Fix err nil deref

Update ssh and garble

Dockerfile

@@ -1,3 +1,12 @@
+#
+# For production:
+#   docker build --target production -t sliver .
+#   docker run -it --rm -v $HOME/.sliver:/home/sliver/.sliver sliver 
+#
+# For unit testing:
+#   docker build --target test .
+#
+
 # STAGE: base
 ## Compiles Sliver for use
 FROM --platform=linux/amd64 golang:1.21.4 as base
@@ -22,25 +31,10 @@ RUN cp -vv sliver-server /opt/sliver-server
 ## Use `--target test` in the docker build command to run this stage
 FROM --platform=linux/amd64 base as test
 
-### Install testing packages
-RUN apt-get update --fix-missing && apt-get -y install \
-    libxml2 libxml2-dev libxslt-dev locate curl \
-    libreadline6-dev libcurl4-openssl-dev git-core \
-    libssl-dev libyaml-dev openssl autoconf libtool \
-    ncurses-dev bison curl xsel postgresql \
-    postgresql-contrib postgresql-client libpq-dev \
-    libapr1 libaprutil1 libsvn1 \
-    libpcap-dev libsqlite3-dev libgmp3-dev \
-    mingw-w64 binutils-mingw-w64 g++-mingw-w64 \
-    nasm gcc-multilib
-
-### Install MSF for testing
-RUN curl https://raw.githubusercontent.com/rapid7/metasploit-omnibus/master/config/templates/metasploit-framework-wrappers/msfupdate.erb > msfinstall \
-    && chmod 755 msfinstall \
-    && ./msfinstall
-RUN mkdir -p ~/.msf4/ \
-    && touch ~/.msf4/initial_setup_complete \
-    && su -l sliver -c 'mkdir -p ~/.msf4/ && touch ~/.msf4/initial_setup_complete'
+RUN apt-get update --fix-missing \
+    && apt-get -y upgrade \
+    && apt-get -y install \
+    curl gcc-multilib build-essential mingw-w64 binutils-mingw-w64 g++-mingw-w64 
 
 RUN /opt/sliver-server unpack --force 
 
@@ -51,17 +45,81 @@ RUN /go/src/github.com/bishopfox/sliver/go-tests.sh
 ## Final dockerized form of Sliver
 FROM --platform=linux/amd64 debian:bookworm-slim as production
 
+### Install production packages
+RUN apt-get update --fix-missing \
+    && apt-get -y upgrade \
+    && apt-get -y install \
+    libxml2 libxml2-dev libxslt-dev locate gnupg \
+    libreadline6-dev libcurl4-openssl-dev git-core \
+    libssl-dev libyaml-dev openssl autoconf libtool \
+    ncurses-dev bison curl xsel postgresql \
+    postgresql-contrib postgresql-client libpq-dev \
+    curl libapr1 libaprutil1 libsvn1 \
+    libpcap-dev libsqlite3-dev libgmp3-dev \
+    mingw-w64 binutils-mingw-w64 g++-mingw-w64 \
+    nasm gcc-multilib
+
+### Install MSF for stager generation
+RUN curl https://raw.githubusercontent.com/rapid7/metasploit-omnibus/master/config/templates/metasploit-framework-wrappers/msfupdate.erb > msfinstall \
+    && chmod 755 msfinstall \
+    && ./msfinstall \
+    && mkdir -p ~/.msf4/ \
+    && touch ~/.msf4/initial_setup_complete 
+
+### Cleanup unneeded packages
+RUN apt-get remove -y curl gnupg \
+    && apt-get autoremove -y \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
+### Add sliver user
+RUN groupadd -g 999 sliver \
+    && useradd -r -u 999 -g sliver sliver \
+    && mkdir -p /home/sliver/ \
+    && chown -R sliver:sliver /home/sliver \
+    && su -l sliver -c 'mkdir -p ~/.msf4/ && touch ~/.msf4/initial_setup_complete'
+
 ### Copy compiled binary
 COPY --from=base /opt/sliver-server  /opt/sliver-server
 
-### Add sliver user
-RUN groupadd -g 999 sliver && useradd -r -u 999 -g sliver sliver
-RUN mkdir -p /home/sliver/ && chown -R sliver:sliver /home/sliver
-
 ### Unpack Sliver:
+USER sliver
+RUN /opt/sliver-server unpack --force 
+
+WORKDIR /home/sliver/
+VOLUME [ "/home/sliver/.sliver" ]
+ENTRYPOINT [ "/opt/sliver-server" ]
+
+
+# STAGE: production-slim (about 1Gb smaller)
+### Slim production image, i.e. without MSF and assoicated libraries
+### Still include GCC and MinGW for cross-platform generation
+FROM --platform=linux/amd64 debian:bookworm-slim as production-slim
+
+### Install production packages
+RUN apt-get update --fix-missing \
+    && apt-get -y upgrade \
+    && apt-get -y install \
+    build-essential mingw-w64 binutils-mingw-w64 g++-mingw-w64 gcc-multilib
+
+### Cleanup unneeded packages
+RUN apt-get autoremove -y \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+
+### Add sliver user
+RUN groupadd -g 999 sliver \
+    && useradd -r -u 999 -g sliver sliver \
+    && mkdir -p /home/sliver/ \
+    && chown -R sliver:sliver /home/sliver
+
+### Copy compiled binary
+COPY --from=base /opt/sliver-server  /opt/sliver-server
+
+### Unpack Sliver:
+USER sliver
 RUN /opt/sliver-server unpack --force 
 
