Adding encryption decryption feature

Signed-off-by: Tarun1 Gupta <gupttaru@deshaw.com>

cmd/podman/common/create.go

@@ -571,9 +571,18 @@ func DefineCreateFlags(cmd *cobra.Command, cf *entities.ContainerCreateOptions,
 		createFlags.StringVar(&cf.PasswdEntry, passwdEntryName, "", "Entry to write to /etc/passwd")
 		_ = cmd.RegisterFlagCompletionFunc(passwdEntryName, completion.AutocompleteNone)
 
+		decryptionKeysFlagName := "decryption-key"
+		createFlags.StringSliceVar(
+			&cf.DecryptionKeys,
+			decryptionKeysFlagName, []string{},
+			"Key needed to decrypt the image (e.g. /path/to/key.pem)",
+		)
+		_ = cmd.RegisterFlagCompletionFunc(decryptionKeysFlagName, completion.AutocompleteNone)
+
 		if registry.IsRemote() {
 			_ = createFlags.MarkHidden("env-host")
 			_ = createFlags.MarkHidden("http-proxy")
+			_ = createFlags.MarkHidden(decryptionKeysFlagName)
 		} else {
 			createFlags.StringVar(
 				&cf.SignaturePolicy,

cmd/podman/containers/create.go

@@ -334,15 +334,21 @@ func PullImage(imageName string, cliVals *entities.ContainerCreateOptions) (stri
 		skipTLSVerify = types.NewOptionalBool(!cliVals.TLSVerify.Value())
 	}
 
+	decConfig, err := util.DecryptConfig(cliVals.DecryptionKeys)
+	if err != nil {
+		return "unable to obtain decryption config", err
+	}
+
 	pullReport, pullErr := registry.ImageEngine().Pull(registry.GetContext(), imageName, entities.ImagePullOptions{
-		Authfile:        cliVals.Authfile,
-		Quiet:           cliVals.Quiet,
-		Arch:            cliVals.Arch,
-		OS:              cliVals.OS,
-		Variant:         cliVals.Variant,
-		SignaturePolicy: cliVals.SignaturePolicy,
-		PullPolicy:      pullPolicy,
-		SkipTLSVerify:   skipTLSVerify,
+		Authfile:         cliVals.Authfile,
+		Quiet:            cliVals.Quiet,
+		Arch:             cliVals.Arch,
+		OS:               cliVals.OS,
+		Variant:          cliVals.Variant,
+		SignaturePolicy:  cliVals.SignaturePolicy,
+		PullPolicy:       pullPolicy,
+		SkipTLSVerify:    skipTLSVerify,
+		OciDecryptConfig: decConfig,
 	})
 	if pullErr != nil {
 		return "", pullErr

cmd/podman/images/pull.go

@@ -23,6 +23,7 @@ type pullOptionsWrapper struct {
 	entities.ImagePullOptions
 	TLSVerifyCLI   bool // CLI only
 	CredentialsCLI string
+	DecryptionKeys []string
 }
 
 var (
@@ -107,6 +108,13 @@ func pullFlags(cmd *cobra.Command) {
 	flags.StringVar(&pullOptions.Authfile, authfileFlagName, auth.GetDefaultAuthFile(), "Path of the authentication file. Use REGISTRY_AUTH_FILE environment variable to override")
 	_ = cmd.RegisterFlagCompletionFunc(authfileFlagName, completion.AutocompleteDefault)
 
+	decryptionKeysFlagName := "decryption-key"
+	flags.StringSliceVar(&pullOptions.DecryptionKeys, decryptionKeysFlagName, nil, "Key needed to decrypt the image (e.g. /path/to/key.pem)")
+	_ = cmd.RegisterFlagCompletionFunc(decryptionKeysFlagName, completion.AutocompleteDefault)
+
+	if registry.IsRemote() {
+		_ = flags.MarkHidden(decryptionKeysFlagName)
+	}
 	if !registry.IsRemote() {
 		certDirFlagName := "cert-dir"
 		flags.StringVar(&pullOptions.CertDir, certDirFlagName, "", "`Pathname` of a directory containing TLS certificates and keys")
@@ -156,6 +164,12 @@ func imagePull(cmd *cobra.Command, args []string) error {
 		pullOptions.Password = creds.Password
 	}
 
