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Add PURL validation support (Issue #17) #20

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124 changes: 124 additions & 0 deletions internal/rules/purl.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,124 @@
package rules

import (
"fmt"
"github.com/package-url/packageurl-go"
"github.com/tidwall/gjson"
"strings"
)

// CheckPurlFormat validates that PURL (Package URL) strings in the CVE record are valid.
// This function checks PURL entries in the "components" section which may be added to CVE schema.
// PURLs should follow the Package URL specification: https://github.com/package-url/packageurl-go
func CheckPurlFormat(json *string) []ValidationError {
if gjson.Get(*json, `cveMetadata.state`).String() != "PUBLISHED" {
// REJECTED records do not require components
return nil
}

var errors []ValidationError

// Check PURLs in components section (if present)
// This path is being added to CVE schema per: https://github.com/CVEProject/cve-schema/pull/407
components := gjson.Get(*json, `containers.cna.components`)
components.ForEach(func(key, value gjson.Result) bool {
purl := value.Get("purl").String()
if purl != "" {
if !strings.HasPrefix(purl, "pkg:") {
errors = append(errors, ValidationError{
Text: fmt.Sprintf("Invalid PURL format: missing 'pkg:' prefix: %s", purl),
JsonPath: value.Get("purl").Path(*json),
})
} else {
_, err := packageurl.FromString(purl)
if err != nil {
errors = append(errors, ValidationError{
Text: fmt.Sprintf("Invalid PURL format: %s (error: %v)", purl, err),
JsonPath: value.Get("purl").Path(*json),
})
}
}
}
return true
})

// Check PURLs in affects section (for version strings that may be PURLs)
// PURLs in version fields are already validated in CheckInvalidVersion,
// but we can add additional validation if needed here

// Check PURLs in references section (if references contain PURL data)
// Some implementations may include PURL data in reference metadata
affected := gjson.Get(*json, `containers.cna.affected`)
affected.ForEach(func(akey, avalue gjson.Result) bool {
// Check for PURL in affected components
purl := avalue.Get("purl").String()
if purl != "" {
if !strings.HasPrefix(purl, "pkg:") {
errors = append(errors, ValidationError{
Text: fmt.Sprintf("Invalid PURL format in affected: missing 'pkg:' prefix: %s", purl),
JsonPath: avalue.Get("purl").Path(*json),
})
} else {
_, err := packageurl.FromString(purl)
if err != nil {
errors = append(errors, ValidationError{
Text: fmt.Sprintf("Invalid PURL format in affected: %s (error: %v)", purl, err),
JsonPath: avalue.Get("purl").Path(*json),
})
}
}
}
return true
})

return errors
}

// CheckPurlConsistency validates that PURLs are consistent with vendor/product information.
// If a PURL is provided, it should align with the vendor and product fields.
func CheckPurlConsistency(json *string) []ValidationError {
if gjson.Get(*json, `cveMetadata.state`).String() != "PUBLISHED" {
return nil
}

var errors []ValidationError

components := gjson.Get(*json, `containers.cna.components`)
components.ForEach(func(key, value gjson.Result) bool {
purl := value.Get("purl").String()
if purl != "" && strings.HasPrefix(purl, "pkg:") {
parsedPurl, err := packageurl.FromString(purl)
if err == nil {
// Get the namespace and name from the component
componentNamespace := value.Get("namespace").String()
componentName := value.Get("name").String()

// Validate that PURL namespace/name matches component data
if componentNamespace != "" && parsedPurl.Namespace != componentNamespace {
errors = append(errors, ValidationError{
Text: fmt.Sprintf(
"PURL namespace '%s' does not match component namespace '%s'",
parsedPurl.Namespace,
componentNamespace,
),
JsonPath: value.Get("purl").Path(*json),
})
}

if componentName != "" && parsedPurl.Name != componentName {
errors = append(errors, ValidationError{
Text: fmt.Sprintf(
"PURL name '%s' does not match component name '%s'",
parsedPurl.Name,
componentName,
),
JsonPath: value.Get("purl").Path(*json),
})
}
}
}
return true
})

return errors
}
261 changes: 261 additions & 0 deletions internal/rules/purl_test.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,261 @@
package rules

import (
"testing"
)

