From 8cd7de276e337f2753c72374ab972d6d8e6b1925 Mon Sep 17 00:00:00 2001
From: Teppei Fukuda <knqyf263@gmail.com>
Date: Thu, 16 Sep 2021 22:20:59 +0300
Subject: [PATCH] feat(alpine): support unfixed vulnerabilities (#1235)

---
 pkg/detector/ospkg/alpine/alpine.go           | 56 ++++++++++++++-----
 pkg/detector/ospkg/alpine/alpine_test.go      | 20 ++++++-
 .../fixtures/{alpine310.yaml => alpine.yaml}  |  7 +++
 3 files changed, 67 insertions(+), 16 deletions(-)
 rename pkg/detector/ospkg/alpine/testdata/fixtures/{alpine310.yaml => alpine.yaml} (81%)

diff --git a/pkg/detector/ospkg/alpine/alpine.go b/pkg/detector/ospkg/alpine/alpine.go
index ae22c44c3989..98357b9bd04b 100644
--- a/pkg/detector/ospkg/alpine/alpine.go
+++ b/pkg/detector/ospkg/alpine/alpine.go
@@ -9,6 +9,7 @@ import (
 	"k8s.io/utils/clock"
 
 	ftypes "github.com/aquasecurity/fanal/types"
+	dbTypes "github.com/aquasecurity/trivy-db/pkg/types"
 	"github.com/aquasecurity/trivy-db/pkg/vulnsrc/alpine"
 	"github.com/aquasecurity/trivy/pkg/log"
 	"github.com/aquasecurity/trivy/pkg/scanner/utils"
@@ -100,26 +101,55 @@ func (s *Scanner) Detect(osVer string, pkgs []ftypes.Package) ([]types.DetectedV
 		}
 
 		for _, adv := range advisories {
-			fixedVersion, err := version.NewVersion(adv.FixedVersion)
-			if err != nil {
-				log.Logger.Debugf("failed to parse Alpine Linux fixed version: %s", err)
+			if !s.isVulnerable(installedVersion, adv) {
 				continue
 			}
-			if installedVersion.LessThan(fixedVersion) {
-				vuln := types.DetectedVulnerability{
-					VulnerabilityID:  adv.VulnerabilityID,
-					PkgName:          pkg.Name,
-					InstalledVersion: installed,
-					FixedVersion:     adv.FixedVersion,
-					Layer:            pkg.Layer,
-				}
-				vulns = append(vulns, vuln)
-			}
+			vulns = append(vulns, types.DetectedVulnerability{
+				VulnerabilityID:  adv.VulnerabilityID,
+				PkgName:          pkg.Name,
+				InstalledVersion: installed,
+				FixedVersion:     adv.FixedVersion,
+				Layer:            pkg.Layer,
+			})
+
 		}
 	}
 	return vulns, nil
 }
 
+func (s *Scanner) isVulnerable(installedVersion version.Version, adv dbTypes.Advisory) bool {
+	// This logic is for unfixed vulnerabilities, but Trivy DB doesn't have advisories for unfixed vulnerabilities for now
+	// because Alpine just provides potentially vulnerable packages. It will cause a lot of false positives.
+	// This is for Aqua commercial products.
+	if adv.AffectedVersion != "" {
+		// AffectedVersion means which version introduced this vulnerability.
+		affectedVersion, err := version.NewVersion(adv.AffectedVersion)
+		if err != nil {
+			log.Logger.Debugf("failed to parse Alpine Linux affected package version: %s", err)
+			return false
+		}
+		if affectedVersion.GreaterThan(installedVersion) {
+			return false
+		}
+	}
+
+	// This logic is also for unfixed vulnerabilities.
+	if adv.FixedVersion == "" {
+		// It means the unfixed vulnerability
+		return true
+	}
+
+	// Compare versions for fixed vulnerabilities
+	fixedVersion, err := version.NewVersion(adv.FixedVersion)
+	if err != nil {
+		log.Logger.Debugf("failed to parse Alpine Linux fixed version: %s", err)
+		return false
+	}
+
+	// It means the fixed vulnerability
+	return installedVersion.LessThan(fixedVersion)
+}
+
 // IsSupportedVersion checks the OSFamily can be scanned using Alpine scanner
 func (s *Scanner) IsSupportedVersion(osFamily, osVer string) bool {
 	if strings.Count(osVer, ".") > 1 {
diff --git a/pkg/detector/ospkg/alpine/alpine_test.go b/pkg/detector/ospkg/alpine/alpine_test.go
index e2d5eadcc295..06f7b701343c 100644
--- a/pkg/detector/ospkg/alpine/alpine_test.go
+++ b/pkg/detector/ospkg/alpine/alpine_test.go
@@ -1,6 +1,7 @@
 package alpine_test
 
