detect Ubuntu Pro/ESM extended support

Mirrors the existing RHEL `ExtendedSupport` detector for Ubuntu so grype can
auto-enable its ESM distro channel on Pro/ESM-enabled scans.

`findUbuntuFeatures` sets `linux.Release.ExtendedSupport` when the scanned OS is
Ubuntu and any of these hold:

- an uncommented apt source (classic `.list` or DEB822 `.sources`, or the
  ubuntu-advantage auth entry) referencing `esm.ubuntu.com`
- an enabled `esm-infra`/`esm-apps` service in the ubuntu-advantage
  `status.json` cache
- an installed dpkg package whose version carries an `[~+]esm` pocket suffix
  (the usual in-image signal, since containers are rarely Pro-attached)

The package fallback reads `s.Artifacts.Packages` from the `DetectFeatures`
SBOM callback, which runs after package cataloging, so no new plumbing was
needed. Conservative by design: plain Ubuntu and disabled/commented ESM
evidence stay false.

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

internal/os/feature_detection.go

@@ -2,6 +2,8 @@ package os
 
 import (
 	"context"
+	"encoding/json"
+	"errors"
 	"fmt"
 	"regexp"
 
@@ -10,6 +12,7 @@ import (
 	"github.com/anchore/syft/internal/sbomsync"
 	"github.com/anchore/syft/syft/file"
 	"github.com/anchore/syft/syft/linux"
+	"github.com/anchore/syft/syft/pkg"
 	"github.com/anchore/syft/syft/sbom"
 )
 
@@ -19,8 +22,11 @@ func DetectFeatures(_ context.Context, resolver file.Resolver, builder sbomsync.
 			return
 		}
 
-		err := findRhelFeatures(resolver, s.Artifacts.LinuxDistribution)
-		if err != nil {
+		if err := findRhelFeatures(resolver, s.Artifacts.LinuxDistribution); err != nil {
+			log.WithFields("error", err, "release", s.Artifacts.LinuxDistribution).Trace("error searching for extended support")
+		}
+
+		if err := findUbuntuFeatures(resolver, s.Artifacts.LinuxDistribution, s.Artifacts.Packages); err != nil {
 			log.WithFields("error", err, "release", s.Artifacts.LinuxDistribution).Trace("error searching for extended support")
 		}
 	})
@@ -28,6 +34,9 @@ func DetectFeatures(_ context.Context, resolver file.Resolver, builder sbomsync.
 	return nil
 }
 
+// rhelEUSPatterns match a RHEL content manifest referencing an extended-update-support (EUS) repo.
+var rhelEUSPatterns = []*regexp.Regexp{regexp.MustCompile(`baseos-eus`), regexp.MustCompile(`baseos-eus|appstream-eus`)}
+
 func findRhelFeatures(resolver file.Resolver, release *linux.Release) error {
 	if release == nil || release.ID != "rhel" {
 		return nil
@@ -37,9 +46,9 @@ func findRhelFeatures(resolver file.Resolver, release *linux.Release) error {
 		return fmt.Errorf("unable to find content manifests: %w", err)
 	}
 	for _, contentManifestFile := range contentManifestFiles {
-		found, err := hasRhelExtendedSupportInContentManifest(resolver, contentManifestFile)
+		found, err := fileMatchesAny(resolver, contentManifestFile, rhelEUSPatterns...)
 		if err != nil {
-			return fmt.Errorf("unable to read content manifest from %s: %w", contentManifestFile.String(), err)
+			return fmt.Errorf("unable to read content manifest from %s: %w", contentManifestFile.RealPath, err)
 		}
 		if found {
 			release.ExtendedSupport = true
@@ -49,13 +58,152 @@ func findRhelFeatures(resolver file.Resolver, release *linux.Release) error {
 	return nil
 }
 
