detect/bsize: Validate against content buffer when available #5028
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This commit updates the bsize documentation 1. Describe what happens when "content" immediately precedes "bsize" 2. Include the operators and 3. Include examples using the operators.
This commit causes the signature to be invalid if a content keyword immediately precedes bsize and the bsize value is incompatible with the content length.
This commit adds test cases that validate behavior when "content" immediately precedes "bsize".
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Could we use detect-engine-uint.c helper functions ? |
I don't think that would be a benefit in this case. |
inashivb
reviewed
Oct 6, 2020
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| .. container:: example-rule | ||
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| alert dns any any -> any any (msg:"test bsize rule"; dns.query; content:"middle"; bsize:5<>15; sid:126; rev:1;) |
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This should probably be bsize:6<>15 as length of "middle" is 6.
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What does 6<>15 mean ? A range ?
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Continued in #5576 |
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Continuation of #5014
This PR adds additional validation when using the
bsizekeyword. If a one or morecontentkeywords immediately precedesbsize, then thebsizevalue is checked against each to see if a match is possible using the operation (=, <, >, <>) and the value.An error is raised if
bsizevalue prevents a match, e.g., the content length exceeds thebsizevalue. Thebsizeoperation and values are used to do the evaluation.Link to redmine ticket: 3682
Describe changes:
Companion Suricata PR #233