Merge pull request #1065 from microsoft/dev/qmuntal/rc4

Implement support for crypto/rc4 using OpenSSL/CNG
microsoft · Oct 18, 2023 · 0ce5483 · 0ce5483
2 parents 0ce9216 + fdcc079
commit 0ce5483
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diff --git a/eng/doc/fips/UserGuide.md b/eng/doc/fips/UserGuide.md
@@ -48,6 +48,7 @@ The Go crypto documentation is available online at https://pkg.go.dev/crypto.
       - [func Prime](#func-prime)
       - [func Read](#func-read)
     - [crypto/rc4](#cryptorc4)
+      - [func NewCipher](#func-newcipher-1)
     - [crypto/sha1](#cryptosha1)
       - [func New](#func-new-1)
       - [func Sum](#func-sum)
@@ -806,7 +807,44 @@ Read is a helper function that calls rand.Reader.Read using io.ReadFull.
 
 ### [crypto/rc4](https://pkg.go.dev/crypto/rc4)
 
-Not implemented by any backend.
+Package rc4 implements RC4 encryption, as defined in Bruce Schneier's Applied Cryptography.
+
+#### func [NewCipher](https://pkg.go.dev/crypto/rc4#NewCipher)
+
+```go
+func rc4.NewCipher() rc4.Cipher
+```
+
+NewCipher creates and returns a new Cipher. The key argument should be the RC4 key, at least 1 byte and at most 256 bytes.
+
+**Requirements**
+
+Some OpenSSL distributions don't implement RC4, e.g., OpenSSL 1.x compiled with `-DOPENSSL_NO_RC4` and OpenSSL 3.x that can't load the legacy provider.
+In those cases, `rc4.NewCipher()` will fall back to standard Go crypto.
+
+**Implementation**
+
+<details><summary>OpenSSL (click for details)</summary>
+
+The cipher is generated using [EVP_CIPHER_CTX_new] and [EVP_CipherInit_ex] with the cipher type [EVP_rc4].
+
+The rc4.Cipher methods are implemented as follows:
+
+- `Reset` using [EVP_CIPHER_CTX_free].
+- `XORKeyStream` using [EVP_EncryptUpdate].
+
+</details>
+
+<details><summary>CNG (click for details)</summary>
+
+The cipher is generated using [BCryptGenerateSymmetricKey] using the `BCRYPT_RC4_ALGORITHM` mode.
+
+The rc4.Cipher methods are implemented as follows:
+
+- `Reset` using [BCryptDestroyKey].
+- `XORKeyStream` using [BCryptEncrypt].
+
+</details>
 
 ### [crypto/sha1](https://pkg.go.dev/crypto/sha1)
 
@@ -1442,6 +1480,7 @@ When using TLS in FIPS-only mode the TLS handshake has the following restriction
 [EVP_aes_128_cbc]: https://www.openssl.org/docs/man3.0/man3/EVP_aes_128_cbc.html
 [EVP_aes_192_cbc]: https://www.openssl.org/docs/man3.0/man3/EVP_aes_192_cbc.html
 [EVP_aes_256_cbc]: https://www.openssl.org/docs/man3.0/man3/EVP_aes_256_cbc.html
+[EVP_rc4]: https://www.openssl.org/docs/man3.0/man3/EVP_rc4.html
 [EVP_sha1]: https://www.openssl.org/docs/man3.0/man3/EVP_sha1.html
 [EVP_sha224]: https://www.openssl.org/docs/man3.0/man3/EVP_sha224.html
 [EVP_sha256]: https://www.openssl.org/docs/man3.0/man3/EVP_sha256.html
@@ -1455,6 +1494,9 @@ When using TLS in FIPS-only mode the TLS handshake has the following restriction
 [EVP_MAC_init]: https://www.openssl.org/docs/man3.0/man3/EVP_MAC_init.html
 [EVP_MAC_update]: https://www.openssl.org/docs/man3.0/man3/EVP_MAC_update.html
 [EVP_MAC_final]: https://www.openssl.org/docs/man3.0/man3/EVP_MAC_final.html
+[EVP_CIPHER_CTX_new]: https://www.openssl.org/docs/man3.0/man3/EVP_CIPHER_CTX_new.html
+[EVP_CipherInit_ex]: https://www.openssl.org/docs/man3.0/man3/EVP_CipherInit_ex.html
+[EVP_CIPHER_CTX_free]: https://www.openssl.org/docs/man3.0/man3/EVP_CIPHER_CTX_free.html
 
