[management,proxy] Add per-target options to reverse proxy (#5501)

management/internals/modules/reverseproxy/service/service.go

@@ -6,13 +6,16 @@ import (
 	"fmt"
 	"math/big"
 	"net"
+	"net/http"
 	"net/url"
 	"regexp"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/rs/xid"
 	log "github.com/sirupsen/logrus"
+	"google.golang.org/protobuf/types/known/durationpb"
 
 	"github.com/netbirdio/netbird/management/internals/modules/reverseproxy/proxy"
 	"github.com/netbirdio/netbird/shared/hash/argon2id"
@@ -49,17 +52,25 @@ const (
 	SourceEphemeral = "ephemeral"
 )
 
+type TargetOptions struct {
+	SkipTLSVerify  bool              `json:"skip_tls_verify"`
+	RequestTimeout time.Duration     `json:"request_timeout,omitempty"`
+	PathRewrite    PathRewriteMode   `json:"path_rewrite,omitempty"`
+	CustomHeaders  map[string]string `gorm:"serializer:json" json:"custom_headers,omitempty"`
+}
+
 type Target struct {
-	ID         uint    `gorm:"primaryKey" json:"-"`
-	AccountID  string  `gorm:"index:idx_target_account;not null" json:"-"`
-	ServiceID  string  `gorm:"index:idx_service_targets;not null" json:"-"`
-	Path       *string `json:"path,omitempty"`
-	Host       string  `json:"host"` // the Host field is only used for subnet targets, otherwise ignored
-	Port       int     `gorm:"index:idx_target_port" json:"port"`
-	Protocol   string  `gorm:"index:idx_target_protocol" json:"protocol"`
-	TargetId   string  `gorm:"index:idx_target_id" json:"target_id"`
-	TargetType string  `gorm:"index:idx_target_type" json:"target_type"`
-	Enabled    bool    `gorm:"index:idx_target_enabled" json:"enabled"`
+	ID         uint          `gorm:"primaryKey" json:"-"`
+	AccountID  string        `gorm:"index:idx_target_account;not null" json:"-"`
+	ServiceID  string        `gorm:"index:idx_service_targets;not null" json:"-"`
+	Path       *string       `json:"path,omitempty"`
+	Host       string        `json:"host"` // the Host field is only used for subnet targets, otherwise ignored
+	Port       int           `gorm:"index:idx_target_port" json:"port"`
+	Protocol   string        `gorm:"index:idx_target_protocol" json:"protocol"`
+	TargetId   string        `gorm:"index:idx_target_id" json:"target_id"`
+	TargetType string        `gorm:"index:idx_target_type" json:"target_type"`
+	Enabled    bool          `gorm:"index:idx_target_enabled" json:"enabled"`
+	Options    TargetOptions `gorm:"embedded" json:"options"`
 }
 
 type PasswordAuthConfig struct {
@@ -194,7 +205,7 @@ func (s *Service) ToAPIResponse() *api.Service {
 	// Convert internal targets to API targets
 	apiTargets := make([]api.ServiceTarget, 0, len(s.Targets))
 	for _, target := range s.Targets {
-		apiTargets = append(apiTargets, api.ServiceTarget{
+		st := api.ServiceTarget{
 			Path:       target.Path,
 			Host:       &target.Host,
 			Port:       target.Port,
@@ -202,7 +213,9 @@ func (s *Service) ToAPIResponse() *api.Service {
 			TargetId:   target.TargetId,
 			TargetType: api.ServiceTargetTargetType(target.TargetType),
 			Enabled:    target.Enabled,
-		})
+		}
+		st.Options = targetOptionsToAPI(target.Options)
+		apiTargets = append(apiTargets, st)
 	}
 
 	meta := api.ServiceMeta{
@@ -256,10 +269,14 @@ func (s *Service) ToProtoMapping(operation Operation, authToken string, oidcConf
 		if target.Path != nil {
 			path = *target.Path
 		}
-		pathMappings = append(pathMappings, &proto.PathMapping{
+
+		pm := &proto.PathMapping{
 			Path:   path,
 			Target: targetURL.String(),
-		})
+		}
+
+		pm.Options = targetOptionsToProto(target.Options)
+		pathMappings = append(pathMappings, pm)
 	}
 
 	auth := &proto.Authentication{
@@ -312,13 +329,87 @@ func isDefaultPort(scheme string, port int) bool {
 	return (scheme == "https" && port == 443) || (scheme == "http" && port == 80)
 }
 