-USER sliver
 WORKDIR /home/sliver/
 VOLUME [ "/home/sliver/.sliver" ]
 ENTRYPOINT [ "/opt/sliver-server" ]

go-assets.sh

@@ -21,7 +21,7 @@ set -e
 # Creates the static go asset archives
 
 GO_VER="1.21.4"
-GARBLE_VER="1.21.4a"
+GARBLE_VER="1.21.4b"
 SGN_VER="0.0.3"
 
 BLOAT_FILES="AUTHORS CONTRIBUTORS PATENTS VERSION favicon.ico robots.txt SECURITY.md CONTRIBUTING.md LICENSE README.md ./doc ./test ./api ./misc"

go.mod

@@ -45,7 +45,7 @@ require (
 	github.com/things-go/go-socks5 v0.0.3
 	github.com/xlab/treeprint v1.2.0
 	github.com/yiya1989/sshkrb5 v0.0.0-20201110125252-a1455b75a35e
-	golang.org/x/crypto v0.14.0
+	golang.org/x/crypto v0.15.0
 	golang.org/x/exp v0.0.0-20230905200255-921286631fa9
 	golang.org/x/net v0.17.0
 	golang.org/x/sys v0.14.0

go.sum

@@ -448,6 +448,8 @@ golang.org/x/crypto v0.0.0-20211108221036-ceb1ce70b4fa/go.mod h1:GvvjBRRGRdwPK5y
 golang.org/x/crypto v0.0.0-20220208050332-20e1d8d225ab/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
 golang.org/x/crypto v0.14.0 h1:wBqGXzWJW6m1XrIKlAH0Hs1JJ7+9KBwnIO8v66Q9cHc=
 golang.org/x/crypto v0.14.0/go.mod h1:MVFd36DqK4CsrnJYDkBA3VC4m2GkXAM0PvzMCn4JQf4=
+golang.org/x/crypto v0.15.0 h1:frVn1TEaCEaZcn3Tmd7Y2b5KKPaZ+I32Q2OA3kYp5TA=
+golang.org/x/crypto v0.15.0/go.mod h1:4ChreQoLWfG3xLDer1WdlH5NdlQ3+mwnQq1YTKY+72g=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20230905200255-921286631fa9 h1:GoHiUyI/Tp2nVkLI2mCxVkOjsbSXD66ic0XW0js0R9g=
 golang.org/x/exp v0.0.0-20230905200255-921286631fa9/go.mod h1:S2oDrQGGwySpoQPVqRShND87VCbxmc6bL1Yd2oYrm6k=

server/c2/jobs.go

@@ -272,7 +272,7 @@ func listenAndServeTLS(srv *http.Server, certPEMBlock, keyPEMBlock []byte) error
 	}
 	config := &tls.Config{}
 	if srv.TLSConfig != nil {
-		*config = *srv.TLSConfig
+		config = srv.TLSConfig
 	}
 	if certs.TLSKeyLogger != nil {
 		config.KeyLogWriter = certs.TLSKeyLogger

server/cli/cli.go

@@ -44,10 +44,11 @@ const (
 	forceFlagStr = "force"
 
 	// Operator flags
-	nameFlagStr  = "name"
-	lhostFlagStr = "lhost"
-	lportFlagStr = "lport"
-	saveFlagStr  = "save"
+	nameFlagStr        = "name"
+	lhostFlagStr       = "lhost"
+	lportFlagStr       = "lport"
+	saveFlagStr        = "save"
+	permissionsFlagStr = "permissions"
 
 	// Cert flags
 	caTypeFlagStr = "type"

server/cli/daemon.go

@@ -71,10 +71,10 @@ var daemonCmd = &cobra.Command{
 	},
 }
 
-func StartPersistentJobs(listenerJobs *[]clientpb.ListenerJob) error {
-	if len(*listenerJobs) > 0 {
+func StartPersistentJobs(listenerJobs []*clientpb.ListenerJob) error {
+	if len(listenerJobs) > 0 {
 		// StartPersistentJobs - Start persistent jobs
-		for _, j := range *listenerJobs {
+		for _, j := range listenerJobs {
 			listenerJob, err := db.ListenerByJobID(j.JobID)
 			if err != nil {
 				return err
@@ -117,7 +117,7 @@ func StartPersistentJobs(listenerJobs *[]clientpb.ListenerJob) error {
 				}
 				j.JobID = uint32(id)
 			}
-			db.UpdateHTTPC2Listener(&j)
+			db.UpdateHTTPC2Listener(j)
 		}
 	}
 

server/cli/operator.go

@@ -33,54 +33,63 @@ var operatorCmd = &cobra.Command{
 	Short: "Generate operator configuration files",
 	Long:  ``,
 	Run: func(cmd *cobra.Command, args []string) {
-
 		name, err := cmd.Flags().GetString(nameFlagStr)
 		if err != nil {
 			fmt.Printf("Failed to parse --%s flag %s", nameFlagStr, err)
-			os.Exit(1)
+			return
 		}
 		if name == "" {
 			fmt.Printf("Must specify --%s", nameFlagStr)
-			os.Exit(1)
+			return
 		}
 
 		lhost, err := cmd.Flags().GetString(lhostFlagStr)
 		if err != nil {
 			fmt.Printf("Failed to parse --%s flag %s", lhostFlagStr, err)
-			os.Exit(1)
+			return
 		}
 		if lhost == "" {
 			fmt.Printf("Must specify --%s", lhostFlagStr)
-			os.Exit(1)
+			return
 		}
 
 		lport, err := cmd.Flags().GetUint16(lportFlagStr)
 		if err != nil {
 			fmt.Printf("Failed to parse --%s flag %s", lportFlagStr, err)
-			os.Exit(1)
+			return
 		}
 
 		save, err := cmd.Flags().GetString(saveFlagStr)
 		if err != nil {
 			fmt.Printf("Failed to parse --%s flag %s", saveFlagStr, err)
-			os.Exit(1)
+			return
 		}
 		if save == "" {
 			save, _ = os.Getwd()
 		}
 
