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fix: Use instance identity session token for git subcommands #4884

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Merged
merged 1 commit into from
Nov 4, 2022
Merged

fix: Use instance identity session token for git subcommands #4884

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28 changes: 18 additions & 10 deletions agent/agent.go
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Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,7 @@ const (

type Options struct {
Filesystem afero.Fs
ExchangeToken func(ctx context.Context) error
ExchangeToken func(ctx context.Context) (string, error)
Client Client
ReconnectingPTYTimeout time.Duration
EnvironmentVariables map[string]string
Expand All @@ -78,6 +78,11 @@ func New(options Options) io.Closer {
if options.Filesystem == nil {
options.Filesystem = afero.NewOsFs()
}
if options.ExchangeToken == nil {
options.ExchangeToken = func(ctx context.Context) (string, error) {
return "", nil
}
}
ctx, cancelFunc := context.WithCancel(context.Background())
server := &agent{
reconnectingPTYTimeout: options.ReconnectingPTYTimeout,
Expand All @@ -97,7 +102,7 @@ func New(options Options) io.Closer {
type agent struct {
logger slog.Logger
client Client
exchangeToken func(ctx context.Context) error
exchangeToken func(ctx context.Context) (string, error)
filesystem afero.Fs

reconnectingPTYs sync.Map
Expand All @@ -110,8 +115,9 @@ type agent struct {

envVars map[string]string
// metadata is atomic because values can change after reconnection.
metadata atomic.Value
sshServer *ssh.Server
metadata atomic.Value
sessionToken atomic.Pointer[string]
sshServer *ssh.Server

network *tailnet.Conn
stats *Stats
Expand Down Expand Up @@ -147,14 +153,13 @@ func (a *agent) run(ctx context.Context) error {
// This allows the agent to refresh it's token if necessary.
// For instance identity this is required, since the instance
// may not have re-provisioned, but a new agent ID was created.
if a.exchangeToken != nil {
err := a.exchangeToken(ctx)
if err != nil {
return xerrors.Errorf("exchange token: %w", err)
}
sessionToken, err := a.exchangeToken(ctx)
if err != nil {
return xerrors.Errorf("exchange token: %w", err)
}
a.sessionToken.Store(&sessionToken)

err := a.client.PostWorkspaceAgentVersion(ctx, buildinfo.Version())
err = a.client.PostWorkspaceAgentVersion(ctx, buildinfo.Version())
if err != nil {
return xerrors.Errorf("update workspace agent version: %w", err)
}
Expand Down Expand Up @@ -576,6 +581,9 @@ func (a *agent) createCommand(ctx context.Context, rawCommand string, env []stri
unixExecutablePath := strings.ReplaceAll(executablePath, "\\", "/")
cmd.Env = append(cmd.Env, fmt.Sprintf(`GIT_SSH_COMMAND=%s gitssh --`, unixExecutablePath))

// Specific Coder subcommands require the agent token exposed!
cmd.Env = append(cmd.Env, fmt.Sprintf("CODER_AGENT_TOKEN=%s", *a.sessionToken.Load()))

// Set SSH connection environment variables (these are also set by OpenSSH
// and thus expected to be present by SSH clients). Since the agent does
// networking in-memory, trying to provide accurate values here would be
Expand Down
8 changes: 4 additions & 4 deletions agent/agent_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -532,9 +532,9 @@ func TestAgent(t *testing.T) {
}
initialized := atomic.Int32{}
closer := agent.New(agent.Options{
ExchangeToken: func(ctx context.Context) error {
ExchangeToken: func(ctx context.Context) (string, error) {
initialized.Add(1)
return nil
return "", nil
},
Client: client,
Logger: slogtest.Make(t, nil).Leveled(slog.LevelInfo),
Expand Down Expand Up @@ -565,8 +565,8 @@ func TestAgent(t *testing.T) {
}
filesystem := afero.NewMemMapFs()
closer := agent.New(agent.Options{
ExchangeToken: func(ctx context.Context) error {
return nil
ExchangeToken: func(ctx context.Context) (string, error) {
return "", nil
},
Client: client,
Logger: slogtest.Make(t, nil).Leveled(slog.LevelInfo),
Expand Down
13 changes: 5 additions & 8 deletions cli/agent.go
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Original file line number Diff line number Diff line change
Expand Up @@ -156,22 +156,19 @@ func workspaceAgent() *cobra.Command {
closer := agent.New(agent.Options{
Client: client,
Logger: logger,
ExchangeToken: func(ctx context.Context) error {
ExchangeToken: func(ctx context.Context) (string, error) {
if exchangeToken == nil {
return nil
return client.SessionToken, nil
}
resp, err := exchangeToken(ctx)
if err != nil {
return err
return "", err
}
client.SessionToken = resp.SessionToken
return nil
return "", nil
},
EnvironmentVariables: map[string]string{
// Override the "CODER_AGENT_TOKEN" variable in all
// shells so "gitssh" and "gitaskpass" works!
"CODER_AGENT_TOKEN": client.SessionToken,
"GIT_ASKPASS": executablePath,
"GIT_ASKPASS": executablePath,
},
})
<-cmd.Context().Done()
Expand Down