[Pkg-virtualbox-devel] Bug#506885: [virtualbox-ose-guest-utils] strange and/or broken path interpretation in mount.vboxsf

[Bruno Kleinert]

Package: virtualbox-ose-guest-utils
Version: 1.6.6-dfsg-3
Severity: normal

--- Please enter the report below this line. ---
hi,

the mount.vboxsf binary and/or vboxvfs kernel module do distinguish
between absolute and relative paths and don't ignore trailing slashes.

i tried the following test scenario to reproduce the bug:

1. just to avoid confusion, there's no vboxvfs mounted:

da:/home/fuddl# mount
/dev/hda1 on / type ext3 (rw,errors=remount-ro)
tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
udev on /dev type tmpfs (rw,mode=0755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
fusectl on /sys/fs/fuse/connections type fusectl (rw)

2. mount a vboxvfs file system and check by calling "mount", if it
succeeded:

da:/home/fuddl# mount -t vboxsf impl ./test
da:/home/fuddl# mount
[...]
impl on ./test type vboxsf (rw)

note that i told mount to mount the filesystem to "./test", which is an
empty directory in the current working directory "/home/fuddl", so i'd
usually expect, that the output of mount would say
"impl on /home/fuddl/test type vboxsf (rw)"

3. if the filesystem is mounted to "./test" i wondered if it's
accessible from another current working directory. it is:

da:/home/fuddl# cd ..
da:/home# ls fuddl/test
ecc-0.2.2.tar.gz  linux-2.6.27.5.tar.bz2  max-home  max-sources


4. after changing the current working directory back to "/home/fuddl" i
want to un-mount the filesystem. running a simple "umount test" does
un-mount the filesystem, but still mount shows the filesystem to be
mounted:

da:/home/fuddl# umount test
da:/home/fuddl# mount
[...]
impl on ./test type vboxsf (rw)

to see if it's still present or really gone, i tried:

da:/home/fuddl# ls test

yes, it's gone, so the output of mount is incostistent.

5. after that i tried "umount ./test" instead of "umount test". it told
me that "./test" isn't mounted, but it helps to make mount print
consistent information:

da:/home/fuddl# umount ./test
umount: ./test: not mounted
da:/home/fuddl# mount
/dev/hda1 on / type ext3 (rw,errors=remount-ro)
tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
udev on /dev type tmpfs (rw,mode=0755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
fusectl on /sys/fs/fuse/connections type fusectl (rw)


i can reproduce the same strange behaviour if a trailing slash is at
the end of the mount -t vboxsf command. then one has to add the
trailing slash also to the umount command to make it un-mount the
filesystem and also make mount no longer show the mount-point.

cheers - fuddl
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 197 bytes
Desc: Dies ist ein digital signierter Nachrichtenteil
Url : http://lists.alioth.debian.org/pipermail/pkg-virtualbox-devel/attachments/20081125/4359f12a/attachment.pgp