More fuzz tests and small fixes for the findings (#10864)
* first pass tests * more tests * Fix two crafted-admin-packet crashes found by the E5 fuzzer Both are reachable from an authorized admin (local from==0, admin channel, or PKC) - remote DoS: 1. SIGFPE in LoRa config validation. A set_config LoRaConfig with use_preset=false and bandwidth=0 makes freqSlotWidth 0, so numFreqSlots is 0 and `hash(name) % numFreqSlots` (RadioInterface.cpp) divides by zero. Guard the modulo; the existing channel_num check then rejects/ clamps the config. 2. Stack overflow in Channels::getKey. A SECONDARY channel at the primary slot with an empty PSK recursed into getKey(primaryIndex) forever. Skip the primary-key borrow when chIndex == primaryIndex. Re-enable the E5 admin fuzzer to hit both triggers again (use_preset both ways incl. bandwidth 0, plus the set_channel tag) as regression guards. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * Correct fuzz-test invariants after the crash fixes - E5 admin fuzz: node eviction under a filling NodeDB is legitimate, so assert only the bounded-count invariant, not that a specific seed node survives 6000 mutating ops. - TMM blitz: scope off the nodeinfo direct-response send path (it needs a fully-wired MeshService/phone queue the fixture doesn't provide; the deterministic directResponse tests cover it). The crafted-nodenum rate/unknown/position cache stress is unchanged. clod helped too * realistic tests * test: dedup fuzz RNG into shared test/support/DeterministicRng.h The four in-tree fuzz suites (test_fuzz_decode, test_fuzz_packets, test_hop_scaling, test_traffic_management) each carried a byte-identical copy of the seeded 64-bit LCG (rngSeed/rngNext/rngByte/rngRange). Hoist it into one shared header so there is a single generator to reason about and no risk of the copies drifting. static inline keeps per-suite state per translation unit and avoids -Wunused-function for suites that don't use every helper. Also corrects a stale comment in test_traffic_management (the blitz's nodeinfo direct-response path is intentionally left off). No behavioral change: same constants, same per-suite seeds. clod helped too * test: fuzz uncovered ProtobufModule handlers and the MQTT downlink ingress Extend the in-tree fuzz coverage to packet sources that previously had none: - test_fuzz_packets E8/E9/E10: drive PositionModule, DeviceTelemetryModule and NeighborInfoModule at handleReceivedProtobuf directly (via using-shims, bypassing the ProtobufModule reply/send path so no router is needed). The fixture already stands up nodeDB/service/channels, and nodeStatus/powerStatus are auto-initialized in main.cpp, so no new globals are required. Adds a shared fuzzRxHeader() helper for crafting adversarial RX packet headers. - test_fuzz_decode: add meshtastic_KeyVerification to the decode table. The KeyVerification and StoreForward handler paths are documented as decode-level only, with the concrete reason each is intrinsic (private-state gating / PSRAM + self-pointer wiring), not a fixture gap. - test_mqtt: test_receiveFuzzServiceEnvelope blitzes the non-RF broker-push ingress (onReceiveProto) two ways - raw garbage bytes that must fail envelope decode cleanly, and a well-formed ServiceEnvelope wrapping a crafted inner MeshPacket over crafted channel_id/gateway_id - exercising the channel match, isFromUs, XEdDSA receive policy and perhapsDecode chain. Adds a deliverRaw() passthrough to MQTTUnitTest. All under the coverage env (ASan/LSan). No firmware/src changes. Full sweep GREEN 27/27, 544 cases. clod helped too * Harden LoRa/channel config against crafted admin messages; consolidate test helpers Production (review findings on the hot-fuzz crash fixes): - Clamp bandwidth at the source (clampBandwidthKHz) in checkOrClampConfigLora and applyModemConfig so numFreqSlots can never be 0 for any consumer; a bandwidth-0 set_config previously passed validation and re-armed the SIGFPE on the next applyModemConfig. - Guard applyModemConfig's hash % numFreqSlots (the validator's sibling modulo was fixed earlier but this one was still unguarded). - Enforce the primary-channel invariant in Channels::onConfigChanged: a config demoting every slot now re-promotes the stale SECONDARY slot (keeping its key) or restores the default channel if the slot