-func hasRhelExtendedSupportInContentManifest(resolver file.Resolver, contentManifestFile file.Location) (bool, error) {
-	contents, err := resolver.FileContentsByLocation(contentManifestFile)
-	if err != nil {
-		return false, fmt.Errorf("unable to read content manifest from %s: %w", contentManifestFile.String(), err)
-	}
-	defer internal.CloseAndLogError(contents, "content-manifest")
+// Ubuntu Pro (formerly Ubuntu Advantage) is Canonical's subscription that unlocks Expanded Security
+// Maintenance (ESM): security fixes past a package's standard support window. we detect the two base ESM
+// streams, esm-infra (the `main` repo) and esm-apps (`universe`), and collapse them into one ExtendedSupport
+// signal; the infra-vs-apps split is disambiguated by the downstream consumer, not by this boolean.
+//
+// the other Pro streams on the same host (esm.ubuntu.com/fips, /fips-updates, /realtime) are deliberately
+// excluded: they are separate compliance products with their own downstream channels, and a host can run
+// them with base ESM disabled, so folding them in would be unsound.
+//
+// detection is deliberately forgiving: apt/status evidence disappears when ESM is disabled, but an installed
+// +esmN package is durable proof ESM content is on disk. so ExtendedSupport means "ESM was or is in effect
+// for this host or its content", not "currently entitled" (mere eligibility, without evidence, is not enough).
 
-	patterns := []*regexp.Regexp{regexp.MustCompile(`baseos-eus`), regexp.MustCompile(`baseos-eus|appstream-eus`)}
+// esmAptSourcePattern matches an uncommented apt source (classic or DEB822) or auth entry pointing at the
+// plain ESM streams esm.ubuntu.com/infra or /apps. it deliberately scopes to /(infra|apps) so the other
+// Pro streams served from the same host (/fips, /fips-updates, /realtime) are never folded into the base
+// esm channel. the [^#\n]* before the host ensures a leading `#` (comment) can never satisfy the match.
+var esmAptSourcePattern = regexp.MustCompile(`(?m)^[^#\n]*esm\.ubuntu\.com/(infra|apps)`)
+
+// esmVersionPattern matches a dpkg version carrying a numbered ESM pocket suffix, e.g. `...+esm1` or
+// `...~esm2`. the trailing \d scopes this to the ESM pocket and excludes other Pro pockets (e.g. +fips).
+var esmVersionPattern = regexp.MustCompile(`[~+]esm\d`)
+
+func findUbuntuFeatures(resolver file.Resolver, release *linux.Release, packages *pkg.Collection) error {
+	if release == nil || release.ID != "ubuntu" {
+		return nil
+	}
+
+	// an uncommented esm.ubuntu.com apt source or an active pro esm service both prove Pro/ESM was enabled.
+	// these are the durable, file-based signals present on attached hosts. a read error in one signal must
+	// not suppress the others, so errors are collected and detection continues to the next signal.
+	var errs error
+	for _, check := range []func() (bool, error){
+		func() (bool, error) { return hasUbuntuESMAptEvidence(resolver) },
+		func() (bool, error) { return hasActiveUbuntuESMService(resolver) },
+	} {
+		found, err := check()
+		if err != nil {
+			errs = errors.Join(errs, err)
+			continue
+		}
+		if found {
+			release.ExtendedSupport = true
+			return errs
+		}
+	}
+
+	// fallback for images (typically not pro-attached): an installed package whose version carries an
+	// +esm/~esm suffix was pulled from an ESM pocket, so ESM was in effect when it was installed.
+	if hasInstalledESMPackage(packages) {
+		release.ExtendedSupport = true
+	}
+	return errs
+}
+
+// hasUbuntuESMAptEvidence reports whether any apt source (classic .list or DEB822 .sources) or auth entry
+// references esm.ubuntu.com via an uncommented line.
+func hasUbuntuESMAptEvidence(resolver file.Resolver) (bool, error) {
+	// apt source files live in a directory (classic .list or DEB822 .sources), the credentials file is a fixed path.
+	sourceLocations, err := resolver.FilesByGlob("/etc/apt/sources.list.d/*")
+	if err != nil {
+		return false, fmt.Errorf("unable to find apt esm sources: %w", err)
+	}
+	authLocations, err := resolver.FilesByPath("/etc/apt/auth.conf.d/90ubuntu-advantage")
+	if err != nil {
+		return false, fmt.Errorf("unable to find apt esm auth: %w", err)
+	}
+
+	// ponytail: a DEB822 source with `Enabled: no` would still match; the pro client removes/comments the
+	// file on disable rather than toggling that key, so this is an accepted false-positive ceiling. the
+	// auth.conf.d entry is deleted by the pro client on disable, so it is a durable positive-only signal.
+	for _, location := range append(sourceLocations, authLocations...) {
+		match, err := fileMatchesAny(resolver, location, esmAptSourcePattern)
+		if err != nil {
+			return false, err
+		}
+		if match {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+// hasActiveUbuntuESMService reports whether the ubuntu-advantage/pro status cache shows an enabled esm service.
+func hasActiveUbuntuESMService(resolver file.Resolver) (bool, error) {
+	locations, err := resolver.FilesByPath("/var/lib/ubuntu-advantage/status.json")
+	if err != nil {
+		return false, fmt.Errorf("unable to find ubuntu-advantage status: %w", err)
+	}
+	for _, location := range locations {
+		enabled, err := hasEnabledESMServiceInStatus(resolver, location)
+		if err != nil {
+			return false, err
+		}
+		if enabled {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+func hasEnabledESMServiceInStatus(resolver file.Resolver, location file.Location) (bool, error) {
+	contents, err := resolver.FileContentsByLocation(location)
+	if err != nil {
+		return false, fmt.Errorf("unable to read ubuntu-advantage status from %s: %w", location.RealPath, err)
+	}
+	defer internal.CloseAndLogError(contents, location.RealPath)
+
+	var status struct {
+		Services []struct {
+			Name   string `json:"name"`
+			Status string `json:"status"`
+		} `json:"services"`
+	}
+	if err := json.NewDecoder(contents).Decode(&status); err != nil {
+		return false, fmt.Errorf("unable to parse ubuntu-advantage status from %s: %w", location.RealPath, err)
+	}
+
+	// pro status values are enabled/disabled/n-a/warning/—; only "enabled" proves the stream is active.
+	// warning/expired states are intentionally excluded here and left to the apt-source and installed-package signals.
+	for _, svc := range status.Services {
+		if (svc.Name == "esm-infra" || svc.Name == "esm-apps") && svc.Status == "enabled" {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+// hasInstalledESMPackage reports whether any installed dpkg package version carries an ESM pocket suffix.
+func hasInstalledESMPackage(packages *pkg.Collection) bool {
+	if packages == nil {
+		return false
+	}
+	for p := range packages.Enumerate(pkg.DebPkg) {
+		if esmVersionPattern.MatchString(p.Version) {
+			return true
+		}
+	}
+	return false
+}
+
+func fileMatchesAny(resolver file.Resolver, location file.Location, patterns ...*regexp.Regexp) (bool, error) {
+	contents, err := resolver.FileContentsByLocation(location)
+	if err != nil {
+		return false, fmt.Errorf("unable to read %s: %w", location.RealPath, err)
+	}
+	defer internal.CloseAndLogError(contents, location.RealPath)
 	return internal.MatchAnyFromReader(contents, patterns...)
 }