 [algorithm identifier]: https://docs.microsoft.com/en-us/windows/win32/seccng/cng-algorithm-identifiers
 [named elliptic curve]: https://docs.microsoft.com/en-us/windows/win32/seccng/cng-named-elliptic-curves
@@ -1474,4 +1516,5 @@ When using TLS in FIPS-only mode the TLS handshake has the following restriction
 [BCRYPT_OAEP_PADDING_INFO]: https://docs.microsoft.com/en-us/windows/win32/api/Bcrypt/ns-bcrypt-bcrypt_oaep_padding_info
 [BCRYPT_PKCS1_PADDING_INFO]: https://docs.microsoft.com/en-us/windows/win32/api/Bcrypt/ns-bcrypt-bcrypt_pkcs1_padding_info
 [BCRYPT_PSS_PADDING_INFO]: https://docs.microsoft.com/en-us/windows/win32/api/Bcrypt/ns-bcrypt-bcrypt_pss_padding_info
-[BCryptDeriveKey]: https://docs.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptderivekey
+[BCryptDeriveKey]: https://docs.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptderivekey
+[BCryptDestroyKey]: https://docs.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptdestroykey
diff --git a/patches/0002-Add-crypto-backend-foundation.patch b/patches/0002-Add-crypto-backend-foundation.patch
@@ -17,15 +17,16 @@ Subject: [PATCH] Add crypto backend foundation
  src/crypto/hmac/hmac.go                      |   2 +-
  src/crypto/hmac/hmac_test.go                 |   2 +-
  src/crypto/internal/backend/backend_test.go  |  30 ++++
- src/crypto/internal/backend/bbig/big.go      |  17 +++
+ src/crypto/internal/backend/bbig/big.go      |  17 ++
  src/crypto/internal/backend/common.go        |  78 ++++++++++
  src/crypto/internal/backend/isrequirefips.go |   9 ++
- src/crypto/internal/backend/nobackend.go     | 145 +++++++++++++++++++
+ src/crypto/internal/backend/nobackend.go     | 154 +++++++++++++++++++
  src/crypto/internal/backend/norequirefips.go |   9 ++
  src/crypto/internal/backend/stub.s           |  10 ++
  src/crypto/md5/md5.go                        |   7 +
  src/crypto/md5/md5_test.go                   |   4 +
  src/crypto/rand/rand_unix.go                 |   2 +-
+ src/crypto/rc4/rc4.go                        |  18 +++
  src/crypto/rsa/boring.go                     |   4 +-
  src/crypto/rsa/notboring.go                  |   2 +-
  src/crypto/rsa/pkcs1v15.go                   |   2 +-
@@ -39,14 +40,14 @@ Subject: [PATCH] Add crypto backend foundation
  src/crypto/sha512/sha512.go                  |   2 +-
  src/crypto/sha512/sha512_test.go             |   2 +-
  src/crypto/tls/cipher_suites.go              |   2 +-
- src/crypto/tls/handshake_client.go           |  25 +++-
- src/crypto/tls/handshake_server.go           |  25 +++-
+ src/crypto/tls/handshake_client.go           |  25 ++-
+ src/crypto/tls/handshake_server.go           |  25 ++-
  src/crypto/tls/key_schedule.go               |  18 ++-
  src/crypto/tls/prf.go                        |  77 +++++++---
  src/crypto/tls/prf_test.go                   |  12 +-
  src/go/build/deps_test.go                    |   2 +
  src/runtime/runtime_boring.go                |   5 +
- 42 files changed, 473 insertions(+), 65 deletions(-)
+ 43 files changed, 500 insertions(+), 65 deletions(-)
  create mode 100644 src/crypto/internal/backend/backend_test.go
  create mode 100644 src/crypto/internal/backend/bbig/big.go
