libpam-mount doesn't pass options to mount.fuse correctly

[Joe Pfeiffer]

Binary package hint: libpam-mount

libpam-mount combines the -o options flag and the options specified in /etc/security/pam_mount.conf.xml as a single command-line argument, e.g.

Oct 18 10:47:04 valiant sshd[15676]: pam_mount(mount.c:196): Mount info: globalconf, user=pfeiffer <volume fstype="fuse" server="(null)" path="encfs#/home.enc/pfeiffer" mountpoint="/home/pfeiffer" cipher="(null)" fskeypath="(null)" fskeycipher="(null)" fskeyhash="(null)" options="nonempty,allow_other" /> fstab=0
Oct 18 10:47:04 valiant sshd[15676]: command: 'mount.fuse' 'encfs#/home.enc/pfeiffer' '/home/pfeiffer' '-ononempty,allow_\other'
Oct 18 10:47:04 valiant sshd[15678]: pam_mount(spawn.c:108): setting uid to user pfeiffer
Oct 18 10:47:04 valiant sshd[15678]: pam_mount(misc.c:38): set_myuid<post>: (uid=1000, euid=1000, gid=100, egid=100)
Oct 18 10:47:04 valiant sshd[15676]: pam_mount(mount.c:64): Errors from underlying mount program:
Oct 18 10:47:04 valiant sshd[15676]: pam_mount(mount.c:68): EncFS Password:
Oct 18 10:47:04 valiant sshd[15676]: pam_mount(mount.c:68): fuse: mountpoint is not empty
Oct 18 10:47:04 valiant sshd[15676]: pam_mount(mount.c:68): fuse: if you are sure this is safe, use the 'nonempty' mount option
Oct 18 10:47:04 valiant sshd[15676]: pam_mount(mount.c:68): fuse failed. Common problems:

The attached patch separates the -o and the options into two command-line arguments:

   Oct 18 10:52:57 valiant gdm-session-worker[1820]: pam_mount(mount.c:196): Mount info: globalconf, user=pfeiffer <volume fstype="fuse" server="(null)" path="encfs#/home.enc/pfeiffer" mountpoint="/home/pfeiffer" cipher="(null)" fskeypath="(null)" fskeycipher="(null)" fskeyhash="(null)" options="nonempty,allow_other" /> fstab=0
Oct 18 10:52:57 valiant gdm-session-worker[1820]: command: 'mount.fuse' 'encfs#/home.enc/pfeiffer' '/home/pfeiffer' '-o' 'nonempty,allow_other'
Oct 18 10:52:57 valiant gdm-session-worker[17148]: pam_mount(spawn.c:108): setting uid to user pfeiffer
Oct 18 10:52:57 valiant gdm-session-worker[17148]: pam_mount(misc.c:38): set_myuid<post>: (uid=1000, euid=1000, gid=100, \
egid=100)
Oct 18 10:52:57 valiant gdm-session-worker[1820]: pam_mount(mount.c:64): Errors from underlying mount program:
Oct 18 10:52:57 valiant gdm-session-worker[1820]: pam_mount(mount.c:68): EncFS Password:

(note that the 'error' referred to in the second log file excerpt is not an error, and the mount does in fact succeed in this case)

This could, of course, equally well have been fixed by making mount.fuse's command-line parsing more robust.

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: libpam-mount 2.3-1 [modified: lib/security/pam_mount.so sbin/mount.crypt]
ProcVersionSignature: Ubuntu 2.6.35-22.34-generic 2.6.35.4
Uname: Linux 2.6.35-22-generic i686
Architecture: i386
Date: Mon Oct 18 11:00:19 2010
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: libpam-mount

[Jan Engelhardt (jengelh)]

This should not be needed, as fuse, since version 2.4.0, uses getopt_long and thus should be able to understand squashed options.

[Joe Pfeiffer (joseph-pfeifferfamily)]

As of version 2.8.4, mount.fuse still does its own argument parsing. Lines 141-146 of mount.fuse.c read:

  } else if (strcmp(argv[i], "-o") == 0) {
   char *opts;
   char *opt;
   i++;
   if (i == argc)
    break;

It doesn't handle squashed options.