internal/os/feature_detection_test.go

@@ -2,6 +2,11 @@ package os_test
 
 import (
 	"context"
+	"io"
+	stdos "os"
+	"path"
+	"path/filepath"
+	"slices"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -11,7 +16,9 @@ import (
 	"github.com/anchore/syft/internal/sbomsync"
 	"github.com/anchore/syft/internal/task"
 	"github.com/anchore/syft/syft"
+	"github.com/anchore/syft/syft/file"
 	"github.com/anchore/syft/syft/linux"
+	"github.com/anchore/syft/syft/pkg"
 	"github.com/anchore/syft/syft/sbom"
 	"github.com/anchore/syft/syft/source"
 )
@@ -99,3 +106,210 @@ func Test_EnvironmentTask(t *testing.T) {
 		})
 	}
 }
+
+func Test_findUbuntuFeatures(t *testing.T) {
+	tests := []struct {
+		name      string
+		dir       string
+		releaseID string
+		packages  []pkg.Package
+		expected  bool
+	}{
+		{
+			name:      "esm apt source present",
+			dir:       "testdata/ubuntu_esm_apt",
+			releaseID: "ubuntu",
+			expected:  true,
+		},
+		{
+			name:      "esm apt source in DEB822 .sources format",
+			dir:       "testdata/ubuntu_esm_deb822",
+			releaseID: "ubuntu",
+			expected:  true,
+		},
+		{
+			name:      "esm evidence in apt auth.conf.d",
+			dir:       "testdata/ubuntu_esm_authconf",
+			releaseID: "ubuntu",
+			expected:  true,
+		},
+		{
+			name:      "active esm service in ubuntu-advantage status",
+			dir:       "testdata/ubuntu_esm_status",
+			releaseID: "ubuntu",
+			expected:  true,
+		},
+		{
+			name:      "only esm-infra enabled (esm-apps disabled)",
+			dir:       "testdata/ubuntu_esm_infra_only",
+			releaseID: "ubuntu",
+			expected:  true,
+		},
+		{
+			name:      "malformed status.json does not panic or match",
+			dir:       "testdata/ubuntu_esm_malformed",
+			releaseID: "ubuntu",
+			expected:  false,
+		},
+		{
+			name:      "installed +esm package version",
+			dir:       "testdata/ubuntu_plain",
+			releaseID: "ubuntu",
+			packages: []pkg.Package{
+				{Name: "openssl", Version: "1.1.1f-1ubuntu2.19+esm1", Type: pkg.DebPkg},
+			},
+			expected: true,
+		},
+		{
+			name:      "installed ~esm package version",
+			dir:       "testdata/ubuntu_plain",
+			releaseID: "ubuntu",
+			packages: []pkg.Package{
+				{Name: "libcap2", Version: "1:2.32-1ubuntu0.1~esm1", Type: pkg.DebPkg},
+			},
+			expected: true,
+		},
+		{
+			name:      "plain ubuntu with no esm evidence",
+			dir:       "testdata/ubuntu_plain",
+			releaseID: "ubuntu",
+			packages: []pkg.Package{
+				{Name: "openssl", Version: "1.1.1f-1ubuntu2.19", Type: pkg.DebPkg},
+			},
+			expected: false,
+		},
+		{
+			name:      "commented esm source and disabled esm service",
+			dir:       "testdata/ubuntu_esm_disabled",
+			releaseID: "ubuntu",
+			expected:  false,
+		},
+		{
+			name:      "esm disabled but +esm package remains installed",
+			dir:       "testdata/ubuntu_esm_disabled",
+			releaseID: "ubuntu",
+			packages: []pkg.Package{
+				{Name: "openssl", Version: "1.1.1f-1ubuntu2.19+esm1", Type: pkg.DebPkg},
+			},
+			expected: true, // durable proof: ESM content is on disk even though the channel is now off
+		},
+		{
+			name:      "fips-only pro host is not plain esm",
+			dir:       "testdata/ubuntu_fips_only",
+			releaseID: "ubuntu",
+			expected:  false, // esm.ubuntu.com/fips must not be folded into the base esm channel
+		},
+		{
+			name:      "non-ubuntu is unaffected by esm evidence",
+			dir:       "testdata/ubuntu_esm_apt",
+			releaseID: "debian",
