dep: update crypto. info: https://golangtutorial.dev/news/fix-in-crypto-package/ (#14078)

go.mod

@@ -104,7 +104,7 @@ require (
 	github.com/yuin/goldmark-meta v0.0.0-20191126180153-f0638e958b60
 	go.jolheiser.com/hcaptcha v0.0.4
 	go.jolheiser.com/pwn v0.0.3
-	golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a
+	golang.org/x/crypto v0.0.0-20201217014255-9d1352758620
 	golang.org/x/net v0.0.0-20200904194848-62affa334b73
 	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d
 	golang.org/x/sys v0.0.0-20200918174421-af09f7315aff

go.sum

@@ -939,6 +939,8 @@ golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPh
 golang.org/x/crypto v0.0.0-20200709230013-948cd5f35899/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a h1:vclmkQCjlDX5OydZ9wv8rBCcS0QyQY66Mpf/7BZbInM=
 golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/crypto v0.0.0-20201217014255-9d1352758620 h1:3wPMTskHO3+O6jqTEXyFcsnuxMQOqYSaHsDxcbUXpqA=
+golang.org/x/crypto v0.0.0-20201217014255-9d1352758620/go.mod h1:jdWPYTVW3xRLrWPugEBEK3UY2ZEsg3UU495nc5E+M+I=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20190510132918-efd6b22b2522/go.mod h1:ZjyILWgesfNpC6sMxTJOJm9Kp84zZh5NQWvqDGG3Qr8=
@@ -1053,6 +1055,8 @@ golang.org/x/sys v0.0.0-20200413165638-669c56c373c4/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200625212154-ddb9806d33ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200918174421-af09f7315aff h1:1CPUrky56AcgSpxz/KfgzQWzfG09u5YOL8MvPYBlrL8=
 golang.org/x/sys v0.0.0-20200918174421-af09f7315aff/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/term v0.0.0-20201117132131-f5c789dd3221 h1:/ZHdbVpdR/jk3g30/d4yUL0JU9kksj8+F/bnQUVLGDM=
+golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.1-0.20180807135948-17ff2d5776d2/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
@@ -1197,6 +1201,7 @@ honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWh
 honnef.co/go/tools v0.0.0-20190418001031-e561f6794a2a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
 honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=
+mvdan.cc/xurls/v2 v2.2.0 h1:NSZPykBXJFCetGZykLAxaL6SIpvbVy/UFEniIfHAa8A=
 mvdan.cc/xurls/v2 v2.2.0/go.mod h1:EV1RMtya9D6G5DMYPGD8zTQzaHet6Jh8gFlRgGRJeO8=
 rsc.io/binaryregexp v0.2.0/go.mod h1:qTv7/COck+e2FymRvadv62gMdZztPaShugOCi3I+8D8=
 strk.kbt.io/projects/go/libravatar v0.0.0-20191008002943-06d1c002b251 h1:mUcz5b3FJbP5Cvdq7Khzn6J9OCUQJaBwgBkCR+MOwSs=

vendor/golang.org/x/crypto/acme/acme.go

@@ -363,6 +363,10 @@ func AcceptTOS(tosURL string) bool { return true }
 // Also see Error's Instance field for when a CA requires already registered accounts to agree
 // to an updated Terms of Service.
 func (c *Client) Register(ctx context.Context, acct *Account, prompt func(tosURL string) bool) (*Account, error) {
+	if c.Key == nil {
+		return nil, errors.New("acme: client.Key must be set to Register")
+	}
+
 	dir, err := c.Discover(ctx)
 	if err != nil {
 		return nil, err

vendor/golang.org/x/crypto/acme/jws.go

@@ -7,17 +7,31 @@ package acme
 import (
 	"crypto"
 	"crypto/ecdsa"
+	"crypto/hmac"
 	"crypto/rand"
 	"crypto/rsa"
 	"crypto/sha256"
+	"crypto/sha512"
 	_ "crypto/sha512" // need for EC keys
 	"encoding/asn1"
 	"encoding/base64"
 	"encoding/json"
+	"errors"
 	"fmt"
+	"hash"
 	"math/big"
 )
 
