syft/syft/pkg/cataloger/debian/parse_dpkg_db.go
Christopher Phillips 319bb12627
chore: do not redesign private
Signed-off-by: Christopher Phillips <32073428+spiffcs@users.noreply.github.com>
2025-09-26 15:07:48 -04:00

287 lines
8.4 KiB
Go

package debian
import (
"bufio"
"context"
"errors"
"fmt"
"io"
"path"
"regexp"
"strings"
"github.com/dustin/go-humanize"
"github.com/go-viper/mapstructure/v2"
"github.com/anchore/go-sync"
"github.com/anchore/syft/internal"
"github.com/anchore/syft/internal/log"
"github.com/anchore/syft/internal/unknown"
"github.com/anchore/syft/syft/artifact"
"github.com/anchore/syft/syft/cataloging"
"github.com/anchore/syft/syft/file"
"github.com/anchore/syft/syft/pkg"
"github.com/anchore/syft/syft/pkg/cataloger/generic"
)
const (
deinstallStatus string = "deinstall"
)
var (
errEndOfPackages = fmt.Errorf("no more packages to read")
sourceRegexp = regexp.MustCompile(`(?P<name>\S+)( \((?P<version>.*)\))?`)
)
func parseDpkgDB(cfg CatalogerConfig) generic.Parser {
return func(ctx context.Context, resolver file.Resolver, env *generic.Environment, reader file.LocationReadCloser) ([]pkg.Package, []artifact.Relationship, error) {
return parseDpkgDBWithConfig(ctx, resolver, env, reader, cfg)
}
}
func parseDpkgDBWithConfig(ctx context.Context, resolver file.Resolver, env *generic.Environment, reader file.LocationReadCloser, cfg CatalogerConfig) ([]pkg.Package, []artifact.Relationship, error) {
metadata, err := parseDpkgStatus(reader, cfg)
if err != nil {
return nil, nil, fmt.Errorf("unable to catalog dpkg DB=%q: %w", reader.RealPath, err)
}
dbLoc := reader.WithAnnotation(pkg.EvidenceAnnotationKey, pkg.PrimaryEvidenceAnnotation)
var pkgs []pkg.Package
_ = sync.CollectSlice(&ctx, cataloging.ExecutorFile, sync.ToSeq(metadata), func(m pkg.DpkgDBEntry) (pkg.Package, error) {
return newDpkgPackage(ctx, m, dbLoc, resolver, env.LinuxRelease, findDpkgInfoFiles(m.Package, resolver, reader.Location)...), nil
}, &pkgs)
return pkgs, nil, unknown.IfEmptyf(pkgs, "unable to determine packages")
}
func findDpkgInfoFiles(name string, resolver file.Resolver, dbLocation file.Location) []file.Location {
if resolver == nil {
return nil
}
if strings.TrimSpace(name) == "" {
return nil
}
// for typical debian-base distributions, the installed package info is at /var/lib/dpkg/status
// and the md5sum information is under /var/lib/dpkg/info/; however, for distroless the installed
// package info is across multiple files under /var/lib/dpkg/status.d/ and the md5sums are contained in
// the same directory
searchPath := path.Dir(dbLocation.RealPath)
if !strings.HasSuffix(searchPath, "status.d") {
searchPath = path.Join(searchPath, "info")
}
// look for /var/lib/dpkg/info/NAME.*
locations, err := resolver.FilesByGlob(path.Join(searchPath, name+".*"))
if err != nil {
log.WithFields("error", err, "pkg", name).Trace("failed to fetch related dpkg info files")
return nil
}
return locations
}
func parseDpkgStatus(reader io.Reader, cfg CatalogerConfig) ([]pkg.DpkgDBEntry, error) {
buffedReader := bufio.NewReader(reader)
var metadata []pkg.DpkgDBEntry
continueProcessing := true
for continueProcessing {
entry, err := parseDpkgStatusEntry(buffedReader, cfg)
if err != nil {
if errors.Is(err, errEndOfPackages) {
continueProcessing = false
} else {
return nil, err
}
}
if entry == nil {
continue
}
metadata = append(metadata, *entry)
}
return metadata, nil
}
// dpkgExtractedMetadata is an adapter struct to capture the fields from the dpkg status file, however, the final
// pkg.DpkgMetadata struct has different types for some fields (e.g. Provides, Depends, and PreDepends is []string, not a string).
