What allows /usr/bin/mount to call /usr/bin/modprobe xxx when needed?

graysky · 2015-04-27 21:47:01

Subject says it all. Thanks.

ewaller · 2015-04-27 22:01:28

/usr/bin/mount has the suid bit set.
http://unix.stackexchange.com/questions … y-bit-work

graysky · 2015-05-02 06:54:03

Hmmm... I'm trying to allow my AUR package for turbostat to `modprobe msr` if it is not already loaded, so I ran `chmod u+s "$pkgdir/usr/bin/$pkgname"` in the PKGBUILD but it does not behave as /usr/bin/mount does in this regard with the suid bit set.

% ls -l /usr/bin/mount          
-rwsr-xr-x 1 root root 40208 Mar 13 10:36 /usr/bin/mount

% ls -l /usr/bin/turbostat
-rwsr-xr-x 1 root root 48984 May  2 02:49 /usr/bin/turbostat

% sudo turbostat
turbostat: no /dev/cpu/0/msr, Try "# modprobe msr" : No such file or directory

Raynman · 2015-05-02 08:28:31

setuid bit and sudo?

Is turbostat even programmed to call modprobe?

I don't think the subject says it all. ewaller answered how mount can be used as a regular user (depending on configuration of course; e.g. 'user'/'users' option), but that might not be exactly what you were after.

ewaller · 2015-05-02 15:17:33

Is turbosat a binary or is it a script? For security reasons, Linux ignores the SUID bit on scripts

graysky · 2015-05-02 15:24:14

Binary

Arch Linux

#1 2015-04-27 21:47:01

What allows /usr/bin/mount to call /usr/bin/modprobe xxx when needed?

#2 2015-04-27 22:01:28

Re: What allows /usr/bin/mount to call /usr/bin/modprobe xxx when needed?

#3 2015-05-02 06:54:03

Re: What allows /usr/bin/mount to call /usr/bin/modprobe xxx when needed?

#4 2015-05-02 08:28:31

Re: What allows /usr/bin/mount to call /usr/bin/modprobe xxx when needed?

#5 2015-05-02 15:17:33

Re: What allows /usr/bin/mount to call /usr/bin/modprobe xxx when needed?

#6 2015-05-02 15:24:14

Re: What allows /usr/bin/mount to call /usr/bin/modprobe xxx when needed?

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