+	decConfig, err := util.DecryptConfig(pullOptions.DecryptionKeys)
+	if err != nil {
+		return fmt.Errorf("unable to obtain decryption config: %w", err)
+	}
+	pullOptions.OciDecryptConfig = decConfig
+
 	if !pullOptions.Quiet {
 		pullOptions.Writer = os.Stderr
 	}

cmd/podman/images/push.go

@@ -1,6 +1,7 @@
 package images
 
 import (
+	"fmt"
 	"os"
 
 	"github.com/containers/common/pkg/auth"
@@ -20,6 +21,8 @@ type pushOptionsWrapper struct {
 	TLSVerifyCLI          bool // CLI only
 	CredentialsCLI        string
 	SignPassphraseFileCLI string
+	EncryptionKeys        []string
+	EncryptLayers         []int
 }
 
 var (
@@ -121,6 +124,14 @@ func pushFlags(cmd *cobra.Command) {
 	flags.StringVar(&pushOptions.CompressionFormat, compressionFormat, "", "compression format to use")
 	_ = cmd.RegisterFlagCompletionFunc(compressionFormat, common.AutocompleteCompressionFormat)
 
+	encryptionKeysFlagName := "encryption-key"
+	flags.StringSliceVar(&pushOptions.EncryptionKeys, encryptionKeysFlagName, nil, "Key with the encryption protocol to use to encrypt the image (e.g. jwe:/path/to/key.pem)")
+	_ = cmd.RegisterFlagCompletionFunc(encryptionKeysFlagName, completion.AutocompleteDefault)
+
+	encryptLayersFlagName := "encrypt-layer"
+	flags.IntSliceVar(&pushOptions.EncryptLayers, encryptLayersFlagName, nil, "Layers to encrypt, 0-indexed layer indices with support for negative indexing (e.g. 0 is the first layer, -1 is the last layer). If not defined, will encrypt all layers if encryption-key flag is specified")
+	_ = cmd.RegisterFlagCompletionFunc(encryptLayersFlagName, completion.AutocompleteDefault)
+
 	if registry.IsRemote() {
 		_ = flags.MarkHidden("cert-dir")
 		_ = flags.MarkHidden("compress")
@@ -129,6 +140,8 @@ func pushFlags(cmd *cobra.Command) {
 		_ = flags.MarkHidden(signByFlagName)
 		_ = flags.MarkHidden(signBySigstorePrivateKeyFlagName)
 		_ = flags.MarkHidden(signPassphraseFileFlagName)
+		_ = flags.MarkHidden(encryptionKeysFlagName)
+		_ = flags.MarkHidden(encryptLayersFlagName)
 	}
 	if !registry.IsRemote() {
 		flags.StringVar(&pushOptions.SignaturePolicy, "signature-policy", "", "Path to a signature-policy file")
@@ -172,6 +185,13 @@ func imagePush(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	encConfig, encLayers, err := util.EncryptConfig(pushOptions.EncryptionKeys, pushOptions.EncryptLayers)
+	if err != nil {
+		return fmt.Errorf("unable to obtain encryption config: %w", err)
+	}
+	pushOptions.OciEncryptConfig = encConfig
+	pushOptions.OciEncryptLayers = encLayers
+
 	// Let's do all the remaining Yoga in the API to prevent us from scattering
 	// logic across (too) many parts of the code.
 	return registry.ImageEngine().Push(registry.GetContext(), source, destination, pushOptions.ImagePushOptions)

docs/source/markdown/options/decryption-key.md

@@ -0,0 +1,7 @@
+####> This option file is used in:
+####>   podman create, pull, run
+####> If you edit this file, make sure your changes
+####> are applicable to all of those.
+#### **--decryption-key**=*key[:passphrase]*
+
+The [key[:passphrase]] to be used for decryption of images. Key can point to keys and/or certificates. Decryption will be tried with all keys. If the key is protected by a passphrase, it is required to be passed in the argument and omitted otherwise.

docs/source/markdown/podman-create.1.md.in

@@ -114,6 +114,8 @@ and specified with a _tag_.
 