+		permissions, err := cmd.Flags().GetStringSlice(permissionsFlagStr)
+		if err != nil {
+			fmt.Printf("Failed to parse --%s flag %s", permissionsFlagStr, err)
+			return
+		}
+		if len(permissions) == 0 {
+			fmt.Printf("Must specify --%s", permissionsFlagStr)
+			return
+		}
+
 		certs.SetupCAs()
-		configJSON, err := console.NewOperatorConfig(name, lhost, lport)
+		configJSON, err := console.NewOperatorConfig(name, lhost, lport, permissions)
 		if err != nil {
 			fmt.Printf("Failed: %s\n", err)
-			os.Exit(1)
+			return
 		}
 
 		saveTo, _ := filepath.Abs(save)
 		fi, err := os.Stat(saveTo)
 		if !os.IsNotExist(err) && !fi.IsDir() {
 			fmt.Printf("File already exists: %s\n", err)
-			os.Exit(1)
+			return
 		}
 		if !os.IsNotExist(err) && fi.IsDir() {
 			filename := fmt.Sprintf("%s_%s.cfg", filepath.Base(name), filepath.Base(lhost))
@@ -89,7 +98,7 @@ var operatorCmd = &cobra.Command{
 		err = os.WriteFile(saveTo, configJSON, 0600)
 		if err != nil {
 			fmt.Printf("Write failed: %s (%s)\n", saveTo, err)
-			os.Exit(1)
+			return
 		}
 	},
 }

server/console/console-admin.go

@@ -24,7 +24,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
@@ -86,13 +85,14 @@ func newOperatorCmd(cmd *cobra.Command, _ []string) {
 	lhost, _ := cmd.Flags().GetString("lhost")
 	lport, _ := cmd.Flags().GetUint16("lport")
 	save, _ := cmd.Flags().GetString("save")
+	permissions, _ := cmd.Flags().GetStringSlice("permissions")
 
 	if save == "" {
 		save, _ = os.Getwd()
 	}
 
 	fmt.Printf(Info + "Generating new client certificate, please wait ... \n")
-	configJSON, err := NewOperatorConfig(name, lhost, lport)
+	configJSON, err := NewOperatorConfig(name, lhost, lport, permissions)
 	if err != nil {
 		fmt.Printf(Warn+"%s\n", err)
 		return
@@ -108,7 +108,7 @@ func newOperatorCmd(cmd *cobra.Command, _ []string) {
 		filename := fmt.Sprintf("%s_%s.cfg", filepath.Base(name), filepath.Base(lhost))
 		saveTo = filepath.Join(saveTo, filename)
 	}
-	err = ioutil.WriteFile(saveTo, configJSON, 0o600)
+	err = os.WriteFile(saveTo, configJSON, 0o600)
 	if err != nil {
 		fmt.Printf(Warn+"Failed to write config to: %s (%s) \n", saveTo, err)
 		return
@@ -117,7 +117,7 @@ func newOperatorCmd(cmd *cobra.Command, _ []string) {
 }
 
 // NewOperatorConfig - Generate a new player/client/operator configuration
-func NewOperatorConfig(operatorName string, lhost string, lport uint16) ([]byte, error) {
+func NewOperatorConfig(operatorName string, lhost string, lport uint16, permissions []string) ([]byte, error) {
 	if !namePattern.MatchString(operatorName) {
 		return nil, errors.New("invalid operator name (alphanumerics only)")
 	}
@@ -127,6 +127,9 @@ func NewOperatorConfig(operatorName string, lhost string, lport uint16) ([]byte,
 	if lhost == "" {
 		return nil, errors.New("invalid lhost")
 	}
+	if len(permissions) == 0 {
+		return nil, errors.New("must specify at least one permission")
+	}
 
 	rawToken := models.GenerateOperatorToken()
 	digest := sha256.Sum256([]byte(rawToken))
@@ -134,6 +137,19 @@ func NewOperatorConfig(operatorName string, lhost string, lport uint16) ([]byte,
 		Name:  operatorName,
 		Token: hex.EncodeToString(digest[:]),
 	}
+	for _, permission := range permissions {
+		switch permission {
+		case "all":
+			dbOperator.PermissionAll = true
+			break
+		case "builder":
+			dbOperator.PermissionBuilder = true
+		case "crackstation":
+			dbOperator.PermissionCrackstation = true
+		default:
+			return nil, fmt.Errorf("invalid permission: %s", permission)
+		}
+	}
 	err := db.Session().Save(dbOperator).Error
 	if err != nil {
 		return nil, err

server/console/console-admin_test.go

@@ -12,7 +12,7 @@ import (
 func TestRootOnlyVerifyCertificate(t *testing.T) {
 	certs.SetupCAs()
 
