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# rtt-fuzzer
Fuzzer for [Rally The Troops!](https://rally-the-troops.com/) boardgame rules.
It uses [Jazzer.js](https://github.com/CodeIntelligenceTesting/jazzer.js/) as a coverage-guided, in-process fuzzer for node.js.
## What is fuzzing?
Fuzzing or fuzz testing is an automated software testing technique that involves providing invalid, unexpected, or random data as inputs to a computer program. With rtt-fuzzer you can test the rules for any RTT module. It will play random moves and check for unexpected errors.
Currently rtt-fuzzer can detect the following errors:
* A game taking an excessive number of steps, this could indicate infinite loops and other logical flaws in the rules. This is configurable via the `MAX_STEPS` environment variable, set it to a positive value to crash and to a negative value to skip & ignore.
* Dead-end game states where no other actions are available (besides `undo`).
* Any crashes of the rules.js module
## Quickstart
To use `rtt-fuzzer` to fuzz any RTT module follow these few simple steps:
1. Install dependency
```
npm install
```
2. Start the rtt-module fuzzer:
```
RTT_RULES=../server/public/field-cloth-gold/rules.js npx jazzer rtt-module
```
You can specify the RTT `rules.js` file with the `RTT_RULES` environment variable, it uses `rules.js` from the current directory by default.
3. Enjoy fuzzing!
## Example output
The following output shows a potential bug in the `move_persian_army` function of `300-earth-and-water/rules.js`:
```
$ RTT_RULES=../server/public/300-earth-and-water/rules.js npx jazzer rtt-module
Loading rtt-fuzzer RTT_RULES='../server/public/300-earth-and-water/rules.js' with MAX_STEPS=2048
INFO: New number of coverage counters 1024
INFO: New number of coverage counters 2048
Dictionary: 4 entries
INFO: Running with entropic power schedule (0xFF, 100).
INFO: Seed: 1668133216
INFO: Loaded 3 modules (2048 inline 8-bit counters): 512 [0x148050000, 0x148050200), 512 [0x148050200, 0x148050400), 1024 [0x148050400, 0x148050800),
INFO: Loaded 3 PC tables (2048 PCs): 512 [0x1124b4000,0x1124b6000), 512 [0x1124b6000,0x1124b8000), 1024 [0x1124b8000,0x1124bc000),
INFO: -max_len is not provided; libFuzzer will not generate inputs larger than 4096 bytes
GAME { seed: 1, scenario: 'Standard', options: {} }
VIEW {
log: [
'Start Campaign 1',
'',
'Persian Preparation Phase',
'Persia bought 6 cards.',
'Persia raised:\n 6 armies in Abydos',
'.hr',
'Greek Preparation Phase',
'Greece bought 6 cards.',
'Greece raised:\nnothing.',
'.hr',
'Persia played card 10 for movement.',
'Persia moved p armies:\nAbydos to E.'
],
active: 'Persia',
campaign: 1,
vp: 0,
trigger: {
darius: 0,
xerxes: 0,
artemisia: 0,
miltiades: 0,
themistocles: 0,
leonidas: 0,
hellespont: 0,
carneia_festival: 0,
acropolis_on_fire: 0
},
units: {
Abydos: [ 0, NaN, 0, 0 ],
Athenai: [ 1, 0, 1, 0 ],
Delphi: [ 0, 0 ],
Ephesos: [ 0, 2, 0, 1 ],
Eretria: [ 0, 0, 0, 0 ],
Korinthos: [ 1, 0 ],
Larissa: [ 0, 0 ],
Naxos: [ 0, 0, 0, 0 ],
Pella: [ 0, 0, 0, 0 ],
Sparta: [ 1, 0, 1, 0 ],
Thebai: [ 0, 0, 0, 0 ],
reserve: [ 6, 14, 3, 5 ]
},
g_cards: 6,
p_cards: 5,
discard: 10,
deck_size: 4,
discard_size: 1,
prompt: 'Persian Land Movement: Select armies to move and then a destination.',
land_movement: 'Abydos',
actions: { city: [ 'Ephesos' ] },
hand: [ 4, 1, 8, 2, 3 ],
draw: 0
}
STEP=24 ACTIVE=Persia ACTION: city "Ephesos"
STATE dumped to 'crash-state.json'
==63262== Uncaught Exception: Jazzer.js: TypeError: Cannot read properties of undefined (reading '1')
TypeError: Cannot read properties of undefined (reading '1')
at move_persian_army /home/user/projects/rtt/server/public/300-earth-and-water/rules.js:448:12)
at Object.city (/home/user/projects/rtt/server/public/300-earth-and-water/rules.js:1159:3)
at Object.action (/home/user/projects/rtt/server/public/300-earth-and-water/rules.js:3448:12)
at module.exports.fuzz (/home/user/projects/rtt/rtt-fuzzer/rtt-module.js:65:27)
at result (/home/user/projects/rtt/rtt-fuzzer/node_modules/@jazzer.js/core/core.ts:357:15)
MS: 0 ; base unit: 0000000000000000000000000000000000000000
artifact_prefix='./'; Test unit written to ./crash-da39a3ee5e6b4b0d3255bfef95601890afd80709
Base64:
```
## What does the status output mean?
```
#2 INITED cov: 387 ft: 387 corp: 1/1b exec/s: 0 rss: 151Mb
#3 NEW cov: 408 ft: 490 corp: 2/2b lim: 4 exec/s: 0 rss: 151Mb L: 1/1 MS: 1 ChangeBinInt-
#4 NEW cov: 412 ft: 532 corp: 3/3b lim: 4 exec/s: 0 rss: 151Mb L: 1/1 MS: 1 ChangeBinInt-
#6 NEW cov: 417 ft: 555 corp: 4/5b lim: 4 exec/s: 0 rss: 151Mb L: 2/2 MS: 2 ShuffleBytes-InsertByte-
```
See the LibFuzzer documentation for more details on the output
https://llvm.org/docs/LibFuzzer.html#output
|
