mirror of
https://github.com/edgelesssys/constellation.git
synced 2024-09-23 01:35:52 +00:00
92 lines
2.8 KiB
Go
92 lines
2.8 KiB
Go
package ssh
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import (
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"context"
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"fmt"
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"log"
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"os"
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"sync"
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"github.com/edgelesssys/constellation/internal/deploy/user"
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)
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// UserKey describes an user that should be created with a corresponding public SSH key.
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type UserKey struct {
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Username string
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PublicKey string
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}
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// SSHAccess reads ssh public keys from a channel, creates the specified users if required and writes the public keys to the users authorized_keys file.
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type SSHAccess struct {
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userManager user.LinuxUserManager
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authorized map[string]bool
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mux sync.Mutex
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}
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// NewSSHAccess creates a new SSHAccess.
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func NewSSHAccess(userManager user.LinuxUserManager) *SSHAccess {
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return &SSHAccess{
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userManager: userManager,
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mux: sync.Mutex{},
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authorized: map[string]bool{},
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}
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}
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// alreadyAuthorized checks if key was written to authorized keys before.
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func (s *SSHAccess) alreadyAuthorized(sshKey UserKey) bool {
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_, ok := s.authorized[fmt.Sprintf("%s:%s", sshKey.Username, sshKey.PublicKey)]
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return ok
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}
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// rememberAuthorized marks this key as already written to authorized keys..
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func (s *SSHAccess) rememberAuthorized(sshKey UserKey) {
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s.authorized[fmt.Sprintf("%s:%s", sshKey.Username, sshKey.PublicKey)] = true
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}
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func (s *SSHAccess) DeploySSHAuthorizedKey(ctx context.Context, sshKey UserKey) error {
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// allow only one thread to write to authorized keys, create users and update the authorized map at a time
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s.mux.Lock()
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defer s.mux.Unlock()
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if s.alreadyAuthorized(sshKey) {
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return nil
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}
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log.Printf("Trying to deploy ssh key for %s\n", sshKey.Username)
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user, err := s.userManager.EnsureLinuxUserExists(ctx, sshKey.Username)
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if err != nil {
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return err
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}
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// CoreOS uses https://github.com/coreos/ssh-key-dir to search for ssh keys in ~/.ssh/authorized_keys.d/*
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sshFolder := fmt.Sprintf("%s/.ssh", user.Home)
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authorized_keys_d := fmt.Sprintf("%s/authorized_keys.d", sshFolder)
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if err := s.userManager.Fs.MkdirAll(authorized_keys_d, 0o700); err != nil {
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return err
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}
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if err := s.userManager.Fs.Chown(sshFolder, user.Uid, user.Gid); err != nil {
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return err
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}
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if err := s.userManager.Fs.Chown(authorized_keys_d, user.Uid, user.Gid); err != nil {
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return err
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}
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authorizedKeysPath := fmt.Sprintf("%s/ssh-keys", authorized_keys_d)
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authorizedKeysFile, err := s.userManager.Fs.OpenFile(authorizedKeysPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
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if err != nil {
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return err
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}
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_, err = authorizedKeysFile.WriteString(fmt.Sprintf("%s %s\n", sshKey.PublicKey, sshKey.Username))
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if err != nil {
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return err
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}
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if err := authorizedKeysFile.Close(); err != nil {
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return err
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}
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if err := s.userManager.Fs.Chown(authorizedKeysPath, user.Uid, user.Gid); err != nil {
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return err
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}
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if err := s.userManager.Fs.Chmod(authorizedKeysPath, 0o644); err != nil {
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return err
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}
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s.rememberAuthorized(sshKey)
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log.Printf("Successfully authorized %s\n", sshKey.Username)
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return nil
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}
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