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// Copyright 2021 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package report
import (
"errors"
"fmt"
"net/url"
"path/filepath"
"regexp"
"strings"
"unicode"
"golang.org/x/exp/slices"
"golang.org/x/mod/module"
"golang.org/x/vulndb/internal/cveschema5"
"golang.org/x/vulndb/internal/derrors"
"golang.org/x/vulndb/internal/ghsa"
"golang.org/x/vulndb/internal/osv"
"golang.org/x/vulndb/internal/osvutils"
"golang.org/x/vulndb/internal/proxy"
"golang.org/x/vulndb/internal/stdlib"
)
func (m *Module) checkModVersions(pc *proxy.Client) error {
var notFound []string
var nonCanonical []string
for _, vr := range m.Versions {
for _, v := range []string{vr.Introduced, vr.Fixed} {
if v == "" {
continue
}
c, err := pc.CanonicalModulePath(m.Module, v)
if err != nil {
notFound = append(notFound, v)
continue
}
if c != m.Module {
nonCanonical = append(nonCanonical, fmt.Sprintf("%s (canonical:%s)", v, c))
}
}
}
var sb strings.Builder
nf, nc := len(notFound), len(nonCanonical)
if nf > 0 {
if nf == 1 {
sb.WriteString(fmt.Sprintf("version %s does not exist", notFound[0]))
} else {
sb.WriteString(fmt.Sprintf("%d versions do not exist: %s", nf, strings.Join(notFound, ", ")))
}
}
if nc > 0 {
if nf > 0 {
sb.WriteString(" and ")
}
sb.WriteString(fmt.Sprintf("module is not canonical at %d version(s): %s", nc, strings.Join(nonCanonical, ", ")))
}
if s := sb.String(); s != "" {
return errors.New(s)
}
return nil
}
var missing = "missing"
func (m *Module) lintVersions(l *linter) {
if u := len(m.UnsupportedVersions); u > 0 {
l.Group("unsupported_versions").Errorf("found %d (want none)", u)
}
vl := l.Group("versions")
ranges := AffectedRanges(m.Versions)
if v := m.VulnerableAt; v != "" {
affected, err := osvutils.AffectsSemver(ranges, v)
if err != nil {
vl.Error(err)
} else if !affected {
l.Group("vulnerable_at").Errorf("%s is not inside vulnerable range", v)
}
} else {
if err := osvutils.ValidateRanges(ranges); err != nil {
vl.Error(err)
}
}
}
func (r *Report) lintCVEs(l *linter) {
for i, cve := range r.CVEs {
if !cveschema5.IsCVE(cve) {
l.Group(name("cves", i, cve)).Error("malformed cve identifier")
}
}
}
func (r *Report) lintGHSAs(l *linter) {
for i, g := range r.GHSAs {
if !ghsa.IsGHSA(g) {
l.Group(name("ghsas", i, g)).Errorf("%s is not a valid GHSA", g)
}
}
}
func name(field string, index int, name string) string {
fieldIndex := fmt.Sprintf("%s[%d]", field, index)
if name != "" {
return fmt.Sprintf("%s %q", fieldIndex, name)
}
return fieldIndex
}
func (r *Report) lintRelated(l *linter) {
if len(r.Related) == 0 {
// Not required.
return
}
aliases := r.Aliases()
for i, related := range r.Related {
rl := l.Group(name("related", i, related))
// In most cases, the related list is very short, so there's no
// need create a map of aliases.
if slices.Contains(aliases, related) {
rl.Error("also listed among aliases")
}
if !isIdentifier(related) {
rl.Error("not a recognized identifier (CVE, GHSA or Go ID)")
}
}
}
func isIdentifier(id string) bool {
return cveschema5.IsCVE(id) || ghsa.IsGHSA(id) || IsGoID(id)
}
var goIDregexp = regexp.MustCompile(`^GO-\d{4}-\d{4,}$`)
func IsGoID(s string) bool {
return goIDregexp.MatchString(s)
}
const maxLineLength = 80
func (r *Report) lintLineLength(l *linter, content string) {
for _, line := range strings.Split(content, "\n") {
if len(line) <= maxLineLength {
continue
}
if !strings.Contains(line, " ") {
continue // A single long word is OK.
