Alex Goodman f893933336
internalize format helpers (#2543)
Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>
2024-01-26 12:16:26 -05:00

109 lines
2.4 KiB
Go

package cyclonedxxml
import (
"encoding/xml"
"fmt"
"io"
"strings"
"github.com/CycloneDX/cyclonedx-go"
"github.com/anchore/syft/internal/log"
"github.com/anchore/syft/syft/format/internal/cyclonedxutil"
"github.com/anchore/syft/syft/format/internal/cyclonedxutil/helpers"
"github.com/anchore/syft/syft/format/internal/stream"
"github.com/anchore/syft/syft/sbom"
)
var _ sbom.FormatDecoder = (*decoder)(nil)
type decoder struct {
decoder cyclonedxutil.Decoder
}
func NewFormatDecoder() sbom.FormatDecoder {
return decoder{
decoder: cyclonedxutil.NewDecoder(cyclonedx.BOMFileFormatXML),
}
}
func (d decoder) Decode(r io.Reader) (*sbom.SBOM, sbom.FormatID, string, error) {
reader, err := stream.SeekableReader(r)
if err != nil {
return nil, "", "", err
}
id, version := d.Identify(reader)
if id != ID {
return nil, "", "", fmt.Errorf("not a cyclonedx xml document")
}
if version == "" {
return nil, "", "", fmt.Errorf("unsupported cyclonedx xml document version")
}
doc, err := d.decoder.Decode(reader)
if err != nil {
return nil, id, version, fmt.Errorf("unable to decode cyclonedx xml document: %w", err)
}
s, err := helpers.ToSyftModel(doc)
if err != nil {
return nil, id, version, err
}
return s, id, version, nil
}
func (d decoder) Identify(r io.Reader) (sbom.FormatID, string) {
reader, err := stream.SeekableReader(r)
if err != nil {
return "", ""
}
if _, err := reader.Seek(0, io.SeekStart); err != nil {
log.Debugf("unable to seek to start of CycloneDX XML SBOM: %+v", err)
return "", ""
}
type Document struct {
XMLNS string `xml:"xmlns,attr"`
}
dec := xml.NewDecoder(reader)
var doc Document
if err = dec.Decode(&doc); err != nil {
// maybe not xml? maybe not valid? doesn't matter, we won't process it.
return "", ""
}
id, version := getFormatInfo(doc.XMLNS)
if version == "" || id != ID {
// not a cyclonedx xml document that we support
return "", ""
}
return id, version
}
func getFormatInfo(xmlns string) (sbom.FormatID, string) {
version := getVersionFromXMLNS(xmlns)
if !strings.Contains(xmlns, "cyclonedx.org/schema/bom") {
// not a cyclonedx xml document
return "", ""
}
spec, err := cyclonedxutil.SpecVersionFromString(version)
if spec < 0 || err != nil {
// not a supported version, but is cyclonedx xml
return ID, ""
}
return ID, version
}
func getVersionFromXMLNS(xmlns string) string {
fields := strings.Split(xmlns, "/")
return fields[len(fields)-1]
}