 @@option cpuset-mems
 
+@@option decryption-key
+
 @@option device
 
 Note: if the user only has access rights via a group, accessing the device

docs/source/markdown/podman-pull.1.md.in

@@ -57,6 +57,8 @@ All tagged images in the repository will be pulled.
 
 @@option creds
 
+@@option decryption-key
+
 @@option disable-content-trust
 
 #### **--help**, **-h**

docs/source/markdown/podman-push.1.md.in

@@ -64,6 +64,14 @@ Note: This flag can only be set when using the **dir** transport
 
 @@option disable-content-trust
 
+#### **--encrypt-layer**=*layer(s)*
+
+Layer(s) to encrypt: 0-indexed layer indices with support for negative indexing (e.g. 0 is the first layer, -1 is the last layer). If not defined, will encrypt all layers if encryption-key flag is specified.
+
+#### **--encryption-key**=*key*
+
+The [protocol:keyfile] specifies the encryption protocol, which can be JWE (RFC7516), PGP (RFC4880), and PKCS7 (RFC2315) and the key material required for image encryption. For instance, jwe:/path/to/key.pem or pgp:admin@example.com or pkcs7:/path/to/x509-file.
+
 #### **--format**, **-f**=*format*
 
 Manifest Type (oci, v2s2, or v2s1) to use when pushing an image.

docs/source/markdown/podman-run.1.md.in

@@ -131,6 +131,8 @@ and specified with a _tag_.
 
 @@option cpuset-mems
 
+@@option decryption-key
+
 #### **--detach**, **-d**
 
 Detached mode: run the container in the background and print the new container ID. The default is *false*.

pkg/domain/entities/images.go

@@ -8,6 +8,7 @@ import (
 	"github.com/containers/common/pkg/config"
 	"github.com/containers/image/v5/manifest"
 	"github.com/containers/image/v5/types"
+	encconfig "github.com/containers/ocicrypt/config"
 	"github.com/containers/podman/v4/pkg/inspect"
 	"github.com/containers/podman/v4/pkg/trust"
 	"github.com/docker/docker/api/types/container"
@@ -158,6 +159,9 @@ type ImagePullOptions struct {
 	PullPolicy config.PullPolicy
 	// Writer is used to display copy information including progress bars.
 	Writer io.Writer
+	// OciDecryptConfig contains the config that can be used to decrypt an image if it is
+	// encrypted if non-nil. If nil, it does not attempt to decrypt an image.
+	OciDecryptConfig *encconfig.DecryptConfig
 }
 
 // ImagePullReport is the response from pulling one or more images.
@@ -227,6 +231,15 @@ type ImagePushOptions struct {
 	CompressionFormat string
 	// Writer is used to display copy information including progress bars.
 	Writer io.Writer
+	// OciEncryptConfig when non-nil indicates that an image should be encrypted.
+	// The encryption options is derived from the construction of EncryptConfig object.
+	OciEncryptConfig *encconfig.EncryptConfig
+	// OciEncryptLayers represents the list of layers to encrypt.
+	// If nil, don't encrypt any layers.
+	// If non-nil and len==0, denotes encrypt all layers.
+	// integers in the slice represent 0-indexed layer indices, with support for negative
+	// indexing. i.e. 0 is the first layer, -1 is the last (top-most) layer.
+	OciEncryptLayers *[]int
 }
 
 // ImagePushReport is the response from pushing an image.

pkg/domain/entities/pods.go

@@ -290,6 +290,7 @@ type ContainerCreateOptions struct {
 	ChrootDirs        []string
 	IsInfra           bool
 	IsClone           bool
+	DecryptionKeys    []string
 
 	Net *NetOptions `json:"net,omitempty"`
 

pkg/domain/infra/abi/images.go

@@ -236,6 +236,7 @@ func (ir *ImageEngine) Pull(ctx context.Context, rawImage string, options entiti
 	pullOptions.SignaturePolicyPath = options.SignaturePolicy
 	pullOptions.InsecureSkipTLSVerify = options.SkipTLSVerify
 	pullOptions.Writer = options.Writer
+	pullOptions.OciDecryptConfig = options.OciDecryptConfig
 