-	data, err := NewOperatorConfig("zerocool", "localhost", uint16(1337))
+	data, err := NewOperatorConfig("zerocool", "localhost", uint16(1337), []string{"all"})
 	if err != nil {
 		t.Fatalf("failed to generate test player profile %s", err)
 	}

server/console/console.go

@@ -85,7 +85,7 @@ func serverOnlyCmds() (commands []*cobra.Command) {
 	newOperator := &cobra.Command{
 		Use:     consts.NewOperatorStr,
 		Short:   "Create a new operator config file",
-		Long:    help.GetHelpFor([]string{consts.NewOperatorStr}),
+		Long:    newOperatorLongHelp,
 		Run:     newOperatorCmd,
 		GroupID: consts.MultiplayerHelpGroup,
 	}
@@ -94,6 +94,7 @@ func serverOnlyCmds() (commands []*cobra.Command) {
 		f.Uint16P("lport", "p", 31337, "listen port")
 		f.StringP("save", "s", "", "directory/file in which to save config")
 		f.StringP("name", "n", "", "operator name")
+		f.StringSliceP("permissions", "P", []string{}, "grant permissions to the operator profile (all, builder, crackstation)")
 	})
 	command.FlagComps(newOperator, func(comp *carapace.ActionMap) {
 		(*comp)["save"] = carapace.ActionDirectories()
@@ -115,3 +116,23 @@ func serverOnlyCmds() (commands []*cobra.Command) {
 
 	return
 }
+
+const newOperatorLongHelp = `
+Create a new operator config file, operator configuration files allow
+remote machines to connect to the Sliver server. They are most commonly
+used for allowing remote operators to connect in "Multiplayer Mode."
+
+To generate a profile for a remote operator, you need to specify the
+the "all" permission to grant the profile access to all gRPC APIs:
+
+new-operator --name <operator name> --lhost <sliver server> --permissions all
+
+Operator profiles can also be used to allow remote machines to connect to
+the Sliver server for other purposes, such as a "Remote Builder" or a
+"Crackstation."
+
+You can restrict profiles' permissions by using the --permissions flag, for
+example, to create a profile that can only be used as a "Remote Builder":
+
+new-operator --name <operator name> --lhost <sliver server> --permissions builder
+`

server/core/connnection.go

@@ -31,11 +31,11 @@ type ImplantConnection struct {
 	ID               string
 	Send             chan *sliverpb.Envelope
 	RespMutex        *sync.RWMutex
-	LastMessageMutex *sync.RWMutex
 	Resp             map[int64]chan *sliverpb.Envelope
 	Transport        string
 	RemoteAddress    string
 	LastMessage      time.Time
+	LastMessageMutex *sync.RWMutex
 	Cleanup          func()
 }
 

server/db/helpers.go

@@ -525,15 +525,15 @@ func ListenerByJobID(JobID uint32) (*clientpb.ListenerJob, error) {
 	return listenerJob.ToProtobuf(), err
 }
 
-func ListenerJobs() (*[]clientpb.ListenerJob, error) {
+func ListenerJobs() ([]*clientpb.ListenerJob, error) {
 	listenerJobs := []models.ListenerJob{}
 	err := Session().Where(&models.ListenerJob{}).Find(&listenerJobs).Error
-	pbListenerJobs := []clientpb.ListenerJob{}
+	pbListenerJobs := []*clientpb.ListenerJob{}
 	for _, listenerJob := range listenerJobs {
-		pbListenerJobs = append(pbListenerJobs, *listenerJob.ToProtobuf())
+		pbListenerJobs = append(pbListenerJobs, listenerJob.ToProtobuf())
 	}
 
-	return &pbListenerJobs, err
+	return pbListenerJobs, err
 }
 
 func DeleteListener(JobID uint32) error {

server/db/models/operator.go

@@ -28,12 +28,15 @@ import (
 	"gorm.io/gorm"
 )
 
-// Operator - Colletions of content to serve from HTTP(S)
+// Operator - Collections of content to serve from HTTP(S)
 type Operator struct {
-	ID        uuid.UUID `gorm:"primaryKey;->;<-:create;type:uuid;"`
-	CreatedAt time.Time `gorm:"->;<-:create;"`
-	Name      string
-	Token     string `gorm:"uniqueIndex"`
+	ID                     uuid.UUID `gorm:"primaryKey;->;<-:create;type:uuid;"`
+	CreatedAt              time.Time `gorm:"->;<-:create;"`
+	Name                   string
+	Token                  string `gorm:"uniqueIndex"`   // NOTE: This is the SHA256 of the token
+	PermissionAll          bool   `gorm:"default:false"` // Access all gRPC APIs
+	PermissionBuilder      bool   `gorm:"default:false"` // Access Builder gRPC APIs
+	PermissionCrackstation bool   `gorm:"default:false"` // Access Crackstation gRPC APIs
 }
 
 // BeforeCreate - GORM hook

server/rpc/rpc-jobs.go

@@ -283,7 +283,7 @@ func PortInUse(newPort uint32) error {
 		return err
 	}
 	var port uint32
-	for _, job := range *listenerJobs {
+	for _, job := range listenerJobs {
 		listener, err := db.ListenerByJobID(job.JobID)
 		if err != nil {
 			return err