func TestCheckPurlFormat(t *testing.T) {
tests := []struct {
name string
json string
expectErrors bool
errorCount int
}{
{
name: "Valid PURL format",
json: `{
"cveMetadata": {"state": "PUBLISHED"},
"containers": {
"cna": {
"components": [
{"purl": "pkg:npm/lodash@4.17.21"}
]
}
}
}`,
expectErrors: false,
errorCount: 0,
},
{
name: "Valid PURL with qualifiers",
json: `{
"cveMetadata": {"state": "PUBLISHED"},
"containers": {
"cna": {
"components": [
{"purl": "pkg:npm/lodash@4.17.21?arch=x86_64"}
]
}
}
}`,
expectErrors: false,
errorCount: 0,
},
{
name: "Invalid PURL - missing pkg: prefix",
json: `{
"cveMetadata": {"state": "PUBLISHED"},
"containers": {
"cna": {
"components": [
{"purl": "npm/lodash@4.17.21"}
]
}
}
}`,
expectErrors: true,
errorCount: 1,
},
{
name: "Invalid PURL format",
json: `{
"cveMetadata": {"state": "PUBLISHED"},
"containers": {
"cna": {
"components": [
{"purl": "pkg:!!!invalid"}
]
}
}
}`,
expectErrors: true,
errorCount: 1,
},
{
name: "Empty PURL should not error",
json: `{
"cveMetadata": {"state": "PUBLISHED"},
"containers": {
"cna": {
"components": [
{"name": "component", "purl": ""}
]
}
}
}`,
expectErrors: false,
errorCount: 0,
},
{
name: "Rejected record should not be checked",
json: `{
"cveMetadata": {"state": "REJECTED"},
"containers": {
"cna": {
"components": [
{"purl": "invalid"}
]
}
}
}`,
expectErrors: false,
errorCount: 0,
},
{
name: "PURL in affected section",
json: `{
"cveMetadata": {"state": "PUBLISHED"},
"containers": {
"cna": {
"affected": [
{
"purl": "pkg:npm/lodash@4.17.21",
"vendor": "lodash",
"product": "lodash",
"versions": [
{"version": "4.17.20", "status": "affected"}
]
}
]
}
}
}`,
expectErrors: false,
errorCount: 0,
},
}

for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
json := tt.json
errors := CheckPurlFormat(&json)

if (len(errors) > 0) != tt.expectErrors {
t.Errorf("Expected errors: %v, got: %v (errors: %v)", tt.expectErrors, len(errors) > 0, errors)
}

if len(errors) != tt.errorCount {
t.Errorf("Expected %d errors, got %d: %v", tt.errorCount, len(errors), errors)
}
})
}
}

func TestCheckPurlConsistency(t *testing.T) {
tests := []struct {
name string
json string
expectErrors bool
errorCount int
}{
{
name: "Consistent PURL and component data",
json: `{
"cveMetadata": {"state": "PUBLISHED"},
"containers": {
"cna": {
"components": [
{
"purl": "pkg:npm/@angular/core@12.0.0",
"namespace": "@angular",
"name": "core"
}
]
}
}
}`,
expectErrors: false,
errorCount: 0,
},
{
name: "Inconsistent PURL namespace",
json: `{
"cveMetadata": {"state": "PUBLISHED"},
"containers": {
"cna": {
"components": [
{
"purl": "pkg:npm/@angular/core@12.0.0",
"namespace": "@react",
"name": "core"
}
]
}
}
}`,
expectErrors: true,
errorCount: 1,
},
{
name: "Inconsistent PURL name",
json: `{
"cveMetadata": {"state": "PUBLISHED"},
"containers": {
"cna": {
"components": [
{
"purl": "pkg:npm/@angular/core@12.0.0",
"namespace": "@angular",
"name": "react"
}
]
}
}
}`,
expectErrors: true,
errorCount: 1,
},
{
name: "No namespace in PURL",
json: `{
"cveMetadata": {"state": "PUBLISHED"},
"containers": {
"cna": {
"components": [
{
"purl": "pkg:npm/lodash@4.17.21",
"name": "lodash"
}
]
}
}
}`,
expectErrors: false,
errorCount: 0,
},
{
name: "Invalid PURL should not be checked for consistency",
json: `{
"cveMetadata": {"state": "PUBLISHED"},
"containers": {
"cna": {
"components": [
{
"purl": "invalid",
"namespace": "ns",
"name": "name"
}
]
}
}
}`,
expectErrors: false,
errorCount: 0,
},
}

for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
json := tt.json
errors := CheckPurlConsistency(&json)

if (len(errors) > 0) != tt.expectErrors {
t.Errorf("Expected errors: %v, got: %v (errors: %v)", tt.expectErrors, len(errors) > 0, errors)
}

if len(errors) != tt.errorCount {
t.Errorf("Expected %d errors, got %d: %v", tt.errorCount, len(errors), errors)
}
})
}
}
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