envoyproxy/envoy

Limit the size of the stat prefix in fuzz tests

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#40,527 opened on Aug 1, 2025

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area/ext_procarea/fuzzingbeginnerbughelp wanted

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Description

Test case file: clusterfuzz-testcase-ext_proc_unit_test_fuzz-5199582416928768.txt

fuzzer generated all dots 1Mb stats prefix. It needs to be limited to avoid excessive CPU cleanup of the stats store.

Steps to reproduce:

Copy downloaded test case file into the test/extensions/filters/http/ext_proc/unit_test_fuzz/ext_proc_corpus/ directory and run:

bazel build --config=asan -c dbg test/extensions/filters/http/ext_proc/unit_test_fuzz/ext_proc_unit_test_fuzz
bazel-bin/test/extensions/filters/http/ext_proc/unit_test_fuzz/ext_proc_unit_test_fuzz test/extensions/filters/http/ext_proc/unit_test_fuzz/ext_proc_corpus/clusterfuzz-testcase-ext_proc_unit_test_fuzz-5199582416928768.txt

Contributor guide

Research direction
Inspect the failing test and trace the stat prefix construction in the ext proc filter. Identify where the prefix string is built and add a size limit to prevent large prefixes.
Tech stack
cpp
Domain
backendnetworking
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GitBazel
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75