Bump to Buildah 1.16.0-dev in upstream

Bump Buildah to v1.16.0-dev in the upstream branch
of Podman.  This will allow us to get a number of new
issues into the upstream branch for use.  The version of
Buildah will need to be bumped to v1.16.0 and then
vendored into Podman before we release Podman v2.0

Signed-off-by: TomSweeneyRedHat <tsweeney@redhat.com>

12 files changed, 1959 insertions, 0 deletions

diff --git a/vendor/go.mozilla.org/pkcs7/.gitignore b/vendor/go.mozilla.org/pkcs7/.gitignore
new file mode 100644
index 000000000..daf913b1b
--- /dev/null
+++ b/vendor/go.mozilla.org/pkcs7/.gitignore
@@ -0,0 +1,24 @@
+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof
diff --git a/vendor/go.mozilla.org/pkcs7/.travis.yml b/vendor/go.mozilla.org/pkcs7/.travis.yml
new file mode 100644
index 000000000..eac4c1762
--- /dev/null
+++ b/vendor/go.mozilla.org/pkcs7/.travis.yml
@@ -0,0 +1,10 @@
+language: go
+go:
+    - "1.11"
+    - "1.12"
+    - "1.13"
+    - tip
+before_install:
+    - make gettools
+script:
+    - make
diff --git a/vendor/go.mozilla.org/pkcs7/LICENSE b/vendor/go.mozilla.org/pkcs7/LICENSE
new file mode 100644
index 000000000..75f320908
--- /dev/null
+++ b/vendor/go.mozilla.org/pkcs7/LICENSE
@@ -0,0 +1,22 @@
+The MIT License (MIT)
+
+Copyright (c) 2015 Andrew Smith
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
diff --git a/vendor/go.mozilla.org/pkcs7/Makefile b/vendor/go.mozilla.org/pkcs7/Makefile
new file mode 100644
index 000000000..47c73b868
--- /dev/null
+++ b/vendor/go.mozilla.org/pkcs7/Makefile
@@ -0,0 +1,20 @@
+all: vet staticcheck test
+
+test:
+	go test -covermode=count -coverprofile=coverage.out .
+
+showcoverage: test
+	go tool cover -html=coverage.out
+
+vet:
+	go vet .
+
+lint:
+	golint .
+
+staticcheck:
+	staticcheck .
+
+gettools:
+	go get -u honnef.co/go/tools/...
+	go get -u golang.org/x/lint/golint
diff --git a/vendor/go.mozilla.org/pkcs7/README.md b/vendor/go.mozilla.org/pkcs7/README.md
new file mode 100644
index 000000000..bf37059c5
--- /dev/null
+++ b/vendor/go.mozilla.org/pkcs7/README.md
@@ -0,0 +1,69 @@
+# pkcs7
+
+[![GoDoc](https://godoc.org/go.mozilla.org/pkcs7?status.svg)](https://godoc.org/go.mozilla.org/pkcs7)
+[![Build Status](https://travis-ci.org/mozilla-services/pkcs7.svg?branch=master)](https://travis-ci.org/mozilla-services/pkcs7)
+
+pkcs7 implements parsing and creating signed and enveloped messages.
+
+```go
+package main
+
+import (
+	"bytes"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+	"os"
+
+    "go.mozilla.org/pkcs7"
+)
+
+func SignAndDetach(content []byte, cert *x509.Certificate, privkey *rsa.PrivateKey) (signed []byte, err error) {
+	toBeSigned, err := NewSignedData(content)
+	if err != nil {
+		err = fmt.Errorf("Cannot initialize signed data: %s", err)
+		return
+	}
+	if err = toBeSigned.AddSigner(cert, privkey, SignerInfoConfig{}); err != nil {
+		err = fmt.Errorf("Cannot add signer: %s", err)
+		return
+	}
+
+	// Detach signature, omit if you want an embedded signature
+	toBeSigned.Detach()
+
+	signed, err = toBeSigned.Finish()
+	if err != nil {
+		err = fmt.Errorf("Cannot finish signing data: %s", err)
+		return
+	}
+
+	// Verify the signature
+	pem.Encode(os.Stdout, &pem.Block{Type: "PKCS7", Bytes: signed})
+	p7, err := pkcs7.Parse(signed)
+	if err != nil {
+		err = fmt.Errorf("Cannot parse our signed data: %s", err)
+		return
+	}
+
+	// since the signature was detached, reattach the content here
+	p7.Content = content
+
+	if bytes.Compare(content, p7.Content) != 0 {
+		err = fmt.Errorf("Our content was not in the parsed data:\n\tExpected: %s\n\tActual: %s", content, p7.Content)
+		return
+	}
+	if err = p7.Verify(); err != nil {
+		err = fmt.Errorf("Cannot verify our signed data: %s", err)
+		return
+	}
+
+	return signed, nil
+}
+```
+
+
+
+## Credits
+This is a fork of [fullsailor/pkcs7](https://github.com/fullsailor/pkcs7)
diff --git a/vendor/go.mozilla.org/pkcs7/ber.go b/vendor/go.mozilla.org/pkcs7/ber.go
new file mode 100644
index 000000000..585256739
--- /dev/null
+++ b/vendor/go.mozilla.org/pkcs7/ber.go
@@ -0,0 +1,251 @@
+package pkcs7
+
+import (
+	"bytes"
+	"errors"
+)
+
+var encodeIndent = 0
+
+type asn1Object interface {
+	EncodeTo(writer *bytes.Buffer) error
+}
+
+type asn1Structured struct {
+	tagBytes []byte
+	content  []asn1Object
+}
+
+func (s asn1Structured) EncodeTo(out *bytes.Buffer) error {
+	//fmt.Printf("%s--> tag: % X\n", strings.Repeat("| ", encodeIndent), s.tagBytes)
+	encodeIndent++
+	inner := new(bytes.Buffer)
+	for _, obj := range s.content {
+		err := obj.EncodeTo(inner)
+		if err != nil {
+			return err
+		}
+	}
+	encodeIndent--
+	out.Write(s.tagBytes)
+	encodeLength(out, inner.Len())
+	out.Write(inner.Bytes())
+	return nil
+}
+
+type asn1Primitive struct {
+	tagBytes []byte
+	length   int
+	content  []byte
+}
+
+func (p asn1Primitive) EncodeTo(out *bytes.Buffer) error {
+	_, err := out.Write(p.tagBytes)
+	if err != nil {
+		return err
+	}
+	if err = encodeLength(out, p.length); err != nil {
+		return err
+	}
+	//fmt.Printf("%s--> tag: % X length: %d\n", strings.Repeat("| ", encodeIndent), p.tagBytes, p.length)
+	//fmt.Printf("%s--> content length: %d\n", strings.Repeat("| ", encodeIndent), len(p.content))
+	out.Write(p.content)
+
+	return nil
+}
+
+func ber2der(ber []byte) ([]byte, error) {
+	if len(ber) == 0 {
+		return nil, errors.New("ber2der: input ber is empty")
+	}
+	//fmt.Printf("--> ber2der: Transcoding %d bytes\n", len(ber))
+	out := new(bytes.Buffer)
+
+	obj, _, err := readObject(ber, 0)
+	if err != nil {
+		return nil, err
+	}
+	obj.EncodeTo(out)
+
+	// if offset < len(ber) {
+	//	return nil, fmt.Errorf("ber2der: Content longer than expected. Got %d, expected %d", offset, len(ber))
+	//}
+
+	return out.Bytes(), nil
+}
+
+// encodes lengths that are longer than 127 into string of bytes
+func marshalLongLength(out *bytes.Buffer, i int) (err error) {
+	n := lengthLength(i)
+
+	for ; n > 0; n-- {
+		err = out.WriteByte(byte(i >> uint((n-1)*8)))
+		if err != nil {
+			return
+		}
+	}
+
+	return nil
+}
+
+// computes the byte length of an encoded length value
+func lengthLength(i int) (numBytes int) {
+	numBytes = 1
+	for i > 255 {
+		numBytes++
+		i >>= 8
+	}
+	return
+}
+
+// encodes the length in DER format
+// If the length fits in 7 bits, the value is encoded directly.
+//
+// Otherwise, the number of bytes to encode the length is first determined.
+// This number is likely to be 4 or less for a 32bit length. This number is
+// added to 0x80. The length is encoded in big endian encoding follow after
+//
+// Examples:
+//  length | byte 1 | bytes n
+//  0      | 0x00   | -
+//  120    | 0x78   | -
+//  200    | 0x81   | 0xC8
+//  500    | 0x82   | 0x01 0xF4
+//
+func encodeLength(out *bytes.Buffer, length int) (err error) {
+	if length >= 128 {
+		l := lengthLength(length)
+		err = out.WriteByte(0x80 | byte(l))
+		if err != nil {
+			return
+		}
+		err = marshalLongLength(out, length)
+		if err != nil {
+			return
+		}
+	} else {
+		err = out.WriteByte(byte(length))
+		if err != nil {
+			return
+		}
+	}
+	return
+}
+
+func readObject(ber []byte, offset int) (asn1Object, int, error) {
+	berLen := len(ber)
+	if offset >= berLen {
+		return nil, 0, errors.New("ber2der: offset is after end of ber data")
+	}
+	tagStart := offset
+	b := ber[offset]
+	offset++
+	if offset >= berLen {
+		return nil, 0, errors.New("ber2der: cannot move offset forward, end of ber data reached")
+	}
+	tag := b & 0x1F // last 5 bits
+	if tag == 0x1F {
+		tag = 0
+		for ber[offset] >= 0x80 {
+			tag = tag*128 + ber[offset] - 0x80
+			offset++
+			if offset > berLen {
+				return nil, 0, errors.New("ber2der: cannot move offset forward, end of ber data reached")
+			}
+		}
+		// jvehent 20170227: this doesn't appear to be used anywhere...