 	if !options.Quiet && pullOptions.Writer == nil {
 		pullOptions.Writer = os.Stderr
@@ -309,6 +310,8 @@ func (ir *ImageEngine) Push(ctx context.Context, source string, destination stri
 	pushOptions.SignSigstorePrivateKeyPassphrase = options.SignSigstorePrivateKeyPassphrase
 	pushOptions.InsecureSkipTLSVerify = options.SkipTLSVerify
 	pushOptions.Writer = options.Writer
+	pushOptions.OciEncryptConfig = options.OciEncryptConfig
+	pushOptions.OciEncryptLayers = options.OciEncryptLayers
 
 	compressionFormat := options.CompressionFormat
 	if compressionFormat == "" {

pkg/domain/infra/tunnel/images.go

@@ -105,6 +105,10 @@ func (ir *ImageEngine) Prune(ctx context.Context, opts entities.ImagePruneOption
 }
 
 func (ir *ImageEngine) Pull(ctx context.Context, rawImage string, opts entities.ImagePullOptions) (*entities.ImagePullReport, error) {
+	if opts.OciDecryptConfig != nil {
+		return nil, fmt.Errorf("decryption is not supported for remote clients")
+	}
+
 	options := new(images.PullOptions)
 	options.WithAllTags(opts.AllTags).WithAuthfile(opts.Authfile).WithArch(opts.Arch).WithOS(opts.OS)
 	options.WithVariant(opts.Variant).WithPassword(opts.Password)
@@ -240,6 +244,10 @@ func (ir *ImageEngine) Import(ctx context.Context, opts entities.ImageImportOpti
 }
 
 func (ir *ImageEngine) Push(ctx context.Context, source string, destination string, opts entities.ImagePushOptions) error {
+	if opts.OciEncryptConfig != nil {
+		return fmt.Errorf("encryption is not supported for remote clients")
+	}
+
 	options := new(images.PushOptions)
 	options.WithAll(opts.All).WithCompress(opts.Compress).WithUsername(opts.Username).WithPassword(opts.Password).WithAuthfile(opts.Authfile).WithFormat(opts.Format).WithRemoveSignatures(opts.RemoveSignatures).WithQuiet(opts.Quiet).WithCompressionFormat(opts.CompressionFormat).WithProgressWriter(opts.Writer)
 

pkg/util/utils.go

@@ -20,6 +20,8 @@ import (
 	"github.com/containers/common/pkg/config"
 	"github.com/containers/common/pkg/util"
 	"github.com/containers/image/v5/types"
+	encconfig "github.com/containers/ocicrypt/config"
+	enchelpers "github.com/containers/ocicrypt/helpers"
 	"github.com/containers/podman/v4/pkg/errorhandling"
 	"github.com/containers/podman/v4/pkg/namespaces"
 	"github.com/containers/podman/v4/pkg/rootless"
@@ -756,3 +758,37 @@ func SizeOfPath(path string) (uint64, error) {
 	})
 	return size, err
 }
+
+// EncryptConfig translates encryptionKeys into a EncriptionsConfig structure
+func EncryptConfig(encryptionKeys []string, encryptLayers []int) (*encconfig.EncryptConfig, *[]int, error) {
+	var encLayers *[]int
+	var encConfig *encconfig.EncryptConfig
+
+	if len(encryptionKeys) > 0 {
+		// encryption
+		encLayers = &encryptLayers
+		ecc, err := enchelpers.CreateCryptoConfig(encryptionKeys, []string{})
+		if err != nil {
+			return nil, nil, fmt.Errorf("invalid encryption keys: %w", err)
+		}
+		cc := encconfig.CombineCryptoConfigs([]encconfig.CryptoConfig{ecc})
+		encConfig = cc.EncryptConfig
+	}
+	return encConfig, encLayers, nil
+}
+
+// DecryptConfig translates decryptionKeys into a DescriptionConfig structure
+func DecryptConfig(decryptionKeys []string) (*encconfig.DecryptConfig, error) {
+	var decryptConfig *encconfig.DecryptConfig
+	if len(decryptionKeys) > 0 {
+		// decryption
+		dcc, err := enchelpers.CreateCryptoConfig([]string{}, decryptionKeys)
+		if err != nil {
+			return nil, fmt.Errorf("invalid decryption keys: %w", err)
+		}
+		cc := encconfig.CombineCryptoConfigs([]encconfig.CryptoConfig{dcc})
+		decryptConfig = cc.DecryptConfig
+	}
+
+	return decryptConfig, nil
+}

test/e2e/pull_test.go

@@ -6,6 +6,7 @@ import (
 	"path/filepath"
 	"runtime"
 