  create mode 100644 src/crypto/internal/backend/common.go
@@ -395,10 +396,10 @@ index 00000000000000..e5d7570d6d4363
 +const isRequireFIPS = true
 diff --git a/src/crypto/internal/backend/nobackend.go b/src/crypto/internal/backend/nobackend.go
 new file mode 100644
-index 00000000000000..275a6078f90514
+index 00000000000000..f45f2fe76d54f1
 --- /dev/null
 +++ b/src/crypto/internal/backend/nobackend.go
-@@ -0,0 +1,145 @@
+@@ -0,0 +1,154 @@
 +// Copyright 2017 The Go Authors. All rights reserved.
 +// Use of this source code is governed by a BSD-style
 +// license that can be found in the LICENSE file.
@@ -544,6 +545,15 @@ index 00000000000000..275a6078f90514
 +func NewDESCipher(key []byte) (cipher.Block, error) { panic("cryptobackend: not available") }
 +
 +func NewTripleDESCipher(key []byte) (cipher.Block, error) { panic("cryptobackend: not available") }
++
++func SupportsRC4() bool { panic("cryptobackend: not available") }
++
++type RC4Cipher struct{}
++
++func (c *RC4Cipher) Reset()                       { panic("cryptobackend: not available") }
++func (c *RC4Cipher) XORKeyStream(dst, src []byte) { panic("cryptobackend: not available") }
++
++func NewRC4Cipher(key []byte) (*RC4Cipher, error) { panic("cryptobackend: not available") }
 diff --git a/src/crypto/internal/backend/norequirefips.go b/src/crypto/internal/backend/norequirefips.go
 new file mode 100644
 index 00000000000000..26bfb5f6a643f3
@@ -642,6 +652,63 @@ index 40fce36314adfa..1d6231ae91d5ae 100644
  	"errors"
  	"io"
  	"os"
+diff --git a/src/crypto/rc4/rc4.go b/src/crypto/rc4/rc4.go
+index f08da0e469cd07..b3e7db0413ed72 100644
+--- a/src/crypto/rc4/rc4.go
++++ b/src/crypto/rc4/rc4.go
+@@ -11,6 +11,7 @@ package rc4
+
+ import (
+ 	"crypto/internal/alias"
++	boring "crypto/internal/backend"
+ 	"strconv"
+ )
+
+@@ -18,6 +19,8 @@ import (
+ type Cipher struct {
+ 	s    [256]uint32
+ 	i, j uint8
++
++	boring *boring.RC4Cipher
+ }
+
+ type KeySizeError int
+@@ -33,6 +36,13 @@ func NewCipher(key []byte) (*Cipher, error) {
+ 	if k < 1 || k > 256 {
+ 		return nil, KeySizeError(k)
+ 	}
++	if boring.Enabled && boring.SupportsRC4() {
++		c, err := boring.NewRC4Cipher(key)
++		if err != nil {
++			return nil, err
++		}
++		return &Cipher{boring: c}, nil
++	}
+ 	var c Cipher
+ 	for i := 0; i < 256; i++ {
+ 		c.s[i] = uint32(i)
+@@ -50,6 +60,10 @@ func NewCipher(key []byte) (*Cipher, error) {
+ // Deprecated: Reset can't guarantee that the key will be entirely removed from
+ // the process's memory.
+ func (c *Cipher) Reset() {
++	if boring.Enabled && boring.SupportsRC4() {
++		c.boring.Reset()
++		return
++	}
+ 	for i := range c.s {
+ 		c.s[i] = 0
+ 	}
+@@ -59,6 +73,10 @@ func (c *Cipher) Reset() {
+ // XORKeyStream sets dst to the result of XORing src with the key stream.
+ // Dst and src must overlap entirely or not at all.
+ func (c *Cipher) XORKeyStream(dst, src []byte) {
++	if boring.Enabled && boring.SupportsRC4() {
++		c.boring.XORKeyStream(dst, src)
++		return
++	}
+ 	if len(src) == 0 {
+ 		return
+ 	}
 diff --git a/src/crypto/rsa/boring.go b/src/crypto/rsa/boring.go
 index b9f9d3154f2589..ecb43aaf264743 100644
 --- a/src/crypto/rsa/boring.go

