return false
	}

	seenExts := make(map[uint16]bool)
	for !extensions.Empty() {
		var extension uint16
		var extData cryptobyte.String
		if !extensions.ReadUint16(&extension) ||
			!extensions.ReadUint16LengthPrefixed(&extData) {
			return false
		}

		if seenExts[extension] {
			return false
		}
		seenExts[extension] = true

		switch extension {

					ext, err := parseExtension(extension)
					if err != nil {
						return nil, err
					}
					oidStr := ext.Id.String()
					if seenExts[oidStr] {
						return nil, fmt.Errorf("x509: certificate contains duplicate extension with OID %q", oidStr)
					}
					seenExts[oidStr] = true
					cert.Extensions = append(cert.Extensions, ext)
				}
				err = processExtensions(cert)
				if err != nil {