+	"github.com/containers/podman/v4/pkg/rootless"
 	. "github.com/containers/podman/v4/test/utils"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
@@ -559,4 +560,89 @@ var _ = Describe("Podman pull", func() {
 		Expect(session).Should(Exit(0))
 		Expect(session.ErrorToString()).To(BeEmpty())
 	})
+
+	Describe("podman pull and decrypt", func() {
+
+		decryptionTestHelper := func(imgPath string) *PodmanSessionIntegration {
+			bitSize := 1024
+			keyFileName := filepath.Join(podmanTest.TempDir, "key")
+			publicKeyFileName, privateKeyFileName, err := WriteRSAKeyPair(keyFileName, bitSize)
+			Expect(err).To(BeNil())
+
+			wrongKeyFileName := filepath.Join(podmanTest.TempDir, "wrong_key")
+			_, wrongPrivateKeyFileName, err := WriteRSAKeyPair(wrongKeyFileName, bitSize)
+			Expect(err).To(BeNil())
+
+			session := podmanTest.Podman([]string{"push", "--encryption-key", "jwe:" + publicKeyFileName, "--tls-verify=false", "--remove-signatures", ALPINE, imgPath})
+			session.WaitWithDefaultTimeout()
+
+			session = podmanTest.Podman([]string{"rmi", ALPINE})
+			session.WaitWithDefaultTimeout()
+			Expect(session).Should(Exit(0))
+
+			// Pulling encrypted image without key should fail
+			session = podmanTest.Podman([]string{"pull", imgPath})
+			session.WaitWithDefaultTimeout()
+			Expect(session).Should(Exit(125))
+
+			// Pulling encrypted image with wrong key should fail
+			session = podmanTest.Podman([]string{"pull", "--decryption-key", wrongPrivateKeyFileName, imgPath})
+			session.WaitWithDefaultTimeout()
+			Expect(session).Should(Exit(125))
+
+			// Pulling encrypted image with correct key should pass
+			session = podmanTest.Podman([]string{"pull", "--decryption-key", privateKeyFileName, imgPath})
+			session.WaitWithDefaultTimeout()
+			Expect(session).Should(Exit(0))
+			session = podmanTest.Podman([]string{"images"})
+			session.WaitWithDefaultTimeout()
+			Expect(session).Should(Exit(0))
+
+			return session
+		}
+
+		It("From oci", func() {
+			SkipIfRemote("Remote pull neither supports oci transport, nor decryption")
+
+			podmanTest.AddImageToRWStore(ALPINE)
+
+			bbdir := filepath.Join(podmanTest.TempDir, "busybox-oci")
+			imgPath := fmt.Sprintf("oci:%s", bbdir)
+
+			session := decryptionTestHelper(imgPath)
+
+			Expect(session.LineInOutputContainsTag(filepath.Join("localhost", bbdir), "latest")).To(BeTrue())
+		})
+
+		It("From local registry", func() {
+			SkipIfRemote("Remote pull does not support decryption")
+
+			if podmanTest.Host.Arch == "ppc64le" {
+				Skip("No registry image for ppc64le")
+			}
+
+			podmanTest.AddImageToRWStore(ALPINE)
+
+			if rootless.IsRootless() {
+				err := podmanTest.RestoreArtifact(REGISTRY_IMAGE)
+				Expect(err).ToNot(HaveOccurred())
+			}
+			lock := GetPortLock("5000")
+			defer lock.Unlock()
+			session := podmanTest.Podman([]string{"run", "-d", "--name", "registry", "-p", "5000:5000", REGISTRY_IMAGE, "/entrypoint.sh", "/etc/docker/registry/config.yml"})
+			session.WaitWithDefaultTimeout()
+			Expect(session).Should(Exit(0))
+
+			if !WaitContainerReady(podmanTest, "registry", "listening on", 20, 1) {
+				Skip("Cannot start docker registry.")
+			}
+
+			imgPath := "localhost:5000/my-alpine"
+
+			session = decryptionTestHelper(imgPath)
+
+			Expect(session.LineInOutputContainsTag(imgPath, "latest")).To(BeTrue())
+		})
+	})
+
 })

test/e2e/push_test.go

@@ -127,6 +127,17 @@ var _ = Describe("Podman push", func() {
 		Expect(output).To(ContainSubstring("Writing manifest to image destination"))
 		Expect(output).To(ContainSubstring("Storing signatures"))
 
