detect/content: account for distance variables #12773
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Under some cases (below), the depth and offset values are used twice. This commit disregards the distance variable (if any), when computing the final depth. These rules are logically equivalent:: 1. alert tcp any any -> any 8080 (msg:"distance name"; flow:to_server; content:"Authorization:"; content:"5f71ycy"; distance:0; byte_extract:1,0,option_len,string,relative; content:!"|38|"; distance:option_len; within:1; content:"|37|"; distance:-1; within:1; content:"|49|"; distance:option_len; within:1; sid:1;) 2. alert tcp any any -> any 8080 (msg:"distance number"; flow:to_server; content:"Authorization:"; content:"5f71ycy"; distance:0; byte_extract:1,0,option_len,string,relative; content:!"|38|"; distance:7; within:1; content:"|37|"; distance:-1; within:1; content:"|49|"; distance:option_len; within:1; sid:2;) The differences: Rule 1: content:!"|38|"; distance:option_len; within:1; //option_len == 7 Rule 2: content:!"|38|"; distance:7; within:1; Without this commit, rule 2 triggers an alert but rule 1 doesn't. Issue: 7390
Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## master #12773 +/- ##
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- Coverage 80.87% 80.87% -0.01%
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Files 936 936
Lines 259748 259755 +7
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+ Hits 210061 210066 +5
- Misses 49687 49689 +2
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WARNING: ERROR: QA failed on SURI_TLPR1_alerts_cmp.
Pipeline 25141 |
This will need to be analyzed, it's the same as with the last PR. No point in further rebases until it is understood why this happens. |
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Continuation of #12297; rebased and recreated to grab fresh QA stats.
In some cases (below), the depth and offset values are used twice. This commit disregards the distance variable (if any), when computing the final depth.
These rules are logically equivalent:
The differences:
Rule 1: content:!"|38|"; distance:option_len; within:1; //option_len == 7
Rule 2: content:!"|38|"; distance:7; within:1;
Rule 2 triggers an alert without this commit, but rule 1 doesn't.
Link to ticket: https://redmine.openinfosecfoundation.org/issues/7390
Describe changes:
distancevariable is involved, don't double addUpdate:
Provide values to any of the below to override the defaults.
link to the pull request in the respective
_BRANCHvariable.SV_REPO=
SV_BRANCH=
SU_REPO=
SU_BRANCH=
LIBHTP_REPO=
LIBHTP_BRANCH=