ikiwiki/doc/bugs/Symlinked_srcdir_requires_trailing_slash.mdwn

If the srcdir is a symlink, Ikiwiki will not render the pages unless the srcdir has a trailing slash.

For example:

    #!/bin/sh
    set -x

    REALSRCDIR=~/tmp/ikiwiki/wikiwc2
    SRCDIR=~/tmp/ikiwiki/wikiwc
    DESTDIR=~/tmp/ikiwiki/public_html/wiki/

    echo "*** Testing without trailing slash."

    rm -rf $REALSRCDIR $SRCDIR $DESTDIR

    # Create the real srcdir and link the srcdir to it
    mkdir -p $REALSRCDIR
    ln -s $REALSRCDIR $SRCDIR

    mkdir -p $DESTDIR

    echo Test > $SRCDIR/index.mdwn

    # No trailing slash after $SRCDIR
    ikiwiki --verbose $SRCDIR $DESTDIR --url=http://example.org/~you/wiki/ --underlaydir /dev/null

    echo "*** Testing with trailing slash."

    rm -rf $REALSRCDIR $SRCDIR $DESTDIR

    # Create the real srcdir and link the srcdir to it
    mkdir -p $REALSRCDIR
    ln -s $REALSRCDIR $SRCDIR

    mkdir -p $DESTDIR

    echo Test > $SRCDIR/index.mdwn

    # Trailing slash after $SRCDIR
    ikiwiki --verbose $SRCDIR/ $DESTDIR --url=http://example.org/~you/wiki/ --underlaydir /dev/null

My output:

    + REALSRCDIR=/home/svend/tmp/ikiwiki/wikiwc2
    + SRCDIR=/home/svend/tmp/ikiwiki/wikiwc
    + DESTDIR=/home/svend/tmp/ikiwiki/public_html/wiki/
    + echo '*** Testing without trailing slash.'
    *** Testing without trailing slash.
    + rm -rf /home/svend/tmp/ikiwiki/wikiwc2 /home/svend/tmp/ikiwiki/wikiwc /home/svend/tmp/ikiwiki/public_html/wiki/
    + mkdir -p /home/svend/tmp/ikiwiki/wikiwc2
    + ln -s /home/svend/tmp/ikiwiki/wikiwc2 /home/svend/tmp/ikiwiki/wikiwc
    + mkdir -p /home/svend/tmp/ikiwiki/public_html/wiki/
    + echo Test
    + ikiwiki --verbose /home/svend/tmp/ikiwiki/wikiwc /home/svend/tmp/ikiwiki/public_html/wiki/ --url=http://example.org/~you/wiki/ --underlaydir /dev/null
    + echo '*** Testing with trailing slash.'
    *** Testing with trailing slash.
    + rm -rf /home/svend/tmp/ikiwiki/wikiwc2 /home/svend/tmp/ikiwiki/wikiwc /home/svend/tmp/ikiwiki/public_html/wiki/
    + mkdir -p /home/svend/tmp/ikiwiki/wikiwc2
    + ln -s /home/svend/tmp/ikiwiki/wikiwc2 /home/svend/tmp/ikiwiki/wikiwc
    + mkdir -p /home/svend/tmp/ikiwiki/public_html/wiki/
    + echo Test
    + ikiwiki --verbose /home/svend/tmp/ikiwiki/wikiwc/ /home/svend/tmp/ikiwiki/public_html/wiki/ --url=http://example.org/~you/wiki/ --underlaydir /dev/null
    scanning index.mdwn
    rendering index.mdwn

Note that index.mdwn was only rendered when srcdir had a trailing slash.

> There are potential [[security]] issues with ikiwiki following a symlink,
> even if it's just a symlink at the top level of the srcdir.
> Consider ikiwiki.info's own setup, where the srcdir is ikiwiki/doc,
> checked out of revision control. A malicious committer could convert
> ikiwiki/doc into a symlink to /etc, then ikiwiki would happily publish
> all of /etc to the web.
> 
> This kind of attack is why ikiwiki does not let File::Find follow
> symlinks when scanning the srcdir. By appending the slash, you're
> actually bypassing that check. Ikiwiki should not let you set
> up a potentially insecure configuration like that. More discussion of
> this hole [[here|security#index29h2]], and I've had to release
> a version of ikiwiki that explicitly checks for that, and fails to work.
> Sorry, but security trumps convenience. [[done]] --[[Joey]]