internal/control/control.go
429 lines · 15623 bytes
1// Package control implements the forge control commands executed over SSH.
2// Every command here is reachable from bare OpenSSH: argv in, JSON or plain
3// text on stdout, diagnostics on stderr, exit code out.
4package control
5
6import (
7 "encoding/json"
8 "errors"
9 "fmt"
10 "io"
11 "reflect"
12 "slices"
13 "strings"
14 "time"
15
16 "gitbay.org/gitbay/internal/config"
17 "gitbay.org/gitbay/internal/protocol"
18 "gitbay.org/gitbay/internal/store"
19)
20
21type Ctx struct {
22 User store.User
23 Scope string // scope of the key that authenticated this session
24 Store *store.Store
25 Cfg config.Config
26 Stdin io.Reader
27 Stdout io.Writer
28 Stderr io.Writer
29 JSON bool
30 // Term is the client's terminal, from GITBAY_TERM. The zero value
31 // is plain output.
32 Term Term
33 // CLIPath is the path the gitbay CLI resolved this call to, from a
34 // leading --path=, when it differs from the registered path being
35 // dispatched (auth keys remove for keys remove). Usage and help
36 // print it in place of the registered path (#267). Empty for stock
37 // ssh, the web and the API.
38 CLIPath string
39 // ViaAPI marks requests arriving over HTTP, from the token API or
40 // the web. Every command runs there; nothing is held back for SSH
41 // any more (#234). The flag stays because the rate limiter and the
42 // audit log want to know which door a request came through.
43 ViaAPI bool
44 // ReadOnly is set for read-scoped API tokens.
45 ReadOnly bool
46 // Source identifies the credential behind this session for the audit
47 // log: an SSH key fingerprint, or "api" for token requests.
48 Source string
49 // TokenID is the API token behind this request, 0 for none. A
50 // credential the request creates records it.
51 TokenID int64
52 // Expires is when the credential behind this request lapses; nil
53 // when it does not. Dispatch refuses MintsCredential commands when
54 // it is set.
55 Expires *time.Time
56 // Cmd is the command being run, set by Dispatch, so a usage error can
57 // print the registered usage rather than a copy of it.
58 Cmd Command
59 // Argv is the command's arguments after its path, global flags
60 // removed, so output can print a command to run next.
61 Argv []string
62 // Done, when the surface has one, closes when nobody is reading any
63 // more: the SSH channel closed or the HTTP request ended. A command
64 // that runs until something happens (build log --follow) stops on it.
65 Done <-chan struct{}
66 // Stopping, when the surface has one, closes when the daemon is
67 // restarting. It closes Done too; a command that ends on Done checks
68 // it to say why.
69 Stopping <-chan struct{}
70}
71
72// SourceWeb is Ctx.Source for a request from a browser session. Its
73// User.SignedInAt is when that session signed in.
74const SourceWeb = "web"
75
76// SourceMail is Ctx.Source for a comment posted by replying to
77// notification mail (#295).
78const SourceMail = "mail"
79
80// ReauthWindow is how long after signing in a browser session may run a
81// NeedsRecentSignIn command. A session lasts days and its cookie is a
82// bearer credential; what it creates or grants must come from a recent
83// sign-in (#297).
84const ReauthWindow = 15 * time.Minute
85
86// ReauthRefusal is what a web session signed in longer ago than
87// ReauthWindow gets; the web shows a sign-in link beside it.
88var ReauthRefusal = fmt.Sprintf("this action from the web needs a sign-in from the last %d minutes; sign in again, then submit the form again",
89 int(ReauthWindow/time.Minute))
90
91// staleSignIn reports whether a web session that signed in at at is too
92// old, at now, to run a NeedsRecentSignIn command. A zero at is stale.
93func staleSignIn(at, now time.Time) bool {
94 return now.Sub(at) > ReauthWindow
95}
96
97// usage reports a bad invocation with the command's registered usage,
98// the one source of it.
