Fix out-of-bounds reads in IcmpLayer getters on truncated packets - #2240
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Fix out-of-bounds reads in IcmpLayer getters on truncated packets#2240Mrmaxmeier wants to merge 1 commit into
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## dev #2240 +/- ##
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+ Coverage 82.71% 82.81% +0.09%
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Files 333 333
Lines 60367 60337 -30
Branches 12879 12509 -370
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+ Hits 49933 49967 +34
- Misses 9021 9498 +477
+ Partials 1413 872 -541
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Every get*Data() method checked only the ICMP message type before casting the layer buffer to the fixed-size structure that type implies, so a truncated capture produced an IcmpLayer shorter than the structure it claims to be and reading any field past the layer was out of bounds. Route those getters through a castMessageData() helper that requires the whole structure to be present, and tighten isDataValid() accordingly. Assisted-By: Claude Opus 5 <noreply@anthropic.com>
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Hi,
we ran into an out-of-bounds read ASAN report with the
FuzzTarget.cppharness:The input is included in this PR under
Tests/Fuzzers/RegressionTests/regression_samples/crash-icmp-info-request-truncated.The
getX()methods inIcmpLayer.hcurrently only check the type field, and return a casted struct without verifying that the underlying buffer has enough data. This PR adjusts these getters to returnnullptrin the case of packets without enough data. It also adds a test that verifies this behaviour for various ICMP message types.Thanks!
Found by the CISPA Fandango team while triaging findings in oss-fuzz harnesses.