+		bitSize := 1024
+		keyFileName := filepath.Join(podmanTest.TempDir, "key")
+		publicKeyFileName, _, err := WriteRSAKeyPair(keyFileName, bitSize)
+		Expect(err).To(BeNil())
+
+		if !IsRemote() { // Remote does not support --encryption-key
+			push = podmanTest.Podman([]string{"push", "--encryption-key", "jwe:" + publicKeyFileName, "--tls-verify=false", "--remove-signatures", ALPINE, "localhost:5000/my-alpine"})
+			push.WaitWithDefaultTimeout()
+			Expect(push).Should(Exit(0))
+		}
+
 		if !IsRemote() { // Remote does not support --digestfile
 			// Test --digestfile option
 			push2 := podmanTest.Podman([]string{"push", "--tls-verify=false", "--digestfile=/tmp/digestfile.txt", "--remove-signatures", ALPINE, "localhost:5000/my-alpine"})
@@ -261,6 +272,25 @@ var _ = Describe("Podman push", func() {
 		Expect(push).Should(Exit(0))
 	})
 
+	It("podman push and encrypt to oci", func() {
+		SkipIfRemote("Remote push neither supports oci transport, nor encryption")
+
+		bbdir := filepath.Join(podmanTest.TempDir, "busybox-oci")
+
+		bitSize := 1024
+		keyFileName := filepath.Join(podmanTest.TempDir, "key")
+		publicKeyFileName, _, err := WriteRSAKeyPair(keyFileName, bitSize)
+		Expect(err).To(BeNil())
+
+		session := podmanTest.Podman([]string{"push", "--encryption-key", "jwe:" + publicKeyFileName, ALPINE, fmt.Sprintf("oci:%s", bbdir)})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+
+		session = podmanTest.Podman([]string{"rmi", ALPINE})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+	})
+
 	It("podman push to docker-archive", func() {
 		SkipIfRemote("Remote push does not support docker-archive transport")
 		tarfn := filepath.Join(podmanTest.TempDir, "alp.tar")

test/e2e/run_test.go

@@ -1996,4 +1996,46 @@ WORKDIR /madethis`, BB)
 		Expect(output).To(ContainSubstring("noexec"))
 		Expect(output).To(ContainSubstring("nodev"))
 	})
+
+	It("podman run and decrypt from local registry", func() {
+		SkipIfRemote("Remote run does not support decryption")
+
+		if podmanTest.Host.Arch == "ppc64le" {
+			Skip("No registry image for ppc64le")
+		}
+
+		podmanTest.AddImageToRWStore(ALPINE)
+
+		if rootless.IsRootless() {
+			err := podmanTest.RestoreArtifact(REGISTRY_IMAGE)
+			Expect(err).ToNot(HaveOccurred())
+		}
+		lock := GetPortLock("5000")
+		defer lock.Unlock()
+		session := podmanTest.Podman([]string{"run", "-d", "--name", "registry", "-p", "5000:5000", REGISTRY_IMAGE, "/entrypoint.sh", "/etc/docker/registry/config.yml"})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+
+		if !WaitContainerReady(podmanTest, "registry", "listening on", 20, 1) {
+			Skip("Cannot start docker registry.")
+		}
+
+		bitSize := 1024
+		keyFileName := filepath.Join(podmanTest.TempDir, "key")
+		publicKeyFileName, privateKeyFileName, err := WriteRSAKeyPair(keyFileName, bitSize)
+		Expect(err).To(BeNil())
+
+		imgPath := "localhost:5000/my-alpine"
+		session = podmanTest.Podman([]string{"push", "--encryption-key", "jwe:" + publicKeyFileName, "--tls-verify=false", "--remove-signatures", ALPINE, imgPath})
+		session.WaitWithDefaultTimeout()
+
+		session = podmanTest.Podman([]string{"rmi", ALPINE})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+
+		session = podmanTest.Podman([]string{"run", "--decryption-key", privateKeyFileName, imgPath})
+		session.WaitWithDefaultTimeout()
+		Expect(session).Should(Exit(0))
+		Expect(session.ErrorToString()).To(ContainSubstring("Trying to pull"))
+	})
 })

test/utils/common_function_test.go

@@ -151,4 +151,20 @@ var _ = Describe("Common functions test", func() {
 		Entry("Docker not in cgroup file", "/tmp/cgroup.test", false, true, false),
 	)
 
