Handling of ShellOpt variable during initialization shouldn't imply null termination (Bugzilla Bug 4872)

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Bugzilla Bug 4872

Date: 2024-11-11T18:40:59+00:00
From: Roman Valov <<roman.valov>>
To: unassigned <>
CC:

Last updated: 2024-11-11T18:40:59+00:00

[tianocore-issues]

Comment 23527

Date: 2024-11-11 18:40:59 +0000
From: Roman Valov <<roman.valov>>

• Industry Specification: ---
• Release Observed: EDK II Master
• Releases to Fix: EDK II Master
• Target OS: ---
• Bugzilla Assignee(s): unassigned <>

Hi there

I'm playing around with UEFI shell configuration via ShellOpt variable. For example I can configure value of ShellOpt using one of following ways:

In Linux:

$ echo -ne "-nomap -delay 11" | iconv -t ucs2 > ./var.bin
$ sudo efivar -w --name=158DEF5A-F656-419C-B027-7A3192C079D2-ShellOpt --datafile=./var.bin

In UEFI Shell:

> setvar ShellOpt -guid 158DEF5A-F656-419C-B027-7A3192C079D2 =L"-nomap -delay 11"

But when I reboot the machine and UEFI attempts to initialize I've got an error like:

11@ is not recognized as an internal or external command, operable program, or script file.

To me it seems that UEFI catches some data that follows variable text in memory. I could workaround it by adding null character to variable text like:

In Linux:

$ echo -ne "-nomap -delay 11\0" | iconv -t ucs2 > ./var.bin
$ sudo efivar -w --name=158DEF5A-F656-419C-B027-7A3192C079D2-ShellOpt --datafile=./var.bin

In UEFI Shell:

> setvar ShellOpt -guid 158DEF5A-F656-419C-B027-7A3192C079D2 =L"-nomap -delay 11" =0000

and now ShellOpt works.

Things go weird given that I can configure ShellOpt variable using shell's set command used to manage shell environment variables:

> set ShellOpt " -nomap -delay 11"

and I've got the same error as described before on following shell initialization.

Given that all the tools in Linux and in UEFI Shell display correct values when I attempt to inspect the varialbe, it looks like ShellOpt processing code expects null terminator to be a part of the variable but it should not. Please fix.

P.S.: I don't know how to escape - sign in the front of variable value when using set command, so I have to prepend the value with a space.