Snort mailing list archives   By Date           By Thread         Issues with the Snort Manual (Patch) From: Date: Tue, 23 Nov 2010 23:03:14 -0500  Hi snort-devel, Reading through the Snort manual, I am bothered by the large number of inconsistencies, spelling errors, missing option parameters, etc found within the manual. Snort is a complicated piece of software. How are we supposed to properly learn it if the documentation doesn't fully explain things or even contradicts itself at times? I've attached a patch to the LaTeX source file from the recent release of snort-2.9.0.1, found in the doc/ subdir. The patch corrects a lot of problems I've identified in the manual pertaining to rule options. I did not review or study the other areas of the manual, but I would not be surprised if a lot of the minor tweaks in the rule options section (mostly inconsistent use of white space) also exist elsewhere. I am also not able to actually build TeX files into PDF, as I lack the appropriate tools at present. Here's a summary of what I changed: - Removed extraneous spaces between a rule option name and its parameter list. I.e., content: "ABC"; --> content:"ABC";. I have noticed that the main SourceFire product will choke when importing text files with rules that contain a space after the colon. There is no guidance in the manual on what it accepted practice. So, looking over VRT and ET rule releases, I adopted the notation that there should be no space between a rule option's name and its parameter list. - Removed extraneous spaces between rule option parameters. I.e., byte_test:1, !&, 128, 0; --> byte_test:1,!&,128,0;. Similar to the above, this is mostly a style change. The common notation is no whitespacing between parameter options. I have probably missed a few of these in other parts of the manual. - dce_iface/dce_opnum: Re-wrote the example syntax to line up with the rest of the manual. - byte_test/byte_jump in DCERPC2: Ditto. - sd_pattern: Added missing semi-colon to the end of the syntax. - reference: Added missing "osvdb" system ID, and updated the "mcafee" HTTP URL from snort-2.9.0.1. - content modifiers depth/offset/distance/within: Added notation that these four options can take either a number OR a string value representing a variable created by the "byte_extract" option. The lack of this mention could lead to confusion and I am surprised that it was missed when byte_extract was added. Also used the \texttt{} operator instead of single quotes in the description fields on a few items. - depth: All four of the numeric content modifiers invoke a ParseInt() function to convert the string value into a number. This ParseInt function accepts -65,535 to 65,535 as a valid range of values. This does not align with the change in depth's documentation from snort-2.9.0 to 2.9.0.1. No change was made pursuant to this notation. However, I changed the documentation to reflect the fact that depth:0; is invalid, because the source code in src/detection-plugins/sp_pattern_match.c, lines 518 to 523, do an explicit check for depth != 0 and that depth is greater-than-or-equal-to the length of the pattern specified in the matched content option. Therefore, it is impossible to have a depth of 0 because you cannot have a content with no length. - http_encode: Removed erroneous LaTeX \hline before the row for "ascii". - byte_test: Removed the '!' operator from the table detailing the possible operators. I reported this once, and found it sloppy that while one or two edits were made to address the original issue on the preceding page, that the table, nor the notation at the bottom, were not updated. - byte_jump: Another case of sloppiness: The example block for byte_test was copied to byte_jump and not changed. So, I am certain a few people might've scratched their heads at the mentioning of an or field, neither of which applies to byte_jump. - byte_extract: The source code does not support the mention that byte_extract's "offset" parameter can also hold a value. src/detection-plugins/sp_byte_extract.c, line 244 to line 251 backs this up. So I removed the table row stating that this was possible. If this IS possible, then the source code needs to be changed. - byte_test/byte_jump/byte_extract: Re-wrote the syntax line to match other elements in the manual. For byte_jump and byte_extract specifically, they mimic the way byte_test mentions its "" and "string," parameter.. - asn1: Listed out the options in the syntax example. I made the assumption that relative_offset and absolute_offset cannot be used together. Clarification on this would be appreciated. Also added the missing "print" option, although, I can find NO documentation explaining what it is for. - ttl: Broke the syntax example up into two pieces, as it's complex and reads better with two syntax examples. Also explicitly spelled out that <= and >= are valid operators. - ipopts: Added missing "lsrre" option. Referenced CVE-1999-0909, but that doesn't explain much. - dsize, icode, itype: Copied the syntax example for urilen and used it with these three options, as that is a more clear example. - flags: Reserved 1 is now CWR, Congestion Window Reduced, and Reserved 2 is ECE, ECN-Echo. This is per the notes on the Wikipedia page for TCP. Flag values still refer to these as "1, and "2". Also removed "0" from the set of allowable values for the optional 'mask' field. - flowbits: Added missing "isnotset" to the list of parameters in the syntax example. Also added the explanation for "reset" to the flowbits table. - icode: The usage example erroneously referred to it as "code". Fixed. - stream_size: Spelled out tht != means "not equal". It previously said "not". - session: Added the missing "binary" option after reviewing the source code. NO explanation for this option exists, so I assumed that it writes out data in some unknown binary format. Clarification on this would be appreciated. - tag: Added optional "0,packets," parameter to the syntax example. Used to override tagged_packet_limit. - replace: Double quotes around the string. - detection_filter/threshold: Shortened the syntax example to one line. Please let me know if there are any issues with any elements of this patch. Also, is there a QA team in place to validate changes to the manual in new releases? Thanks!, --J Attachment: snort-manual_2.9.0.1-fixes.patch Description: snort-manual_2.9.0.1-fixes.patch ------------------------------------------------------------------------------ Increase Visibility of Your 3D Game App & Earn a Chance To Win $500! Tap into the largest installed PC base & get more eyes on your game by optimizing for Intel(R) Graphics Technology. Get started today with the Intel(R) Software Partner Program. Five$500 cash prizes are up for grabs. http://p.sf.net/sfu/intelisp-dev2dev_______________________________________________ Snort-devel mailing list Snort-devel () lists sourceforge net https://lists.sourceforge.net/lists/listinfo/snort-devel  Current thread: Issues with the Snort Manual (Patch) Joshua.Kinard (Nov 27) Re: Issues with the Snort Manual (Patch) Joel Esler (Nov 27) Re: Issues with the Snort Manual (Patch) Joshua.Kinard (Nov 29) Re: Issues with the Snort Manual (Patch) Joel Esler (Nov 27) Re: Issues with the Snort Manual (Patch) Joshua.Kinard (Nov 29) Re: Issues with the Snort Manual (Patch) Joel Esler (Nov 30) Re: Issues with the Snort Manual (Patch) Joshua.Kinard (Nov 30) Re: Issues with the Snort Manual (Patch) Joel Esler (Nov 30) Re: Issues with the Snort Manual (Patch) Ryan Jordan (Dec 08) Re: Issues with the Snort Manual (Patch) Joshua.Kinard (Dec 09)
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