Snort mailing list archives
Re: THREAD_LOCAL
From: Sancho Panza <sancho () posteo de>
Date: Sun, 25 Jan 2015 16:21:58 +0100
On Fr, 2015-01-23 at 16:04 +0000, Russ Combs (rucombs) wrote:
* No, IpsOptions are instantiated as rules are parsed and should only hold configuration. What kind of state information are you trying to update? Is it per thread or per session? If you really want global, you will need to synchronize access (which impacts performance).
I am writing an IPs option that will adds some kind of "probability score" to a generated alert. The idea is as follows: By default, an event triggered by a rule that lacks my option gets a score of 5 (neutral). My option will then allow you to specify things like: Packet Node: Either of "Source" or "Destination" Correlation Attribute: "Operating System", "Architecture", etc... Attribute Value (depending on the attribute): "linux", "windows", "x86", "SPARC", etc... Success: 0-10 (value to add to default score on match) Failure: 0-10 (value to subtract from score on failue to match) When the option evaluates, it will look the source or destination node up in some sort of dictionary to find out whether the packet matches and increment or decrement the default score accordingly. I already saw that the LUA kind of option makes use of an array to keep the LUA state of each thread in a separate value. But even that does not help me. The problem is that it should be possible to use this option more than once in a rule, and when the second option for a rule and packet evaluates, it should of course modify the result of the first evaluation (NOT the default value!) I already saw that it's also NOT an option to store that value in the packet itself, because for each rule that's checked against the packet, this value must be reset to the default value. I think whats necessary is some kind of argument that can be passed to the eval function like so (pseudo code): for each packet p: score = DEFAULT for each rule r: for each option o in r: o.evaluate(p, &score); When an event is generated for a given combination of (packet and rule), the corresponding score shall be written into the event structure... Can you confirm this is only possible by changing the signature of the eval function? Thanks Sancho
Many thanks Sancho ------------------------------------------------------------------------------ New Year. New Location. New Benefits. New Data Center in Ashburn, VA. GigeNET is offering a free month of service with a new server in Ashburn. Choose from 2 high performing configs, both with 100TB of bandwidth. Higher redundancy.Lower latency.Increased capacity.Completely compliant. http://p.sf.net/sfu/gigenet _______________________________________________ Snort-devel mailing list Snort-devel () lists sourceforge net https://lists.sourceforge.net/lists/listinfo/snort-devel Archive: http://sourceforge.net/mailarchive/forum.php?forum_name=snort-devel Please visit http://blog.snort.org for the latest news about Snort!
------------------------------------------------------------------------------ New Year. New Location. New Benefits. New Data Center in Ashburn, VA. GigeNET is offering a free month of service with a new server in Ashburn. Choose from 2 high performing configs, both with 100TB of bandwidth. Higher redundancy.Lower latency.Increased capacity.Completely compliant. http://p.sf.net/sfu/gigenet _______________________________________________ Snort-devel mailing list Snort-devel () lists sourceforge net https://lists.sourceforge.net/lists/listinfo/snort-devel Archive: http://sourceforge.net/mailarchive/forum.php?forum_name=snort-devel Please visit http://blog.snort.org for the latest news about Snort!
Current thread:
- THREAD_LOCAL Sancho Panza (Jan 23)
- Re: THREAD_LOCAL Russ Combs (rucombs) (Jan 23)
- Re: THREAD_LOCAL Sancho Panza (Jan 25)
- Re: THREAD_LOCAL Russ Combs (rucombs) (Jan 26)
- Re: THREAD_LOCAL Sancho Panza (Jan 25)
- Re: THREAD_LOCAL Russ Combs (rucombs) (Jan 23)