+		//tag = tag*128 + ber[offset] - 0x80
+		offset++
+		if offset > berLen {
+			return nil, 0, errors.New("ber2der: cannot move offset forward, end of ber data reached")
+		}
+	}
+	tagEnd := offset
+
+	kind := b & 0x20
+	if kind == 0 {
+		debugprint("--> Primitive\n")
+	} else {
+		debugprint("--> Constructed\n")
+	}
+	// read length
+	var length int
+	l := ber[offset]
+	offset++
+	if offset > berLen {
+		return nil, 0, errors.New("ber2der: cannot move offset forward, end of ber data reached")
+	}
+	hack := 0
+	if l > 0x80 {
+		numberOfBytes := (int)(l & 0x7F)
+		if numberOfBytes > 4 { // int is only guaranteed to be 32bit
+			return nil, 0, errors.New("ber2der: BER tag length too long")
+		}
+		if numberOfBytes == 4 && (int)(ber[offset]) > 0x7F {
+			return nil, 0, errors.New("ber2der: BER tag length is negative")
+		}
+		if (int)(ber[offset]) == 0x0 {
+			return nil, 0, errors.New("ber2der: BER tag length has leading zero")
+		}
+		debugprint("--> (compute length) indicator byte: %x\n", l)
+		debugprint("--> (compute length) length bytes: % X\n", ber[offset:offset+numberOfBytes])
+		for i := 0; i < numberOfBytes; i++ {
+			length = length*256 + (int)(ber[offset])
+			offset++
+			if offset > berLen {
+				return nil, 0, errors.New("ber2der: cannot move offset forward, end of ber data reached")
+			}
+		}
+	} else if l == 0x80 {
+		// find length by searching content
+		markerIndex := bytes.LastIndex(ber[offset:], []byte{0x0, 0x0})
+		if markerIndex == -1 {
+			return nil, 0, errors.New("ber2der: Invalid BER format")
+		}
+		length = markerIndex
+		hack = 2
+		debugprint("--> (compute length) marker found at offset: %d\n", markerIndex+offset)
+	} else {
+		length = (int)(l)
+	}
+	if length < 0 {
+		return nil, 0, errors.New("ber2der: invalid negative value found in BER tag length")
+	}
+	//fmt.Printf("--> length        : %d\n", length)
+	contentEnd := offset + length
+	if contentEnd > len(ber) {
+		return nil, 0, errors.New("ber2der: BER tag length is more than available data")
+	}
+	debugprint("--> content start : %d\n", offset)
+	debugprint("--> content end   : %d\n", contentEnd)
+	debugprint("--> content       : % X\n", ber[offset:contentEnd])
+	var obj asn1Object
+	if kind == 0 {
+		obj = asn1Primitive{
+			tagBytes: ber[tagStart:tagEnd],
+			length:   length,
+			content:  ber[offset:contentEnd],
+		}
+	} else {
+		var subObjects []asn1Object
+		for offset < contentEnd {
+			var subObj asn1Object
+			var err error
+			subObj, offset, err = readObject(ber[:contentEnd], offset)
+			if err != nil {
+				return nil, 0, err
+			}
+			subObjects = append(subObjects, subObj)
+		}
+		obj = asn1Structured{
+			tagBytes: ber[tagStart:tagEnd],
+			content:  subObjects,
+		}
+	}
+
+	return obj, contentEnd + hack, nil
+}
+
+func debugprint(format string, a ...interface{}) {
+	//fmt.Printf(format, a)
+}
diff --git a/vendor/go.mozilla.org/pkcs7/decrypt.go b/vendor/go.mozilla.org/pkcs7/decrypt.go
new file mode 100644
index 000000000..0d088d628
--- /dev/null
+++ b/vendor/go.mozilla.org/pkcs7/decrypt.go
@@ -0,0 +1,177 @@
+package pkcs7
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/des"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/asn1"
+	"errors"
+	"fmt"
+)
+
+// ErrUnsupportedAlgorithm tells you when our quick dev assumptions have failed
+var ErrUnsupportedAlgorithm = errors.New("pkcs7: cannot decrypt data: only RSA, DES, DES-EDE3, AES-256-CBC and AES-128-GCM supported")
+
+// ErrNotEncryptedContent is returned when attempting to Decrypt data that is not encrypted data
+var ErrNotEncryptedContent = errors.New("pkcs7: content data is a decryptable data type")
+
+// Decrypt decrypts encrypted content info for recipient cert and private key
+func (p7 *PKCS7) Decrypt(cert *x509.Certificate, pkey crypto.PrivateKey) ([]byte, error) {
+	data, ok := p7.raw.(envelopedData)
+	if !ok {
+		return nil, ErrNotEncryptedContent
+	}
+	recipient := selectRecipientForCertificate(data.RecipientInfos, cert)
+	if recipient.EncryptedKey == nil {
+		return nil, errors.New("pkcs7: no enveloped recipient for provided certificate")
+	}
+	switch pkey := pkey.(type) {
+	case *rsa.PrivateKey:
+		var contentKey []byte
+		contentKey, err := rsa.DecryptPKCS1v15(rand.Reader, pkey, recipient.EncryptedKey)
+		if err != nil {
+			return nil, err
+		}
+		return data.EncryptedContentInfo.decrypt(contentKey)
+	}
+	return nil, ErrUnsupportedAlgorithm
+}
+
+// DecryptUsingPSK decrypts encrypted data using caller provided
+// pre-shared secret
+func (p7 *PKCS7) DecryptUsingPSK(key []byte) ([]byte, error) {
+	data, ok := p7.raw.(encryptedData)
+	if !ok {
+		return nil, ErrNotEncryptedContent
+	}
+	return data.EncryptedContentInfo.decrypt(key)
+}
+
+func (eci encryptedContentInfo) decrypt(key []byte) ([]byte, error) {
+	alg := eci.ContentEncryptionAlgorithm.Algorithm
+	if !alg.Equal(OIDEncryptionAlgorithmDESCBC) &&
+		!alg.Equal(OIDEncryptionAlgorithmDESEDE3CBC) &&
+		!alg.Equal(OIDEncryptionAlgorithmAES256CBC) &&
+		!alg.Equal(OIDEncryptionAlgorithmAES128CBC) &&
+		!alg.Equal(OIDEncryptionAlgorithmAES128GCM) &&
+		!alg.Equal(OIDEncryptionAlgorithmAES256GCM) {
+		fmt.Printf("Unsupported Content Encryption Algorithm: %s\n", alg)
+		return nil, ErrUnsupportedAlgorithm
+	}
+
+	// EncryptedContent can either be constructed of multple OCTET STRINGs
+	// or _be_ a tagged OCTET STRING
+	var cyphertext []byte
+	if eci.EncryptedContent.IsCompound {
+		// Complex case to concat all of the children OCTET STRINGs
+		var buf bytes.Buffer
+		cypherbytes := eci.EncryptedContent.Bytes
+		for {
+			var part []byte
+			cypherbytes, _ = asn1.Unmarshal(cypherbytes, &part)
+			buf.Write(part)
+			if cypherbytes == nil {
+				break
+			}
+		}
+		cyphertext = buf.Bytes()
+	} else {
+		// Simple case, the bytes _are_ the cyphertext
+		cyphertext = eci.EncryptedContent.Bytes
+	}
+
+	var block cipher.Block
+	var err error
+
+	switch {
+	case alg.Equal(OIDEncryptionAlgorithmDESCBC):
+		block, err = des.NewCipher(key)
+	case alg.Equal(OIDEncryptionAlgorithmDESEDE3CBC):
+		block, err = des.NewTripleDESCipher(key)
+	case alg.Equal(OIDEncryptionAlgorithmAES256CBC), alg.Equal(OIDEncryptionAlgorithmAES256GCM):
+		fallthrough
+	case alg.Equal(OIDEncryptionAlgorithmAES128GCM), alg.Equal(OIDEncryptionAlgorithmAES128CBC):
+		block, err = aes.NewCipher(key)
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	if alg.Equal(OIDEncryptionAlgorithmAES128GCM) || alg.Equal(OIDEncryptionAlgorithmAES256GCM) {
+		params := aesGCMParameters{}
+		paramBytes := eci.ContentEncryptionAlgorithm.Parameters.Bytes
+
+		_, err := asn1.Unmarshal(paramBytes, &params)
+		if err != nil {
+			return nil, err
+		}
+
+		gcm, err := cipher.NewGCM(block)
+		if err != nil {
+			return nil, err
+		}
+
+		if len(params.Nonce) != gcm.NonceSize() {
+			return nil, errors.New("pkcs7: encryption algorithm parameters are incorrect")
+		}
+		if params.ICVLen != gcm.Overhead() {
+			return nil, errors.New("pkcs7: encryption algorithm parameters are incorrect")
+		}
+
+		plaintext, err := gcm.Open(nil, params.Nonce, cyphertext, nil)
+		if err != nil {
+			return nil, err
+		}
+
+		return plaintext, nil
+	}
+
+	iv := eci.ContentEncryptionAlgorithm.Parameters.Bytes
+	if len(iv) != block.BlockSize() {
+		return nil, errors.New("pkcs7: encryption algorithm parameters are malformed")
+	}
+	mode := cipher.NewCBCDecrypter(block, iv)
+	plaintext := make([]byte, len(cyphertext))
+	mode.CryptBlocks(plaintext, cyphertext)
+	if plaintext, err = unpad(plaintext, mode.BlockSize()); err != nil {
+		return nil, err
+	}
+	return plaintext, nil
+}
+