type dpkgExtractedMetadata struct {
Package string `mapstructure:"Package"`
Source string `mapstructure:"Source"`
Version string `mapstructure:"Version"`
SourceVersion string `mapstructure:"SourceVersion"`
Architecture string `mapstructure:"Architecture"`
Maintainer string `mapstructure:"Maintainer"`
InstalledSize int `mapstructure:"InstalledSize"`
Description string `mapstructure:"Description"`
Provides string `mapstructure:"Provides"`
Depends string `mapstructure:"Depends"`
PreDepends string `mapstructure:"PreDepends"` // note: original doc is Pre-Depends
Status string `mapstructure:"Status"`
}
func parseDpkgStatusEntry(reader *bufio.Reader, cfg CatalogerConfig) (*pkg.DpkgDBEntry, error) {
var retErr error
dpkgFields, err := extractAllFields(reader)
if err != nil {
if !errors.Is(err, errEndOfPackages) {
return nil, err
}
if len(dpkgFields) == 0 {
return nil, err
}
retErr = err
}
raw := dpkgExtractedMetadata{}
err = mapstructure.Decode(dpkgFields, &raw)
if err != nil {
return nil, err
}
// Skip entries which have been removed but not purged, e.g. "rc" status in dpkg -l
if !cfg.IncludeDeInstalled && strings.Contains(raw.Status, deinstallStatus) {
return nil, nil
}
sourceName, sourceVersion := extractSourceVersion(raw.Source)
if sourceVersion != "" {
raw.SourceVersion = sourceVersion
raw.Source = sourceName
}
if raw.Package == "" {
return nil, retErr
}
entry := pkg.DpkgDBEntry{
Package: raw.Package,
Source: raw.Source,
Version: raw.Version,
SourceVersion: raw.SourceVersion,
Architecture: raw.Architecture,
Maintainer: raw.Maintainer,
InstalledSize: raw.InstalledSize,
Description: raw.Description,
Provides: splitPkgList(raw.Provides),
Depends: splitPkgList(raw.Depends),
PreDepends: splitPkgList(raw.PreDepends),
}
// there may be an optional conffiles section that we should persist as files
if conffilesSection, exists := dpkgFields["Conffiles"]; exists && conffilesSection != nil {
if sectionStr, ok := conffilesSection.(string); ok {
entry.Files = parseDpkgConffileInfo(strings.NewReader(sectionStr))
}
}
if entry.Files == nil {
// ensure the default value for a collection is never nil since this may be shown as JSON
entry.Files = make([]pkg.DpkgFileRecord, 0)
}
return &entry, retErr
}
func splitPkgList(pkgList string) (ret []string) {
fields := strings.Split(pkgList, ",")
for _, field := range fields {
field = strings.TrimSpace(field)
if field != "" {
ret = append(ret, field)
}
}
return ret
}
func extractAllFields(reader *bufio.Reader) (map[string]interface{}, error) {
dpkgFields := make(map[string]interface{})
var key string
for {
line, err := reader.ReadString('\n')
if err != nil {
if errors.Is(err, io.EOF) {
return dpkgFields, errEndOfPackages
}
return nil, err
}
line = strings.TrimRight(line, "\n")
// empty line indicates end of entry
if len(line) == 0 {
// if the entry has not started, keep parsing lines
if len(dpkgFields) == 0 {
continue
}
break
}
switch {
case strings.HasPrefix(line, " "):
// a field-body continuation
if len(key) == 0 {
return nil, fmt.Errorf("no match for continuation: line: '%s'", line)
}
val, ok := dpkgFields[key]
if !ok {
return nil, fmt.Errorf("no previous key exists, expecting: %s", key)
}
// concatenate onto previous value
val = fmt.Sprintf("%s\n %s", val, strings.TrimSpace(line))
dpkgFields[key] = val
default:
// parse a new key
var val interface{}
key, val, err = handleNewKeyValue(line)
if err != nil {
log.Tracef("parsing dpkg status: extracting key-value from line: %s err: %v", line, err)
continue
}
if _, ok := dpkgFields[key]; ok {
return nil, fmt.Errorf("duplicate key discovered: %s", key)
}
dpkgFields[key] = val
}
}
return dpkgFields, nil
}
// If the source entry string is of the form "<name> (<version>)" then parse and return the components, if
// of the "<name>" form, then return name and nil
func extractSourceVersion(source string) (string, string) {
// special handling for the Source field since it has formatted data
match := internal.MatchNamedCaptureGroups(sourceRegexp, source)
return match["name"], match["version"]
}
// handleNewKeyValue parse a new key-value pair from the given unprocessed line
func handleNewKeyValue(line string) (key string, val interface{}, err error) {
if i := strings.Index(line, ":"); i > 0 {
key = strings.TrimSpace(line[0:i])
// mapstruct cant handle "-"
key = strings.ReplaceAll(key, "-", "")
val := strings.TrimSpace(line[i+1:])
// further processing of values based on the key that was discovered
switch key {
case "InstalledSize":
s, err := humanize.ParseBytes(val)
if err != nil {
return "", nil, fmt.Errorf("bad installed-size value=%q: %w", val, err)
}
return key, int(s), nil
default:
return key, val, nil
}
}
return "", nil, fmt.Errorf("cannot parse field from line: '%s'", line)
}