+	It("Test WriteRSAKeyPair", func() {
+		fileName := "/tmp/test_key"
+		bitSize := 1024
+
+		publicKeyFileName, privateKeyFileName, err := WriteRSAKeyPair(fileName, bitSize)
+		Expect(err).To(BeNil(), "Failed to write RSA key pair to files.")
+
+		read, err := os.Open(publicKeyFileName)
+		Expect(err).To(BeNil(), "Cannot find the public key file after we write it.")
+		defer read.Close()
+
+		read, err = os.Open(privateKeyFileName)
+		Expect(err).To(BeNil(), "Cannot find the private key file after we write it.")
+		defer read.Close()
+	})
+
 })

test/utils/utils.go

@@ -11,6 +11,11 @@ import (
 	"strings"
 	"time"
 
+	crypto_rand "crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+
 	"github.com/sirupsen/logrus"
 
 	"github.com/containers/storage/pkg/parsers/kernel"
@@ -523,3 +528,76 @@ func RandomString(n int) string {
 	}
 	return string(b)
 }
+
+// Encode *rsa.PublicKey and store it in a file.
+// Adds appropriate extension to the fileName, and returns the complete fileName of
+// the file storing the public key.
+func savePublicKey(fileName string, publicKey *rsa.PublicKey) (string, error) {
+	// Encode public key to PKIX, ASN.1 DER form
+	pubBytes, err := x509.MarshalPKIXPublicKey(publicKey)
+	if err != nil {
+		return "", err
+	}
+
+	pubPEM := pem.EncodeToMemory(
+		&pem.Block{
+			Type:  "RSA PUBLIC KEY",
+			Bytes: pubBytes,
+		},
+	)
+
+	// Write public key to file
+	publicKeyFileName := fileName + ".rsa.pub"
+	if err := os.WriteFile(publicKeyFileName, pubPEM, 0600); err != nil {
+		return "", err
+	}
+
+	return publicKeyFileName, nil
+}
+
+// Encode *rsa.PrivateKey and store it in a file.
+// Adds appropriate extension to the fileName, and returns the complete fileName of
+// the file storing the private key.
+func savePrivateKey(fileName string, privateKey *rsa.PrivateKey) (string, error) {
+	// Encode private key to PKCS#1, ASN.1 DER form
+	privBytes := x509.MarshalPKCS1PrivateKey(privateKey)
+	keyPEM := pem.EncodeToMemory(
+		&pem.Block{
+			Type:  "RSA PRIVATE KEY",
+			Bytes: privBytes,
+		},
+	)
+
+	// Write private key to file
+	privateKeyFileName := fileName + ".rsa"
+	if err := os.WriteFile(privateKeyFileName, keyPEM, 0600); err != nil {
+		return "", err
+	}
+
+	return privateKeyFileName, nil
+}
+
+// Generate RSA key pair of specified bit size and write them to files.
+// Adds appropriate extension to the fileName, and returns the complete fileName of
+// the files storing the public and private key respectively.
+func WriteRSAKeyPair(fileName string, bitSize int) (string, string, error) {
+	// Generate RSA key
+	privateKey, err := rsa.GenerateKey(crypto_rand.Reader, bitSize)
+	if err != nil {
+		return "", "", err
+	}
+
+	publicKey := privateKey.Public().(*rsa.PublicKey)
+
+	publicKeyFileName, err := savePublicKey(fileName, publicKey)
+	if err != nil {
+		return "", "", err
+	}
+
+	privateKeyFileName, err := savePrivateKey(fileName, privateKey)
+	if err != nil {
+		return "", "", err
+	}
+
+	return publicKeyFileName, privateKeyFileName, nil
+}