server/transport/middleware.go

@@ -29,6 +29,7 @@ import (
 	"github.com/bishopfox/sliver/server/configs"
 	"github.com/bishopfox/sliver/server/core"
 	"github.com/bishopfox/sliver/server/db"
+	"github.com/bishopfox/sliver/server/db/models"
 	"github.com/bishopfox/sliver/server/log"
 	grpc_auth "github.com/grpc-ecosystem/go-grpc-middleware/auth"
 	grpc_logrus "github.com/grpc-ecosystem/go-grpc-middleware/logging/logrus"
@@ -64,6 +65,7 @@ func initMiddleware(remoteAuth bool) []grpc.ServerOption {
 		return []grpc.ServerOption{
 			grpc.ChainUnaryInterceptor(
 				grpc_auth.UnaryServerInterceptor(tokenAuthFunc),
+				permissionsUnaryServerInterceptor(),
 				auditLogUnaryServerInterceptor(),
 				grpc_tags.UnaryServerInterceptor(grpc_tags.WithFieldExtractor(grpc_tags.CodeGenRequestFieldExtractor)),
 				grpc_logrus.UnaryServerInterceptor(logrusEntry, logrusOpts...),
@@ -71,6 +73,7 @@ func initMiddleware(remoteAuth bool) []grpc.ServerOption {
 			),
 			grpc.ChainStreamInterceptor(
 				grpc_auth.StreamServerInterceptor(tokenAuthFunc),
+				permissionsStreamServerInterceptor(),
 				grpc_tags.StreamServerInterceptor(grpc_tags.WithFieldExtractor(grpc_tags.CodeGenRequestFieldExtractor)),
 				grpc_logrus.StreamServerInterceptor(logrusEntry, logrusOpts...),
 				grpc_logrus.PayloadStreamServerInterceptor(logrusEntry, deciderStream),
@@ -123,23 +126,93 @@ func tokenAuthFunc(ctx context.Context) (context.Context, error) {
 	digest := sha256.Sum256([]byte(rawToken))
 	token := hex.EncodeToString(digest[:])
 	newCtx := context.WithValue(ctx, Transport, "mtls")
-	if name, ok := tokenCache.Load(token); ok {
+	if op, ok := tokenCache.Load(token); ok {
 		mtlsLog.Debugf("Token in cache!")
-		newCtx = context.WithValue(newCtx, Operator, name.(string))
+		newCtx = context.WithValue(newCtx, Operator, op.(*models.Operator))
 		return newCtx, nil
 	}
 	operator, err := db.OperatorByToken(token)
 	if err != nil || operator == nil {
-		mtlsLog.Errorf("Authentication failure: %s", err)
+		mtlsLog.Errorf("Authentication failure: %v", err)
 		return nil, status.Error(codes.Unauthenticated, "Authentication failure")
 	}
-	mtlsLog.Debugf("Valid user token for %s", operator.Name)
-	tokenCache.Store(token, operator.Name)
+	mtlsLog.Debugf("Valid token for %s", operator.Name)
+	tokenCache.Store(token, operator)
 
-	newCtx = context.WithValue(newCtx, Operator, operator.Name)
+	newCtx = context.WithValue(newCtx, Operator, operator)
 	return newCtx, nil
 }
 
+var (
+	// Builder - Allowed methods
+	builderMethods = map[string]bool{
+		"/rpcpb.SliverRPC/GetVersion":                     true,
+		"/rpcpb.SliverRPC/GenerateExternalGetBuildConfig": true,
+		"/rpcpb.SliverRPC/GenerateExternalSaveBuild":      true,
+		"/rpcpb.SliverRPC/BuilderRegister":                true,
+		"/rpcpb.SliverRPC/BuilderTrigger":                 true,
+		"/rpcpb.SliverRPC/Builders":                       true,
+	}
+	// Crackstation - Allowed methods
+	crackstationMethods = map[string]bool{
+		"/rpcpb.SliverRPC/GetVersion":             true,
+		"/rpcpb.SliverRPC/CrackstationRegister":   true,
+		"/rpcpb.SliverRPC/CrackstationTrigger":    true,
+		"/rpcpb.SliverRPC/CrackstationBenchmark":  true,
+		"/rpcpb.SliverRPC/Crackstations":          true,
+		"/rpcpb.SliverRPC/CrackTaskByID":          true,
+		"/rpcpb.SliverRPC/CrackTaskUpdate":        true,
+		"/rpcpb.SliverRPC/CrackFilesList":         true,
+		"/rpcpb.SliverRPC/CrackFileCreate":        true,
+		"/rpcpb.SliverRPC/CrackFileChunkUpload":   true,
+		"/rpcpb.SliverRPC/CrackFileChunkDownload": true,
+		"/rpcpb.SliverRPC/CrackFileComplete":      true,
+		"/rpcpb.SliverRPC/CrackFileDelete":        true,
+	}
+)
+
+func permissionsUnaryServerInterceptor() grpc.UnaryServerInterceptor {
+	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (_ interface{}, err error) {
+		operator := ctx.Value(Operator).(*models.Operator)
+		if operator.PermissionAll {
+			return handler(ctx, req)
+		}
+		if operator.PermissionBuilder {
+			if ok, _ := builderMethods[info.FullMethod]; ok {
+				return handler(ctx, req)
+			}
+		}
+		if operator.PermissionCrackstation {
+			if ok, _ := crackstationMethods[info.FullMethod]; ok {
+				return handler(ctx, req)
+			}
+		}
+		mtlsLog.Warnf("Permission denied for %s attempting to access %s", operator.Name, info.FullMethod)
+		return nil, status.Error(codes.PermissionDenied, "Permission denied")
+	}
+}
+
+func permissionsStreamServerInterceptor() grpc.StreamServerInterceptor {
+	return func(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
+		operator := ss.Context().Value(Operator).(*models.Operator)
+		if operator.PermissionAll {
+			return handler(srv, ss)
+		}
+		if operator.PermissionBuilder {
+			if ok, _ := builderMethods[info.FullMethod]; ok {
+				return handler(srv, ss)
+			}
+		}
+		if operator.PermissionCrackstation {
+			if ok, _ := crackstationMethods[info.FullMethod]; ok {
+				return handler(srv, ss)
+			}
+		}
+		mtlsLog.Warnf("Permission denied for %s attempting to access %s", operator.Name, info.FullMethod)
+		return status.Error(codes.PermissionDenied, "Permission denied")
+	}
+}
+
 func deciderUnary(_ context.Context, _ string, _ interface{}) bool {
 	return serverConfig.Logs.GRPCUnaryPayloads
 }

vendor/golang.org/x/crypto/acme/version_go112.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build go1.12
-// +build go1.12
 
 package acme
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build amd64 && gc && !purego
-// +build amd64,gc,!purego
 
 package argon2
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build amd64 && gc && !purego
-// +build amd64,gc,!purego
 