is DISABLED, instead of leaving every getPrimaryIndex() reader on a non-primary slot. The getKey recursion guard stays as defense-in-depth. Tests: - New test/support/MockMeshService.h and AdminModuleTestShim.h replace four byte-identical mocks and three divergent admin shims (test_mqtt's capturing mock is genuinely different and stays). - DeterministicRng.h: add rngFill() (replaces 14 hand-rolled fill loops) and rngEdgeNodeNum() (unifies the three NodeNum boundary pools). - Extract fuzzChannelSettings() shared by the set_channel case and fuzzBeacon. - fuzzBeacon: the un-terminated branch now fills the whole buffer with non-NUL bytes so the strnlen bound is actually stressed (~50% of iterations, not ~4%). - E6 beacon fuzz: replace the TEST_ASSERT_TRUE(true) tautology with real invariants (handler never consumes; offers land in lastReceivedOffer keyed to the sender). - Trim the seven over-long comment blocks flagged against the 1-2 line rule; the FINDINGS trailer moves to this commit message (see production notes). Full native suite GREEN 27/27 under the coverage (ASan/LSan) env. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * Clamp UTF-8 char length in the emote walkers; add test_fuzz_emotes A TEXT_MESSAGE payload is opaque protobuf bytes, so PB_VALIDATE_UTF8 never screens it - invalid UTF-8 and truncated multi-byte lead bytes reach the emote/width render path verbatim. EmoteRenderer's walkers advanced by utf8CharLen(lead) without clamping to the bytes actually remaining, so a truncated lead (e.g. a lone 0xF0, which claims 4 bytes) near the end of the buffer made getUtf8ChunkWidth's memcpy read past the string. ASan confirms a heap-buffer-overflow READ from measureStringWithEmotes. Add utf8CharLenClamped() and use it at every walk site (width measure, truncation cut-loop, and the draw-path text-run/chunk builders); the one already-guarded site (matchAtIgnoringModifiers) is unchanged. New test/test_fuzz_emotes drives measureStringWithEmotes and truncateToWidth over adversarial byte strings (biased to embed/end in truncated multi-byte leads) in exact-sized heap buffers so any over-read is a hard ASan fault. Its headless display uses a synthetic font (firstChar 0, fontData centered in a large buffer) so the stock OLEDDisplay::getStringWidth - which indexes the font jump table with a signed char and over-reads for any byte >= 0x80 - does not mask the finding. native-suite-count bumped 27 -> 28. Full native suite GREEN 28/28 under the coverage (ASan/LSan) env. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * Keep emote width measurement in-bounds for non-ASCII bytes OLEDDisplay::getStringWidth (the utf8=false path EmoteRenderer uses on default builds) indexes the font jump table by (c - firstChar) with a signed char and no bounds check, so any byte outside printable ASCII - high bytes from UTF-8 text, but also a stray control byte like 0x0A - reads outside the font array. On-device this reads adjacent flash and returns a garbage width; under ASan the test_fuzz_emotes fuzzer flags it as a global-buffer-overflow, and it made the non-ASCII width measurement meaningless either way. The OLED driver is a pinned upstream dependency, so guard it firmware-side in EmoteRenderer's getStringWidth helper: measure a sanitized copy where any byte outside [0x20, 0x7E] counts as a '?' placeholder. Printable ASCII is unchanged and the UA/RU lookup path is untouched. test_fuzz_emotes now drives a real ArialMT font instead of the synthetic in-bounds font it needed before this fix, so the suite exercises the true production width path (utf8CharLen clamp + this sanitizer) end to end. The same fuzzer tripped the global-buffer-overflow before this change. Full native suite GREEN 28/28 under the coverage (ASan/LSan) env. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> --------- Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
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@@ -106,6 +106,10 @@ static uint32_t makeDistributedNodeId(uint32_t baseId, uint32_t ordinal, uint32_
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return baseId + salt + (ordinal * 33u);
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}
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// Deterministic RNG (rngSeed/rngNext/rngRange) - shared seeded LCG.
