main.go

Documentation: go.mongodb.org/mongo-driver/cmd/build-oss-fuzz-corpus

     1  // Copyright (C) MongoDB, Inc. 2023-present.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License"); you may
     4  // not use this file except in compliance with the License. You may obtain
     5  // a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
     6  
     7  // Entry point for the MongoDB Go Driver integration into the Google "oss-fuzz" project
     8  // (https://github.com/google/oss-fuzz).
     9  package main
    10  
    11  import (
    12  	"archive/zip"
    13  	"crypto/sha256"
    14  	"encoding/json"
    15  	"fmt"
    16  	"io/ioutil"
    17  	"log"
    18  	"os"
    19  	"path"
    20  	"path/filepath"
    21  
    22  	"go.mongodb.org/mongo-driver/bson"
    23  )
    24  
    25  const dataDir = "testdata/bson-corpus/"
    26  
    27  type validityTestCase struct {
    28  	Description       string  `json:"description"`
    29  	CanonicalExtJSON  string  `json:"canonical_extjson"`
    30  	RelaxedExtJSON    *string `json:"relaxed_extjson"`
    31  	DegenerateExtJSON *string `json:"degenerate_extjson"`
    32  	ConvertedExtJSON  *string `json:"converted_extjson"`
    33  }
    34  
    35  func findJSONFilesInDir(dir string) ([]string, error) {
    36  	files := make([]string, 0)
    37  
    38  	entries, err := ioutil.ReadDir(dir)
    39  	if err != nil {
    40  		return nil, err
    41  	}
    42  
    43  	for _, entry := range entries {
    44  		if entry.IsDir() || path.Ext(entry.Name()) != ".json" {
    45  			continue
    46  		}
    47  
    48  		files = append(files, entry.Name())
    49  	}
    50  
    51  	return files, nil
    52  }
    53  
    54  // jsonToNative decodes the extended JSON string (ej) into a native Document
    55  func jsonToNative(ej, ejType, testDesc string) (bson.D, error) {
    56  	var doc bson.D
    57  	if err := bson.UnmarshalExtJSON([]byte(ej), ejType != "relaxed", &doc); err != nil {
    58  		return nil, fmt.Errorf("%s: decoding %s extended JSON: %w", testDesc, ejType, err)
    59  	}
    60  	return doc, nil
    61  }
    62  
    63  // jsonToBytes decodes the extended JSON string (ej) into canonical BSON and then encodes it into a byte slice.
    64  func jsonToBytes(ej, ejType, testDesc string) ([]byte, error) {
    65  	native, err := jsonToNative(ej, ejType, testDesc)
    66  	if err != nil {
    67  		return nil, err
    68  	}
    69  
    70  	b, err := bson.Marshal(native)
    71  	if err != nil {
    72  		return nil, fmt.Errorf("%s: encoding %s BSON: %w", testDesc, ejType, err)
    73  	}
    74  
    75  	return b, nil
    76  }
    77  
    78  // seedExtJSON will add the byte representation of the "extJSON" string to the fuzzer's coprus.
    79  func seedExtJSON(zw *zip.Writer, extJSON string, extJSONType string, desc string) {
    80  	jbytes, err := jsonToBytes(extJSON, extJSONType, desc)
    81  	if err != nil {
    82  		log.Fatalf("failed to convert JSON to bytes: %v", err)
    83  	}
    84  
    85  	// Use a SHA256 hash of the BSON bytes for the filename. This isn't an oss-fuzz requirement, it
    86  	// just simplifies file naming.
    87  	zipFile := fmt.Sprintf("%x", sha256.Sum256(jbytes))
    88  
    89  	f, err := zw.Create(zipFile)
    90  	if err != nil {
    91  		log.Fatalf("error creating zip file: %v", err)
    92  	}
    93  
    94  	_, err = f.Write(jbytes)
    95  	if err != nil {
    96  		log.Fatalf("failed to write file: %s into zip file: %v", zipFile, err)
    97  	}
    98  }
    99  
   100  // seedTestCase will add the byte representation for each "extJSON" string of each valid test case to the fuzzer's
   101  // corpus.
   102  func seedTestCase(zw *zip.Writer, tcase []*validityTestCase) {
   103  	for _, vtc := range tcase {
   104  		seedExtJSON(zw, vtc.CanonicalExtJSON, "canonical", vtc.Description)
   105  
   106  		// Seed the relaxed extended JSON.
   107  		if vtc.RelaxedExtJSON != nil {
   108  			seedExtJSON(zw, *vtc.RelaxedExtJSON, "relaxed", vtc.Description)
   109  		}
   110  
   111  		// Seed the degenerate extended JSON.
   112  		if vtc.DegenerateExtJSON != nil {
   113  			seedExtJSON(zw, *vtc.DegenerateExtJSON, "degenerate", vtc.Description)
   114  		}
   115  
   116  		// Seed the converted extended JSON.
   117  		if vtc.ConvertedExtJSON != nil {
   118  			seedExtJSON(zw, *vtc.ConvertedExtJSON, "converted", vtc.Description)
   119  		}
   120  	}
   121  }
   122  
   123  // seedBSONCorpus will unmarshal the data from "testdata/bson-corpus" into a slice of "testCase" structs and then
   124  // marshal the "*_extjson" field of each "validityTestCase" into a slice of bytes to seed the fuzz corpus.
   125  func seedBSONCorpus(zw *zip.Writer) {
   126  	fileNames, err := findJSONFilesInDir(dataDir)
   127  	if err != nil {
   128  		log.Fatalf("failed to find JSON files in directory %q: %v", dataDir, err)
   129  	}
   130  
   131  	for _, fileName := range fileNames {
   132  		filePath := path.Join(dataDir, fileName)
   133  
   134  		file, err := os.Open(filePath)
   135  		if err != nil {
   136  			log.Fatalf("failed to open file %q: %v", filePath, err)
   137  		}
   138  
   139  		tc := struct {
   140  			Valid []*validityTestCase `json:"valid"`
   141  		}{}
   142  
   143  		if err := json.NewDecoder(file).Decode(&tc); err != nil {
   144  			log.Fatalf("failed to decode file %q: %v", filePath, err)
   145  		}
   146  
   147  		seedTestCase(zw, tc.Valid)
   148  	}
   149  }
   150  
   151  // main packs the local corpus as <fuzzer_name>_seed_corpus.zip, which is used by OSS-Fuzz to seed remote fuzzing
   152  // of the MongoDB Go Driver. See here for more details: https://google.github.io/oss-fuzz/architecture/
   153  func main() {
   154  	seedCorpus := os.Args[1]
   155  	if filepath.Ext(seedCorpus) != ".zip" {
   156  		log.Fatalf("expected zip file <corpus>.zip, got %s", seedCorpus)
   157  	}
   158  
   159  	zipFile, err := os.Create(seedCorpus)
   160  	if err != nil {
   161  		log.Fatalf("failed creating zip file: %v", err)
   162  	}
   163  
   164  	defer func() {
   165  		err := zipFile.Close()
   166  		if err != nil {
   167  			log.Fatalf("failed to close zip file: %v", err)
   168  		}
   169  	}()
   170  
   171  	zipWriter := zip.NewWriter(zipFile)
   172  	seedBSONCorpus(zipWriter)
   173  
   174  	if err := zipWriter.Close(); err != nil {
   175  		log.Fatalf("failed to close zip writer: %v", err)
   176  	}
   177  }
   178
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