 #include "textflag.h"
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !amd64 || purego || !gc
-// +build !amd64 purego !gc
 
 package argon2
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build go1.7 && amd64 && gc && !purego
-// +build go1.7,amd64,gc,!purego
 
 package blake2b
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build go1.7 && amd64 && gc && !purego
-// +build go1.7,amd64,gc,!purego
 
 #include "textflag.h"
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !go1.7 && amd64 && gc && !purego
-// +build !go1.7,amd64,gc,!purego
 
 package blake2b
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build amd64 && gc && !purego
-// +build amd64,gc,!purego
 
 #include "textflag.h"
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !amd64 || purego || !gc
-// +build !amd64 purego !gc
 
 package blake2b
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build go1.9
-// +build go1.9
 
 package blake2b
 

vendor/golang.org/x/crypto/blake2s/blake2s_386.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build 386 && gc && !purego
-// +build 386,gc,!purego
 
 package blake2s
 

vendor/golang.org/x/crypto/blake2s/blake2s_386.s

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build 386 && gc && !purego
-// +build 386,gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/blake2s/blake2s_amd64.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build amd64 && gc && !purego
-// +build amd64,gc,!purego
 
 package blake2s
 

vendor/golang.org/x/crypto/blake2s/blake2s_amd64.s

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build amd64 && gc && !purego
-// +build amd64,gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/blake2s/blake2s_ref.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build (!amd64 && !386) || !gc || purego
-// +build !amd64,!386 !gc purego
 
 package blake2s
 

vendor/golang.org/x/crypto/blake2s/register.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build go1.9
-// +build go1.9
 
 package blake2s
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 package chacha20
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 #include "textflag.h"
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build (!arm64 && !s390x && !ppc64le) || !gc || purego
-// +build !arm64,!s390x,!ppc64le !gc purego
 
 package chacha20
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 package chacha20
 

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

@@ -20,7 +20,6 @@
 // due to the calling conventions and initialization of constants.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 #include "textflag.h"
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 package chacha20
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 #include "go_asm.h"
 #include "textflag.h"

vendor/golang.org/x/crypto/chacha20poly1305/chacha20poly1305_amd64.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 package chacha20poly1305
 

vendor/golang.org/x/crypto/chacha20poly1305/chacha20poly1305_amd64.s

@@ -5,7 +5,6 @@
 // This file was originally from https://golang.org/cl/24717 by Vlad Krasnov of CloudFlare.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 #include "textflag.h"
 // General register allocation
@@ -184,11 +183,31 @@ GLOBL ·andMask<>(SB), (NOPTR+RODATA), $240
 #define shiftD1Right BYTE $0x66; BYTE $0x45; BYTE $0x0f; BYTE $0x3a; BYTE $0x0f; BYTE $0xd2; BYTE $0x04 // PALIGNR $4, X10, X10
 #define shiftD2Right BYTE $0x66; BYTE $0x45; BYTE $0x0f; BYTE $0x3a; BYTE $0x0f; BYTE $0xdb; BYTE $0x04 // PALIGNR $4, X11, X11
 #define shiftD3Right BYTE $0x66; BYTE $0x45; BYTE $0x0f; BYTE $0x3a; BYTE $0x0f; BYTE $0xff; BYTE $0x04 // PALIGNR $4, X15, X15
+
 // Some macros
+
+// ROL rotates the uint32s in register R left by N bits, using temporary T.
+#define ROL(N, R, T) \
+	MOVO R, T; PSLLL $(N), T; PSRLL $(32-(N)), R; PXOR T, R
+
+// ROL16 rotates the uint32s in register R left by 16, using temporary T if needed.
+#ifdef GOAMD64_v2
+#define ROL16(R, T) PSHUFB ·rol16<>(SB), R
+#else
+#define ROL16(R, T) ROL(16, R, T)
+#endif
+
+// ROL8 rotates the uint32s in register R left by 8, using temporary T if needed.
+#ifdef GOAMD64_v2
+#define ROL8(R, T) PSHUFB ·rol8<>(SB), R
+#else
+#define ROL8(R, T) ROL(8, R, T)
+#endif
+
 #define chachaQR(A, B, C, D, T) \
-	PADDD B, A; PXOR A, D; PSHUFB ·rol16<>(SB), D                            \
+	PADDD B, A; PXOR A, D; ROL16(D, T) \
 	PADDD D, C; PXOR C, B; MOVO B, T; PSLLL $12, T; PSRLL $20, B; PXOR T, B \
-	PADDD B, A; PXOR A, D; PSHUFB ·rol8<>(SB), D                             \
+	PADDD B, A; PXOR A, D; ROL8(D, T) \
 	PADDD D, C; PXOR C, B; MOVO B, T; PSLLL $7, T; PSRLL $25, B; PXOR T, B
 
 #define chachaQR_AVX2(A, B, C, D, T) \

vendor/golang.org/x/crypto/chacha20poly1305/chacha20poly1305_noasm.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !amd64 || !gc || purego
-// +build !amd64 !gc purego
 
 package chacha20poly1305
 

vendor/golang.org/x/crypto/curve25519/internal/field/fe_amd64.go

@@ -1,7 +1,6 @@
 // Code generated by command: go run fe_amd64_asm.go -out ../fe_amd64.s -stubs ../fe_amd64.go -pkg field. DO NOT EDIT.
 
 //go:build amd64 && gc && !purego
-// +build amd64,gc,!purego
 
 package field
 

vendor/golang.org/x/crypto/curve25519/internal/field/fe_amd64.s

@@ -1,7 +1,6 @@
 // Code generated by command: go run fe_amd64_asm.go -out ../fe_amd64.s -stubs ../fe_amd64.go -pkg field. DO NOT EDIT.
 