+			expected:  false,
+		},
+		{
+			name:      "non-ubuntu is unaffected by esm package version",
+			dir:       "testdata/ubuntu_plain",
+			releaseID: "debian",
+			packages: []pkg.Package{
+				{Name: "openssl", Version: "1.1.1f-1ubuntu2.19+esm1", Type: pkg.DebPkg},
+			},
+			expected: false,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			resolver := fixtureResolverForDir(t, test.dir)
+
+			s := sbom.SBOM{}
+			s.Artifacts.LinuxDistribution = &linux.Release{ID: test.releaseID}
+			s.Artifacts.Packages = pkg.NewCollection(test.packages...)
+
+			err := os.DetectFeatures(context.Background(), resolver, sbomsync.NewBuilder(&s))
+			require.NoError(t, err)
+
+			require.Equal(t, test.expected, s.Artifacts.LinuxDistribution.ExtendedSupport)
+		})
+	}
+}
+
+// a read error in the apt-source signal must not suppress the ubuntu-advantage status signal; the three
+// signals are meant to be independent fallbacks.
+func Test_findUbuntuFeatures_signalErrorDoesNotSuppressOthers(t *testing.T) {
+	resolver := errOnGlobResolver{
+		fixtureResolver: fixtureResolverForDir(t, "testdata/ubuntu_esm_status").(fixtureResolver),
+		errOnGlob:       "/etc/apt/sources.list.d/*",
+	}
+
+	s := sbom.SBOM{}
+	s.Artifacts.LinuxDistribution = &linux.Release{ID: "ubuntu"}
+	s.Artifacts.Packages = pkg.NewCollection()
+
+	require.NoError(t, os.DetectFeatures(context.Background(), resolver, sbomsync.NewBuilder(&s)))
+
+	// the apt glob errors, but the status.json signal (esm-infra enabled) should still be consulted
+	require.True(t, s.Artifacts.LinuxDistribution.ExtendedSupport)
+}
+
+// errOnGlobResolver injects a failure for a specific glob to simulate an unreadable apt directory.
+type errOnGlobResolver struct {
+	fixtureResolver
+	errOnGlob string
+}
+
+func (r errOnGlobResolver) FilesByGlob(patterns ...string) ([]file.Location, error) {
+	if slices.Contains(patterns, r.errOnGlob) {
+		return nil, stdos.ErrPermission
+	}
+	return r.fixtureResolver.FilesByGlob(patterns...)
+}
+
+// fixtureResolver maps in-image logical paths to on-disk fixture files so DetectFeatures can be driven
+// without building a container image.
+type fixtureResolver struct {
+	file.Resolver // unused methods; nil is fine since only the three below are called
+	files         map[string]string
+}
+
+func (r fixtureResolver) FilesByGlob(patterns ...string) ([]file.Location, error) {
+	var out []file.Location
+	for logical := range r.files {
+		for _, p := range patterns {
+			if ok, _ := path.Match(p, logical); ok {
+				out = append(out, file.NewLocation(logical))
+				break
+			}
+		}
+	}
+	return out, nil
+}
+
+func (r fixtureResolver) FilesByPath(paths ...string) ([]file.Location, error) {
+	var out []file.Location
+	for _, p := range paths {
+		if _, ok := r.files[p]; ok {
+			out = append(out, file.NewLocation(p))
+		}
+	}
+	return out, nil
+}
+
+func (r fixtureResolver) FileContentsByLocation(l file.Location) (io.ReadCloser, error) {
+	return stdos.Open(r.files[l.RealPath])
+}
+
+func fixtureResolverForDir(t *testing.T, dir string) file.Resolver {
+	t.Helper()
+	files := map[string]string{}
+	require.NoError(t, filepath.WalkDir(dir, func(p string, d stdos.DirEntry, err error) error {
+		if err != nil || d.IsDir() {
+			return err
+		}
+		rel, err := filepath.Rel(dir, p)
+		if err != nil {
+			return err
+		}
+		files["/"+filepath.ToSlash(rel)] = p
+		return nil
+	}))
+	return fixtureResolver{files: files}
+}

