Complete overhaul

client/cmd/ssh_exec_unix.go

@@ -0,0 +1,74 @@
+//go:build unix
+
+package cmd
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+
+	sshserver "github.com/netbirdio/netbird/client/ssh/server"
+)
+
+var (
+	sshExecUID        uint32
+	sshExecGID        uint32
+	sshExecGroups     []uint
+	sshExecWorkingDir string
+	sshExecShell      string
+	sshExecCommand    string
+	sshExecPTY        bool
+)
+
+// sshExecCmd represents the hidden ssh exec subcommand for privilege dropping
+var sshExecCmd = &cobra.Command{
+	Use:    "exec",
+	Short:  "Internal SSH execution with privilege dropping (hidden)",
+	Hidden: true,
+	RunE:   runSSHExec,
+}
+
+func init() {
+	sshExecCmd.Flags().Uint32Var(&sshExecUID, "uid", 0, "Target user ID")
+	sshExecCmd.Flags().Uint32Var(&sshExecGID, "gid", 0, "Target group ID")
+	sshExecCmd.Flags().UintSliceVar(&sshExecGroups, "groups", nil, "Supplementary group IDs (can be repeated)")
+	sshExecCmd.Flags().StringVar(&sshExecWorkingDir, "working-dir", "", "Working directory")
+	sshExecCmd.Flags().StringVar(&sshExecShell, "shell", "/bin/sh", "Shell to execute")
+	sshExecCmd.Flags().BoolVar(&sshExecPTY, "pty", false, "Request PTY (will fail as executor doesn't support PTY)")
+	sshExecCmd.Flags().StringVar(&sshExecCommand, "cmd", "", "Command to execute")
+
+	if err := sshExecCmd.MarkFlagRequired("uid"); err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "failed to mark uid flag as required: %v\n", err)
+		os.Exit(1)
+	}
+	if err := sshExecCmd.MarkFlagRequired("gid"); err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "failed to mark gid flag as required: %v\n", err)
+		os.Exit(1)
+	}
+
+	sshCmd.AddCommand(sshExecCmd)
+}
+
+// runSSHExec handles the SSH exec subcommand execution.
+func runSSHExec(cmd *cobra.Command, _ []string) error {
+	privilegeDropper := sshserver.NewPrivilegeDropper()
+
+	var groups []uint32
+	for _, groupInt := range sshExecGroups {
+		groups = append(groups, uint32(groupInt))
+	}
+
+	config := sshserver.ExecutorConfig{
+		UID:        sshExecUID,
+		GID:        sshExecGID,
+		Groups:     groups,
+		WorkingDir: sshExecWorkingDir,
+		Shell:      sshExecShell,
+		Command:    sshExecCommand,
+		PTY:        sshExecPTY,
+	}
+
+	privilegeDropper.ExecuteWithPrivilegeDrop(cmd.Context(), config)
+	return nil
+}