Errors Launching Program and Saving Settings When Using Double Quotes in kernel parameters

[Lucas McCarthy]

If there are double quotes in the kernel parameters field under General Settings, Grub Customizer encounters an error when saving settings or launching the program.

This appears to be a result of double quotes being interpreted as the start or end of a string literal rather than part of the string literal assigned to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub. There may be similar issues with other special characters (see https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_02) and this issue may not be restricted to the kernel parameters field.

If a user does not remedy this before closing Grub Customizer, they will be unable to launch the program - and, by extension, use it to correct the error - essentially locking them out. The error may be resolved, however, by editing /etc/default/grub and prepending the double quotes with a backslash, replacing them with single quotes, or otherwise removing them.

Admittedly, I'm not sure if this qualifies as a bug so much as user error, but it may be worth adding a measure to prevent this from happening, such as some sort of input validation or automatically prepending double quotes with a backslash.

Going into specifics, I encountered this issue after adding the following to the kernel parameters field:
>acpi_os_name="Windows 2001"
For the record, the full contents of the field were as follows:
>loglevel=3 rw rootfstype=ext4 rootflags=rw,errors=remount-ro,noatime acpi_os_name="Windows 2001" pci=nomsi,noaer
On clicking save, Grub Customizer displayed the following error:
>Failed saving grub configuration!
>Please take a look at the command line output below. If you think this is a bug of Grub Customizer, please create one at https://launchpad.net/grub-customizer! Generally Grub Customizer should prevent errors like this.
>
>failed running 'grub-mkconfig -o "/boot/grub/grub.cfg"' output:
>/etc/default/grub: line 6: 2001 pci=nomsi,noaer: command not found
It was late, so I decided to worry about it later and just closed the program. The next day, I tried launching Grub Customizer but was met with a somewhat similar error message:
>grub-mkconfig couldn't be executed successfully. error message:
>/etc/default/grub: line 6: 2001 pci=nomsi,noaer: command not found
Although I was unable to fix the issue via Grub Customizer, I was able to do so by directly editing /etc/default/grub and replacing the double quotes with single quotes.