-func (s *Service) FromAPIRequest(req *api.ServiceRequest, accountID string) {
+// PathRewriteMode controls how the request path is rewritten before forwarding.
+type PathRewriteMode string
+
+const (
+	PathRewritePreserve PathRewriteMode = "preserve"
+)
+
+func pathRewriteToProto(mode PathRewriteMode) proto.PathRewriteMode {
+	switch mode {
+	case PathRewritePreserve:
+		return proto.PathRewriteMode_PATH_REWRITE_PRESERVE
+	default:
+		return proto.PathRewriteMode_PATH_REWRITE_DEFAULT
+	}
+}
+
+func targetOptionsToAPI(opts TargetOptions) *api.ServiceTargetOptions {
+	if !opts.SkipTLSVerify && opts.RequestTimeout == 0 && opts.PathRewrite == "" && len(opts.CustomHeaders) == 0 {
+		return nil
+	}
+	apiOpts := &api.ServiceTargetOptions{}
+	if opts.SkipTLSVerify {
+		apiOpts.SkipTlsVerify = &opts.SkipTLSVerify
+	}
+	if opts.RequestTimeout != 0 {
+		s := opts.RequestTimeout.String()
+		apiOpts.RequestTimeout = &s
+	}
+	if opts.PathRewrite != "" {
+		pr := api.ServiceTargetOptionsPathRewrite(opts.PathRewrite)
+		apiOpts.PathRewrite = &pr
+	}
+	if len(opts.CustomHeaders) > 0 {
+		apiOpts.CustomHeaders = &opts.CustomHeaders
+	}
+	return apiOpts
+}
+
+func targetOptionsToProto(opts TargetOptions) *proto.PathTargetOptions {
+	if !opts.SkipTLSVerify && opts.PathRewrite == "" && opts.RequestTimeout == 0 && len(opts.CustomHeaders) == 0 {
+		return nil
+	}
+	popts := &proto.PathTargetOptions{
+		SkipTlsVerify: opts.SkipTLSVerify,
+		PathRewrite:   pathRewriteToProto(opts.PathRewrite),
+		CustomHeaders: opts.CustomHeaders,
+	}
+	if opts.RequestTimeout != 0 {
+		popts.RequestTimeout = durationpb.New(opts.RequestTimeout)
+	}
+	return popts
+}
+
+func targetOptionsFromAPI(idx int, o *api.ServiceTargetOptions) (TargetOptions, error) {
+	var opts TargetOptions
+	if o.SkipTlsVerify != nil {
+		opts.SkipTLSVerify = *o.SkipTlsVerify
+	}
+	if o.RequestTimeout != nil {
+		d, err := time.ParseDuration(*o.RequestTimeout)
+		if err != nil {
+			return opts, fmt.Errorf("target %d: parse request_timeout %q: %w", idx, *o.RequestTimeout, err)
+		}
+		opts.RequestTimeout = d
+	}
+	if o.PathRewrite != nil {
+		opts.PathRewrite = PathRewriteMode(*o.PathRewrite)
+	}
+	if o.CustomHeaders != nil {
+		opts.CustomHeaders = *o.CustomHeaders
+	}
+	return opts, nil
+}
+
+func (s *Service) FromAPIRequest(req *api.ServiceRequest, accountID string) error {
 	s.Name = req.Name
 	s.Domain = req.Domain
 	s.AccountID = accountID
 
 	targets := make([]*Target, 0, len(req.Targets))
-	for _, apiTarget := range req.Targets {
+	for i, apiTarget := range req.Targets {
 		target := &Target{
 			AccountID:  accountID,
 			Path:       apiTarget.Path,
@@ -331,6 +422,13 @@ func (s *Service) FromAPIRequest(req *api.ServiceRequest, accountID string) {
 		if apiTarget.Host != nil {
 			target.Host = *apiTarget.Host
 		}
+		if apiTarget.Options != nil {
+			opts, err := targetOptionsFromAPI(i, apiTarget.Options)
+			if err != nil {
+				return err
+			}
+			target.Options = opts
+		}
 		targets = append(targets, target)
 	}
 	s.Targets = targets
@@ -368,6 +466,8 @@ func (s *Service) FromAPIRequest(req *api.ServiceRequest, accountID string) {
 		}
 		s.Auth.BearerAuth = bearerAuth
 	}
+
+	return nil
 }
 
 func (s *Service) Validate() error {
@@ -400,11 +500,113 @@ func (s *Service) Validate() error {
 		if target.TargetId == "" {
 			return fmt.Errorf("target %d has empty target_id", i)
 		}
+		if err := validateTargetOptions(i, &target.Options); err != nil {
+			return err
+		}
 	}
 
