tcpdump mailing list archives
Re: OpenBSD work on Tcpdump privilege separation
From: Guy Harris <gharris () sonic net>
Date: Sun, 22 Feb 2004 15:14:53 -0800
On Sun, Feb 22, 2004 at 09:36:33AM +0200, Pekka Savola wrote:
The current tcpdump just drops privileges before pretty much anything is done. Now looking at the code, maybe the privilege separation could be done even slightly earlier in the "pcap_open_live" branch, e.g., after pcap_open_live, but I haven't tested this. I guess it depends on whether pcap_set_datalink, pcap_snapshot (this one might be dangerous with root!) for or pcap_lookupnet requires root privileges.
"pcap_set_datalink()" doesn't, at least on the BSDs, require root privileges; the ioctl either isn't present (in which case you can't set the data link type) or is unprivileged. Given that "pcap_snapshot()" just returns "p->snapshot", which is set from the argument supplied to "pcap_open_live()" and from the capture file header by "pcap_open_offline()", I'm not sure why it'd be dangerous with root or why it'd require root privileges. "pcap_lookupnet()", however, might well require extended privileges on some OSes, in order to fetch the netmask for a given adapter. However, on BSDs, even "pcap_open_live()" doesn't necessarily require root privileges! It doesn't require them on my machines: % ls -l /dev/bpf* crw------- 1 guy wheel 23, 0 Jun 9 2002 /dev/bpf0 crw------- 1 guy wheel 23, 1 Jun 9 2002 /dev/bpf1 which means that I just run tcpdump - and Ethereal - as myself, and they don't have any privileges to drop. - This is the TCPDUMP workers list. It is archived at http://www.tcpdump.org/lists/workers/index.html To unsubscribe use mailto:tcpdump-workers-request () tcpdump org?body=unsubscribe
Current thread:
- OpenBSD work on Tcpdump privilege separation Richard Bejtlich (Feb 21)
- Re: OpenBSD work on Tcpdump privilege separation Pekka Savola (Feb 21)
- Re: OpenBSD work on Tcpdump privilege separation Guy Harris (Feb 22)
- SIOCGIFCONF under Linux on Itanium in 32 bit compatibility mode Shaun (Feb 22)
- Re: SIOCGIFCONF under Linux on Itanium in 32 bit compatibility mode Guy Harris (Feb 22)
- Re: SIOCGIFCONF under Linux on Itanium in 32 bit compatibility mode Shaun (Feb 22)
- Re: SIOCGIFCONF under Linux on Itanium in 32 bit compatibility mode Guy Harris (Feb 27)
- Re: OpenBSD work on Tcpdump privilege separation Guy Harris (Feb 22)
- Re: OpenBSD work on Tcpdump privilege separation Pekka Savola (Feb 21)
- Re: OpenBSD work on Tcpdump privilege separation Guy Harris (Feb 22)
- Re: OpenBSD work on Tcpdump privilege separation Jefferson Ogata (Feb 23)
- Re: OpenBSD work on Tcpdump privilege separation Pekka Savola (Feb 23)
- Re: OpenBSD work on Tcpdump privilege separation Jefferson Ogata (Feb 24)