|
| 1 | +package writer |
| 2 | + |
| 3 | +import ( |
| 4 | + "fmt" |
| 5 | + "net/netip" |
| 6 | + "os" |
| 7 | + "path/filepath" |
| 8 | + |
| 9 | + "github.com/maxmind/mmdbwriter" |
| 10 | + "github.com/maxmind/mmdbwriter/mmdbtype" |
| 11 | + "go4.org/netipx" |
| 12 | +) |
| 13 | + |
| 14 | +// WriteBadDataDBs writes intentionally corrupt or extreme MMDB databases |
| 15 | +// for testing error handling in reader implementations. |
| 16 | +func (w *Writer) WriteBadDataDBs(target string) error { |
| 17 | + //nolint:gosec // not security sensitive. |
| 18 | + if err := os.MkdirAll(target, os.ModePerm); err != nil { |
| 19 | + return fmt.Errorf("creating bad-data directory: %w", err) |
| 20 | + } |
| 21 | + |
| 22 | + // Raw binary databases — can't use mmdbwriter because the data is |
| 23 | + // intentionally invalid or uses values mmdbwriter can't represent. |
| 24 | + for _, db := range []struct { |
| 25 | + name string |
| 26 | + data []byte |
| 27 | + }{ |
| 28 | + {"libmaxminddb-oversized-array.mmdb", buildOversizedArrayDB()}, |
| 29 | + {"libmaxminddb-oversized-map.mmdb", buildOversizedMapDB()}, |
| 30 | + {"libmaxminddb-uint64-max-epoch.mmdb", buildUint64MaxEpochDB()}, |
| 31 | + {"libmaxminddb-corrupt-search-tree.mmdb", buildCorruptSearchTreeDB()}, |
| 32 | + } { |
| 33 | + if err := writeRawDB(target, db.name, db.data); err != nil { |
| 34 | + return fmt.Errorf("writing %s: %w", db.name, err) |
| 35 | + } |
| 36 | + } |
| 37 | + |
| 38 | + // Deep nesting uses mmdbwriter — structurally valid, just 600 levels deep. |
| 39 | + if err := writeDeepNestingDB(target); err != nil { |
| 40 | + return fmt.Errorf("writing deep nesting database: %w", err) |
| 41 | + } |
| 42 | + |
| 43 | + if err := writeDeepArrayNestingDB(target); err != nil { |
| 44 | + return fmt.Errorf("writing deep array nesting database: %w", err) |
| 45 | + } |
| 46 | + |
| 47 | + return nil |
| 48 | +} |
| 49 | + |
| 50 | +func writeRawDB(dir, name string, data []byte) error { |
| 51 | + path := filepath.Join(dir, name) |
| 52 | + if err := os.WriteFile(path, data, 0o644); err != nil { |
| 53 | + return fmt.Errorf("writing file: %w", err) |
| 54 | + } |
| 55 | + return nil |
| 56 | +} |
| 57 | + |
| 58 | +// writeDeepArrayNestingDB creates an MMDB with 600 levels of nested arrays. |
| 59 | +// This exceeds libmaxminddb's MAXIMUM_DATA_STRUCTURE_DEPTH (512) and |
| 60 | +// should trigger MMDB_INVALID_DATA_ERROR during data extraction. |
| 61 | +func writeDeepArrayNestingDB(dir string) (retErr error) { |
| 62 | + dbWriter, err := mmdbwriter.New( |
| 63 | + mmdbwriter.Options{ |
| 64 | + DatabaseType: "Test", |
| 65 | + BuildEpoch: 1_000_000_000, |
| 66 | + IPVersion: 4, |
| 67 | + RecordSize: 24, |
| 68 | + }, |
| 69 | + ) |
| 70 | + if err != nil { |
| 71 | + return fmt.Errorf("creating mmdbwriter: %w", err) |
| 72 | + } |
| 73 | + |
| 74 | + // Build 600-level nested arrays: [[[... "x" ...]]] |
| 75 | + const depth = 600 |
| 76 | + var value mmdbtype.DataType = mmdbtype.String("x") |
| 77 | + for range depth { |
| 78 | + value = mmdbtype.Slice{value} |
| 79 | + } |
