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Fix concurrent map writes in codespace port forwarding #13313

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Merged
BagToad merged 6 commits into from
Jul 2, 2026
Merged

Fix concurrent map writes in codespace port forwarding #13313

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6957ebd
fix concurrent map writes in port forward
williammartin Apr 29, 2026
21d69cb
refactor: store connection as pointer instead of shallow copy
williammartin May 12, 2026
8736e0b
refactor: use require/assert in port forwarder tests
williammartin May 12, 2026
d5c4951
refactor: use defer for mutex unlock in UpdatePortVisibility
williammartin May 13, 2026
e33c0ee
refactor: fix TOCTOU in UpdatePortVisibility and revert signal change
williammartin May 13, 2026
619ea54
style(codespace): remove stray blank line in import group
BagToad Jul 2, 2026
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refactor: fix TOCTOU in UpdatePortVisibility and revert signal change 
- Hold ManagerMu across the entire get/check/delete sequence in
  UpdatePortVisibility to eliminate a time-of-check-time-of-use gap
- Remove IIFE pattern in favor of explicit lock/unlock
- Revert signal.NotifyContext change in cmd.go (out of scope)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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@williammartin
williammartin and Copilot committed May 13, 2026
commit e33c0eee5dc75b7a17397abb43a47bffa3e21871
18 changes: 8 additions & 10 deletions internal/codespaces/portforwarder/port_forwarder.go
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Original file line number Diff line number Diff line change
Expand Up @@ -270,30 +270,28 @@ func (fwd *CodespacesPortForwarder) ListPorts(ctx context.Context) (ports []*tun

// UpdatePortVisibility changes the visibility (private, org, public) of the specified port.
func (fwd *CodespacesPortForwarder) UpdatePortVisibility(ctx context.Context, remotePort int, visibility string) error {
tunnelPort, err := func() (*tunnels.TunnelPort, error) {
fwd.connection.ManagerMu.Lock()
defer fwd.connection.ManagerMu.Unlock()
return fwd.connection.TunnelManager.GetTunnelPort(ctx, fwd.connection.Tunnel, remotePort, fwd.connection.Options)
}()
fwd.connection.ManagerMu.Lock()
tunnelPort, err := fwd.connection.TunnelManager.GetTunnelPort(ctx, fwd.connection.Tunnel, remotePort, fwd.connection.Options)
if err != nil {
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williammartin marked this conversation as resolved.
fwd.connection.ManagerMu.Unlock()
return fmt.Errorf("error getting tunnel port: %w", err)
}

// If the port visibility isn't changing, don't do anything
if AccessControlEntriesToVisibility(tunnelPort.AccessControl.Entries) == visibility {
fwd.connection.ManagerMu.Unlock()
return nil
}

// Delete the existing tunnel port to update
port, err := convertIntToUint16(remotePort)
if err != nil {
fwd.connection.ManagerMu.Unlock()
return fmt.Errorf("error converting port: %w", err)
}
if err := func() error {
fwd.connection.ManagerMu.Lock()
defer fwd.connection.ManagerMu.Unlock()
return fwd.connection.TunnelManager.DeleteTunnelPort(ctx, fwd.connection.Tunnel, port, fwd.connection.Options)
}(); err != nil {
err = fwd.connection.TunnelManager.DeleteTunnelPort(ctx, fwd.connection.Tunnel, port, fwd.connection.Options)
fwd.connection.ManagerMu.Unlock()
if err != nil {
return fmt.Errorf("error deleting tunnel port: %w", err)
}

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9 changes: 2 additions & 7 deletions internal/ghcmd/cmd.go
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ import (
"net"
"os"
"os/exec"
"os/signal"

"path/filepath"
"slices"
"strconv"
Expand Down Expand Up @@ -135,12 +135,7 @@ func Main() exitCode {
}
}

// Intercept SIGINT/SIGTERM so that defers (e.g. telemetry flush) run
// before the process exits. Without this, the Go runtime's default
// signal handler calls os.Exit immediately, skipping all defers.
ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
defer stop()

ctx := context.Background()
updateCtx, updateCancel := context.WithCancel(ctx)
defer updateCancel()
updateMessageChan := make(chan *update.ReleaseInfo)
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