+func unpad(data []byte, blocklen int) ([]byte, error) {
+	if blocklen < 1 {
+		return nil, fmt.Errorf("invalid blocklen %d", blocklen)
+	}
+	if len(data)%blocklen != 0 || len(data) == 0 {
+		return nil, fmt.Errorf("invalid data len %d", len(data))
+	}
+
+	// the last byte is the length of padding
+	padlen := int(data[len(data)-1])
+
+	// check padding integrity, all bytes should be the same
+	pad := data[len(data)-padlen:]
+	for _, padbyte := range pad {
+		if padbyte != byte(padlen) {
+			return nil, errors.New("invalid padding")
+		}
+	}
+
+	return data[:len(data)-padlen], nil
+}
+
+func selectRecipientForCertificate(recipients []recipientInfo, cert *x509.Certificate) recipientInfo {
+	for _, recp := range recipients {
+		if isCertMatchForIssuerAndSerial(cert, recp.IssuerAndSerialNumber) {
+			return recp
+		}
+	}
+	return recipientInfo{}
+}
diff --git a/vendor/go.mozilla.org/pkcs7/encrypt.go b/vendor/go.mozilla.org/pkcs7/encrypt.go
new file mode 100644
index 000000000..da57ae643
--- /dev/null
+++ b/vendor/go.mozilla.org/pkcs7/encrypt.go
@@ -0,0 +1,399 @@
+package pkcs7
+
+import (
+	"bytes"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/des"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"errors"
+	"fmt"
+)
+
+type envelopedData struct {
+	Version              int
+	RecipientInfos       []recipientInfo `asn1:"set"`
+	EncryptedContentInfo encryptedContentInfo
+}
+
+type encryptedData struct {
+	Version              int
+	EncryptedContentInfo encryptedContentInfo
+}
+
+type recipientInfo struct {
+	Version                int
+	IssuerAndSerialNumber  issuerAndSerial
+	KeyEncryptionAlgorithm pkix.AlgorithmIdentifier
+	EncryptedKey           []byte
+}
+
+type encryptedContentInfo struct {
+	ContentType                asn1.ObjectIdentifier
+	ContentEncryptionAlgorithm pkix.AlgorithmIdentifier
+	EncryptedContent           asn1.RawValue `asn1:"tag:0,optional,explicit"`
+}
+
+const (
+	// EncryptionAlgorithmDESCBC is the DES CBC encryption algorithm
+	EncryptionAlgorithmDESCBC = iota
+
+	// EncryptionAlgorithmAES128CBC is the AES 128 bits with CBC encryption algorithm
+	// Avoid this algorithm unless required for interoperability; use AES GCM instead.
+	EncryptionAlgorithmAES128CBC
+
+	// EncryptionAlgorithmAES256CBC is the AES 256 bits with CBC encryption algorithm
+	// Avoid this algorithm unless required for interoperability; use AES GCM instead.
+	EncryptionAlgorithmAES256CBC
+
+	// EncryptionAlgorithmAES128GCM is the AES 128 bits with GCM encryption algorithm
+	EncryptionAlgorithmAES128GCM
+
+	// EncryptionAlgorithmAES256GCM is the AES 256 bits with GCM encryption algorithm
+	EncryptionAlgorithmAES256GCM
+)
+
+// ContentEncryptionAlgorithm determines the algorithm used to encrypt the
+// plaintext message. Change the value of this variable to change which
+// algorithm is used in the Encrypt() function.
+var ContentEncryptionAlgorithm = EncryptionAlgorithmDESCBC
+
+// ErrUnsupportedEncryptionAlgorithm is returned when attempting to encrypt
+// content with an unsupported algorithm.
+var ErrUnsupportedEncryptionAlgorithm = errors.New("pkcs7: cannot encrypt content: only DES-CBC, AES-CBC, and AES-GCM supported")
+
+// ErrPSKNotProvided is returned when attempting to encrypt
+// using a PSK without actually providing the PSK.
+var ErrPSKNotProvided = errors.New("pkcs7: cannot encrypt content: PSK not provided")
+
+const nonceSize = 12
+
+type aesGCMParameters struct {
+	Nonce  []byte `asn1:"tag:4"`
+	ICVLen int
+}
+
+func encryptAESGCM(content []byte, key []byte) ([]byte, *encryptedContentInfo, error) {
+	var keyLen int
+	var algID asn1.ObjectIdentifier
+	switch ContentEncryptionAlgorithm {
+	case EncryptionAlgorithmAES128GCM:
+		keyLen = 16
+		algID = OIDEncryptionAlgorithmAES128GCM
+	case EncryptionAlgorithmAES256GCM:
+		keyLen = 32
+		algID = OIDEncryptionAlgorithmAES256GCM
+	default:
+		return nil, nil, fmt.Errorf("invalid ContentEncryptionAlgorithm in encryptAESGCM: %d", ContentEncryptionAlgorithm)
+	}
+	if key == nil {
+		// Create AES key
+		key = make([]byte, keyLen)
+
+		_, err := rand.Read(key)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+
+	// Create nonce
+	nonce := make([]byte, nonceSize)
+
+	_, err := rand.Read(nonce)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Encrypt content
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	ciphertext := gcm.Seal(nil, nonce, content, nil)
+
+	// Prepare ASN.1 Encrypted Content Info
+	paramSeq := aesGCMParameters{
+		Nonce:  nonce,
+		ICVLen: gcm.Overhead(),
+	}
+
+	paramBytes, err := asn1.Marshal(paramSeq)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	eci := encryptedContentInfo{
+		ContentType: OIDData,
+		ContentEncryptionAlgorithm: pkix.AlgorithmIdentifier{
+			Algorithm: algID,
+			Parameters: asn1.RawValue{
+				Tag:   asn1.TagSequence,
+				Bytes: paramBytes,
+			},
+		},
+		EncryptedContent: marshalEncryptedContent(ciphertext),
+	}
+
+	return key, &eci, nil
+}
+
+func encryptDESCBC(content []byte, key []byte) ([]byte, *encryptedContentInfo, error) {
+	if key == nil {
+		// Create DES key
+		key = make([]byte, 8)
+
+		_, err := rand.Read(key)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+
+	// Create CBC IV
+	iv := make([]byte, des.BlockSize)
+	_, err := rand.Read(iv)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Encrypt padded content
+	block, err := des.NewCipher(key)
+	if err != nil {
+		return nil, nil, err
+	}
+	mode := cipher.NewCBCEncrypter(block, iv)
+	plaintext, err := pad(content, mode.BlockSize())
+	if err != nil {
+		return nil, nil, err
+	}
+	cyphertext := make([]byte, len(plaintext))
+	mode.CryptBlocks(cyphertext, plaintext)
+
+	// Prepare ASN.1 Encrypted Content Info
+	eci := encryptedContentInfo{
+		ContentType: OIDData,
+		ContentEncryptionAlgorithm: pkix.AlgorithmIdentifier{
+			Algorithm:  OIDEncryptionAlgorithmDESCBC,
+			Parameters: asn1.RawValue{Tag: 4, Bytes: iv},
+		},
+		EncryptedContent: marshalEncryptedContent(cyphertext),
+	}
+
+	return key, &eci, nil
+}
+
+func encryptAESCBC(content []byte, key []byte) ([]byte, *encryptedContentInfo, error) {
+	var keyLen int
+	var algID asn1.ObjectIdentifier
+	switch ContentEncryptionAlgorithm {
+	case EncryptionAlgorithmAES128CBC:
+		keyLen = 16
+		algID = OIDEncryptionAlgorithmAES128CBC
+	case EncryptionAlgorithmAES256CBC:
+		keyLen = 32
+		algID = OIDEncryptionAlgorithmAES256CBC
+	default:
+		return nil, nil, fmt.Errorf("invalid ContentEncryptionAlgorithm in encryptAESCBC: %d", ContentEncryptionAlgorithm)
+	}
+
+	if key == nil {
+		// Create AES key
+		key = make([]byte, keyLen)
+
+		_, err := rand.Read(key)
+		if err != nil {
+			return nil, nil, err
+		}
+	}
+
+	// Create CBC IV
+	iv := make([]byte, aes.BlockSize)
+	_, err := rand.Read(iv)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	// Encrypt padded content
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, nil, err
+	}
+	mode := cipher.NewCBCEncrypter(block, iv)
+	plaintext, err := pad(content, mode.BlockSize())
+	if err != nil {
+		return nil, nil, err
+	}
+	cyphertext := make([]byte, len(plaintext))
+	mode.CryptBlocks(cyphertext, plaintext)
+
+	// Prepare ASN.1 Encrypted Content Info
+	eci := encryptedContentInfo{
+		ContentType: OIDData,
+		ContentEncryptionAlgorithm: pkix.AlgorithmIdentifier{
+			Algorithm:  algID,
+			Parameters: asn1.RawValue{Tag: 4, Bytes: iv},
+		},
+		EncryptedContent: marshalEncryptedContent(cyphertext),
+	}
+
+	return key, &eci, nil
+}
+
+// Encrypt creates and returns an envelope data PKCS7 structure with encrypted
+// recipient keys for each recipient public key.
