Snort mailing list archives
Re: Problems with umask on Snort 3
From: Noah Dietrich <noah_dietrich () 86penny org>
Date: Fri, 4 Jan 2019 19:22:41 +0100
that works, thanks! it might make more sense for snort to generate logs using the system default umask, so that newly crated files have the same permissions as the system default without having to specifically set the mask when calling snort. thanks again, noah On Fri, Jan 4, 2019 at 7:18 PM Carter Waxman (cwaxman) <cwaxman () cisco com> wrote:
Snort default if not explicitly set: umask(077); /* set default to be sane */ Adding -m0x1f (000 011 111) on top of user / group settings will give you a max of rwx-r---- instead of the default rwx------ *From: *Noah Dietrich <noah_dietrich () 86penny org> *Date: *Friday, January 4, 2019 at 1:09 PM *To: *"Carter Waxman (cwaxman)" <cwaxman () cisco com> *Cc: *"snort-devel () lists snort org" <snort-devel () lists snort org> *Subject: *Re: [Snort-devel] Problems with umask on Snort 3 I'm still getting this problem when i run snort with the 'snort' user and group. I can't seem to get snort3 to output log files with any permissions beyond rw for the owner. I've tried creating new log directories, verified the default umask on the system, and i can't seem to get snort to grant read rights to the group or other sets. Snort doesn't seem to follow the system mask when creating files. for example, when i (as a regular user) go to create a file: noah@snort3:~$ touch abc noah@snort3:~$ ls -l -rw-rw-r-- 1 noah noah 0 Jan 4 12:37 abc Verify my umask: noah@snort3:~$ umask 0002 if then (as a regular user) i try to run snort and create logs: snort -c /usr/local/etc/snort/snort.lua -r ~/pcaps/maccdc2012_00000.pcap -l /home/noah/snort-logs/ i can then check the permissions on those log files: noah@snort3:~$ ls -l snort-logs/ -rw------- 1 noah noah 1045217 Jan 4 12:56 alert_csv.txt.1546624609 you can see that snort creates files with 600 for the file permissions, when the system default is 644. I can't get snort in any way (root, different user account, working with the -m option) to create files with 644 mode. if i run snort with the snort user and group: sudo mkdir /var/log/snort sudo chown snort:snort /var/log/snort sudo snort -c /usr/local/etc/snort/snort.lua -r ~/pcaps/maccdc2012_00000.pcap -l /var/log/snort -u snort -g snort then check the output, You can see snort switching user and group id's: Commencing packet processing ++ [0] /home/noah/pcaps/maccdc2012_00000.pcap Set GID to 1002 Set UID to 999 and in the output file, the user and group are correct (snort:snort), but the permissions are again 600, not 644 as you'd expect noah@snort3:~$ ls -l /var/log/snort -rw------- 1 snort snort 514546 Jan 4 13:06 alert_csv.txt.1546625184 Is this a bug with snort, or am i doing something wrong? thanks for your help. On Fri, Jan 4, 2019 at 5:39 PM Carter Waxman (cwaxman) <cwaxman () cisco com> wrote: *lowercase u and g *From: *Snort-devel <snort-devel-bounces () lists snort org> on behalf of "Carter Waxman (cwaxman) via Snort-devel" <snort-devel () lists snort org> *Reply-To: *"Carter Waxman (cwaxman)" <cwaxman () cisco com> *Date: *Friday, January 4, 2019 at 11:38 AM *To: *Noah Dietrich <noah_dietrich () 86penny org>, " snort-devel () lists snort org" <snort-devel () lists snort org> *Subject: *Re: [Snort-devel] Problems with umask on Snort 3 Setting umask places limits on newly created files, it doesn’t set the actual permissions. Also, the permissions in umask are inverted, so umask of 0x01FF will actually not allow any permission bits to be set. It sounds like what you actually want is to create a user for your Snort process (for writing, leaving it root isn’t a good idea…), a group for Snort readers, and set the process user / group with -U / -G. -Carter *From: *Snort-devel <snort-devel-bounces () lists snort org> on behalf of Noah Dietrich <noah_dietrich () 86penny org> *Date: *Thursday, January 3, 2019 at 1:09 PM *To: *"snort-devel () lists snort org" <snort-devel () lists snort org> *Subject: *[Snort-devel] Problems with umask on Snort 3 Hello, I am trying to get the umask option (-m) working with snort 3, and i'm not sure what is going wrong. I'm trying to have Snort generate logs that users and other can read (644), but when I use the -m option with snort, I don't get the results i expect. I can only seem to affect the read and write owner portion of the permissions. For example: -m 0x000 leads to -rw------- -m 0x01FF leads to ---------- -m 0x00FF leads to -r-------- without using the -m flag, the default permissions are -rw------- The command i'm running is sudo snort -c /usr/local/etc/snort/snort.lua -r ~/pcaps/maccdc2012_00000.pcap -l /var/log/test -s 65535 -k none -q -m 0x00FF Version of snort: noah@snort3:~$ snort -V ,,_ -*> Snort++ <*- o" )~ Version 3.0.0 (Build 250) from 2.9.11 '''' By Martin Roesch & The Snort Team http://snort.org/contact#team Copyright (C) 2014-2018 Cisco and/or its affiliates. All rights reserved. Copyright (C) 1998-2013 Sourcefire, Inc., et al. Using DAQ version 2.2.2 Using LuaJIT version 2.1.0-beta3 Using OpenSSL 1.1.0g 2 Nov 2017 Using libpcap version 1.8.1 Using PCRE version 8.39 2016-06-14 Using ZLIB version 1.2.11 Using FlatBuffers 1.10.0 Using Hyperscan version 5.0.0 2018-12-08 Using LZMA version 5.2.2 I'm not sure if i'm doing something wrong, or if this is a bug. thanks Noah
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Current thread:
- Problems with umask on Snort 3 Noah Dietrich (Jan 03)
- Re: Problems with umask on Snort 3 Carter Waxman (cwaxman) via Snort-devel (Jan 04)
- Re: Problems with umask on Snort 3 Carter Waxman (cwaxman) via Snort-devel (Jan 04)
- Re: Problems with umask on Snort 3 Noah Dietrich (Jan 04)
- Re: Problems with umask on Snort 3 Carter Waxman (cwaxman) via Snort-devel (Jan 04)
- Re: Problems with umask on Snort 3 Noah Dietrich (Jan 04)
- Re: Problems with umask on Snort 3 Carter Waxman (cwaxman) via Snort-devel (Jan 04)
- Re: Problems with umask on Snort 3 Carter Waxman (cwaxman) via Snort-devel (Jan 04)