}
l.Errorf("contains line > %v characters long: %q", maxLineLength, line)
return
}
}
// Regex patterns for standard links.
var (
prRegex = regexp.MustCompile(`https://go.dev/cl/\d+`)
commitRegex = regexp.MustCompile(`https://go.googlesource.com/[^/]+/\+/([^/]+)`)
issueRegex = regexp.MustCompile(`https://go.dev/issue/\d+`)
announceRegex = regexp.MustCompile(`https://groups.google.com/g/golang-(announce|dev|nuts)/c/([^/]+)`)
nistRegex = regexp.MustCompile(`^https://nvd.nist.gov/vuln/detail/(` + cveschema5.RegexStr + `)$`)
ghsaLinkRegex = regexp.MustCompile(`^https://github.com/.*/(` + ghsa.Regex + `)$`)
mitreRegex = regexp.MustCompile(`^https://cve.mitre.org/.*(` + cveschema5.RegexStr + `)$`)
)
func (ref *Reference) lint(l *linter, r *Report) {
// Checks specific to first-party reports.
if r.IsFirstParty() {
switch ref.Type {
case osv.ReferenceTypeAdvisory:
l.Errorf("%q: advisory reference must not be set for first-party issues", ref.URL)
case osv.ReferenceTypeFix:
if !prRegex.MatchString(ref.URL) && !commitRegex.MatchString(ref.URL) {
l.Errorf("%q: fix reference must match %q or %q", ref.URL, prRegex, commitRegex)
}
case osv.ReferenceTypeReport:
if !issueRegex.MatchString(ref.URL) {
l.Errorf("%q: report reference must match regex %q", ref.URL, issueRegex)
}
case osv.ReferenceTypeWeb:
if !announceRegex.MatchString(ref.URL) {
l.Errorf("%q: web reference must match regex %q", ref.URL, announceRegex)
}
}
}
if !slices.Contains(osv.ReferenceTypes, ref.Type) {
l.Errorf("invalid reference type %q", ref.Type)
}
u := ref.URL
if _, err := url.ParseRequestURI(u); err != nil {
l.Error("invalid URL")
}
if fixed := fixURL(u); fixed != u {
l.Errorf("should be %q (can be auto-fixed)", fixURL(u))
}
if ref.Type != osv.ReferenceTypeAdvisory {
// An ADVISORY reference to a CVE/GHSA indicates that it
// is the canonical source of information on this vuln.
//
// A reference to a CVE/GHSA that is not an alias of this
// report indicates that it may contain related information.
//
// A reference to a CVE/GHSA that appears in the CVEs/GHSAs
// aliases is redundant.
for _, re := range []*regexp.Regexp{nistRegex, mitreRegex, ghsaLinkRegex} {
if m := re.FindStringSubmatch(ref.URL); len(m) > 0 {
id := m[1]
if slices.Contains(r.CVEs, id) || slices.Contains(r.GHSAs, id) {
l.Errorf("redundant non-advisory reference to %v", id)
}
}
}
}
}
func (r *Report) lintReferences(l *linter) {
advisoryCount := 0
for i, ref := range r.References {
rl := l.Group(name("references", i, ref.URL))
ref.lint(rl, r)
if ref.Type == osv.ReferenceTypeAdvisory {
advisoryCount++
}
}
// Find missing references.
rl := l.Group("references")
if advisoryCount > 1 {
rl.Errorf("too many advisories (found %d, want <=1)", advisoryCount)
}
if !r.IsExcluded() {
if r.IsFirstParty() {
var hasFixLink, hasReportLink, hasAnnounceLink bool
for _, ref := range r.References {
switch ref.Type {
case osv.ReferenceTypeFix:
hasFixLink = true
case osv.ReferenceTypeReport:
hasReportLink = true
case osv.ReferenceTypeWeb:
if announceRegex.MatchString(ref.URL) {
hasAnnounceLink = true
}
}
}
if !hasFixLink {
rl.Error("must contain at least one fix")
}
if !hasReportLink {
rl.Error("must contain at least one report")
}
if !hasAnnounceLink {
rl.Errorf("must contain an announcement link matching regex %q", announceRegex)
}
}
if advisoryCount == 0 && r.Description == "" && r.CVEMetadata == nil {
rl.Error("missing advisory (required because report has no description)")
}
}
}
func (d *Description) lint(l *linter, r *Report) {
desc := d.String()
checkNoMarkdown(l, desc)
r.lintLineLength(l, desc)
if !r.IsExcluded() && desc == "" {
if r.CVEMetadata != nil {
l.Error("missing (reports with Go CVEs must have a description)")
}
}
}
func (s *Summary) lint(l *linter, r *Report) {
summary := s.String()
if !r.IsExcluded() && len(summary) == 0 {
l.Error(missing)
}
// Nothing to lint.
