detect/absent: Add error_or, must_error, and must_succeed options#15745
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jlucovsky wants to merge 8 commits into
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detect/absent: Add error_or, must_error, and must_succeed options#15745jlucovsky wants to merge 8 commits into
jlucovsky wants to merge 8 commits into
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SCInspectionBufferSetupAndApplyTransforms resets buffer->flags to 0, which clobbered the DCE byte-order flag when it was set first. Reorder so the byte-order flag is applied after the buffer is set up. Without this, dcepayload-15 (and similar tests that depend on the DCE byte-order flag reaching content inspection) fail. Issue: 7114
Issue: 7114 Add a way to flag inspection buffer errors. Add a new flag to track those.
Add parsing and engine analyzer support for the error_or, must_error, and must_succeed options to the absent keyword. Use enum DetectAbsentMode instead of individual bool fields. Validate that error_or/must_error/must_succeed require a failing transform, or_else rejects failing transforms, and must_error cannot be combined with other keywords. Issue: 7114
Issue: 7114 Mark from_base64 with SIGMATCH_TRANSFORM_CAN_FAIL and call SCInspectionBufferSetError when decode produces zero bytes.
Reset buffer->flags in InspectionBuffer setup functions so stale flags don't carry over across uses. Propagate buffer->flags into ciflags in detect-filename, detect-filemagic, detect-file-data, and detect-http-client-body so transform error flags reach content inspection. Issue: 7114
Document error_or, must_error, and must_succeed options for the absent keyword with examples and comparison of all five modes. Issue: 7114
Mark pcrexform with SIGMATCH_TRANSFORM_CAN_FAIL and call SCInspectionBufferSetError when the pcre match fails or capture group extraction fails. This enables error_or and must_error to detect pcrexform failures, and must_succeed to prevent false matches when the transform fails. Issue: 7114
Document that pcrexform signals an error when the pattern does not match, enabling use with absent: error_or, must_error, and must_succeed. Issue: 7114
jlucovsky
requested review from
jasonish,
jufajardini and
victorjulien
as code owners
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## main #15745 +/- ##
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+ Coverage 82.95% 82.97% +0.01%
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Lines 275096 275371 +275
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+ Hits 228217 228494 +277
+ Misses 46879 46877 -2
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Continuation of #15739
Add
error_orandmust_erroroptions to theabsentkeyword, enablingrules to detect when a transform operation (such as base64 decoding or
pcre matching) fails on an inspection buffer.
The five
absentmodes:absent— matches only when the buffer is absent (existing behavior)absent: or_else— matches when absent OR subsequent keywords match (existing behavior, renamed)absent: error_or— matches when a transform error occurs OR subsequent keywords matchabsent: must_error— matches only when a transform error occurs; no other keywords allowed on the same bufferPrevents false positives by ensuring content inspection only runs on successfully transformed data.
Link to ticket: https://redmine.openinfosecfoundation.org/issues/7114
Describe changes:
SCInspectionBufferSetError()to flag when a transform cannot complete with theDETECT_CI_FLAGS_ERRORflag. When this is set, the buffer data is not modified.from_base64andpcrexformsignal errors when the transform cannot complete.are paired with a can-fail transform; thator_elseis not paired with a can-fail transform (use error_or instead); thatmust_erroris not combined with other content keywords; thatabsentandfast_pattern` are not used on the same buffer; and that only one absent keyword appears per buffer.absent.modestringUpdates:
must_succeed-- matches on transform success only.Provide values to any of the below to override the defaults.
link to the pull request in the respective
_BRANCHvariable.SV_REPO=
SV_BRANCH=OISF/suricata-verify#2982
SU_REPO=
SU_BRANCH=