internal/os/testdata/ubuntu_esm_apt/etc/apt/sources.list.d/ubuntu-esm-infra.list

@@ -0,0 +1,6 @@
+# Written by ubuntu-advantage-tools
+deb https://esm.ubuntu.com/infra/ubuntu focal-infra-security main
+# deb-src https://esm.ubuntu.com/infra/ubuntu focal-infra-security main
+
+deb https://esm.ubuntu.com/infra/ubuntu focal-infra-updates main
+# deb-src https://esm.ubuntu.com/infra/ubuntu focal-infra-updates main

internal/os/testdata/ubuntu_esm_authconf/etc/apt/auth.conf.d/90ubuntu-advantage

@@ -0,0 +1,2 @@
+machine esm.ubuntu.com/infra/ubuntu/ login bearer password DUMMYTOKENREDACTED  # ubuntu-pro-client
+machine esm.ubuntu.com/apps/ubuntu/ login bearer password DUMMYTOKENREDACTED  # ubuntu-pro-client

internal/os/testdata/ubuntu_esm_deb822/etc/apt/sources.list.d/ubuntu-esm-infra.sources

@@ -0,0 +1,5 @@
+Types: deb
+URIs: https://esm.ubuntu.com/infra/ubuntu
+Suites: noble-infra-security noble-infra-updates
+Components: main
+Signed-By: /usr/share/keyrings/ubuntu-pro-esm-infra-keyring.gpg

internal/os/testdata/ubuntu_esm_disabled/etc/apt/sources.list.d/ubuntu-esm-infra.list