+//
+// The algorithm used to perform encryption is determined by the current value
+// of the global ContentEncryptionAlgorithm package variable. By default, the
+// value is EncryptionAlgorithmDESCBC. To use a different algorithm, change the
+// value before calling Encrypt(). For example:
+//
+//     ContentEncryptionAlgorithm = EncryptionAlgorithmAES128GCM
+//
+// TODO(fullsailor): Add support for encrypting content with other algorithms
+func Encrypt(content []byte, recipients []*x509.Certificate) ([]byte, error) {
+	var eci *encryptedContentInfo
+	var key []byte
+	var err error
+
+	// Apply chosen symmetric encryption method
+	switch ContentEncryptionAlgorithm {
+	case EncryptionAlgorithmDESCBC:
+		key, eci, err = encryptDESCBC(content, nil)
+	case EncryptionAlgorithmAES128CBC:
+		fallthrough
+	case EncryptionAlgorithmAES256CBC:
+		key, eci, err = encryptAESCBC(content, nil)
+	case EncryptionAlgorithmAES128GCM:
+		fallthrough
+	case EncryptionAlgorithmAES256GCM:
+		key, eci, err = encryptAESGCM(content, nil)
+
+	default:
+		return nil, ErrUnsupportedEncryptionAlgorithm
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	// Prepare each recipient's encrypted cipher key
+	recipientInfos := make([]recipientInfo, len(recipients))
+	for i, recipient := range recipients {
+		encrypted, err := encryptKey(key, recipient)
+		if err != nil {
+			return nil, err
+		}
+		ias, err := cert2issuerAndSerial(recipient)
+		if err != nil {
+			return nil, err
+		}
+		info := recipientInfo{
+			Version:               0,
+			IssuerAndSerialNumber: ias,
+			KeyEncryptionAlgorithm: pkix.AlgorithmIdentifier{
+				Algorithm: OIDEncryptionAlgorithmRSA,
+			},
+			EncryptedKey: encrypted,
+		}
+		recipientInfos[i] = info
+	}
+
+	// Prepare envelope content
+	envelope := envelopedData{
+		EncryptedContentInfo: *eci,
+		Version:              0,
+		RecipientInfos:       recipientInfos,
+	}
+	innerContent, err := asn1.Marshal(envelope)
+	if err != nil {
+		return nil, err
+	}
+
+	// Prepare outer payload structure
+	wrapper := contentInfo{
+		ContentType: OIDEnvelopedData,
+		Content:     asn1.RawValue{Class: 2, Tag: 0, IsCompound: true, Bytes: innerContent},
+	}
+
+	return asn1.Marshal(wrapper)
+}
+
+// EncryptUsingPSK creates and returns an encrypted data PKCS7 structure,
+// encrypted using caller provided pre-shared secret.
+func EncryptUsingPSK(content []byte, key []byte) ([]byte, error) {
+	var eci *encryptedContentInfo
+	var err error
+
+	if key == nil {
+		return nil, ErrPSKNotProvided
+	}
+
+	// Apply chosen symmetric encryption method
+	switch ContentEncryptionAlgorithm {
+	case EncryptionAlgorithmDESCBC:
+		_, eci, err = encryptDESCBC(content, key)
+
+	case EncryptionAlgorithmAES128GCM:
+		fallthrough
+	case EncryptionAlgorithmAES256GCM:
+		_, eci, err = encryptAESGCM(content, key)
+
+	default:
+		return nil, ErrUnsupportedEncryptionAlgorithm
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	// Prepare encrypted-data content
+	ed := encryptedData{
+		Version:              0,
+		EncryptedContentInfo: *eci,
+	}
+	innerContent, err := asn1.Marshal(ed)
+	if err != nil {
+		return nil, err
+	}
+
+	// Prepare outer payload structure
+	wrapper := contentInfo{
+		ContentType: OIDEncryptedData,
+		Content:     asn1.RawValue{Class: 2, Tag: 0, IsCompound: true, Bytes: innerContent},
+	}
+
+	return asn1.Marshal(wrapper)
+}
+
+func marshalEncryptedContent(content []byte) asn1.RawValue {
+	asn1Content, _ := asn1.Marshal(content)
+	return asn1.RawValue{Tag: 0, Class: 2, Bytes: asn1Content, IsCompound: true}
+}
+
+func encryptKey(key []byte, recipient *x509.Certificate) ([]byte, error) {
+	if pub := recipient.PublicKey.(*rsa.PublicKey); pub != nil {
+		return rsa.EncryptPKCS1v15(rand.Reader, pub, key)
+	}
+	return nil, ErrUnsupportedAlgorithm
+}
+
+func pad(data []byte, blocklen int) ([]byte, error) {
+	if blocklen < 1 {
+		return nil, fmt.Errorf("invalid blocklen %d", blocklen)
+	}
+	padlen := blocklen - (len(data) % blocklen)
+	if padlen == 0 {
+		padlen = blocklen
+	}
+	pad := bytes.Repeat([]byte{byte(padlen)}, padlen)
+	return append(data, pad...), nil
+}
diff --git a/vendor/go.mozilla.org/pkcs7/go.mod b/vendor/go.mozilla.org/pkcs7/go.mod
new file mode 100644
index 000000000..10ddff325
--- /dev/null
+++ b/vendor/go.mozilla.org/pkcs7/go.mod
@@ -0,0 +1,3 @@
+module go.mozilla.org/pkcs7
+
+go 1.11
diff --git a/vendor/go.mozilla.org/pkcs7/pkcs7.go b/vendor/go.mozilla.org/pkcs7/pkcs7.go
new file mode 100644
index 000000000..ccc6cc6df
--- /dev/null
+++ b/vendor/go.mozilla.org/pkcs7/pkcs7.go
@@ -0,0 +1,291 @@
+// Package pkcs7 implements parsing and generation of some PKCS#7 structures.
+package pkcs7
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/dsa"
+	"crypto/ecdsa"
+	"crypto/rsa"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"errors"
+	"fmt"
+	"sort"
+
+	_ "crypto/sha1" // for crypto.SHA1
+)
+
+// PKCS7 Represents a PKCS7 structure
+type PKCS7 struct {
+	Content      []byte
+	Certificates []*x509.Certificate
+	CRLs         []pkix.CertificateList
+	Signers      []signerInfo
+	raw          interface{}
+}
+
+type contentInfo struct {
+	ContentType asn1.ObjectIdentifier
+	Content     asn1.RawValue `asn1:"explicit,optional,tag:0"`
+}
+
+// ErrUnsupportedContentType is returned when a PKCS7 content is not supported.
+// Currently only Data (1.2.840.113549.1.7.1), Signed Data (1.2.840.113549.1.7.2),
+// and Enveloped Data are supported (1.2.840.113549.1.7.3)
+var ErrUnsupportedContentType = errors.New("pkcs7: cannot parse data: unimplemented content type")
+
+type unsignedData []byte
+
+var (
+	// Signed Data OIDs
+	OIDData                   = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 7, 1}
+	OIDSignedData             = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 7, 2}
+	OIDEnvelopedData          = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 7, 3}
+	OIDEncryptedData          = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 7, 6}
+	OIDAttributeContentType   = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 3}
+	OIDAttributeMessageDigest = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 4}
+	OIDAttributeSigningTime   = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 5}
+
+	// Digest Algorithms
+	OIDDigestAlgorithmSHA1   = asn1.ObjectIdentifier{1, 3, 14, 3, 2, 26}
+	OIDDigestAlgorithmSHA256 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 1}
+	OIDDigestAlgorithmSHA384 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 2}
+	OIDDigestAlgorithmSHA512 = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 2, 3}
+
+	OIDDigestAlgorithmDSA     = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 1}
+	OIDDigestAlgorithmDSASHA1 = asn1.ObjectIdentifier{1, 2, 840, 10040, 4, 3}
+
+	OIDDigestAlgorithmECDSASHA1   = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 1}
+	OIDDigestAlgorithmECDSASHA256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 2}
+	OIDDigestAlgorithmECDSASHA384 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 3}
+	OIDDigestAlgorithmECDSASHA512 = asn1.ObjectIdentifier{1, 2, 840, 10045, 4, 3, 4}
+
+	// Signature Algorithms
+	OIDEncryptionAlgorithmRSA       = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}
+	OIDEncryptionAlgorithmRSASHA1   = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5}
+	OIDEncryptionAlgorithmRSASHA256 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 11}
+	OIDEncryptionAlgorithmRSASHA384 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 12}
+	OIDEncryptionAlgorithmRSASHA512 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 13}
+
+	OIDEncryptionAlgorithmECDSAP256 = asn1.ObjectIdentifier{1, 2, 840, 10045, 3, 1, 7}
+	OIDEncryptionAlgorithmECDSAP384 = asn1.ObjectIdentifier{1, 3, 132, 0, 34}
+	OIDEncryptionAlgorithmECDSAP521 = asn1.ObjectIdentifier{1, 3, 132, 0, 35}
+
+	// Encryption Algorithms
