/nanopi-r6s-linux-6-3-arm-soc-updates/153072/28

 

Edited June 19, 2023 by Dantes

[Dantes]

found serial in:
 

/proc/cpuinfo
/proc/device-tree/serial-number
/sys/firmware/devicetree/base/serial-number

 

https://community.toradex.com/t/cpu-serial-in-proc-cpuinfo-on-imx7/6390
 

The serial number available in cpuinfo is set by U-Boot from the data available in config block.

 

https://elixir.free-electrons.com/linux/v6.4-rc7/source/arch/arm/kernel/setup.c

 

function that passes serial number to kernel

 

some more info i could find:

https://forums.raspberrypi.com/viewtopic.php?t=183474

 

[Dantes]

Booted into u-boot via the usb-c console. I have some issues with the serial setup running minicom/screen.

Used the basic settings: 1500000 8N1 and disabled hard/soft flow. But when I dump out with 'printenv' half of the settings appear.

 

Back to the topic. I tried to overwrite the serial to see if it could be done, but no

 

setenv serial# 0000000000000000

 

I got an error that read-only variables could not be overwritten.