The needed folders defined in the database section are not created

meliurwen commented 2 years ago

Bug report

mpd does not try to automatically create the needed folders defined in the database section; specifically defined in path and cache_directory settings.

To circumvent this issue the user has to create by hand the missing needed folder(s).

A command like mkdir -p ~/.local/share/mpd is enough, but this extra step on the user part is bothersome and implies some knowledge on their part.

Expected Behavior

Launch mpd with a config file with a database section pointing to filesystem paths in path and/or cache_directory .
If the paths are nonexistent, mpd tries to create the needed directories
- If it fails (due to incompatible permissions or whatever) it exits with an error code like it is doing now
- If it succeeds it continues the flow

Actual Behavior

The user setup the database section instead of the old db_file setting:

#db_file "~/.config/mpd/mpd.db"

database {
    plugin "simple"
    path "~/.local/share/mpd/db"
    cache_directory "~/.local/share/mpd/cache"
}

The paths defined in path and cache_directory does not exists (in this case they both have the same dirpath ~/.local/share/mpd).
Launching the command mpd --stdout --no-daemon the program exits with an error code preceded by the logs listed in the "Log" section below.

Version

Music Player Daemon 0.23.5 (0.23.5)
Copyright 2003-2007 Warren Dukes <warren.dukes@gmail.com>
Copyright 2008-2021 Max Kellermann <max.kellermann@gmail.com>
This is free software; see the source for copying conditions.  There is NO
warranty; not even MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Database plugins:
 simple proxy upnp

Storage plugins:
 local smbclient udisks nfs curl

Neighbor plugins:
 smbclient upnp udisks

Decoders plugins:
 [mad] mp3 mp2
 [mpg123] mp3
 [vorbis] ogg oga
 [oggflac] ogg oga
 [flac] flac
 [opus] opus ogg oga
 [sndfile] wav aiff aif au snd paf iff svx sf voc w64 pvf xi htk caf sd2
 [audiofile] wav au aiff aif
 [dsdiff] dff
 [dsf] dsf
 [hybrid_dsd] m4a
 [faad] aac
 [mpcdec] mpc
 [wavpack] wv
 [openmpt] mptm mod s3m xm it 669 amf ams c67 dbm digi dmf dsm dtm far imf ice j2b m15 mdl med mms mt2 mtm nst okt plm psm pt36 ptm sfx sfx2 st26 stk stm stp ult wow gdm mo3 oxm umx xpk ppm mmcmp
 [modplug] 669 amf ams dbm dfm dsm far it med mdl mod mtm mt2 okt s3m stm ult umx xm
 [mikmod] amf dsm far gdm imf it med mod mtm s3m stm stx ult uni xm
 [sidplay] sid mus str prg P00
 [wildmidi] mid
 [fluidsynth] mid
 [adplug] amd d00 hsc laa rad raw sa2
 [ffmpeg] 16sv 3g2 3gp 4xm 8svx aa3 aac ac3 adx afc aif aifc aiff al alaw amr anim apc ape asf atrac au aud avi avm2 avs bap bfi c93 cak cin cmv cpk daud dct divx dts dv dvd dxa eac3 film flac flc fli fll flx flv g726 gsm gxf iss m1v m2v m2t m2ts m4a m4b m4v mad mj2 mjpeg mjpg mka mkv mlp mm mmf mov mp+ mp1 mp2 mp3 mp4 mpc mpeg mpg mpga mpp mpu mve mvi mxf nc nsv nut nuv oga ogm ogv ogx oma ogg omg opus psp pva qcp qt r3d ra ram rl2 rm rmvb roq rpl rvc shn smk snd sol son spx str swf tak tgi tgq tgv thp ts tsp tta xa xvid uv uv2 vb vid vob voc vp6 vmd wav webm wma wmv wsaud wsvga wv wve rtp:// rtsp:// rtsps://
 [gme] ay gbs gym hes kss nsf nsfe rsn sap spc vgm vgz
 [pcm]

Filters:
 libsamplerate soxr

Tag plugins:
 id3tag

Output plugins:
 shout null fifo sndio pipe alsa ao oss openal pipewire pulse jack httpd snapcast recorder

Encoder plugins:
 null vorbis opus lame wave flac

Archive plugins:
 [bz2] bz2
 [zzip] zip
 [iso] iso

Input plugins:
 file io_uring archive alsa curl ffmpeg smbclient nfs mms cdio_paranoia

Playlist plugins:
 extm3u m3u pls xspf asx rss soundcloud flac cue embcue

Protocols:
 file:// alsa:// cdda:// ftp:// ftps:// gopher:// hls+http:// hls+https:// http:// https:// mms:// mmsh:// mmst:// mmsu:// nfs:// rtmp:// rtmps:// rtmpt:// rtmpts:// rtp:// rtsp:// rtsps:// scp:// sftp:// smb:// srtp://

Other features:
 avahi dbus udisks epoll icu inotify ipv6 systemd tcp un

Log

Command: mpd --stdout --no-daemon

exception: Failed to open '/home/user/.local/share/mpd/db': No such file or directory
exception: Failed to open database plugin; On parent directory of db file; Failed to access /home/user/.local/share/mpd: No such file or directory

ostrosablin commented 2 years ago

I believe folder creation, even if it's intended to prevent tedious manual folder creation for users, is out of scope for MPD. It opens up a whole lot of permission-related problems and potential security holes.

I mean, in most distros, default MPD configuration is a global daemon and required directories are created automatically when package is installed. Per-user setup is a non-standard scenario and has to be configured responsibly, understanding exactly what's happening.

Consider this: if user has a writable MPD config (or even worse, a world-writable 777 MPD config, if user is very lazy and incompetent) and MPD is configured to run as another user, then it would be possible to exploit MPD into creating arbitrary directories in filesystem and arbitrary files within them as another user by manipulating the config file, possibly further exploiting and/or breaking system.

This is certainly an unnecessary expansion of MPD's attack surface, even though it may seem to be more friendly for end user.

MaxKellermann commented 2 years ago

Agree with @tmp6154 - if you configure files in certain directories, you should create those directories first.

MusicPlayerDaemon / MPD