diff --git a/patches/0003-Add-BoringSSL-crypto-backend.patch b/patches/0003-Add-BoringSSL-crypto-backend.patch
@@ -5,8 +5,8 @@ Subject: [PATCH] Add BoringSSL crypto backend
 
 ---
  .../internal/backend/bbig/big_boring.go       |  12 ++
- src/crypto/internal/backend/boring_linux.go   | 175 ++++++++++++++++++
- 2 files changed, 187 insertions(+)
+ src/crypto/internal/backend/boring_linux.go   | 186 ++++++++++++++++++
+ 2 files changed, 198 insertions(+)
  create mode 100644 src/crypto/internal/backend/bbig/big_boring.go
  create mode 100644 src/crypto/internal/backend/boring_linux.go
 
@@ -30,10 +30,10 @@ index 00000000000000..0b62cef68546d0
 +var Dec = bbig.Dec
 diff --git a/src/crypto/internal/backend/boring_linux.go b/src/crypto/internal/backend/boring_linux.go
 new file mode 100644
-index 00000000000000..bc5c54b02acf2f
+index 00000000000000..af2d4b857df333
 --- /dev/null
 +++ b/src/crypto/internal/backend/boring_linux.go
-@@ -0,0 +1,175 @@
+@@ -0,0 +1,186 @@
 +// Copyright 2017 The Go Authors. All rights reserved.
 +// Use of this source code is governed by a BSD-style
 +// license that can be found in the LICENSE file.
@@ -209,3 +209,14 @@ index 00000000000000..bc5c54b02acf2f
 +func NewTripleDESCipher(key []byte) (cipher.Block, error) {
 +	panic("cryptobackend: not available")
 +}
++
++func SupportsRC4() bool { return false }
++
++type RC4Cipher struct{}
++
++func (c *RC4Cipher) Reset()                       { panic("cryptobackend: not available") }
++func (c *RC4Cipher) XORKeyStream(dst, src []byte) { panic("cryptobackend: not available") }
++
++func NewRC4Cipher(key []byte) (*RC4Cipher, error) {
++	panic("cryptobackend: not available")
++}
diff --git a/patches/0004-Add-OpenSSL-crypto-backend.patch b/patches/0004-Add-OpenSSL-crypto-backend.patch
@@ -14,7 +14,7 @@ Subject: [PATCH] Add OpenSSL crypto backend
  src/crypto/ecdsa/notboring.go                 |   2 +-
  src/crypto/internal/backend/bbig/big.go       |   2 +-
  .../internal/backend/bbig/big_openssl.go      |  12 +
- src/crypto/internal/backend/openssl_linux.go  | 279 ++++++++++++++++++
+ src/crypto/internal/backend/openssl_linux.go  | 287 ++++++++++++++++++
  src/crypto/internal/boring/fipstls/stub.s     |   2 +-
  src/crypto/internal/boring/fipstls/tls.go     |   2 +-
  src/crypto/rsa/boring.go                      |   2 +-
@@ -37,7 +37,7 @@ Subject: [PATCH] Add OpenSSL crypto backend
  .../goexperiment/exp_opensslcrypto_on.go      |   9 +
  src/internal/goexperiment/flags.go            |   1 +
  src/os/exec/exec_test.go                      |   9 +
- 33 files changed, 361 insertions(+), 23 deletions(-)
+ 33 files changed, 369 insertions(+), 23 deletions(-)
  create mode 100644 src/crypto/internal/backend/bbig/big_openssl.go
  create mode 100644 src/crypto/internal/backend/openssl_linux.go
  create mode 100644 src/internal/goexperiment/exp_opensslcrypto_off.go
@@ -190,10 +190,10 @@ index 00000000000000..e6695dd66b1d02
 +var Dec = bbig.Dec
 diff --git a/src/crypto/internal/backend/openssl_linux.go b/src/crypto/internal/backend/openssl_linux.go
 new file mode 100644
-index 00000000000000..d342e4b0f11e23
+index 00000000000000..ff02e561452aa3
 --- /dev/null
 +++ b/src/crypto/internal/backend/openssl_linux.go
-@@ -0,0 +1,279 @@
+@@ -0,0 +1,287 @@
 +// Copyright 2017 The Go Authors. All rights reserved.
 +// Use of this source code is governed by a BSD-style
 +// license that can be found in the LICENSE file.
@@ -322,14 +322,14 @@ index 00000000000000..d342e4b0f11e23
 +	return openssl.SupportsHash(h)
 +}
 +
-+func NewMD5() hash.Hash   { return openssl.NewMD5() }
++func NewMD5() hash.Hash    { return openssl.NewMD5() }
 +func NewSHA1() hash.Hash   { return openssl.NewSHA1() }
 +func NewSHA224() hash.Hash { return openssl.NewSHA224() }
 +func NewSHA256() hash.Hash { return openssl.NewSHA256() }
 +func NewSHA384() hash.Hash { return openssl.NewSHA384() }
 +func NewSHA512() hash.Hash { return openssl.NewSHA512() }
 +
-+func MD5(p []byte) (sum [16]byte)   { return openssl.MD5(p) }
++func MD5(p []byte) (sum [16]byte)    { return openssl.MD5(p) }
 +func SHA1(p []byte) (sum [20]byte)   { return openssl.SHA1(p) }
 +func SHA224(p []byte) (sum [28]byte) { return openssl.SHA224(p) }
 +func SHA256(p []byte) (sum [32]byte) { return openssl.SHA256(p) }
@@ -473,6 +473,14 @@ index 00000000000000..d342e4b0f11e23
 +func NewTripleDESCipher(key []byte) (cipher.Block, error) {
 +	return openssl.NewTripleDESCipher(key)
 +}
++
++func SupportsRC4() bool {
++	return openssl.SupportsRC4()
++}
++
++type RC4Cipher = openssl.RC4Cipher
++
++func NewRC4Cipher(key []byte) (*RC4Cipher, error) { return openssl.NewRC4Cipher(key) }
 diff --git a/src/crypto/internal/boring/fipstls/stub.s b/src/crypto/internal/boring/fipstls/stub.s
 index f2e5a503eaacb6..1dc7116efdff2e 100644
 --- a/src/crypto/internal/boring/fipstls/stub.s
@@ -669,24 +677,24 @@ index c83a7272c9f01f..a0548a7f9179c5 100644
  package x509
 