 import (
+	"sort"
 	"testing"
 	"time"
 
@@ -29,7 +30,7 @@ func TestScanner_Detect(t *testing.T) {
 	}{
 		{
 			name:     "happy path",
-			fixtures: []string{"testdata/fixtures/alpine310.yaml"},
+			fixtures: []string{"testdata/fixtures/alpine.yaml"},
 			args: args{
 				osVer: "3.10.2",
 				pkgs: []ftypes.Package{
@@ -60,11 +61,20 @@ func TestScanner_Detect(t *testing.T) {
 						DiffID: "sha256:932da51564135c98a49a34a193d6cd363d8fa4184d957fde16c9d8527b3f3b02",
 					},
 				},
+				{
+					PkgName:          "ansible",
+					VulnerabilityID:  "CVE-2021-20191",
+					InstalledVersion: "2.6.4",
+					FixedVersion:     "",
+					Layer: ftypes.Layer{
+						DiffID: "sha256:932da51564135c98a49a34a193d6cd363d8fa4184d957fde16c9d8527b3f3b02",
+					},
+				},
 			},
 		},
 		{
 			name:     "contain rc",
-			fixtures: []string{"testdata/fixtures/alpine310.yaml"},
+			fixtures: []string{"testdata/fixtures/alpine.yaml"},
 			args: args{
 				osVer: "3.10",
 				pkgs: []ftypes.Package{
@@ -87,7 +97,7 @@ func TestScanner_Detect(t *testing.T) {
 		},
 		{
 			name:     "contain pre",
-			fixtures: []string{"testdata/fixtures/alpine310.yaml"},
+			fixtures: []string{"testdata/fixtures/alpine.yaml"},
 			args: args{
 				osVer: "3.10",
 				pkgs: []ftypes.Package{
@@ -143,6 +153,10 @@ func TestScanner_Detect(t *testing.T) {
 				assert.Contains(t, err.Error(), tt.wantErr)
 				return
 			}
+
+			sort.Slice(got, func(i, j int) bool {
+				return got[i].VulnerabilityID < got[j].VulnerabilityID
+			})
 			assert.NoError(t, err)
 			assert.Equal(t, tt.want, got)
 		})
diff --git a/pkg/detector/ospkg/alpine/testdata/fixtures/alpine310.yaml b/pkg/detector/ospkg/alpine/testdata/fixtures/alpine.yaml
similarity index 81%
rename from pkg/detector/ospkg/alpine/testdata/fixtures/alpine310.yaml
rename to pkg/detector/ospkg/alpine/testdata/fixtures/alpine.yaml
index 1d56e4c066ea..810578368790 100644
--- a/pkg/detector/ospkg/alpine/testdata/fixtures/alpine310.yaml
+++ b/pkg/detector/ospkg/alpine/testdata/fixtures/alpine.yaml
@@ -8,6 +8,13 @@
         - key: CVE-2019-10217
           value:
             FixedVersion: "2.8.4-r0"
+        - key: CVE-2020-1740
+          value:
+            FixedVersion: ""
+            AffectedVersion: "2.6.5"
+        - key: CVE-2021-20191
+          value:
+            FixedVersion: ""
         - key: CVE-2019-INVALID
           value:
             FixedVersion: "invalid"