 	return nil
 }
 
+const (
+	maxRequestTimeout = 5 * time.Minute
+	maxCustomHeaders  = 16
+	maxHeaderKeyLen   = 128
+	maxHeaderValueLen = 4096
+)
+
+// httpHeaderNameRe matches valid HTTP header field names per RFC 7230 token definition.
+var httpHeaderNameRe = regexp.MustCompile(`^[!#$%&'*+\-.^_` + "`" + `|~0-9A-Za-z]+$`)
+
+// hopByHopHeaders are headers that must not be set as custom headers
+// because they are connection-level and stripped by the proxy.
+var hopByHopHeaders = map[string]struct{}{
+	"Connection":          {},
+	"Keep-Alive":          {},
+	"Proxy-Authenticate":  {},
+	"Proxy-Authorization": {},
+	"Proxy-Connection":    {},
+	"Te":                  {},
+	"Trailer":             {},
+	"Transfer-Encoding":   {},
+	"Upgrade":             {},
+}
+
+// reservedHeaders are set authoritatively by the proxy or control HTTP framing
+// and cannot be overridden.
+var reservedHeaders = map[string]struct{}{
+	"Content-Length":      {},
+	"Content-Type":        {},
+	"Cookie":              {},
+	"Forwarded":           {},
+	"X-Forwarded-For":     {},
+	"X-Forwarded-Host":    {},
+	"X-Forwarded-Port":    {},
+	"X-Forwarded-Proto":   {},
+	"X-Real-Ip":           {},
+}
+
+func validateTargetOptions(idx int, opts *TargetOptions) error {
+	if opts.PathRewrite != "" && opts.PathRewrite != PathRewritePreserve {
+		return fmt.Errorf("target %d: unknown path_rewrite mode %q", idx, opts.PathRewrite)
+	}
+
+	if opts.RequestTimeout != 0 {
+		if opts.RequestTimeout <= 0 {
+			return fmt.Errorf("target %d: request_timeout must be positive", idx)
+		}
+		if opts.RequestTimeout > maxRequestTimeout {
+			return fmt.Errorf("target %d: request_timeout exceeds maximum of %s", idx, maxRequestTimeout)
+		}
+	}
+
+	if err := validateCustomHeaders(idx, opts.CustomHeaders); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func validateCustomHeaders(idx int, headers map[string]string) error {
+	if len(headers) > maxCustomHeaders {
+		return fmt.Errorf("target %d: custom_headers count %d exceeds maximum of %d", idx, len(headers), maxCustomHeaders)
+	}
+	seen := make(map[string]string, len(headers))
+	for key, value := range headers {
+		if !httpHeaderNameRe.MatchString(key) {
+			return fmt.Errorf("target %d: custom header key %q is not a valid HTTP header name", idx, key)
+		}
+		if len(key) > maxHeaderKeyLen {
+			return fmt.Errorf("target %d: custom header key %q exceeds maximum length of %d", idx, key, maxHeaderKeyLen)
+		}
+		if len(value) > maxHeaderValueLen {
+			return fmt.Errorf("target %d: custom header %q value exceeds maximum length of %d", idx, key, maxHeaderValueLen)
+		}
+		if containsCRLF(key) || containsCRLF(value) {
+			return fmt.Errorf("target %d: custom header %q contains invalid characters", idx, key)
+		}
+		canonical := http.CanonicalHeaderKey(key)
+		if prev, ok := seen[canonical]; ok {
+			return fmt.Errorf("target %d: custom header keys %q and %q collide (both canonicalize to %q)", idx, prev, key, canonical)
+		}
+		seen[canonical] = key
+		if _, ok := hopByHopHeaders[canonical]; ok {
+			return fmt.Errorf("target %d: custom header %q is a hop-by-hop header and cannot be set", idx, key)
+		}
+		if _, ok := reservedHeaders[canonical]; ok {
+			return fmt.Errorf("target %d: custom header %q is managed by the proxy and cannot be overridden", idx, key)
+		}
+		if canonical == "Host" {
+			return fmt.Errorf("target %d: use pass_host_header instead of setting Host as a custom header", idx)
+		}
+	}
+	return nil
+}
+
+func containsCRLF(s string) bool {
+	return strings.ContainsAny(s, "\r\n")
+}
+
 func (s *Service) EventMeta() map[string]any {
 	return map[string]any{"name": s.Name, "domain": s.Domain, "proxy_cluster": s.ProxyCluster, "source": s.Source, "auth": s.isAuthEnabled()}
 }
@@ -417,6 +619,12 @@ func (s *Service) Copy() *Service {
 	targets := make([]*Target, len(s.Targets))
 	for i, target := range s.Targets {
 		targetCopy := *target
+		if len(target.Options.CustomHeaders) > 0 {
+			targetCopy.Options.CustomHeaders = make(map[string]string, len(target.Options.CustomHeaders))
+			for k, v := range target.Options.CustomHeaders {
+				targetCopy.Options.CustomHeaders[k] = v
+			}
+		}
 		targets[i] = &targetCopy
 	}