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Code Issues 3.0k Packages Projects Releases 10 Wiki Activity

Split prepareAgentSocketDir to reduce cognitive complexity

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This commit is contained in:
Viktor Liu
2026-05-25 15:09:28 +02:00
parent 3bcacffd2c
commit 6cd5d6084f
1 changed files with 53 additions and 34 deletions
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87
client/vnc/server/agent_darwin.go
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@@ -143,42 +143,12 @@ func (m *darwinAgentManager) Resolve(ctx context.Context) (string, string, uint3
// directory) so a low-priv user cannot redirect the chown that follows.
func prepareAgentSocketDir(uid uint32) (string, error) {
parent := configs.RuntimeDir
if parent == "" {
return "", fmt.Errorf("no runtime directory configured for this platform")
if err := ensureAgentSocketParent(parent); err != nil {
return "", err
}
if err := os.MkdirAll(parent, 0o755); err != nil {
return "", fmt.Errorf("mkdir %s: %w", parent, err)
}
pInfo, err := os.Lstat(parent)
if err != nil {
return "", fmt.Errorf("lstat %s: %w", parent, err)
}
if pInfo.Mode()&os.ModeSymlink != 0 {
return "", fmt.Errorf("%s is a symlink", parent)
}
if st, ok := pInfo.Sys().(*syscall.Stat_t); ok && st.Uid != 0 {
return "", fmt.Errorf("%s not owned by root (uid=%d)", parent, st.Uid)
}
subdir := fmt.Sprintf("%s/vnc-%d", parent, uid)
// If a leftover entry exists, refuse it unless it's a real dir owned
// by the right uid with strict perms: otherwise remove and recreate
// from scratch under our control. Using os.Lstat (not Stat) so a
// symlink is detected and torn down.
if info, err := os.Lstat(subdir); err == nil {
bad := false
if info.Mode()&os.ModeSymlink != 0 {
bad = true
} else if !info.IsDir() {
bad = true
} else if st, ok := info.Sys().(*syscall.Stat_t); !ok || st.Uid != uid || info.Mode().Perm() != 0o700 {
bad = true
}
if bad {
if err := os.RemoveAll(subdir); err != nil {
return "", fmt.Errorf("remove stale %s: %w", subdir, err)
}
}
if err := purgeStaleAgentSubdir(subdir, uid); err != nil {
return "", err
}
if err := os.Mkdir(subdir, 0o700); err != nil && !errors.Is(err, os.ErrExist) {
return "", fmt.Errorf("mkdir %s: %w", subdir, err)
@@ -192,6 +162,55 @@ func prepareAgentSocketDir(uid uint32) (string, error) {
return subdir, nil
}
// ensureAgentSocketParent verifies the runtime parent dir exists, is not a
// symlink, and is owned by root.
func ensureAgentSocketParent(parent string) error {
if parent == "" {
return fmt.Errorf("no runtime directory configured for this platform")
}
if err := os.MkdirAll(parent, 0o755); err != nil {
return fmt.Errorf("mkdir %s: %w", parent, err)
}
info, err := os.Lstat(parent)
if err != nil {
return fmt.Errorf("lstat %s: %w", parent, err)
}
if info.Mode()&os.ModeSymlink != 0 {
return fmt.Errorf("%s is a symlink", parent)
}
if st, ok := info.Sys().(*syscall.Stat_t); ok && st.Uid != 0 {
return fmt.Errorf("%s not owned by root (uid=%d)", parent, st.Uid)
}
return nil
}
// purgeStaleAgentSubdir removes a leftover subdir unless it is a real dir
// owned by uid with mode 0700. Lstat (not Stat) so a symlink is detected.
func purgeStaleAgentSubdir(subdir string, uid uint32) error {
info, err := os.Lstat(subdir)
if err != nil {
return nil
}
if agentSubdirOK(info, uid) {
return nil
}
if err := os.RemoveAll(subdir); err != nil {
return fmt.Errorf("remove stale %s: %w", subdir, err)
}
return nil
}
func agentSubdirOK(info os.FileInfo, uid uint32) bool {
if info.Mode()&os.ModeSymlink != 0 || !info.IsDir() {
return false
}
st, ok := info.Sys().(*syscall.Stat_t)
if !ok {
return false
}
return st.Uid == uid && info.Mode().Perm() == 0o700
}
// stop terminates the spawned agent, if any. Intended for daemon shutdown.
func (m *darwinAgentManager) stop() {
m.mu.Lock()