--allow-local-files fails on chromium in snap environment

[matoken]

It happens in npm, npx, Standalone binary in Debian sid adm64 environment.

$ marp --allow-local-files --pdf test.md
[  INFO ] Converting 1 markdown...
[  WARN ] Insecure local file accessing is enabled for conversion from test.md.
[  WARN ] Marp CLI has detected accessing to local file. That is blocked by security reason. Instead we recommend using assets uploaded to
          online. (Or you can use --allow-local-files option if you are understood of security risk)
[ ERROR ] Failed converting Markdown. (net::ERR_FILE_NOT_FOUND at file:///tmp/tmp-1187272jpnBmJk9frtF.html)

Chromium in this environment includes a snap version and a Debian package version.

$ which chromium
/snap/bin/chromium
$ PATH=`echo $PATH|tr : '\n'|grep -v snap|tr "\n" :` which chromium
/usr/bin/chromium

Using the package version instead of the snap version worked fine.

$ PATH=`echo $PATH|tr : '\n'|grep -v snap|tr "\n" :` marp --allow-local-files --pdf hoge.md

[yhatt]

See also similar issue happened by Snap Chromium: marp-team/marp-vscode#94, https://forum.snapcraft.io/t/sharing-files-via-tmp/1613

A simple workaround:

CHROME_PATH=/usr/bin/chromium marp --allow-local-files --pdf foobar.md

[matoken]

Thank you.
Chromium could be specified by using CHROME_PATH.
It seems to be helpful if a warning is displayed when using the snap version of Chromium.

[yhatt]

The suggested warning may be helpful for CLI user, but does not resolve marp-team/marp-vscode#94 so thinking about radical solution would be better.

Owing to your report, we recognized the Snapd Chromium cannot access from the sandbox container to user-land /tmp/, due to strict snap confinement. Snapd Chromium only allows reading visible files from $HOME.

Marp CLI should create visible tmp file into $HOME when the resolved Chromium path starts with /snap.

[yhatt]

Fixed in v0.17.1.

[zhelnio]

Looks like this bug still appears

• Ubuntu 20.04.1 LTS, updated
• chromium installed using the system default apt install (installs snap package)

$ npx marp slides_ru.md --allow-local-files --output out/slides_ru.pdf
[  INFO ] Converting 1 markdown...
[  WARN ] Insecure local file accessing is enabled for conversion from slides_ru.md.
[  WARN ] The local file is missing and will be ignored. Make sure the file path is correct.
[ ERROR ] Failed converting Markdown. (net::ERR_FILE_NOT_FOUND at file:///tmp/tmp-32659-D1CkptSeH8No-.html)

$ which chromium
/snap/bin/chromium

$ npx marp --version
@marp-team/marp-cli v0.21.0 (w/ @marp-team/marp-core v1.3.0)

[yhatt]

@zhelnio Thanks!

Previously Marp CLI could find out /snap/bin/chromium and detect the snap chromium from the path starting with /snap/. But now, Marp is trying to use /usr/bin/chromium-browser, that is a proxy script for calling /snap/bin/chromium likely added at some point in the past half of year.

yhatt@yhatt-ubuntu2004:~$ echo '# Marp' | DEBUG=puppeteer:launcher npx @marp-team/marp-cli -o ~/marp.pdf --allow-local-files
[  INFO ] Converting 1 markdown...
[  WARN ] Insecure local file accessing is enabled for conversion from -.
  puppeteer:launcher Calling /usr/bin/chromium-browser --disable-background-networking --enable-features=NetworkService,NetworkServiceInProcess --disable-background-timer-throttling --disable-backgrounding-occluded-windows --disable-breakpad --disable-client-side-phishing-detection --disable-component-extensions-with-background-pages --disable-default-apps --disable-dev-shm-usage --disable-extensions --disable-features=TranslateUI --disable-hang-monitor --disable-ipc-flooding-protection --disable-popup-blocking --disable-prompt-on-repost --disable-renderer-backgrounding --disable-sync --force-color-profile=srgb --metrics-recording-only --no-first-run --enable-automation --password-store=basic --use-mock-keychain --user-data-dir=/tmp/marp-cli-conversion --headless --hide-scrollbars --mute-audio about:blank --export-tagged-pdf --remote-debugging-pipe +0ms
[  WARN ] The local file is missing and will be ignored. Make sure the file path is correct.
[ ERROR ] Failed converting Markdown. (net::ERR_FILE_NOT_FOUND at file:///tmp/tmp-9964-KRtSNXzO5F7m-.html)

yhatt@yhatt-ubuntu2004:~$ tail /usr/bin/chromium-browser 
      }
    }
EOF
  )"
  qdbus org.kde.plasmashell /PlasmaShell org.kde.PlasmaShell.evaluateScript "$SCRIPT" 2> /dev/null
fi

# TODO: handle other desktop environments

exec /snap/bin/chromium "$@"

Probably we should check the path of "real" process launched by Puppeteer.

[zhelnio]

@yhatt I've tried to set CHROME_PATH but it did not help

$ CHROME_PATH=/snap/bin/chromium npx marp slides_ru.md --allow-local-files --output out/slides_ru.pdf
[  INFO ] Converting 1 markdown...
[  WARN ] Insecure local file accessing is enabled for conversion from slides_ru.md.
[ ERROR ] Failed converting Markdown. (dir option must be relative to "/tmp", found "/home/user".)

[yhatt]

I think it may be another problem that has brought from #259 and #264 (released in v0.20.0). Is CHROME_PATH=/snap/bin/chromium npx @marp-team/[email protected] working?

[zhelnio]

No, it does not

$ CHROME_PATH=/snap/bin/chromium npx @marp-team/[email protected] slides_ru.md --allow-local-files --output out/slides_ru.pdf
npx: installed 271 in 24.933s
[  INFO ] Converting 1 markdown...
[  WARN ] Insecure local file accessing is enabled for conversion from slides_ru.md.
[ ERROR ] Failed converting Markdown. (dir option must be relative to "/tmp", found "/home/user".)

[yhatt]

Ah, it didn't a real matter. Probably we've missed a breaking change of node-tmp to create tmpfile for conversion.

[yhatt]

Fixed again in v0.21.1.