 //go:build amd64 && gc && !purego
-// +build amd64,gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/curve25519/internal/field/fe_amd64_noasm.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !amd64 || !gc || purego
-// +build !amd64 !gc purego
 
 package field
 

vendor/golang.org/x/crypto/curve25519/internal/field/fe_arm64.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build arm64 && gc && !purego
-// +build arm64,gc,!purego
 
 package field
 

vendor/golang.org/x/crypto/curve25519/internal/field/fe_arm64.s

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build arm64 && gc && !purego
-// +build arm64,gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/curve25519/internal/field/fe_arm64_noasm.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !arm64 || !gc || purego
-// +build !arm64 !gc purego
 
 package field
 

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

@@ -56,7 +56,9 @@ func (f *hkdf) Read(p []byte) (int, error) {
 
 	// Fill the rest of the buffer
 	for len(p) > 0 {
-		f.expander.Reset()
+		if f.counter > 1 {
+			f.expander.Reset()
+		}
 		f.expander.Write(f.prev)
 		f.expander.Write(f.info)
 		f.expander.Write([]byte{f.counter})

vendor/golang.org/x/crypto/internal/alias/alias.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !purego
-// +build !purego
 
 // Package alias implements memory aliasing tests.
 package alias

vendor/golang.org/x/crypto/internal/alias/alias_purego.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build purego
-// +build purego
 
 // Package alias implements memory aliasing tests.
 package alias

vendor/golang.org/x/crypto/internal/poly1305/bits_compat.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !go1.13
-// +build !go1.13
 
 package poly1305
 

vendor/golang.org/x/crypto/internal/poly1305/bits_go1.13.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build go1.13
-// +build go1.13
 
 package poly1305
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build (!amd64 && !ppc64le && !s390x) || !gc || purego
-// +build !amd64,!ppc64le,!s390x !gc purego
 
 package poly1305
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 package poly1305
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 #include "textflag.h"
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 package poly1305
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 #include "textflag.h"
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 package poly1305
 

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

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !purego
-// +build gc,!purego
 
 #include "textflag.h"
 

vendor/golang.org/x/crypto/salsa20/salsa/salsa20_amd64.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build amd64 && !purego && gc
-// +build amd64,!purego,gc
 
 package salsa
 

vendor/golang.org/x/crypto/salsa20/salsa/salsa20_amd64.s

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build amd64 && !purego && gc
-// +build amd64,!purego,gc
 
 // This code was translated into a form compatible with 6a from the public
 // domain sources in SUPERCOP: https://bench.cr.yp.to/supercop.html

vendor/golang.org/x/crypto/salsa20/salsa/salsa20_noasm.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !amd64 || purego || !gc
-// +build !amd64 purego !gc
 
 package salsa
 

vendor/golang.org/x/crypto/ssh/agent/client.go

@@ -141,9 +141,14 @@ const (
 	agentAddSmartcardKeyConstrained = 26
 
 	// 3.7 Key constraint identifiers
-	agentConstrainLifetime  = 1
-	agentConstrainConfirm   = 2
-	agentConstrainExtension = 3
+	agentConstrainLifetime = 1
+	agentConstrainConfirm  = 2
+	// Constraint extension identifier up to version 2 of the protocol. A
+	// backward incompatible change will be required if we want to add support
+	// for SSH_AGENT_CONSTRAIN_MAXSIGN which uses the same ID.
+	agentConstrainExtensionV00 = 3
+	// Constraint extension identifier in version 3 and later of the protocol.
+	agentConstrainExtension = 255
 )
 
 // maxAgentResponseBytes is the maximum agent reply size that is accepted. This
@@ -205,7 +210,7 @@ type constrainLifetimeAgentMsg struct {
 }
 
 type constrainExtensionAgentMsg struct {
-	ExtensionName    string `sshtype:"3"`
+	ExtensionName    string `sshtype:"255|3"`
 	ExtensionDetails []byte
 
 	// Rest is a field used for parsing, not part of message

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

@@ -208,7 +208,7 @@ func parseConstraints(constraints []byte) (lifetimeSecs uint32, confirmBeforeUse
 		case agentConstrainConfirm:
 			confirmBeforeUse = true
 			constraints = constraints[1:]
-		case agentConstrainExtension:
+		case agentConstrainExtension, agentConstrainExtensionV00:
 			var msg constrainExtensionAgentMsg
 			if err = ssh.Unmarshal(constraints, &msg); err != nil {
 				return 0, false, nil, err

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

@@ -10,7 +10,6 @@ import (
 	"fmt"
 	"io"
 	"math"
-	"strings"
 	"sync"
 
 	_ "crypto/sha1"
@@ -140,8 +139,6 @@ var supportedPubKeyAuthAlgos = []string{
 	KeyAlgoDSA,
 }
 
-var supportedPubKeyAuthAlgosList = strings.Join(supportedPubKeyAuthAlgos, ",")
-
 // unexpectedMessageError results when the SSH message that we received didn't
 // match what we wanted.
 func unexpectedMessageError(expected, got uint8) error {

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

@@ -11,6 +11,7 @@ import (
 	"io"
 	"log"
 	"net"
+	"strings"
 	"sync"
 )
 
@@ -50,6 +51,10 @@ type handshakeTransport struct {
 	// connection.
 	hostKeys []Signer
 