+	OIDEncryptionAlgorithmDESCBC     = asn1.ObjectIdentifier{1, 3, 14, 3, 2, 7}
+	OIDEncryptionAlgorithmDESEDE3CBC = asn1.ObjectIdentifier{1, 2, 840, 113549, 3, 7}
+	OIDEncryptionAlgorithmAES256CBC  = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 1, 42}
+	OIDEncryptionAlgorithmAES128GCM  = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 1, 6}
+	OIDEncryptionAlgorithmAES128CBC  = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 1, 2}
+	OIDEncryptionAlgorithmAES256GCM  = asn1.ObjectIdentifier{2, 16, 840, 1, 101, 3, 4, 1, 46}
+)
+
+func getHashForOID(oid asn1.ObjectIdentifier) (crypto.Hash, error) {
+	switch {
+	case oid.Equal(OIDDigestAlgorithmSHA1), oid.Equal(OIDDigestAlgorithmECDSASHA1),
+		oid.Equal(OIDDigestAlgorithmDSA), oid.Equal(OIDDigestAlgorithmDSASHA1),
+		oid.Equal(OIDEncryptionAlgorithmRSA):
+		return crypto.SHA1, nil
+	case oid.Equal(OIDDigestAlgorithmSHA256), oid.Equal(OIDDigestAlgorithmECDSASHA256):
+		return crypto.SHA256, nil
+	case oid.Equal(OIDDigestAlgorithmSHA384), oid.Equal(OIDDigestAlgorithmECDSASHA384):
+		return crypto.SHA384, nil
+	case oid.Equal(OIDDigestAlgorithmSHA512), oid.Equal(OIDDigestAlgorithmECDSASHA512):
+		return crypto.SHA512, nil
+	}
+	return crypto.Hash(0), ErrUnsupportedAlgorithm
+}
+
+// getDigestOIDForSignatureAlgorithm takes an x509.SignatureAlgorithm
+// and returns the corresponding OID digest algorithm
+func getDigestOIDForSignatureAlgorithm(digestAlg x509.SignatureAlgorithm) (asn1.ObjectIdentifier, error) {
+	switch digestAlg {
+	case x509.SHA1WithRSA, x509.ECDSAWithSHA1:
+		return OIDDigestAlgorithmSHA1, nil
+	case x509.SHA256WithRSA, x509.ECDSAWithSHA256:
+		return OIDDigestAlgorithmSHA256, nil
+	case x509.SHA384WithRSA, x509.ECDSAWithSHA384:
+		return OIDDigestAlgorithmSHA384, nil
+	case x509.SHA512WithRSA, x509.ECDSAWithSHA512:
+		return OIDDigestAlgorithmSHA512, nil
+	}
+	return nil, fmt.Errorf("pkcs7: cannot convert hash to oid, unknown hash algorithm")
+}
+
+// getOIDForEncryptionAlgorithm takes the private key type of the signer and
+// the OID of a digest algorithm to return the appropriate signerInfo.DigestEncryptionAlgorithm
+func getOIDForEncryptionAlgorithm(pkey crypto.PrivateKey, OIDDigestAlg asn1.ObjectIdentifier) (asn1.ObjectIdentifier, error) {
+	switch pkey.(type) {
+	case *rsa.PrivateKey:
+		switch {
+		default:
+			return OIDEncryptionAlgorithmRSA, nil
+		case OIDDigestAlg.Equal(OIDEncryptionAlgorithmRSA):
+			return OIDEncryptionAlgorithmRSA, nil
+		case OIDDigestAlg.Equal(OIDDigestAlgorithmSHA1):
+			return OIDEncryptionAlgorithmRSASHA1, nil
+		case OIDDigestAlg.Equal(OIDDigestAlgorithmSHA256):
+			return OIDEncryptionAlgorithmRSASHA256, nil
+		case OIDDigestAlg.Equal(OIDDigestAlgorithmSHA384):
+			return OIDEncryptionAlgorithmRSASHA384, nil
+		case OIDDigestAlg.Equal(OIDDigestAlgorithmSHA512):
+			return OIDEncryptionAlgorithmRSASHA512, nil
+		}
+	case *ecdsa.PrivateKey:
+		switch {
+		case OIDDigestAlg.Equal(OIDDigestAlgorithmSHA1):
+			return OIDDigestAlgorithmECDSASHA1, nil
+		case OIDDigestAlg.Equal(OIDDigestAlgorithmSHA256):
+			return OIDDigestAlgorithmECDSASHA256, nil
+		case OIDDigestAlg.Equal(OIDDigestAlgorithmSHA384):
+			return OIDDigestAlgorithmECDSASHA384, nil
+		case OIDDigestAlg.Equal(OIDDigestAlgorithmSHA512):
+			return OIDDigestAlgorithmECDSASHA512, nil
+		}
+	case *dsa.PrivateKey:
+		return OIDDigestAlgorithmDSA, nil
+	}
+	return nil, fmt.Errorf("pkcs7: cannot convert encryption algorithm to oid, unknown private key type %T", pkey)
+
+}
+
+// Parse decodes a DER encoded PKCS7 package
+func Parse(data []byte) (p7 *PKCS7, err error) {
+	if len(data) == 0 {
+		return nil, errors.New("pkcs7: input data is empty")
+	}
+	var info contentInfo
+	der, err := ber2der(data)
+	if err != nil {
+		return nil, err
+	}
+	rest, err := asn1.Unmarshal(der, &info)
+	if len(rest) > 0 {
+		err = asn1.SyntaxError{Msg: "trailing data"}
+		return
+	}
+	if err != nil {
+		return
+	}
+
+	// fmt.Printf("--> Content Type: %s", info.ContentType)
+	switch {
+	case info.ContentType.Equal(OIDSignedData):
+		return parseSignedData(info.Content.Bytes)
+	case info.ContentType.Equal(OIDEnvelopedData):
+		return parseEnvelopedData(info.Content.Bytes)
+	case info.ContentType.Equal(OIDEncryptedData):
+		return parseEncryptedData(info.Content.Bytes)
+	}
+	return nil, ErrUnsupportedContentType
+}
+
+func parseEnvelopedData(data []byte) (*PKCS7, error) {
+	var ed envelopedData
+	if _, err := asn1.Unmarshal(data, &ed); err != nil {
+		return nil, err
+	}
+	return &PKCS7{
+		raw: ed,
+	}, nil
+}
+
+func parseEncryptedData(data []byte) (*PKCS7, error) {
+	var ed encryptedData
+	if _, err := asn1.Unmarshal(data, &ed); err != nil {
+		return nil, err
+	}
+	return &PKCS7{
+		raw: ed,
+	}, nil
+}
+
+func (raw rawCertificates) Parse() ([]*x509.Certificate, error) {
+	if len(raw.Raw) == 0 {
+		return nil, nil
+	}
+
+	var val asn1.RawValue
+	if _, err := asn1.Unmarshal(raw.Raw, &val); err != nil {
+		return nil, err
+	}
+
+	return x509.ParseCertificates(val.Bytes)
+}
+
+func isCertMatchForIssuerAndSerial(cert *x509.Certificate, ias issuerAndSerial) bool {
+	return cert.SerialNumber.Cmp(ias.SerialNumber) == 0 && bytes.Equal(cert.RawIssuer, ias.IssuerName.FullBytes)
+}
+
+// Attribute represents a key value pair attribute. Value must be marshalable byte
+// `encoding/asn1`
+type Attribute struct {
+	Type  asn1.ObjectIdentifier
+	Value interface{}
+}
+
+type attributes struct {
+	types  []asn1.ObjectIdentifier
+	values []interface{}
+}
+
+// Add adds the attribute, maintaining insertion order
+func (attrs *attributes) Add(attrType asn1.ObjectIdentifier, value interface{}) {
+	attrs.types = append(attrs.types, attrType)
+	attrs.values = append(attrs.values, value)
+}
+
+type sortableAttribute struct {
+	SortKey   []byte
+	Attribute attribute
+}
+
+type attributeSet []sortableAttribute
+
+func (sa attributeSet) Len() int {
+	return len(sa)
+}
+
+func (sa attributeSet) Less(i, j int) bool {
+	return bytes.Compare(sa[i].SortKey, sa[j].SortKey) < 0
+}
+
+func (sa attributeSet) Swap(i, j int) {
+	sa[i], sa[j] = sa[j], sa[i]
+}
+
+func (sa attributeSet) Attributes() []attribute {
+	attrs := make([]attribute, len(sa))
+	for i, attr := range sa {
+		attrs[i] = attr.Attribute
+	}
+	return attrs
+}
+
+func (attrs *attributes) ForMarshalling() ([]attribute, error) {
+	sortables := make(attributeSet, len(attrs.types))
+	for i := range sortables {
+		attrType := attrs.types[i]
+		attrValue := attrs.values[i]
+		asn1Value, err := asn1.Marshal(attrValue)
+		if err != nil {
+			return nil, err
+		}
+		attr := attribute{
+			Type:  attrType,
+			Value: asn1.RawValue{Tag: 17, IsCompound: true, Bytes: asn1Value}, // 17 == SET tag
+		}
+		encoded, err := asn1.Marshal(attr)
+		if err != nil {
+			return nil, err
+		}
+		sortables[i] = sortableAttribute{
+			SortKey:   encoded,
+			Attribute: attr,
+		}
+	}
+	sort.Sort(sortables)
+	return sortables.Attributes(), nil
+}
diff --git a/vendor/go.mozilla.org/pkcs7/sign.go b/vendor/go.mozilla.org/pkcs7/sign.go
new file mode 100644
index 000000000..addd76383
--- /dev/null
+++ b/vendor/go.mozilla.org/pkcs7/sign.go
@@ -0,0 +1,429 @@
+package pkcs7
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/dsa"
+	"crypto/rand"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"errors"
+	"fmt"
+	"math/big"
+	"time"
+)
+
+// SignedData is an opaque data structure for creating signed data payloads
+type SignedData struct {
+	sd                  signedData
+	certs               []*x509.Certificate
+	data, messageDigest []byte
+	digestOid           asn1.ObjectIdentifier
+	encryptionOid       asn1.ObjectIdentifier
+}
+
+// NewSignedData takes data and initializes a PKCS7 SignedData struct that is
+// ready to be signed via AddSigner. The digest algorithm is set to SHA1 by default
+// and can be changed by calling SetDigestAlgorithm.
+func NewSignedData(data []byte) (*SignedData, error) {
+	content, err := asn1.Marshal(data)
+	if err != nil {
+		return nil, err
+	}
+	ci := contentInfo{
+		ContentType: OIDData,
+		Content:     asn1.RawValue{Class: 2, Tag: 0, Bytes: content, IsCompound: true},
+	}
+	sd := signedData{
+		ContentInfo: ci,
+		Version:     1,
+	}
+	return &SignedData{sd: sd, data: data, digestOid: OIDDigestAlgorithmSHA1}, nil
+}
+
+// SignerInfoConfig are optional values to include when adding a signer
+type SignerInfoConfig struct {
+	ExtraSignedAttributes   []Attribute
+	ExtraUnsignedAttributes []Attribute
+}
+
+type signedData struct {
+	Version                    int                        `asn1:"default:1"`
+	DigestAlgorithmIdentifiers []pkix.AlgorithmIdentifier `asn1:"set"`
+	ContentInfo                contentInfo
+	Certificates               rawCertificates        `asn1:"optional,tag:0"`
+	CRLs                       []pkix.CertificateList `asn1:"optional,tag:1"`
+	SignerInfos                []signerInfo           `asn1:"set"`
+}
+
+type signerInfo struct {
+	Version                   int `asn1:"default:1"`
+	IssuerAndSerialNumber     issuerAndSerial
+	DigestAlgorithm           pkix.AlgorithmIdentifier
+	AuthenticatedAttributes   []attribute `asn1:"optional,omitempty,tag:0"`
+	DigestEncryptionAlgorithm pkix.AlgorithmIdentifier
+	EncryptedDigest           []byte
+	UnauthenticatedAttributes []attribute `asn1:"optional,omitempty,tag:1"`
+}
+
+type attribute struct {
+	Type  asn1.ObjectIdentifier
+	Value asn1.RawValue `asn1:"set"`
+}
+
+func marshalAttributes(attrs []attribute) ([]byte, error) {
+	encodedAttributes, err := asn1.Marshal(struct {
+		A []attribute `asn1:"set"`
+	}{A: attrs})
+	if err != nil {
+		return nil, err
+	}
+
+	// Remove the leading sequence octets
+	var raw asn1.RawValue
+	asn1.Unmarshal(encodedAttributes, &raw)
+	return raw.Bytes, nil
+}
+
+type rawCertificates struct {
+	Raw asn1.RawContent
+}
+
+type issuerAndSerial struct {
+	IssuerName   asn1.RawValue
+	SerialNumber *big.Int
+}
+
+// SetDigestAlgorithm sets the digest algorithm to be used in the signing process.
+//
+// This should be called before adding signers
+func (sd *SignedData) SetDigestAlgorithm(d asn1.ObjectIdentifier) {
+	sd.digestOid = d
+}
+
+// SetEncryptionAlgorithm sets the encryption algorithm to be used in the signing process.
+//
+// This should be called before adding signers
+func (sd *SignedData) SetEncryptionAlgorithm(d asn1.ObjectIdentifier) {
+	sd.encryptionOid = d
+}
+
+// AddSigner is a wrapper around AddSignerChain() that adds a signer without any parent.
+func (sd *SignedData) AddSigner(ee *x509.Certificate, pkey crypto.PrivateKey, config SignerInfoConfig) error {
+	var parents []*x509.Certificate
+	return sd.AddSignerChain(ee, pkey, parents, config)
+}
+
+// AddSignerChain signs attributes about the content and adds certificates
+// and signers infos to the Signed Data. The certificate and private key
+// of the end-entity signer are used to issue the signature, and any
+// parent of that end-entity that need to be added to the list of
+// certifications can be specified in the parents slice.
+//
+// The signature algorithm used to hash the data is the one of the end-entity
+// certificate.
+func (sd *SignedData) AddSignerChain(ee *x509.Certificate, pkey crypto.PrivateKey, parents []*x509.Certificate, config SignerInfoConfig) error {
+// Following RFC 2315, 9.2 SignerInfo type, the distinguished name of
+// the issuer of the end-entity signer is stored in the issuerAndSerialNumber
+// section of the SignedData.SignerInfo, alongside the serial number of
+// the end-entity.
+	var ias issuerAndSerial
+	ias.SerialNumber = ee.SerialNumber
+	if len(parents) == 0 {
+		// no parent, the issuer is the end-entity cert itself
+		ias.IssuerName = asn1.RawValue{FullBytes: ee.RawIssuer}
+	} else {
+		err := verifyPartialChain(ee, parents)
+		if err != nil {
+			return err
+		}
+		// the first parent is the issuer
+		ias.IssuerName = asn1.RawValue{FullBytes: parents[0].RawSubject}
+	}
+	sd.sd.DigestAlgorithmIdentifiers = append(sd.sd.DigestAlgorithmIdentifiers,
+		pkix.AlgorithmIdentifier{Algorithm: sd.digestOid},
+	)
+	hash, err := getHashForOID(sd.digestOid)
+	if err != nil {
+		return err
+	}
+	h := hash.New()
+	h.Write(sd.data)
+	sd.messageDigest = h.Sum(nil)
+	encryptionOid, err := getOIDForEncryptionAlgorithm(pkey, sd.digestOid)
+	if err != nil {
+		return err
+	}
+	attrs := &attributes{}
+	attrs.Add(OIDAttributeContentType, sd.sd.ContentInfo.ContentType)
+	attrs.Add(OIDAttributeMessageDigest, sd.messageDigest)
+	attrs.Add(OIDAttributeSigningTime, time.Now().UTC())
+	for _, attr := range config.ExtraSignedAttributes {
+		attrs.Add(attr.Type, attr.Value)
+	}
+	finalAttrs, err := attrs.ForMarshalling()
+	if err != nil {
+		return err
+	}
+	unsignedAttrs := &attributes{}
+	for _, attr := range config.ExtraUnsignedAttributes {
+		unsignedAttrs.Add(attr.Type, attr.Value)
+	}
+	finalUnsignedAttrs, err := unsignedAttrs.ForMarshalling()
+	if err != nil {
+		return err
+	}
+	// create signature of signed attributes
+	signature, err := signAttributes(finalAttrs, pkey, hash)
+	if err != nil {
+		return err
+	}
+	signer := signerInfo{
+		AuthenticatedAttributes:   finalAttrs,
+		UnauthenticatedAttributes: finalUnsignedAttrs,
+		DigestAlgorithm:           pkix.AlgorithmIdentifier{Algorithm: sd.digestOid},
+		DigestEncryptionAlgorithm: pkix.AlgorithmIdentifier{Algorithm: encryptionOid},
+		IssuerAndSerialNumber:     ias,
+		EncryptedDigest:           signature,
+		Version:                   1,
+	}
+	sd.certs = append(sd.certs, ee)
+	if len(parents) > 0 {
+		sd.certs = append(sd.certs, parents...)
+	}
+	sd.sd.SignerInfos = append(sd.sd.SignerInfos, signer)
+	return nil
+}
+
+// SignWithoutAttr issues a signature on the content of the pkcs7 SignedData.
+// Unlike AddSigner/AddSignerChain, it calculates the digest on the data alone
+// and does not include any signed attributes like timestamp and so on.
+//
+// This function is needed to sign old Android APKs, something you probably
+// shouldn't do unless you're maintaining backward compatibility for old
+// applications.
+func (sd *SignedData) SignWithoutAttr(ee *x509.Certificate, pkey crypto.PrivateKey, config SignerInfoConfig) error {
+	var signature []byte
+	sd.sd.DigestAlgorithmIdentifiers = append(sd.sd.DigestAlgorithmIdentifiers, pkix.AlgorithmIdentifier{Algorithm: sd.digestOid})
+	hash, err := getHashForOID(sd.digestOid)
+	if err != nil {
+		return err
+	}
+	h := hash.New()
+	h.Write(sd.data)
+	sd.messageDigest = h.Sum(nil)
+	switch pkey := pkey.(type) {
+	case *dsa.PrivateKey:
+		// dsa doesn't implement crypto.Signer so we make a special case
+		// https://github.com/golang/go/issues/27889
+		r, s, err := dsa.Sign(rand.Reader, pkey, sd.messageDigest)
+		if err != nil {
+			return err
+		}
+		signature, err = asn1.Marshal(dsaSignature{r, s})
+		if err != nil {
+			return err
+		}
+	default:
+		key, ok := pkey.(crypto.Signer)
+		if !ok {
+			return errors.New("pkcs7: private key does not implement crypto.Signer")
+		}
+		signature, err = key.Sign(rand.Reader, sd.messageDigest, hash)
+		if err != nil {
+			return err
+		}
+	}
+	var ias issuerAndSerial
+	ias.SerialNumber = ee.SerialNumber
+	// no parent, the issue is the end-entity cert itself
+	ias.IssuerName = asn1.RawValue{FullBytes: ee.RawIssuer}
+	if sd.encryptionOid == nil {
+		// if the encryption algorithm wasn't set by SetEncryptionAlgorithm,
+		// infer it from the digest algorithm
+		sd.encryptionOid, err = getOIDForEncryptionAlgorithm(pkey, sd.digestOid)
+	}
+	if err != nil {
+		return err
+	}
+	signer := signerInfo{
+		DigestAlgorithm:           pkix.AlgorithmIdentifier{Algorithm: sd.digestOid},
+		DigestEncryptionAlgorithm: pkix.AlgorithmIdentifier{Algorithm: sd.encryptionOid},
+		IssuerAndSerialNumber:     ias,
+		EncryptedDigest:           signature,
+		Version:                   1,
+	}
+	// create signature of signed attributes
+	sd.certs = append(sd.certs, ee)
+	sd.sd.SignerInfos = append(sd.sd.SignerInfos, signer)
+	return nil
+}
+
+func (si *signerInfo) SetUnauthenticatedAttributes(extraUnsignedAttrs []Attribute) error {
+	unsignedAttrs := &attributes{}
+	for _, attr := range extraUnsignedAttrs {
+		unsignedAttrs.Add(attr.Type, attr.Value)
+	}
+	finalUnsignedAttrs, err := unsignedAttrs.ForMarshalling()
+	if err != nil {
+		return err
+	}
+
+	si.UnauthenticatedAttributes = finalUnsignedAttrs
+
+	return nil
+}
+
+// AddCertificate adds the certificate to the payload. Useful for parent certificates
+func (sd *SignedData) AddCertificate(cert *x509.Certificate) {
+	sd.certs = append(sd.certs, cert)
+}
+
+// Detach removes content from the signed data struct to make it a detached signature.