 diff --git a/src/go.mod b/src/go.mod
-index 8f7dd5c0b69932..b5222cd4fb66b3 100644
+index 8f7dd5c0b69932..0a9f28adb67211 100644
 --- a/src/go.mod
 +++ b/src/go.mod
 @@ -3,6 +3,7 @@ module std
  go 1.22
 
  require (
-+	github.com/golang-fips/openssl/v2 v2.0.0-rc.3.0.20230926133027-251d5fd9efa6
++	github.com/golang-fips/openssl/v2 v2.0.0-rc.3.0.20231013091736-92d3f16e56cd
  	golang.org/x/crypto v0.14.0
  	golang.org/x/net v0.17.0
  )
 diff --git a/src/go.sum b/src/go.sum
-index 22511da608a07b..2e071695221e13 100644
+index 22511da608a07b..afa147f35171de 100644
 --- a/src/go.sum
 +++ b/src/go.sum
 @@ -1,3 +1,5 @@
-+github.com/golang-fips/openssl/v2 v2.0.0-rc.3.0.20230926133027-251d5fd9efa6 h1:htngJbDceHA29WbezaO55msU/iITDkdto1p1iHHmjC0=
-+github.com/golang-fips/openssl/v2 v2.0.0-rc.3.0.20230926133027-251d5fd9efa6/go.mod h1:7tuBqX2Zov8Yq5mJ2yzlKhpnxOnWyEzi38AzeWRuQdg=
++github.com/golang-fips/openssl/v2 v2.0.0-rc.3.0.20231013091736-92d3f16e56cd h1:+SvJEqhqQ8d/wzyk+xmTgBpHDOYQtnS/F8283hznEAc=
++github.com/golang-fips/openssl/v2 v2.0.0-rc.3.0.20231013091736-92d3f16e56cd/go.mod h1:7tuBqX2Zov8Yq5mJ2yzlKhpnxOnWyEzi38AzeWRuQdg=
  golang.org/x/crypto v0.14.0 h1:wBqGXzWJW6m1XrIKlAH0Hs1JJ7+9KBwnIO8v66Q9cHc=
  golang.org/x/crypto v0.14.0/go.mod h1:MVFd36DqK4CsrnJYDkBA3VC4m2GkXAM0PvzMCn4JQf4=
  golang.org/x/net v0.17.0 h1:pVaXccu2ozPjCXewfr1S7xza/zcXTity9cCdXQYSjIM=