@@ -0,0 +1,3 @@
+# Written by ubuntu-advantage-tools
+# deb https://esm.ubuntu.com/infra/ubuntu focal-infra-security main
+# deb-src https://esm.ubuntu.com/infra/ubuntu focal-infra-security main

internal/os/testdata/ubuntu_esm_disabled/var/lib/ubuntu-advantage/status.json

@@ -0,0 +1,18 @@
+{
+  "_schema_version": "0.1",
+  "attached": true,
+  "services": [
+    {
+      "name": "esm-apps",
+      "available": "yes",
+      "entitled": "yes",
+      "status": "disabled"
+    },
+    {
+      "name": "esm-infra",
+      "available": "yes",
+      "entitled": "yes",
+      "status": "disabled"
+    }
+  ]
+}

internal/os/testdata/ubuntu_esm_infra_only/var/lib/ubuntu-advantage/status.json

@@ -0,0 +1,21 @@
+{
+  "_schema_version": "0.1",
+  "attached": true,
+  "execution_status": "success",
+  "services": [
+    {
+      "name": "esm-apps",
+      "description": "Expanded Security Maintenance for Applications",
+      "available": "yes",
+      "entitled": "yes",
+      "status": "disabled"
+    },
+    {
+      "name": "esm-infra",
+      "description": "Expanded Security Maintenance for Infrastructure",
+      "available": "yes",
+      "entitled": "yes",
+      "status": "enabled"
+    }
+  ]
+}

internal/os/testdata/ubuntu_esm_malformed/var/lib/ubuntu-advantage/status.json

@@ -0,0 +1 @@
+{ this is not valid json

internal/os/testdata/ubuntu_esm_status/var/lib/ubuntu-advantage/status.json

@@ -0,0 +1,28 @@
+{
+  "_doc": "Content provided in json response is currently considered Experimental and may change",
+  "_schema_version": "0.1",
+  "attached": true,
+  "services": [
+    {
+      "name": "esm-apps",
+      "description": "Expanded Security Maintenance for Applications",
+      "available": "yes",
+      "entitled": "yes",
+      "status": "enabled"
+    },
+    {
+      "name": "esm-infra",
+      "description": "Expanded Security Maintenance for Infrastructure",
+      "available": "yes",
+      "entitled": "yes",
+      "status": "enabled"
+    },
+    {
+      "name": "fips",
+      "description": "NIST-certified FIPS crypto packages",
+      "available": "no",
+      "entitled": "no",
+      "status": "n/a"
+    }
+  ]
+}

internal/os/testdata/ubuntu_fips_only/etc/apt/sources.list.d/ubuntu-fips.list

@@ -0,0 +1,3 @@
+# Written by ubuntu-pro-client
+deb https://esm.ubuntu.com/fips/ubuntu focal main
+# deb-src https://esm.ubuntu.com/fips/ubuntu focal main

internal/os/testdata/ubuntu_fips_only/var/lib/ubuntu-advantage/status.json

@@ -0,0 +1,28 @@
+{
+  "_schema_version": "0.1",
+  "attached": true,
+  "execution_status": "success",
+  "services": [
+    {
+      "name": "esm-apps",
+      "description": "Expanded Security Maintenance for Applications",
+      "available": "yes",
+      "entitled": "yes",
+      "status": "disabled"
+    },
+    {
+      "name": "esm-infra",
+      "description": "Expanded Security Maintenance for Infrastructure",
+      "available": "yes",
+      "entitled": "yes",
+      "status": "disabled"
+    },
+    {
+      "name": "fips",
+      "description": "NIST-certified FIPS crypto packages",
+      "available": "yes",
+      "entitled": "yes",
+      "status": "enabled"
+    }
+  ]
+}

internal/os/testdata/ubuntu_plain/etc/apt/sources.list.d/ubuntu.sources

@@ -0,0 +1,5 @@
+Types: deb
+URIs: http://archive.ubuntu.com/ubuntu/
+Suites: noble noble-updates noble-backports
+Components: main restricted universe multiverse
+Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg