From 8f91c777559748fa6e857d9fc1f4ae079a532813 Mon Sep 17 00:00:00 2001 From: Christopher Speller Date: Mon, 3 Oct 2016 16:03:15 -0400 Subject: Adding ability to serve TLS directly from Mattermost server (#4119) --- vendor/gopkg.in/square/go-jose.v1/symmetric.go | 349 +++++++++++++++++++++++++ 1 file changed, 349 insertions(+) create mode 100644 vendor/gopkg.in/square/go-jose.v1/symmetric.go (limited to 'vendor/gopkg.in/square/go-jose.v1/symmetric.go') diff --git a/vendor/gopkg.in/square/go-jose.v1/symmetric.go b/vendor/gopkg.in/square/go-jose.v1/symmetric.go new file mode 100644 index 000000000..51f8cb394 --- /dev/null +++ b/vendor/gopkg.in/square/go-jose.v1/symmetric.go @@ -0,0 +1,349 @@ +/*- + * Copyright 2014 Square Inc. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package jose + +import ( + "crypto/aes" + "crypto/cipher" + "crypto/hmac" + "crypto/rand" + "crypto/sha256" + "crypto/sha512" + "crypto/subtle" + "errors" + "hash" + "io" + + "gopkg.in/square/go-jose.v1/cipher" +) + +// Random reader (stubbed out in tests) +var randReader = rand.Reader + +// Dummy key cipher for shared symmetric key mode +type symmetricKeyCipher struct { + key []byte // Pre-shared content-encryption key +} + +// Signer/verifier for MAC modes +type symmetricMac struct { + key []byte +} + +// Input/output from an AEAD operation +type aeadParts struct { + iv, ciphertext, tag []byte +} + +// A content cipher based on an AEAD construction +type aeadContentCipher struct { + keyBytes int + authtagBytes int + getAead func(key []byte) (cipher.AEAD, error) +} + +// Random key generator +type randomKeyGenerator struct { + size int +} + +// Static key generator +type staticKeyGenerator struct { + key []byte +} + +// Create a new content cipher based on AES-GCM +func newAESGCM(keySize int) contentCipher { + return &aeadContentCipher{ + keyBytes: keySize, + authtagBytes: 16, + getAead: func(key []byte) (cipher.AEAD, error) { + aes, err := aes.NewCipher(key) + if err != nil { + return nil, err + } + + return cipher.NewGCM(aes) + }, + } +} + +// Create a new content cipher based on AES-CBC+HMAC +func newAESCBC(keySize int) contentCipher { + return &aeadContentCipher{ + keyBytes: keySize * 2, + authtagBytes: 16, + getAead: func(key []byte) (cipher.AEAD, error) { + return josecipher.NewCBCHMAC(key, aes.NewCipher) + }, + } +} + +// Get an AEAD cipher object for the given content encryption algorithm +func getContentCipher(alg ContentEncryption) contentCipher { + switch alg { + case A128GCM: + return newAESGCM(16) + case A192GCM: + return newAESGCM(24) + case A256GCM: + return newAESGCM(32) + case A128CBC_HS256: + return newAESCBC(16) + case A192CBC_HS384: + return newAESCBC(24) + case A256CBC_HS512: + return newAESCBC(32) + default: + return nil + } +} + +// newSymmetricRecipient creates a JWE encrypter based on AES-GCM key wrap. +func newSymmetricRecipient(keyAlg KeyAlgorithm, key []byte) (recipientKeyInfo, error) { + switch keyAlg { + case DIRECT, A128GCMKW, A192GCMKW, A256GCMKW, A128KW, A192KW, A256KW: + default: + return recipientKeyInfo{}, ErrUnsupportedAlgorithm + } + + return recipientKeyInfo{ + keyAlg: keyAlg, + keyEncrypter: &symmetricKeyCipher{ + key: key, + }, + }, nil +} + +// newSymmetricSigner creates a recipientSigInfo based on the given key. +func newSymmetricSigner(sigAlg SignatureAlgorithm, key []byte) (recipientSigInfo, error) { + // Verify that key management algorithm is supported by this encrypter + switch sigAlg { + case HS256, HS384, HS512: + default: + return recipientSigInfo{}, ErrUnsupportedAlgorithm + } + + return recipientSigInfo{ + sigAlg: sigAlg, + signer: &symmetricMac{ + key: key, + }, + }, nil +} + +// Generate a random key for the given content cipher +func (ctx randomKeyGenerator) genKey() ([]byte, rawHeader, error) { + key := make([]byte, ctx.size) + _, err := io.ReadFull(randReader, key) + if err != nil { + return nil, rawHeader{}, err + } + + return key, rawHeader{}, nil +} + +// Key size for random generator +func (ctx randomKeyGenerator) keySize() int { + return ctx.size +} + +// Generate a static key (for direct mode) +func (ctx staticKeyGenerator) genKey() ([]byte, rawHeader, error) { + cek := make([]byte, len(ctx.key)) + copy(cek, ctx.key) + return cek, rawHeader{}, nil +} + +// Key size for static generator +func (ctx staticKeyGenerator) keySize() int { + return len(ctx.key) +} + +// Get key size for this cipher +func (ctx aeadContentCipher) keySize() int { + return ctx.keyBytes +} + +// Encrypt some data +func (ctx aeadContentCipher) encrypt(key, aad, pt []byte) (*aeadParts, error) { + // Get a new AEAD instance + aead, err := ctx.getAead(key) + if err != nil { + return nil, err + } + + // Initialize a new nonce + iv := make([]byte, aead.NonceSize()) + _, err = io.ReadFull(randReader, iv) + if err != nil { + return nil, err + } + + ciphertextAndTag := aead.Seal(nil, iv, pt, aad) + offset := len(ciphertextAndTag) - ctx.authtagBytes + + return &aeadParts{ + iv: iv, + ciphertext: ciphertextAndTag[:offset], + tag: ciphertextAndTag[offset:], + }, nil +} + +// Decrypt some data +func (ctx aeadContentCipher) decrypt(key, aad []byte, parts *aeadParts) ([]byte, error) { + aead, err := ctx.getAead(key) + if err != nil { + return nil, err + } + + return aead.Open(nil, parts.iv, append(parts.ciphertext, parts.tag...), aad) +} + +// Encrypt the content encryption key. +func (ctx *symmetricKeyCipher) encryptKey(cek []byte, alg KeyAlgorithm) (recipientInfo, error) { + switch alg { + case DIRECT: + return recipientInfo{ + header: &rawHeader{}, + }, nil + case A128GCMKW, A192GCMKW, A256GCMKW: + aead := newAESGCM(len(ctx.key)) + + parts, err := aead.encrypt(ctx.key, []byte{}, cek) + if err != nil { + return recipientInfo{}, err + } + + return recipientInfo{ + header: &rawHeader{ + Iv: newBuffer(parts.iv), + Tag: newBuffer(parts.tag), + }, + encryptedKey: parts.ciphertext, + }, nil + case A128KW, A192KW, A256KW: + block, err := aes.NewCipher(ctx.key) + if err != nil { + return recipientInfo{}, err + } + + jek, err := josecipher.KeyWrap(block, cek) + if err != nil { + return recipientInfo{}, err + } + + return recipientInfo{ + encryptedKey: jek, + header: &rawHeader{}, + }, nil + } + + return recipientInfo{}, ErrUnsupportedAlgorithm +} + +// Decrypt the content encryption key. +func (ctx *symmetricKeyCipher) decryptKey(headers rawHeader, recipient *recipientInfo, generator keyGenerator) ([]byte, error) { + switch KeyAlgorithm(headers.Alg) { + case DIRECT: + cek := make([]byte, len(ctx.key)) + copy(cek, ctx.key) + return cek, nil + case A128GCMKW, A192GCMKW, A256GCMKW: + aead := newAESGCM(len(ctx.key)) + + parts := &aeadParts{ + iv: headers.Iv.bytes(), + ciphertext: recipient.encryptedKey, + tag: headers.Tag.bytes(), + } + + cek, err := aead.decrypt(ctx.key, []byte{}, parts) + if err != nil { + return nil, err + } + + return cek, nil + case A128KW, A192KW, A256KW: + block, err := aes.NewCipher(ctx.key) + if err != nil { + return nil, err + } + + cek, err := josecipher.KeyUnwrap(block, recipient.encryptedKey) + if err != nil { + return nil, err + } + return cek, nil + } + + return nil, ErrUnsupportedAlgorithm +} + +// Sign the given payload +func (ctx symmetricMac) signPayload(payload []byte, alg SignatureAlgorithm) (Signature, error) { + mac, err := ctx.hmac(payload, alg) + if err != nil { + return Signature{}, errors.New("square/go-jose: failed to compute hmac") + } + + return Signature{ + Signature: mac, + protected: &rawHeader{}, + }, nil +} + +// Verify the given payload +func (ctx symmetricMac) verifyPayload(payload []byte, mac []byte, alg SignatureAlgorithm) error { + expected, err := ctx.hmac(payload, alg) + if err != nil { + return errors.New("square/go-jose: failed to compute hmac") + } + + if len(mac) != len(expected) { + return errors.New("square/go-jose: invalid hmac") + } + + match := subtle.ConstantTimeCompare(mac, expected) + if match != 1 { + return errors.New("square/go-jose: invalid hmac") + } + + return nil +} + +// Compute the HMAC based on the given alg value +func (ctx symmetricMac) hmac(payload []byte, alg SignatureAlgorithm) ([]byte, error) { + var hash func() hash.Hash + + switch alg { + case HS256: + hash = sha256.New + case HS384: + hash = sha512.New384 + case HS512: + hash = sha512.New + default: + return nil, ErrUnsupportedAlgorithm + } + + hmac := hmac.New(hash, ctx.key) + + // According to documentation, Write() on hash never fails + _, _ = hmac.Write(payload) + return hmac.Sum(nil), nil +} -- cgit v1.2.3-1-g7c22