+	// publicKeyAuthAlgorithms is non-empty if we are the server. In that case,
+	// it contains the supported client public key authentication algorithms.
+	publicKeyAuthAlgorithms []string
+
 	// hostKeyAlgorithms is non-empty if we are the client. In that case,
 	// we accept these key types from the server as host key.
 	hostKeyAlgorithms []string
@@ -141,6 +146,7 @@ func newClientTransport(conn keyingTransport, clientVersion, serverVersion []byt
 func newServerTransport(conn keyingTransport, clientVersion, serverVersion []byte, config *ServerConfig) *handshakeTransport {
 	t := newHandshakeTransport(conn, &config.Config, clientVersion, serverVersion)
 	t.hostKeys = config.hostKeys
+	t.publicKeyAuthAlgorithms = config.PublicKeyAuthAlgorithms
 	go t.readLoop()
 	go t.kexLoop()
 	return t
@@ -649,6 +655,7 @@ func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
 	// message with the server-sig-algs extension if the client supports it. See
 	// RFC 8308, Sections 2.4 and 3.1, and [PROTOCOL], Section 1.9.
 	if !isClient && firstKeyExchange && contains(clientInit.KexAlgos, "ext-info-c") {
+		supportedPubKeyAuthAlgosList := strings.Join(t.publicKeyAuthAlgorithms, ",")
 		extInfo := &extInfoMsg{
 			NumExtensions: 2,
 			Payload:       make([]byte, 0, 4+15+4+len(supportedPubKeyAuthAlgosList)+4+16+4+1),

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

@@ -1232,16 +1232,27 @@ func ParseRawPrivateKeyWithPassphrase(pemBytes, passphrase []byte) (interface{},
 		return nil, fmt.Errorf("ssh: cannot decode encrypted private keys: %v", err)
 	}
 
+	var result interface{}
+
 	switch block.Type {
 	case "RSA PRIVATE KEY":
-		return x509.ParsePKCS1PrivateKey(buf)
+		result, err = x509.ParsePKCS1PrivateKey(buf)
 	case "EC PRIVATE KEY":
-		return x509.ParseECPrivateKey(buf)
+		result, err = x509.ParseECPrivateKey(buf)
 	case "DSA PRIVATE KEY":
-		return ParseDSAPrivateKey(buf)
+		result, err = ParseDSAPrivateKey(buf)
 	default:
-		return nil, fmt.Errorf("ssh: unsupported key type %q", block.Type)
+		err = fmt.Errorf("ssh: unsupported key type %q", block.Type)
 	}
+	// Because of deficiencies in the format, DecryptPEMBlock does not always
+	// detect an incorrect password. In these cases decrypted DER bytes is
+	// random noise. If the parsing of the key returns an asn1.StructuralError
+	// we return x509.IncorrectPasswordError.
+	if _, ok := err.(asn1.StructuralError); ok {
+		return nil, x509.IncorrectPasswordError
+	}
+
+	return result, err
 }
 
 // ParseDSAPrivateKey returns a DSA private key from its ASN.1 DER encoding, as

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

@@ -64,6 +64,13 @@ type ServerConfig struct {
 	// Config contains configuration shared between client and server.
 	Config
 
+	// PublicKeyAuthAlgorithms specifies the supported client public key
+	// authentication algorithms. Note that this should not include certificate
+	// types since those use the underlying algorithm. This list is sent to the
+	// client if it supports the server-sig-algs extension. Order is irrelevant.
+	// If unspecified then a default set of algorithms is used.
+	PublicKeyAuthAlgorithms []string
+
 	hostKeys []Signer
 
 	// NoClientAuth is true if clients are allowed to connect without
@@ -201,6 +208,15 @@ func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewCha
 	if fullConf.MaxAuthTries == 0 {
 		fullConf.MaxAuthTries = 6
 	}
+	if len(fullConf.PublicKeyAuthAlgorithms) == 0 {
+		fullConf.PublicKeyAuthAlgorithms = supportedPubKeyAuthAlgos
+	} else {
+		for _, algo := range fullConf.PublicKeyAuthAlgorithms {
+			if !contains(supportedPubKeyAuthAlgos, algo) {
+				return nil, nil, nil, fmt.Errorf("ssh: unsupported public key authentication algorithm %s", algo)
+			}
+		}
+	}
 	// Check if the config contains any unsupported key exchanges
 	for _, kex := range fullConf.KeyExchanges {
 		if _, ok := serverForbiddenKexAlgos[kex]; ok {
@@ -524,7 +540,7 @@ userAuthLoop:
 				return nil, parseError(msgUserAuthRequest)
 			}
 			algo := string(algoBytes)
-			if !contains(supportedPubKeyAuthAlgos, underlyingAlgo(algo)) {
+			if !contains(config.PublicKeyAuthAlgorithms, underlyingAlgo(algo)) {
 				authErr = fmt.Errorf("ssh: algorithm %q not accepted", algo)
 				break
 			}
@@ -591,7 +607,7 @@ userAuthLoop:
 				// algorithm name that corresponds to algo with
 				// sig.Format.  This is usually the same, but
 				// for certs, the names differ.
-				if !contains(supportedPubKeyAuthAlgos, sig.Format) {
+				if !contains(config.PublicKeyAuthAlgorithms, sig.Format) {
 					authErr = fmt.Errorf("ssh: algorithm %q not accepted", sig.Format)
 					break
 				}

vendor/modules.txt

@@ -736,8 +736,8 @@ go4.org/mem
 # go4.org/netipx v0.0.0-20230824141953-6213f710f925
 ## explicit; go 1.18
 go4.org/netipx
-# golang.org/x/crypto v0.14.0
-## explicit; go 1.17
+# golang.org/x/crypto v0.15.0
+## explicit; go 1.18
 golang.org/x/crypto/acme
 golang.org/x/crypto/acme/autocert
 golang.org/x/crypto/argon2