+// This must be called right before Finish()
+func (sd *SignedData) Detach() {
+	sd.sd.ContentInfo = contentInfo{ContentType: OIDData}
+}
+
+// GetSignedData returns the private Signed Data
+func (sd *SignedData) GetSignedData() *signedData {
+	return &sd.sd
+}
+
+// Finish marshals the content and its signers
+func (sd *SignedData) Finish() ([]byte, error) {
+	sd.sd.Certificates = marshalCertificates(sd.certs)
+	inner, err := asn1.Marshal(sd.sd)
+	if err != nil {
+		return nil, err
+	}
+	outer := contentInfo{
+		ContentType: OIDSignedData,
+		Content:     asn1.RawValue{Class: 2, Tag: 0, Bytes: inner, IsCompound: true},
+	}
+	return asn1.Marshal(outer)
+}
+
+// RemoveAuthenticatedAttributes removes authenticated attributes from signedData
+// similar to OpenSSL's PKCS7_NOATTR or -noattr flags
+func (sd *SignedData) RemoveAuthenticatedAttributes() {
+	for i := range sd.sd.SignerInfos {
+		sd.sd.SignerInfos[i].AuthenticatedAttributes = nil
+	}
+}
+
+// RemoveUnauthenticatedAttributes removes unauthenticated attributes from signedData
+func (sd *SignedData) RemoveUnauthenticatedAttributes() {
+	for i := range sd.sd.SignerInfos {
+		sd.sd.SignerInfos[i].UnauthenticatedAttributes = nil
+	}
+}
+
+// verifyPartialChain checks that a given cert is issued by the first parent in the list,
+// then continue down the path. It doesn't require the last parent to be a root CA,
+// or to be trusted in any truststore. It simply verifies that the chain provided, albeit
+// partial, makes sense.
+func verifyPartialChain(cert *x509.Certificate, parents []*x509.Certificate) error {
+	if len(parents) == 0 {
+		return fmt.Errorf("pkcs7: zero parents provided to verify the signature of certificate %q", cert.Subject.CommonName)
+	}
+	err := cert.CheckSignatureFrom(parents[0])
+	if err != nil {
+		return fmt.Errorf("pkcs7: certificate signature from parent is invalid: %v", err)
+	}
+	if len(parents) == 1 {
+		// there is no more parent to check, return
+		return nil
+	}
+	return verifyPartialChain(parents[0], parents[1:])
+}
+
+func cert2issuerAndSerial(cert *x509.Certificate) (issuerAndSerial, error) {
+	var ias issuerAndSerial
+	// The issuer RDNSequence has to match exactly the sequence in the certificate
+	// We cannot use cert.Issuer.ToRDNSequence() here since it mangles the sequence
+	ias.IssuerName = asn1.RawValue{FullBytes: cert.RawIssuer}
+	ias.SerialNumber = cert.SerialNumber
+
+	return ias, nil
+}
+
+// signs the DER encoded form of the attributes with the private key
+func signAttributes(attrs []attribute, pkey crypto.PrivateKey, digestAlg crypto.Hash) ([]byte, error) {
+	attrBytes, err := marshalAttributes(attrs)
+	if err != nil {
+		return nil, err
+	}
+	h := digestAlg.New()
+	h.Write(attrBytes)
+	hash := h.Sum(nil)
+
+	// dsa doesn't implement crypto.Signer so we make a special case
+	// https://github.com/golang/go/issues/27889
+	switch pkey := pkey.(type) {
+	case *dsa.PrivateKey:
+		r, s, err := dsa.Sign(rand.Reader, pkey, hash)
+		if err != nil {
+			return nil, err
+		}
+		return asn1.Marshal(dsaSignature{r, s})
+	}
+
+	key, ok := pkey.(crypto.Signer)
+	if !ok {
+		return nil, errors.New("pkcs7: private key does not implement crypto.Signer")
+	}
+	return key.Sign(rand.Reader, hash, digestAlg)
+}
+
+type dsaSignature struct {
+	R, S *big.Int
+}
+
+// concats and wraps the certificates in the RawValue structure
+func marshalCertificates(certs []*x509.Certificate) rawCertificates {
+	var buf bytes.Buffer
+	for _, cert := range certs {
+		buf.Write(cert.Raw)
+	}
+	rawCerts, _ := marshalCertificateBytes(buf.Bytes())
+	return rawCerts
+}
+
+// Even though, the tag & length are stripped out during marshalling the
+// RawContent, we have to encode it into the RawContent. If its missing,
+// then `asn1.Marshal()` will strip out the certificate wrapper instead.
+func marshalCertificateBytes(certs []byte) (rawCertificates, error) {
+	var val = asn1.RawValue{Bytes: certs, Class: 2, Tag: 0, IsCompound: true}
+	b, err := asn1.Marshal(val)
+	if err != nil {
+		return rawCertificates{}, err
+	}
+	return rawCertificates{Raw: b}, nil
+}
+
+// DegenerateCertificate creates a signed data structure containing only the
+// provided certificate or certificate chain.
+func DegenerateCertificate(cert []byte) ([]byte, error) {
+	rawCert, err := marshalCertificateBytes(cert)
+	if err != nil {
+		return nil, err
+	}
+	emptyContent := contentInfo{ContentType: OIDData}
+	sd := signedData{
+		Version:      1,
+		ContentInfo:  emptyContent,
+		Certificates: rawCert,
+		CRLs:         []pkix.CertificateList{},
+	}
+	content, err := asn1.Marshal(sd)
+	if err != nil {
+		return nil, err
+	}
+	signedContent := contentInfo{
+		ContentType: OIDSignedData,
+		Content:     asn1.RawValue{Class: 2, Tag: 0, Bytes: content, IsCompound: true},
+	}
+	return asn1.Marshal(signedContent)
+}
diff --git a/vendor/go.mozilla.org/pkcs7/verify.go b/vendor/go.mozilla.org/pkcs7/verify.go
new file mode 100644
index 000000000..c8ead2362
--- /dev/null
+++ b/vendor/go.mozilla.org/pkcs7/verify.go
@@ -0,0 +1,264 @@
+package pkcs7
+
+import (
+	"crypto/subtle"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"errors"
+	"fmt"
+	"time"
+)
+
+// Verify is a wrapper around VerifyWithChain() that initializes an empty
+// trust store, effectively disabling certificate verification when validating
+// a signature.
+func (p7 *PKCS7) Verify() (err error) {
+	return p7.VerifyWithChain(nil)
+}
+
+// VerifyWithChain checks the signatures of a PKCS7 object.
+// If truststore is not nil, it also verifies the chain of trust of the end-entity
+// signer cert to one of the root in the truststore.
