linux-kernel - Re: Sysctl syscall

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <200611171138.33469.hasso@estpak.ee>
Date:	Fri, 17 Nov 2006 11:38:33 +0200
From:	Hasso Tepper <hasso@...pak.ee>
To:	Andi Kleen <ak@...e.de>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Sysctl syscall

Andi Kleen wrote:
> On Friday 17 November 2006 09:07, Hasso Tepper wrote:
> > I have process which drops root privileges after startup and retains
> > only some privileges using CAP_NET_ADMIN and CAP_SYS_ADMIN
> > capabilities. I can change values in /proc/sys/net/ipv[46]/* (like
> > turning forwarding on/off) from this process using sysctl syscall,
> > but I can't write directly into /proc/sys/net/ipv[46]/* from it.
>
> That sounds more like a security bug than a feature to be preserved.

Why? IMHO it's normal that process with CAP_NET_ADMIN capabilities can 
modify settings in /proc/sys/net/. From /usr/include/sys/capability.h:

/* Allow interface configuration */
/* Allow administration of IP firewall, masquerading and accounting */
/* Allow setting debug option on sockets */
/* Allow modification of routing tables */
/* Allow setting arbitrary process / process group ownership on
   sockets */
/* Allow binding to any address for transparent proxying */
/* Allow setting TOS (type of service) */
/* Allow setting promiscuous mode */
/* Allow clearing driver statistics */
/* Allow multicasting */
/* Allow read/write of device-specific registers */
/* Allow activation of ATM control sockets */

#define CAP_NET_ADMIN        12


regards,

-- 
Hasso Tepper
Elion Enterprises Ltd. [AS3249]
Data Communication Network Administrator
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/