if len(summary) == 0 {
return
}
if hasTODO(summary) {
l.Error(hasTODOErr)
// No need to keep linting, as this is likely a placeholder value.
return
}
checkNoMarkdown(l, summary)
if ln := len(summary); ln > 100 {
l.Errorf("too long (found %d characters, want <=100)", ln)
}
if strings.HasSuffix(summary, ".") {
l.Error("must not end in a period (should be a phrase, not a sentence)")
}
for i, r := range summary {
if i != 0 {
break
}
if !unicode.IsUpper(r) {
l.Error("must begin with a capital letter")
}
}
// Summary must contain one of the listed module or package
// paths. (Except in the "std" module, where a specific package
// must be mentioned).
// If there are no such paths listed in the report at all,
// another lint will complain, so reduce noise by not erroring here.
if paths := r.nonStdPaths(); len(paths) > 0 {
if ok := containsPath(summary, paths); !ok {
l.Errorf("must contain an affected module or package path (e.g. %q)", paths[0])
}
}
}
// containsPath returns whether the summary contains one of
// the paths in paths.
// As a special case, if the summary contains a word that contains a "/"
// and is a prefix of a path, the function returns true. This gives us a
// workaround for reports that affect a lot of modules and/or have very long
// module paths.
func containsPath(summary string, paths []string) bool {
if len(paths) == 0 {
return false
}
for _, possiblePath := range strings.Fields(summary) {
possiblePath := strings.TrimRight(possiblePath, ":,.")
for _, path := range paths {
if possiblePath == path {
return true
}
if strings.Contains(possiblePath, "/") &&
strings.HasPrefix(path, possiblePath) {
return true
}
}
}
return false
}
// nonStdPaths returns all module and package paths (except "std")
// mentioned in the report.
func (r *Report) nonStdPaths() (paths []string) {
for _, m := range r.Modules {
if m.Module != "" && m.Module != stdlib.ModulePath {
paths = append(paths, m.Module)
}
for _, p := range m.Packages {
if p.Package != "" {
paths = append(paths, p.Package)
}
}
}
return paths
}
func (r *Report) IsExcluded() bool {
return r.Excluded != ""
}
var (
errWrongDir = errors.New("report is in incorrect directory")
errWrongID = errors.New("report ID mismatch")
)
// CheckFilename errors if the filename is inconsistent with the report.
func (r *Report) CheckFilename(filename string) (err error) {
defer derrors.Wrap(&err, "CheckFilename(%q)", filename)
dir := filepath.Base(filepath.Dir(filename)) // innermost folder
excluded := r.IsExcluded()
if excluded && dir != excludedFolder {
return fmt.Errorf("%w (want %s, found %s)", errWrongDir, excludedFolder, dir)
}
if !excluded && dir != reportsFolder {
return fmt.Errorf("%w (want %s, found %s)", errWrongDir, reportsFolder, dir)
}
wantID := GoID(filename)
if r.ID != wantID {
return fmt.Errorf("%w (want %s, found %s)", errWrongID, wantID, r.ID)
}
return nil
}
// Lint checks the content of a Report and outputs a list of strings
// representing lint errors.
// TODO: It might make sense to include warnings or informational things
// alongside errors, especially during for use during the triage process.
func (r *Report) Lint(pc *proxy.Client) []string {
result := r.lint(pc)
if pc == nil {
result = append(result, "proxy client is nil; cannot perform all lint checks")
}
return result
}
// LintAsNotes works like Lint, but modifies r by adding any lints found
// to the notes section, instead of returning them.
// Removes any pre-existing lint notes.