+func (p7 *PKCS7) VerifyWithChain(truststore *x509.CertPool) (err error) {
+	if len(p7.Signers) == 0 {
+		return errors.New("pkcs7: Message has no signers")
+	}
+	for _, signer := range p7.Signers {
+		if err := verifySignature(p7, signer, truststore); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func verifySignature(p7 *PKCS7, signer signerInfo, truststore *x509.CertPool) (err error) {
+	signedData := p7.Content
+	ee := getCertFromCertsByIssuerAndSerial(p7.Certificates, signer.IssuerAndSerialNumber)
+	if ee == nil {
+		return errors.New("pkcs7: No certificate for signer")
+	}
+	signingTime := time.Now().UTC()
+	if len(signer.AuthenticatedAttributes) > 0 {
+		// TODO(fullsailor): First check the content type match
+		var digest []byte
+		err := unmarshalAttribute(signer.AuthenticatedAttributes, OIDAttributeMessageDigest, &digest)
+		if err != nil {
+			return err
+		}
+		hash, err := getHashForOID(signer.DigestAlgorithm.Algorithm)
+		if err != nil {
+			return err
+		}
+		h := hash.New()
+		h.Write(p7.Content)
+		computed := h.Sum(nil)
+		if subtle.ConstantTimeCompare(digest, computed) != 1 {
+			return &MessageDigestMismatchError{
+				ExpectedDigest: digest,
+				ActualDigest:   computed,
+			}
+		}
+		signedData, err = marshalAttributes(signer.AuthenticatedAttributes)
+		if err != nil {
+			return err
+		}
+		err = unmarshalAttribute(signer.AuthenticatedAttributes, OIDAttributeSigningTime, &signingTime)
+		if err == nil {
+			// signing time found, performing validity check
+			if signingTime.After(ee.NotAfter) || signingTime.Before(ee.NotBefore) {
+				return fmt.Errorf("pkcs7: signing time %q is outside of certificate validity %q to %q",
+					signingTime.Format(time.RFC3339),
+					ee.NotBefore.Format(time.RFC3339),
+					ee.NotBefore.Format(time.RFC3339))
+			}
+		}
+	}
+	if truststore != nil {
+		_, err = verifyCertChain(ee, p7.Certificates, truststore, signingTime)
+		if err != nil {
+			return err
+		}
+	}
+	sigalg, err := getSignatureAlgorithm(signer.DigestEncryptionAlgorithm, signer.DigestAlgorithm)
+	if err != nil {
+		return err
+	}
+	return ee.CheckSignature(sigalg, signedData, signer.EncryptedDigest)
+}
+
+// GetOnlySigner returns an x509.Certificate for the first signer of the signed
+// data payload. If there are more or less than one signer, nil is returned
+func (p7 *PKCS7) GetOnlySigner() *x509.Certificate {
+	if len(p7.Signers) != 1 {
+		return nil
+	}
+	signer := p7.Signers[0]
+	return getCertFromCertsByIssuerAndSerial(p7.Certificates, signer.IssuerAndSerialNumber)
+}
+
+// UnmarshalSignedAttribute decodes a single attribute from the signer info
+func (p7 *PKCS7) UnmarshalSignedAttribute(attributeType asn1.ObjectIdentifier, out interface{}) error {
+	sd, ok := p7.raw.(signedData)
+	if !ok {
+		return errors.New("pkcs7: payload is not signedData content")
+	}
+	if len(sd.SignerInfos) < 1 {
+		return errors.New("pkcs7: payload has no signers")
+	}
+	attributes := sd.SignerInfos[0].AuthenticatedAttributes
+	return unmarshalAttribute(attributes, attributeType, out)
+}
+
+func parseSignedData(data []byte) (*PKCS7, error) {
+	var sd signedData
+	asn1.Unmarshal(data, &sd)
+	certs, err := sd.Certificates.Parse()
+	if err != nil {
+		return nil, err
+	}
+	// fmt.Printf("--> Signed Data Version %d\n", sd.Version)
+
+	var compound asn1.RawValue
+	var content unsignedData
+
+	// The Content.Bytes maybe empty on PKI responses.
+	if len(sd.ContentInfo.Content.Bytes) > 0 {
+		if _, err := asn1.Unmarshal(sd.ContentInfo.Content.Bytes, &compound); err != nil {
+			return nil, err
+		}
+	}
+	// Compound octet string
+	if compound.IsCompound {
+		if compound.Tag == 4 {
+			if _, err = asn1.Unmarshal(compound.Bytes, &content); err != nil {
+				return nil, err
+			}
+		} else {
+			content = compound.Bytes
+		}
+	} else {
+		// assuming this is tag 04
+		content = compound.Bytes
+	}
+	return &PKCS7{
+		Content:      content,
+		Certificates: certs,
+		CRLs:         sd.CRLs,
+		Signers:      sd.SignerInfos,
+		raw:          sd}, nil
+}
+
+// verifyCertChain takes an end-entity certs, a list of potential intermediates and a
+// truststore, and built all potential chains between the EE and a trusted root.
+//
+// When verifying chains that may have expired, currentTime can be set to a past date
+// to allow the verification to pass. If unset, currentTime is set to the current UTC time.
+func verifyCertChain(ee *x509.Certificate, certs []*x509.Certificate, truststore *x509.CertPool, currentTime time.Time) (chains [][]*x509.Certificate, err error) {
+	intermediates := x509.NewCertPool()
+	for _, intermediate := range certs {
+		intermediates.AddCert(intermediate)
+	}
+	verifyOptions := x509.VerifyOptions{
+		Roots:         truststore,
+		Intermediates: intermediates,
+		KeyUsages:     []x509.ExtKeyUsage{x509.ExtKeyUsageAny},
+		CurrentTime:   currentTime,
+	}
+	chains, err = ee.Verify(verifyOptions)
+	if err != nil {
+		return chains, fmt.Errorf("pkcs7: failed to verify certificate chain: %v", err)
+	}
+	return
+}
+
+// MessageDigestMismatchError is returned when the signer data digest does not
+// match the computed digest for the contained content
+type MessageDigestMismatchError struct {
+	ExpectedDigest []byte
+	ActualDigest   []byte
+}
+
+func (err *MessageDigestMismatchError) Error() string {
+	return fmt.Sprintf("pkcs7: Message digest mismatch\n\tExpected: %X\n\tActual  : %X", err.ExpectedDigest, err.ActualDigest)
+}
+
+func getSignatureAlgorithm(digestEncryption, digest pkix.AlgorithmIdentifier) (x509.SignatureAlgorithm, error) {
+	switch {
+	case digestEncryption.Algorithm.Equal(OIDDigestAlgorithmECDSASHA1):
+		return x509.ECDSAWithSHA1, nil
+	case digestEncryption.Algorithm.Equal(OIDDigestAlgorithmECDSASHA256):
+		return x509.ECDSAWithSHA256, nil
+	case digestEncryption.Algorithm.Equal(OIDDigestAlgorithmECDSASHA384):
+		return x509.ECDSAWithSHA384, nil
+	case digestEncryption.Algorithm.Equal(OIDDigestAlgorithmECDSASHA512):
+		return x509.ECDSAWithSHA512, nil
+	case digestEncryption.Algorithm.Equal(OIDEncryptionAlgorithmRSA),
+		digestEncryption.Algorithm.Equal(OIDEncryptionAlgorithmRSASHA1),
+		digestEncryption.Algorithm.Equal(OIDEncryptionAlgorithmRSASHA256),
+		digestEncryption.Algorithm.Equal(OIDEncryptionAlgorithmRSASHA384),
+		digestEncryption.Algorithm.Equal(OIDEncryptionAlgorithmRSASHA512):
+		switch {
+		case digest.Algorithm.Equal(OIDDigestAlgorithmSHA1):
+			return x509.SHA1WithRSA, nil
+		case digest.Algorithm.Equal(OIDDigestAlgorithmSHA256):
+			return x509.SHA256WithRSA, nil
+		case digest.Algorithm.Equal(OIDDigestAlgorithmSHA384):
+			return x509.SHA384WithRSA, nil
+		case digest.Algorithm.Equal(OIDDigestAlgorithmSHA512):
+			return x509.SHA512WithRSA, nil
+		default:
+			return -1, fmt.Errorf("pkcs7: unsupported digest %q for encryption algorithm %q",
+				digest.Algorithm.String(), digestEncryption.Algorithm.String())
+		}
+	case digestEncryption.Algorithm.Equal(OIDDigestAlgorithmDSA),
+		digestEncryption.Algorithm.Equal(OIDDigestAlgorithmDSASHA1):
+		switch {
+		case digest.Algorithm.Equal(OIDDigestAlgorithmSHA1):
+			return x509.DSAWithSHA1, nil
+		case digest.Algorithm.Equal(OIDDigestAlgorithmSHA256):
+			return x509.DSAWithSHA256, nil
+		default:
+			return -1, fmt.Errorf("pkcs7: unsupported digest %q for encryption algorithm %q",
+				digest.Algorithm.String(), digestEncryption.Algorithm.String())
+		}
+	case digestEncryption.Algorithm.Equal(OIDEncryptionAlgorithmECDSAP256),
+		digestEncryption.Algorithm.Equal(OIDEncryptionAlgorithmECDSAP384),
+		digestEncryption.Algorithm.Equal(OIDEncryptionAlgorithmECDSAP521):
+		switch {
+		case digest.Algorithm.Equal(OIDDigestAlgorithmSHA1):
+			return x509.ECDSAWithSHA1, nil
+		case digest.Algorithm.Equal(OIDDigestAlgorithmSHA256):
+			return x509.ECDSAWithSHA256, nil
+		case digest.Algorithm.Equal(OIDDigestAlgorithmSHA384):
+			return x509.ECDSAWithSHA384, nil
+		case digest.Algorithm.Equal(OIDDigestAlgorithmSHA512):
+			return x509.ECDSAWithSHA512, nil
+		default:
+			return -1, fmt.Errorf("pkcs7: unsupported digest %q for encryption algorithm %q",
+				digest.Algorithm.String(), digestEncryption.Algorithm.String())
+		}
+	default:
+		return -1, fmt.Errorf("pkcs7: unsupported algorithm %q",
+			digestEncryption.Algorithm.String())
+	}
+}
+
+func getCertFromCertsByIssuerAndSerial(certs []*x509.Certificate, ias issuerAndSerial) *x509.Certificate {
+	for _, cert := range certs {
+		if isCertMatchForIssuerAndSerial(cert, ias) {
+			return cert
+		}
+	}
+	return nil
+}
+
+func unmarshalAttribute(attrs []attribute, attributeType asn1.ObjectIdentifier, out interface{}) error {
+	for _, attr := range attrs {
+		if attr.Type.Equal(attributeType) {
+			_, err := asn1.Unmarshal(attr.Value.Bytes, out)
+			return err
+		}
+	}
+	return errors.New("pkcs7: attribute type not in attributes")
+}