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#include "support/DeterministicRng.h"
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static constexpr uint64_t FUZZ_SEED = 0x00F0B5CA1EULL;
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// ---------------------------------------------------------------------------
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// Helpers - mesh topology builders
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// ---------------------------------------------------------------------------
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@@ -661,6 +665,57 @@ static void test_memory_layout()
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// Unity setup / teardown / main
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// ---------------------------------------------------------------------------
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// ---------------------------------------------------------------------------
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// Fuzz - crafted-nodenum blitz of the hop histogram
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// ---------------------------------------------------------------------------
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// The scenario tests above check the scaling *math* with realistic topologies. This one is adversarial:
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// it floods samplePacketForHistogram with node numbers chosen to maximize table churn (a tiny colliding
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// pool, boundary values, broad random) plus denominator swings and hourly rolls, and asserts the fixed
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// 128-entry table's invariants hold on every step. hopCount is kept in 0..MAX_HOP: the wire caps hops at
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// 7 (3-bit protobuf field), so out-of-range hops are not a reachable input. Runs under ASan/LSan.
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void test_fuzz_nodenum_blitz(void)
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{
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TEST_MSG_FMT("=== Fuzz: crafted-nodenum histogram blitz (seed=0x%llx) ===", (unsigned long long)FUZZ_SEED);
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rngSeed(FUZZ_SEED);
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static HopScalingTestShim shim; // static: OSThread-derived (Unity longjmp skips dtors on a failed assert)
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shim.clear();
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shim.setHistogramDenominator(HopScalingModule::DENOM_MIN); // sample-all: maximum admission / churn
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for (unsigned k = 0; k < 40000; k++) {
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NodeNum id;
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switch (rngRange(4)) {
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case 0:
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id = rngEdgeNodeNum(&kLocalNode, 1);
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break; // shared boundary pool (0/1/broadcast) + local node
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case 1:
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id = rngNext() & 0xFFu;
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break; // tiny pool: forces hash reuse (update path) and collisions
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default:
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id = ((NodeNum)rngNext() << 1) ^ rngNext();
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break; // broad random
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}
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uint8_t hop = (uint8_t)rngRange(HopScalingModule::MAX_HOP + 1); // 0..7, wire-bounded
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shim.samplePacketForHistogram(id, hop);
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// Occasionally swing the sampling denominator and roll the hour to drive trim / eviction /
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// the hourly rolling + scaling under sustained churn. Denominators stay powers of two (1..128) -
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// the only states the module actually produces (its passesFilter uses hash & (denom-1)).
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if (rngRange(256) == 0)
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shim.setHistogramDenominator((uint8_t)(1u << rngRange(8))); // 1, 2, 4, ... 128
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if (rngRange(512) == 0) {
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mockTime += ONE_HOUR_MS;
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shim.rollHourTest();
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}
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// Invariants that must hold on every step regardless of input.
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TEST_ASSERT_TRUE_MESSAGE(shim.getEntryCount() <= HopScalingModule::CAPACITY, "histogram overran CAPACITY");
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TEST_ASSERT_TRUE_MESSAGE(shim.getFillPercentage() <= 100, "fill percentage exceeded 100");
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TEST_ASSERT_TRUE_MESSAGE(shim.getLastRequiredHop() <= HOP_MAX, "required-hop recommendation exceeded HOP_MAX");
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}
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}
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void setUp(void)
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{
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if (!mockNodeDB)
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@@ -712,6 +767,9 @@ void setup()
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RUN_TEST(test_filtering_denom_steps_down_gradually);
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RUN_TEST(test_full_at_denom_max_drops_entry);
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printf("\n=== Fuzz ===\n");
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RUN_TEST(test_fuzz_nodenum_blitz);
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printf("\n=== Summary ===\n");
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RUN_TEST(test_memory_layout);
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RUN_TEST(test_scenario_summary_output);
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