// Returns true if any lints were found.
func (r *Report) LintAsNotes(pc *proxy.Client) bool {
r.Notes = slices.DeleteFunc(r.Notes, func(n *Note) bool {
return n.Type == NoteTypeLint
})
if lints := r.Lint(pc); len(lints) > 0 {
slices.Sort(lints)
for _, lint := range lints {
r.Notes = append(r.Notes, &Note{
Body: lint,
Type: NoteTypeLint,
})
}
return true
}
return false
}
// LintOffline performs all lint checks that don't require a network connection.
func (r *Report) LintOffline() []string {
return r.lint(nil)
}
func (r *Report) lint(pc *proxy.Client) []string {
l := NewLinter("")
if r.ID == "" {
l.Group("id").Error(missing)
}
r.Summary.lint(l.Group("summary"), r)
r.Description.lint(l.Group("description"), r)
r.Excluded.lint(l.Group("excluded"))
r.lintModules(l, pc)
r.CVEMetadata.lint(l.Group("cve_metadata"), r)
if r.IsExcluded() && len(r.Aliases()) == 0 {
l.Group("cves,ghsas").Error()
}
r.lintCVEs(l)
r.lintGHSAs(l)
r.lintRelated(l)
r.lintReferences(l)
return l.Errors()
}
func (m *Module) lint(l *linter, r *Report, pc *proxy.Client) {
if m.Module == "" {
l.Error("no module name")
}
if !m.IsFirstParty() && pc != nil {
if err := m.checkModVersions(pc); err != nil {
l.Error(err)
}
}
if m.IsFirstParty() && len(m.Packages) == 0 {
l.Error("no packages")
}
for i, p := range m.Packages {
p.lint(l.Group(name("packages", i, p.Package)), m, r)
}
m.lintVersions(l)
}
func (p *Package) lint(l *linter, m *Module, r *Report) {
if p.Package == "" {
l.Error("no package name")
} else {
if m.Module != stdlib.ModulePath {
if !strings.HasPrefix(p.Package, m.Module) {
l.Error("module must be a prefix of package")
}
} else if strings.HasPrefix(p.Package, stdlib.ToolchainModulePath) {
// As a special case, check for "cmd/" packages that are
// mistakenly placed in the "std" module.
l.Error("must be in module cmd")
}
if !m.IsFirstParty() {
if err := module.CheckImportPath(p.Package); err != nil {
l.Error(err)
}
}
}
if !r.IsExcluded() {
if m.VulnerableAt == "" && p.SkipFix == "" {
l.Error("at least one of vulnerable_at and skip_fix must be set")
}
}
}
func (r *Report) lintModules(l *linter, pc *proxy.Client) {
if r.Excluded != "NOT_GO_CODE" && len(r.Modules) == 0 {
l.Group("modules").Error(missing)
}
for i, m := range r.Modules {
m.lint(l.Group(name("modules", i, m.Module)), r, pc)
}
}
func (r *Report) IsFirstParty() bool {
for _, m := range r.Modules {
if m.IsFirstParty() {
return true
}
}
return false
}
func (m *Module) IsFirstParty() bool {
return stdlib.IsStdModule(m.Module) || stdlib.IsCmdModule(m.Module)
}
func (e *ExcludedReason) lint(l *linter) {
if e == nil || *e == "" {
return
}
if !slices.Contains(ExcludedReasons, *e) {
l.Errorf("excluded reason (%q) is not a valid excluded reason (accepted: %v)", *e, ExcludedReasons)
}
}
func (m *CVEMeta) lint(l *linter, r *Report) {
if m == nil {
return
}
il := l.Group("id")
if m.ID == "" {
il.Error(missing)
} else if !cveschema5.IsCVE(m.ID) {
il.Error("not a valid CVE")
}
cl := l.Group("cwe")
if m.CWE == "" {
cl.Error(missing)
}
if hasTODO(m.CWE) {
cl.Error(hasTODOErr)
}
r.lintLineLength(l.Group("description"), m.Description)
}
var hasTODOErr = "contains a TODO"
func hasTODO(s string) bool {
return strings.Contains(s, "TODO")
}
// Regular expressions for markdown-style elements that shouldn't
// be in our descriptions/summaries.
var (
backtickRE = regexp.MustCompile("(`.*`)")
linkRE = regexp.MustCompile(`(\[.*\]\(.*\))`)
headingRE = regexp.MustCompile(`(#+ )`)
)
func checkNoMarkdown(l *linter, s string) {
for _, re := range []*regexp.Regexp{backtickRE, linkRE, headingRE} {
matches := re.FindStringSubmatch(s)
if len(matches) > 0 {
l.Errorf("possible markdown formatting (found %s)", matches[1])
}
}
}