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RE: Can a driver give root privileges to a process?
I think that it's euid which is changed here... Actually your euid is checked to
check privilege things like passwd binary. If you do this :-
$ ls -l `which passwd`
-r-s--x--x 1 root root 16336 Feb 14 2003 /usr/bin/passwd
As you can see here that "s" [Superuser bit] is set for this binary and using this
program any user can change "/etc/passwd" contents, because when a use runs
this binary, euid of the user process is set to the superuser and then it can access
and modify "/etc/passwd" file which a normal user can't modify using normal text
editors or some other tools...
You can refer to book written by Vijay Mukhi [Boundless C] for this stuff.
Thanks.
Sumit Sharma.
On Wed, 01 Sep 2004 Dhiman,Gaurav wrote :
>
>I hope, if you change the "uid" or "euid" (not sure which one) in
>"task_struct" of current process to the uid of root, you process will
>have root privileges. This is what "login" user program do, using set
>_uid systemcall.
>
>There are specific significance of uid, euid, suid fields in
>task_struct, before modifying them, do check there significance.
>
>I might be wrong, not sure about it, if I am wrong, please correct me.
>
>Regards,
>Gaurav
>
>
>-----Original Message-----
> From: kernelnewbies-bounce@xxxxxxxxxxxx
>[mailto:kernelnewbies-bounce@xxxxxxxxxxxx] On Behalf Of Timur Tabi
>Sent: Wednesday, September 01, 2004 8:12 PM
>To: arjanv@xxxxxxxxxx
>Cc: kernelnewbies@xxxxxxxxxxxx
>Subject: Re: Can a driver give root privileges to a process?
>
>Arjan van de Ven wrote:
>
> > Yes it is possible. The moment you do though your driver will end up
>on
> > bugtraq pretty fast. I can't believe "lets ignore security"!
>
>I know I need to consider the security issues before delivering the
>product, but I want to at least explore the option first.
>
>However, I was hoping you would tell me HOW I give root privileges to a
>process from a driver.
>
>
>--
>Timur Tabi
>Staff Software Engineer
>timur.tabi@xxxxxxxxxxx
>
>--
>Kernelnewbies: Help each other learn about the Linux kernel.
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