+// MACAlgorithm represents a JWS MAC signature algorithm.
+// See https://tools.ietf.org/html/rfc7518#section-3.1 for more details.
+type MACAlgorithm string
+
+const (
+	MACAlgorithmHS256 = MACAlgorithm("HS256")
+	MACAlgorithmHS384 = MACAlgorithm("HS384")
+	MACAlgorithmHS512 = MACAlgorithm("HS512")
+)
+
 // keyID is the account identity provided by a CA during registration.
 type keyID string
 
@@ -31,6 +45,14 @@ const noKeyID = keyID("")
 // See https://tools.ietf.org/html/rfc8555#section-6.3 for more details.
 const noPayload = ""
 
+// jsonWebSignature can be easily serialized into a JWS following
+// https://tools.ietf.org/html/rfc7515#section-3.2.
+type jsonWebSignature struct {
+	Protected string `json:"protected"`
+	Payload   string `json:"payload"`
+	Sig       string `json:"signature"`
+}
+
 // jwsEncodeJSON signs claimset using provided key and a nonce.
 // The result is serialized in JSON format containing either kid or jwk
 // fields based on the provided keyID value.
@@ -71,12 +93,7 @@ func jwsEncodeJSON(claimset interface{}, key crypto.Signer, kid keyID, nonce, ur
 	if err != nil {
 		return nil, err
 	}
-
+	enc := jsonWebSignature{
-	enc := struct {
-		Protected string `json:"protected"`
-		Payload   string `json:"payload"`
-		Sig       string `json:"signature"`
-	}{
 		Protected: phead,
 		Payload:   payload,
 		Sig:       base64.RawURLEncoding.EncodeToString(sig),
@@ -84,6 +101,32 @@ func jwsEncodeJSON(claimset interface{}, key crypto.Signer, kid keyID, nonce, ur
 	return json.Marshal(&enc)
 }
 
+// jwsWithMAC creates and signs a JWS using the given key and algorithm.
+// "rawProtected" and "rawPayload" should not be base64-URL-encoded.
+func jwsWithMAC(key []byte, alg MACAlgorithm, rawProtected, rawPayload []byte) (*jsonWebSignature, error) {
+	if len(key) == 0 {
+		return nil, errors.New("acme: cannot sign JWS with an empty MAC key")
+	}
+	protected := base64.RawURLEncoding.EncodeToString(rawProtected)
+	payload := base64.RawURLEncoding.EncodeToString(rawPayload)
+
+	// Only HMACs are currently supported.
+	hmac, err := newHMAC(key, alg)
+	if err != nil {
+		return nil, err
+	}
+	if _, err := hmac.Write([]byte(protected + "." + payload)); err != nil {
+		return nil, err
+	}
+	mac := hmac.Sum(nil)
+
+	return &jsonWebSignature{
+		Protected: protected,
+		Payload:   payload,
+		Sig:       base64.RawURLEncoding.EncodeToString(mac),
+	}, nil
+}
+
 // jwkEncode encodes public part of an RSA or ECDSA key into a JWK.
 // The result is also suitable for creating a JWK thumbprint.
 // https://tools.ietf.org/html/rfc7517
@@ -175,6 +218,20 @@ func jwsHasher(pub crypto.PublicKey) (string, crypto.Hash) {
 	return "", 0
 }
 
+// newHMAC returns an appropriate HMAC for the given MACAlgorithm.
+func newHMAC(key []byte, alg MACAlgorithm) (hash.Hash, error) {
+	switch alg {
+	case MACAlgorithmHS256:
+		return hmac.New(sha256.New, key), nil
+	case MACAlgorithmHS384:
+		return hmac.New(sha512.New384, key), nil
+	case MACAlgorithmHS512:
+		return hmac.New(sha512.New, key), nil
+	default:
+		return nil, fmt.Errorf("acme: unsupported MAC algorithm: %v", alg)
+	}
+}
+
 // JWKThumbprint creates a JWK thumbprint out of pub
 // as specified in https://tools.ietf.org/html/rfc7638.
 func JWKThumbprint(pub crypto.PublicKey) (string, error) {

vendor/golang.org/x/crypto/acme/rfc8555.go

@@ -5,6 +5,7 @@
 package acme
 
 import (
+	"bytes"
 	"context"
 	"crypto"
 	"encoding/base64"
@@ -37,9 +38,8 @@ func (c *Client) DeactivateReg(ctx context.Context) error {
 	return nil
 }
 
-// registerRFC is quivalent to c.Register but for CAs implementing RFC 8555.
+// registerRFC is equivalent to c.Register but for CAs implementing RFC 8555.
 // It expects c.Discover to have already been called.
-// TODO: Implement externalAccountBinding.
 func (c *Client) registerRFC(ctx context.Context, acct *Account, prompt func(tosURL string) bool) (*Account, error) {
 	c.cacheMu.Lock() // guard c.kid access
 	defer c.cacheMu.Unlock()
@@ -47,12 +47,23 @@ func (c *Client) registerRFC(ctx context.Context, acct *Account, prompt func(tos
 	req := struct {
 		TermsAgreed            bool              `json:"termsOfServiceAgreed,omitempty"`
 		Contact                []string          `json:"contact,omitempty"`
+		ExternalAccountBinding *jsonWebSignature `json:"externalAccountBinding,omitempty"`
 	}{
 		Contact: acct.Contact,
 	}
 	if c.dir.Terms != "" {
 		req.TermsAgreed = prompt(c.dir.Terms)
 	}
+
+	// set 'externalAccountBinding' field if requested
+	if acct.ExternalAccountBinding != nil {
+		eabJWS, err := c.encodeExternalAccountBinding(acct.ExternalAccountBinding)
+		if err != nil {
+			return nil, fmt.Errorf("acme: failed to encode external account binding: %v", err)
+		}
+		req.ExternalAccountBinding = eabJWS
+	}
+
 	res, err := c.post(ctx, c.Key, c.dir.RegURL, req, wantStatus(
 		http.StatusOK,      // account with this key already registered
 		http.StatusCreated, // new account created
@@ -75,7 +86,19 @@ func (c *Client) registerRFC(ctx context.Context, acct *Account, prompt func(tos
 	return a, nil
 }
 
-// updateGegRFC is equivalent to c.UpdateReg but for CAs implementing RFC 8555.
+// encodeExternalAccountBinding will encode an external account binding stanza
+// as described in https://tools.ietf.org/html/rfc8555#section-7.3.4.
+func (c *Client) encodeExternalAccountBinding(eab *ExternalAccountBinding) (*jsonWebSignature, error) {
+	jwk, err := jwkEncode(c.Key.Public())
+	if err != nil {
+		return nil, err
+	}
+	var rProtected bytes.Buffer
+	fmt.Fprintf(&rProtected, `{"alg":%q,"kid":%q,"url":%q}`, eab.Algorithm, eab.KID, c.dir.RegURL)
+	return jwsWithMAC(eab.Key, eab.Algorithm, rProtected.Bytes(), []byte(jwk))
+}
+
+// updateRegRFC is equivalent to c.UpdateReg but for CAs implementing RFC 8555.
 // It expects c.Discover to have already been called.
 func (c *Client) updateRegRFC(ctx context.Context, a *Account) (*Account, error) {
 	url := string(c.accountKID(ctx))

vendor/golang.org/x/crypto/acme/types.go

@@ -199,6 +199,31 @@ type Account struct {
 	//
 	// It is non-RFC 8555 compliant and is obsoleted by OrdersURL.
 	Certificates string
+
+	// ExternalAccountBinding represents an arbitrary binding to an account of
+	// the CA which the ACME server is tied to.
+	// See https://tools.ietf.org/html/rfc8555#section-7.3.4 for more details.
+	ExternalAccountBinding *ExternalAccountBinding
+}
+
+// ExternalAccountBinding contains the data needed to form a request with
+// an external account binding.
+// See https://tools.ietf.org/html/rfc8555#section-7.3.4 for more details.
+type ExternalAccountBinding struct {
+	// KID is the Key ID of the symmetric MAC key that the CA provides to
+	// identify an external account from ACME.
+	KID string
+
+	// Key is the bytes of the symmetric key that the CA provides to identify
+	// the account. Key must correspond to the KID.
+	Key []byte
+
+	// Algorithm used to sign the JWS.
+	Algorithm MACAlgorithm
+}
+
+func (e *ExternalAccountBinding) String() string {
+	return fmt.Sprintf("&{KID: %q, Key: redacted, Algorithm: %v}", e.KID, e.Algorithm)
 }
 
 // Directory is ACME server discovery data.

vendor/golang.org/x/crypto/argon2/blamka_amd64.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build amd64,!gccgo,!appengine
+// +build amd64,gc,!purego
 
 package argon2
 

vendor/golang.org/x/crypto/argon2/blamka_amd64.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build amd64,!gccgo,!appengine
+// +build amd64,gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/argon2/blamka_ref.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !amd64 appengine gccgo
+// +build !amd64 purego !gc
 
 package argon2
 

vendor/golang.org/x/crypto/blake2b/blake2bAVX2_amd64.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build go1.7,amd64,!gccgo,!appengine
+// +build go1.7,amd64,gc,!purego
 
 package blake2b
 

vendor/golang.org/x/crypto/blake2b/blake2bAVX2_amd64.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build go1.7,amd64,!gccgo,!appengine
+// +build go1.7,amd64,gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/blake2b/blake2b_amd64.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !go1.7,amd64,!gccgo,!appengine
+// +build !go1.7,amd64,gc,!purego
 
 package blake2b
 

vendor/golang.org/x/crypto/blake2b/blake2b_amd64.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build amd64,!gccgo,!appengine
+// +build amd64,gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/blake2b/blake2b_ref.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !amd64 appengine gccgo
+// +build !amd64 purego !gc
 
 package blake2b
 

vendor/golang.org/x/crypto/chacha20/chacha_arm64.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build go1.11,!gccgo,!purego
+// +build go1.11,gc,!purego
 
 package chacha20
 

vendor/golang.org/x/crypto/chacha20/chacha_arm64.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build go1.11,!gccgo,!purego
+// +build go1.11,gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/chacha20/chacha_noasm.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !arm64,!s390x,!ppc64le arm64,!go1.11 gccgo purego
+// +build !arm64,!s390x,!ppc64le arm64,!go1.11 !gc purego
 
 package chacha20
 

vendor/golang.org/x/crypto/chacha20/chacha_ppc64le.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !gccgo,!purego
+// +build gc,!purego
 
 package chacha20
 

vendor/golang.org/x/crypto/chacha20/chacha_ppc64le.s

@@ -19,7 +19,7 @@
 // The differences in this and the original implementation are
 // due to the calling conventions and initialization of constants.
 
-// +build !gccgo,!purego
+// +build gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/chacha20/chacha_s390x.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !gccgo,!purego
+// +build gc,!purego
 
 package chacha20
 

vendor/golang.org/x/crypto/chacha20/chacha_s390x.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !gccgo,!purego
+// +build gc,!purego
 
 #include "go_asm.h"
 #include "textflag.h"

vendor/golang.org/x/crypto/curve25519/curve25519_amd64.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build amd64,!gccgo,!appengine,!purego
+// +build amd64,gc,!purego
 
 package curve25519
 

vendor/golang.org/x/crypto/curve25519/curve25519_amd64.s

@@ -5,7 +5,7 @@
 // This code was translated into a form compatible with 6a from the public
 // domain sources in SUPERCOP: https://bench.cr.yp.to/supercop.html
 
-// +build amd64,!gccgo,!appengine,!purego
+// +build amd64,gc,!purego
 
 #define REDMASK51     0x0007FFFFFFFFFFFF
 

vendor/golang.org/x/crypto/curve25519/curve25519_noasm.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !amd64 gccgo appengine purego
+// +build !amd64 !gc purego
 
 package curve25519
 

vendor/golang.org/x/crypto/internal/subtle/aliasing.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !appengine
+// +build !purego
 
 // Package subtle implements functions that are often useful in cryptographic
 // code but require careful thought to use correctly.

vendor/golang.org/x/crypto/internal/subtle/aliasing_purego.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build appengine
+// +build purego
 
