/boot/dietpi/func/dietpi-set_swapfile 128 /dev/zram0 fails

[mennerausr]

Details:

• Date | Tue Oct 27 00:08:37 CET 2020
• DietPi version | v6.33.3 (MichaIng/master)
• Image creator | DietPi Core Team
• Pre-image | Raspbian Lite
• Hardware | RPi Zero W (armv6l) (ID=1)
• Kernel version | Linux raspi0w 5.4.72+ #1356 Thu Oct 22 13:56:00 BST 2020 armv6l GNU/Linux
• Distro | buster (ID=5,RASPBIAN=1)
• Command | swapon /dev/zram0
• Exit code | 255
• Software title | DietPi-Set_swapfile

Steps to reproduce:

1. ...
2. ...

Expected behaviour:

• ...

Actual behaviour:

• ...

Extra details:

• ...

Additional logs:

swapon: /dev/zram0: insecure permissions 0644, 0600 suggested.
swapon: /dev/zram0: swapon failed: Invalid argument

[MichaIng]

Many thanks for your report.

Interesting, AFAIK permissions were correct automatically when we implemented this. I'll try to replicate on VM, else it doesn't hurt to re-set the permissions, 600 simply makes sense for RAM content.

... works fine here:

2020-10-27 00:25:40 root@VM-Buster:~# /boot/dietpi/func/dietpi-set_swapfile 128 zram
[ SUB1 ] DietPi-Set_swapfile > Applying 128 zram
[ INFO ] DietPi-Set_swapfile | Disabling and deleting all existing swap files
[  OK  ] DietPi-Set_swapfile | swapoff -a
[  OK  ] DietPi-Set_swapfile | Generating new swap space
[ INFO ] DietPi-Set_swapfile | Size = 128 MiB
[ INFO ] DietPi-Set_swapfile | Path = /dev/zram0
[  OK  ] DietPi-Set_swapfile | modprobe zram
[  OK  ] DietPi-Set_swapfile | eval echo 1 > /sys/block/zram0/reset
[  OK  ] DietPi-Set_swapfile | eval echo '128M' > /sys/block/zram0/disksize
[  OK  ] DietPi-Set_swapfile | mkswap /dev/zram0
[  OK  ] DietPi-Set_swapfile | swapon /dev/zram0
[  OK  ] DietPi-Set_swapfile | eval echo 'zram' > /etc/modules-load.d/dietpi-zram-swap.conf
[  OK  ] DietPi-Set_swapfile | eval echo 'SUBSYSTEM=="block", KERNEL=="zram0", ACTION=="add", ATTR{disksize}="128M", RUN+="/sbin/mkswap /dev/zram0", RUN+="/sbin/swapon /dev/zram0"' > /etc/udev/rules.d/98-dietpi-zram-swap.rules
[  OK  ] DietPi-Set_swapfile | eval echo 'swappiness=50' > /etc/sysctl.d/98-dietpi-zram-swap.conf
[  OK  ] DietPi-Set_swapfile | Setting in /boot/dietpi.txt adjusted: AUTO_SETUP_SWAPFILE_SIZE=128
[  OK  ] DietPi-Set_swapfile | Setting in /boot/dietpi.txt adjusted: AUTO_SETUP_SWAPFILE_LOCATION=zram
[ INFO ] DietPi-Set_swapfile | Setting /tmp tmpfs size: 1061 MiB
[  OK  ] DietPi-Set_swapfile | mount -o remount /tmp
2020-10-27 00:26:09 root@VM-Buster:~# l /dev/zram0
brw-rw---- 1 root disk 254, 0 Oct 27 00:26 /dev/zram0

But indeed disk group has R/W access. Not sure why swapon is not complaining here but we should apply 600 definitely. Please try:

sed -i '\|/sys/block/zram0/disksize|a\\t\t\tG_EXEC chmod 0600 /dev/zram0' /boot/dietpi/func/dietpi-set_swapfile

........

---

Ah now I see difference: Please use zram only as argument, not /dev/zram0. Probably we should allow both 😉. But the hardened permissions are still a reasonable enhancement.

[MichaIng]

This fixes both, hardens the zram-swap device permissions and allows /dev/zram0 input to be interpreted correctly: #3870