Fix /etc/redhat-release file parsing when resolving distro details (#3688)

syft/linux/identify_release.go

@@ -171,18 +171,36 @@ func parseSystemReleaseCPE(contents string) (*Release, error) {
 }
 
 // example: "CentOS release 6.10 (Final)"
-var redhatReleaseMatcher = regexp.MustCompile(`(.*?)\srelease\s(\d\.\d+)`)
+var redhatReleaseMatcher = regexp.MustCompile(`(?P<name>.*?)\srelease\s(?P<version>(?P<versionid>\d\.\d+).*)`)
 
 // parseRedhatRelease is a fallback parsing method for determining distro information in older redhat versions
 func parseRedhatRelease(contents string) (*Release, error) {
-	matches := redhatReleaseMatcher.FindAllStringSubmatch(contents, -1)
-	for _, match := range matches {
-		if len(match) < 3 {
-			continue
-		}
-		return simpleRelease(match[1], strings.ToLower(match[1]), match[2], ""), nil
-	}
+	contents = strings.TrimSpace(contents)
+	matches := internal.MatchNamedCaptureGroups(redhatReleaseMatcher, contents)
+	name := matches["name"]
+	version := matches["version"]
+	versionID := matches["versionid"]
+	if name == "" || versionID == "" {
 		return nil, nil
+	}
+
+	id := strings.ToLower(name)
+	switch {
+	case strings.HasPrefix(id, "red hat enterprise linux"):
+		id = "rhel"
+	case strings.HasPrefix(id, "centos"):
+		// ignore the parenthetical version information
+		version = versionID
+	}
+
+	return &Release{
+		PrettyName: contents,
+		Name:       name,
+		ID:         id,
+		IDLike:     []string{id},
+		Version:    version,
+		VersionID:  versionID,
+	}, nil
 }
 
 func simpleRelease(prettyName, name, version, cpe string) *Release {

syft/linux/identify_release_test.go

@@ -107,7 +107,7 @@ func TestIdentifyRelease(t *testing.T) {
 			},
 		},
 		{
-			fixture: "test-fixtures/os/redhat",
+			fixture: "test-fixtures/os/redhat/from-os-release",
 			release: &Release{
 				PrettyName:   "Red Hat Enterprise Linux Server 7.3 (Maipo)",
 				Name:         "Red Hat Enterprise Linux Server",
@@ -120,6 +120,17 @@ func TestIdentifyRelease(t *testing.T) {
 				CPEName:      "cpe:/o:redhat:enterprise_linux:7.3:GA:server",
 			},
 		},
+		{
+			fixture: "test-fixtures/os/redhat/from-redhat-release",
+			release: &Release{
+				PrettyName: "Red Hat Enterprise Linux release 8.10 (Ootpa)",
+				Name:       "Red Hat Enterprise Linux",
+				ID:         "rhel",
+				IDLike:     []string{"rhel"},
+				Version:    "8.10 (Ootpa)",
+				VersionID:  "8.10",
+			},
+		},
 		{
 			fixture: "test-fixtures/os/ubuntu",
 			release: &Release{
@@ -266,8 +277,8 @@ func TestIdentifyRelease(t *testing.T) {
 		{
 			fixture: "test-fixtures/os/centos5",
 			release: &Release{
-				PrettyName: "CentOS",
-				Name:       "centos",
+				PrettyName: "CentOS release 5.7 (Final)",
+				Name:       "CentOS",
 				ID:         "centos",
 				IDLike:     []string{"centos"},
 				Version:    "5.7",
@@ -506,8 +517,8 @@ func TestParseRedhatRelease(t *testing.T) {
 			fixture: "test-fixtures/os/centos5/etc/redhat-release",
 			name:    "Centos 5",
 			release: &Release{
-				PrettyName: "CentOS",
-				Name:       "centos",
+				PrettyName: "CentOS release 5.7 (Final)",
+				Name:       "CentOS",
 				ID:         "centos",
 				IDLike:     []string{"centos"},
 				Version:    "5.7",

syft/linux/test-fixtures/os/redhat/from-redhat-release/etc/redhat-release

@@ -0,0 +1 @@
+Red Hat Enterprise Linux release 8.10 (Ootpa)