| 80 | + |
| 81 | + for _, cidr := range []string{"0.0.0.0/1", "128.0.0.0/1"} { |
| 82 | + prefix, err := netip.ParsePrefix(cidr) |
| 83 | + if err != nil { |
| 84 | + return fmt.Errorf("parsing prefix %s: %w", cidr, err) |
| 85 | + } |
| 86 | + if err := dbWriter.Insert(netipx.PrefixIPNet(prefix), value); err != nil { |
| 87 | + return fmt.Errorf("inserting %s: %w", cidr, err) |
| 88 | + } |
| 89 | + } |
| 90 | + |
| 91 | + path := filepath.Join(dir, "libmaxminddb-deep-array-nesting.mmdb") |
| 92 | + outputFile, err := os.Create(filepath.Clean(path)) |
| 93 | + if err != nil { |
| 94 | + return fmt.Errorf("creating file: %w", err) |
| 95 | + } |
| 96 | + defer func() { |
| 97 | + if err := outputFile.Close(); err != nil && retErr == nil { |
| 98 | + retErr = fmt.Errorf("closing file: %w", err) |
| 99 | + } |
| 100 | + }() |
| 101 | + |
| 102 | + if _, err := dbWriter.WriteTo(outputFile); err != nil { |
| 103 | + return fmt.Errorf("writing file: %w", err) |
| 104 | + } |
| 105 | + |
| 106 | + return nil |
| 107 | +} |
| 108 | + |
| 109 | +// writeDeepNestingDB creates an MMDB with 600 levels of nested maps. |
| 110 | +// This exceeds libmaxminddb's MAXIMUM_DATA_STRUCTURE_DEPTH (512) and |
| 111 | +// should trigger MMDB_INVALID_DATA_ERROR during data extraction. |
| 112 | +func writeDeepNestingDB(dir string) (retErr error) { |
| 113 | + dbWriter, err := mmdbwriter.New( |
| 114 | + mmdbwriter.Options{ |
| 115 | + DatabaseType: "Test", |
| 116 | + BuildEpoch: 1_000_000_000, |
| 117 | + IPVersion: 4, |
| 118 | + RecordSize: 24, |
| 119 | + }, |
| 120 | + ) |
| 121 | + if err != nil { |
| 122 | + return fmt.Errorf("creating mmdbwriter: %w", err) |
| 123 | + } |
| 124 | + |
| 125 | + // Build 600-level nested structure: {"a": {"a": ... "x" ...}} |
| 126 | + const depth = 600 |
| 127 | + var value mmdbtype.DataType = mmdbtype.String("x") |
| 128 | + for range depth { |
| 129 | + value = mmdbtype.Map{"a": value} |
| 130 | + } |
| 131 | + |
| 132 | + // Insert for 0.0.0.0/1 and 128.0.0.0/1 to cover all IPv4 addresses. |
| 133 | + for _, cidr := range []string{"0.0.0.0/1", "128.0.0.0/1"} { |
| 134 | + prefix, err := netip.ParsePrefix(cidr) |
| 135 | + if err != nil { |
| 136 | + return fmt.Errorf("parsing prefix %s: %w", cidr, err) |
| 137 | + } |
| 138 | + if err := dbWriter.Insert(netipx.PrefixIPNet(prefix), value); err != nil { |
| 139 | + return fmt.Errorf("inserting %s: %w", cidr, err) |
| 140 | + } |
| 141 | + } |
| 142 | + |
| 143 | + path := filepath.Join(dir, "libmaxminddb-deep-nesting.mmdb") |
| 144 | + outputFile, err := os.Create(filepath.Clean(path)) |
| 145 | + if err != nil { |
| 146 | + return fmt.Errorf("creating file: %w", err) |
| 147 | + } |
| 148 | + defer func() { |
| 149 | + if err := outputFile.Close(); err != nil && retErr == nil { |
| 150 | + retErr = fmt.Errorf("closing file: %w", err) |
| 151 | + } |
| 152 | + }() |
| 153 | + |
| 154 | + if _, err := dbWriter.WriteTo(outputFile); err != nil { |
| 155 | + return fmt.Errorf("writing file: %w", err) |
| 156 | + } |
| 157 | + |
| 158 | + return nil |
| 159 | +} |
0 commit comments