 // Package subtle implements functions that are often useful in cryptographic
 // code but require careful thought to use correctly.

vendor/golang.org/x/crypto/poly1305/mac_noasm.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !amd64,!ppc64le,!s390x gccgo purego
+// +build !amd64,!ppc64le,!s390x !gc purego
 
 package poly1305
 

vendor/golang.org/x/crypto/poly1305/sum_amd64.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !gccgo,!purego
+// +build gc,!purego
 
 package poly1305
 

vendor/golang.org/x/crypto/poly1305/sum_amd64.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !gccgo,!purego
+// +build gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/poly1305/sum_ppc64le.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !gccgo,!purego
+// +build gc,!purego
 
 package poly1305
 

vendor/golang.org/x/crypto/poly1305/sum_ppc64le.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !gccgo,!purego
+// +build gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/poly1305/sum_s390x.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !gccgo,!purego
+// +build gc,!purego
 
 package poly1305
 

vendor/golang.org/x/crypto/poly1305/sum_s390x.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !gccgo,!purego
+// +build gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/ssh/client_auth.go

@@ -471,7 +471,7 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe
 		}
 
 		if len(answers) != len(prompts) {
-			return authFailure, nil, errors.New("ssh: not enough answers from keyboard-interactive callback")
+			return authFailure, nil, fmt.Errorf("ssh: incorrect number of answers from keyboard-interactive callback %d (expected %d)", len(answers), len(prompts))
 		}
 		responseLength := 1 + 4
 		for _, a := range answers {

vendor/golang.org/x/crypto/ssh/kex.go

@@ -557,8 +557,6 @@ type dhGEXSHA struct {
 	hashFunc crypto.Hash
 }
 
-const numMRTests = 64
-
 const (
 	dhGroupExchangeMinimumBits   = 2048
 	dhGroupExchangePreferredBits = 2048
@@ -602,15 +600,8 @@ func (gex dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshake
 	gex.p = kexDHGexGroup.P
 	gex.g = kexDHGexGroup.G
 
-	// Check if p is safe by verifing that p and (p-1)/2 are primes
-	one := big.NewInt(1)
-	var pHalf = &big.Int{}
-	pHalf.Rsh(gex.p, 1)
-	if !gex.p.ProbablyPrime(numMRTests) || !pHalf.ProbablyPrime(numMRTests) {
-		return nil, fmt.Errorf("ssh: server provided gex p is not safe")
-	}
-
 	// Check if g is safe by verifing that g > 1 and g < p - 1
+	one := big.NewInt(1)
 	var pMinusOne = &big.Int{}
 	pMinusOne.Sub(gex.p, one)
 	if gex.g.Cmp(one) != 1 && gex.g.Cmp(pMinusOne) != -1 {
@@ -618,6 +609,8 @@ func (gex dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshake
 	}
 
 	// Send GexInit
+	var pHalf = &big.Int{}
+	pHalf.Rsh(gex.p, 1)
 	x, err := rand.Int(randSource, pHalf)
 	if err != nil {
 		return nil, err

vendor/golang.org/x/crypto/ssh/server.go

@@ -572,6 +572,10 @@ userAuthLoop:
 				perms = candidate.perms
 			}
 		case "gssapi-with-mic":
+			if config.GSSAPIWithMICConfig == nil {
+				authErr = errors.New("ssh: gssapi-with-mic auth not configured")
+				break
+			}
 			gssapiConfig := config.GSSAPIWithMICConfig
 			userAuthRequestGSSAPI, err := parseGSSAPIPayload(userAuthReq.Payload)
 			if err != nil {

vendor/modules.txt

@@ -778,7 +778,7 @@ go.mongodb.org/mongo-driver/bson/bsonrw
 go.mongodb.org/mongo-driver/bson/bsontype
 go.mongodb.org/mongo-driver/bson/primitive
 go.mongodb.org/mongo-driver/x/bsonx/bsoncore
-# golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a
+# golang.org/x/crypto v0.0.0-20201217014255-9d1352758620
 ## explicit
 golang.org/x/crypto/acme
 golang.org/x/crypto/acme/autocert