70 lines
2.0 KiB
Go
70 lines
2.0 KiB
Go
package ctwatch
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import (
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"errors"
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"bytes"
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"encoding/binary"
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"encoding/asn1"
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"unicode/utf8"
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)
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func stringFromByteSlice (chars []byte) string {
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runes := make([]rune, len(chars))
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for i, ch := range chars {
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runes[i] = rune(ch)
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}
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return string(runes)
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}
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func stringFromUint16Slice (chars []uint16) string {
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runes := make([]rune, len(chars))
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for i, ch := range chars {
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runes[i] = rune(ch)
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}
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return string(runes)
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}
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func stringFromUint32Slice (chars []uint32) string {
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runes := make([]rune, len(chars))
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for i, ch := range chars {
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runes[i] = rune(ch)
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}
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return string(runes)
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}
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func decodeASN1String (value *asn1.RawValue) (string, error) {
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if !value.IsCompound && value.Class == 0 {
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if value.Tag == 12 {
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// UTF8String
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if !utf8.Valid(value.Bytes) {
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return "", errors.New("Malformed UTF8String")
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}
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return string(value.Bytes), nil
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} else if value.Tag == 19 || value.Tag == 22 || value.Tag == 20 {
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// * PrintableString - subset of ASCII
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// * IA5String - ASCII
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// * TeletexString - 8 bit charset; not quite ISO-8859-1, but often treated as such
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// Don't enforce character set rules. Allow any 8 bit character, since
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// CAs routinely mess this up
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return stringFromByteSlice(value.Bytes), nil
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} else if value.Tag == 30 {
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// BMPString - Unicode, encoded in big-endian format using two octets
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runes := make([]uint16, len(value.Bytes) / 2)
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if err := binary.Read(bytes.NewReader(value.Bytes), binary.BigEndian, runes); err != nil {
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return "", errors.New("Malformed BMPString: " + err.Error())
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}
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return stringFromUint16Slice(runes), nil
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} else if value.Tag == 28 {
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// UniversalString - Unicode, encoded in big-endian format using four octets
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runes := make([]uint32, len(value.Bytes) / 4)
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if err := binary.Read(bytes.NewReader(value.Bytes), binary.BigEndian, runes); err != nil {
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return "", errors.New("Malformed UniversalString: " + err.Error())
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}
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return stringFromUint32Slice(runes), nil
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}
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}
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return "", errors.New("Not a string")
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}
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