blkid shouldn't need root privileges

[Christoph Langner]

Binary package hint: e2fsprogs

When I execute blkid without root privileges I get an empty result. Only when i add a sudo to the command i get an output:

$ blkid
$ sudo blkid
/dev/mapper/stein-root: UUID="505a1f5d-8a14-40c7-b873-009b722d3782" SEC_TYPE="ext2" TYPE="ext3"
/dev/mapper/stein-swap_1: TYPE="swap" UUID="0cf47458-4a05-4b8a-aedf-238d7d047b18"
/dev/sda5: UUID="cdb51a1e-b277-43e3-8130-eb7b992efda2" TYPE="crypt_LUKS"
/dev/sda1: UUID="2d6fdebf-54bc-4987-a46e-7b3352737b14" SEC_TYPE="ext2" TYPE="ext3"
/dev/mapper/sda5_crypt: UUID="nmmiO3-4W3N-zaP1-DQdP-hlQT-yooV-KGSjOg" TYPE="lvm2pv"

This is quite strange since blkid reads /etc/blkid.tab and reformats the file. /etc/blkid.tab is readable for all users:

$ ls -al /etc/blkid.tab
-rw-r--r-- 1 root root 663 2008-04-21 17:13 /etc/blkid.tab
$ cat /etc/blkid.tab
<device DEVNO="0xfe01" TIME="1208790785" UUID="505a1f5d-8a14-40c7-b873-009b722d3782" SEC_TYPE="ext2" TYPE="ext3">/dev/mapper/stein-root</device>
<device DEVNO="0xfe02" TIME="1208790785" TYPE="swap" UUID="0cf47458-4a05-4b8a-aedf-238d7d047b18">/dev/mapper/stein-swap_1</device>
<device DEVNO="0x0805" TIME="1208790785" UUID="cdb51a1e-b277-43e3-8130-eb7b992efda2" TYPE="crypt_LUKS">/dev/sda5</device>
<device DEVNO="0x0801" TIME="1208790785" UUID="2d6fdebf-54bc-4987-a46e-7b3352737b14" SEC_TYPE="ext2" TYPE="ext3">/dev/sda1</device>
<device DEVNO="0xfe00" TIME="1208790785" UUID="nmmiO3-4W3N-zaP1-DQdP-hlQT-yooV-KGSjOg" TYPE="lvm2pv">/dev/mapper/sda5_crypt</device>

I can reproduce the problem on several installations with Ubuntu Hardy and inside a clean VM with Ubuntu Hardy RC1 booted from the Live-CD.

ProblemType: Bug
Architecture: i386
Date: Mon Apr 21 17:14:37 2008
DistroRelease: Ubuntu 8.04
Package: e2fsprogs 1.40.8-2ubuntu2
PackageArchitecture: i386
ProcEnviron:
 SHELL=/bin/bash
 PATH=/home/username/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=de_DE.UTF-8
SourcePackage: e2fsprogs
Uname: Linux 2.6.24-16-generic i686

[Theodore Ts'o (tytso)]

Can you send me the output of "ls -dl /dev /dev/mapper"? That is, I want to see the ownership and permissions of the /dev and /dev/mapper directories. I suspect they might not be world-readable, and causing blkid to fail in a way that causes it not to print. I can replicate the problem on my system if I chmod /dev/mapper to mode 700. I agree that blkid should not fail in such a way, and I'll look into trying to fix it, but I'd like some confirmation that this is the same root cause for the problem you are seeing on your system.

Thanks, regards,

--- Ted

[Christoph Langner (chrissss)]

Here it is :)

$ ls -dl /dev /dev/mapper
drwxr-xr-x 16 root root 14220 2008-04-21 23:55 /dev
drwxr-xr-x 2 root root 120 2008-04-21 20:08 /dev/mapper

[Christoph Langner (chrissss)]

This bug is fixed in intrepid. I can execute blkid without root-rights.

$ blkid
/dev/mapper/stein-root: UUID="115e7f77-a5e1-4ae1-ace4-cbcbed78be46" TYPE="ext3"
/dev/mapper/stein-swap_1: UUID="6ef7cec4-ffee-45c4-a404-50301d735707" TYPE="swap"
/dev/sda1: UUID="d1c47f80-64bd-4c28-b5fd-587597012e43" TYPE="ext3"
/dev/sda5: UUID="35893d2e-da1b-4170-b65b-aac693a1d3c5" TYPE="ext3"
/dev/dm-0: UUID="1JO8Ld-CdsV-Lb2G-2Bml-sUHi-UlB4-j4Mhc4" TYPE="lvm2pv"

[Khurshid Alam (khurshid-alam)]

LOL!....On 16.04 it still requires root.

[Jamie (jamalex)]

It seems that when run without root, it reads from the cached results in /etc/blkid.tab, which are only populated if blkid was previously run as root. That could explain why it worked for chrissss, if he had previously run as root.

In other words, this doesn't seem to be fixed; an ordinary user can't run blkid and expect results.