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Date:      Mon, 27 Oct 2025 10:02:51 +0000
From:      bugzilla-noreply@freebsd.org
To:        bugs@FreeBSD.org
Subject:   [Bug 290564] "jail -e" output is ambiguous regarding list values
Message-ID:  <bug-290564-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=290564

            Bug ID: 290564
           Summary: "jail -e" output is ambiguous regarding list values
           Product: Base System
           Version: Unspecified
          Hardware: Any
                OS: Any
            Status: New
          Severity: Affects Some People
          Priority: ---
         Component: bin
          Assignee: bugs@FreeBSD.org
          Reporter: markus@stoffdv.at

PROBLEM

When printing jail.conf(5) parameter lists via "jail -e", the separation of the
individual list values is ambiguous.

For example, consider the following jail.conf:

    some-jail {
        single  = 'abc,def';
        list    = 'abc';
        list   += 'def';
        tricky  = 'abc';
        tricky += 'def,ghi';
    }

Expected output (via "jail -e $'\n'"):

    single="abc,def"
    list=abc,def
    tricky=abc,"def,ghi"

Actual output:

    single=abc,def
    list=abc,def
    tricky=abc,def,ghi  # no, it doesn't help to _know_ that this is a list


ANALYSIS

A simple solution would be to add the comma to the list of characters causing a
quoted string (like a space). To simulate the behaviour, let's add a space
after each comma in the example above:

    some-jail {
        single  = 'abc, def';
        list    = 'abc';
        list   += 'def';
        tricky  = 'abc';
        tricky += 'def, ghi';
    }

Result:

    single="abc, def"
    list=abc,def
    tricky=abc,"def, ghi"

As an additional remark: newline characters should also be escaped - or better
even - all control characters (ASCII <= 31) should be escaped.

To provide a feasible solution to the "parsing jail configurations by shell
script" (or any other language for that matter), list values could be printed
double-quoted by convention. This way values would _always_ be separated by
'","' (dquote-comma-dquote), which could never occur _within_ a value, as a
double-quote within double-quotes must always be escaped ("\"").

Wishful thinking example output for the example above (plus bonus line):

    single="abc,def"
    list=abc,def
    tricky="abc","def,ghi"
    verytricky="abc\",\"def","ghi"

How to process this safely in /bin/sh:

    while read -r param; do
        name=$(echo "${param}" | cut -d = -f 1)
        value=$(echo "${param}" | cut -d = -f 2-)

        if echo "${value}" | grep -q '^[^"]' || echo "${value}" | grep -qv
'","'; then
            echo "${name} = ${value}"
            continue
        fi  

        echo "${name}:"
        IFS=$'\n'
        for item in $(echo "${value}" | sed 's/","/"\n"/g'); do
           echo "- ${item}"
        done
    done

Result:

    name = some-jail
    single = "abc,def"
    list:
    - "abc"
    - "def"
    tricky:
    - "abc"
    - "def,ghi"
    verytricky:
    - "abc"
    - "def\",\"ghi"


HOW TO REPRODUCE

    cat << EOF | jail -e $'\n' -f -
    some-jail {
        single = 'abc, def';
        list = 'abc';
        list += 'def';
        tricky = 'abc';
        tricky += 'def, ghi';
        verytricky = 'abc';
        verytricky += 'def","ghi\'';
    }

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