diff options
Diffstat (limited to 'vendor/github.com/oschwald/maxminddb-golang/verifier.go')
-rw-r--r-- | vendor/github.com/oschwald/maxminddb-golang/verifier.go | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/vendor/github.com/oschwald/maxminddb-golang/verifier.go b/vendor/github.com/oschwald/maxminddb-golang/verifier.go new file mode 100644 index 0000000..ace9d35 --- /dev/null +++ b/vendor/github.com/oschwald/maxminddb-golang/verifier.go @@ -0,0 +1,185 @@ +package maxminddb + +import "reflect" + +type verifier struct { + reader *Reader +} + +// Verify checks that the database is valid. It validates the search tree, +// the data section, and the metadata section. This verifier is stricter than +// the specification and may return errors on databases that are readable. +func (r *Reader) Verify() error { + v := verifier{r} + if err := v.verifyMetadata(); err != nil { + return err + } + + return v.verifyDatabase() +} + +func (v *verifier) verifyMetadata() error { + metadata := v.reader.Metadata + + if metadata.BinaryFormatMajorVersion != 2 { + return testError( + "binary_format_major_version", + 2, + metadata.BinaryFormatMajorVersion, + ) + } + + if metadata.BinaryFormatMinorVersion != 0 { + return testError( + "binary_format_minor_version", + 0, + metadata.BinaryFormatMinorVersion, + ) + } + + if metadata.DatabaseType == "" { + return testError( + "database_type", + "non-empty string", + metadata.DatabaseType, + ) + } + + if len(metadata.Description) == 0 { + return testError( + "description", + "non-empty slice", + metadata.Description, + ) + } + + if metadata.IPVersion != 4 && metadata.IPVersion != 6 { + return testError( + "ip_version", + "4 or 6", + metadata.IPVersion, + ) + } + + if metadata.RecordSize != 24 && + metadata.RecordSize != 28 && + metadata.RecordSize != 32 { + return testError( + "record_size", + "24, 28, or 32", + metadata.RecordSize, + ) + } + + if metadata.NodeCount == 0 { + return testError( + "node_count", + "positive integer", + metadata.NodeCount, + ) + } + return nil +} + +func (v *verifier) verifyDatabase() error { + offsets, err := v.verifySearchTree() + if err != nil { + return err + } + + if err := v.verifyDataSectionSeparator(); err != nil { + return err + } + + return v.verifyDataSection(offsets) +} + +func (v *verifier) verifySearchTree() (map[uint]bool, error) { + offsets := make(map[uint]bool) + + it := v.reader.Networks() + for it.Next() { + offset, err := v.reader.resolveDataPointer(it.lastNode.pointer) + if err != nil { + return nil, err + } + offsets[uint(offset)] = true + } + if err := it.Err(); err != nil { + return nil, err + } + return offsets, nil +} + +func (v *verifier) verifyDataSectionSeparator() error { + separatorStart := v.reader.Metadata.NodeCount * v.reader.Metadata.RecordSize / 4 + + separator := v.reader.buffer[separatorStart : separatorStart+dataSectionSeparatorSize] + + for _, b := range separator { + if b != 0 { + return newInvalidDatabaseError("unexpected byte in data separator: %v", separator) + } + } + return nil +} + +func (v *verifier) verifyDataSection(offsets map[uint]bool) error { + pointerCount := len(offsets) + + decoder := v.reader.decoder + + var offset uint + bufferLen := uint(len(decoder.buffer)) + for offset < bufferLen { + var data interface{} + rv := reflect.ValueOf(&data) + newOffset, err := decoder.decode(offset, rv, 0) + if err != nil { + return newInvalidDatabaseError("received decoding error (%v) at offset of %v", err, offset) + } + if newOffset <= offset { + return newInvalidDatabaseError("data section offset unexpectedly went from %v to %v", offset, newOffset) + } + + pointer := offset + + if _, ok := offsets[pointer]; ok { + delete(offsets, pointer) + } else { + return newInvalidDatabaseError("found data (%v) at %v that the search tree does not point to", data, pointer) + } + + offset = newOffset + } + + if offset != bufferLen { + return newInvalidDatabaseError( + "unexpected data at the end of the data section (last offset: %v, end: %v)", + offset, + bufferLen, + ) + } + + if len(offsets) != 0 { + return newInvalidDatabaseError( + "found %v pointers (of %v) in the search tree that we did not see in the data section", + len(offsets), + pointerCount, + ) + } + return nil +} + +func testError( + field string, + expected interface{}, + actual interface{}, +) error { + return newInvalidDatabaseError( + "%v - Expected: %v Actual: %v", + field, + expected, + actual, + ) +} |