99func (c *Ctx) usage() int {
100 return c.fail(protocol.ExitUsage, "usage: %s", c.cmdUsage())
101}
102
103// usageWith reports a specific problem with the arguments, then the
104// registered usage, so a person always sees the shape that was expected.
105func (c *Ctx) usageWith(msg string) int {
106 return c.fail(protocol.ExitUsage, "%s\nusage: %s", msg, c.cmdUsage())
107}
108
109// Flag is one flag in a command's help.
110type Flag struct {
111 Name string `json:"name"` // "--state"
112 Arg string `json:"arg,omitempty"` // "open|closed|all"; empty for a switch
113 Desc string `json:"desc,omitempty"` // what it does, lower case, no full stop
114 Default string `json:"default,omitempty"` // empty for none
115}
116
117type Command struct {
118 Path []string // e.g. ["keys", "add"]
119 // Summary is one line of prose: what the command does, no argument
120 // syntax. Usage is the argument syntax, opening with the command path.
121 // help renders them separately, so neither may carry the other's job.
122 Summary string
123 Usage string
124 Flags []Flag
125 Examples []string // full argv after the program, repository named
126 ReadsStdin bool
127 ReadOnly bool // safe for read-scoped API tokens
128 // MintsCredential marks a command that creates a credential or a way
129 // to obtain one: tokens, keys, login links, invites, accounts,
130 // verified addresses. An expiring credential may not run it.
131 MintsCredential bool
132 // NeedsRecentSignIn marks a command a browser session may run only
133 // within ReauthWindow of signing in: every MintsCredential command,
134 // and those that give an account lasting access or open a standing
135 // channel out of the instance.
136 NeedsRecentSignIn bool
137 Run func(c *Ctx, args []string) int
138}
139
140var registry []Command
141
142func register(cmd Command) { registry = append(registry, cmd) }
143
144// Commands returns the registry, for the bare-ssh reachability test.
145func Commands() []Command { return registry }
146
147// Lookup resolves argv to a command by longest path match, returning the
148// command and the remaining arguments.
149func Lookup(argv []string) (Command, []string, bool) {
150 best := -1
151 var found Command
152 for _, cmd := range registry {
153 if len(cmd.Path) <= len(argv) && slices.Equal(cmd.Path, argv[:len(cmd.Path)]) && len(cmd.Path) > best {
154 best = len(cmd.Path)
155 found = cmd
156 }
157 }
158 if best < 0 {
159 return Command{}, nil, false
160 }
161 return found, argv[best:], true
162}
163
164// Dispatch runs argv for an authenticated session. The dispatcher — not the
165// handlers — enforces key scope: control commands require a full-scope key.
166func Dispatch(c *Ctx, argv []string) int {
167 if len(argv) == 0 {
168 return c.fail(protocol.ExitUsage, "no command given; try: ssh <host> help")
169 }
170 // A leading --term=<v> selects terminal output for this session, the
171 // same as GITBAY_TERM; a leading --path=<v> is the CLI's own path for
172 // the command (Ctx.CLIPath). Both come off before Lookup, in either
173 // order: Lookup matches argv against a command's Path, and either in
174 // front would never match one. Over HTTP both are dropped unread: the
175 // web and the API render no terminal and have no CLI path.
176 for len(argv) > 0 {
177 if v, ok := strings.CutPrefix(argv[0], "--term="); ok {
178 if !c.ViaAPI {
179 c.Term = ParseTerm(v)
180 }
181 } else if v, ok := strings.CutPrefix(argv[0], "--path="); ok {
182 if !c.ViaAPI {
183 c.CLIPath = v
184 }
185 } else {
186 break
187 }
188 argv = argv[1:]
189 }
190 if len(argv) == 0 {
191 return c.fail(protocol.ExitUsage, "no command given; try: ssh <host> help")
192 }
193 cmd, rest, ok := Lookup(argv)
194 c.Cmd = cmd
195 if !ok {
196 return c.fail(protocol.ExitUsage, "unknown command %q", argv[0])
197 }
198 // Strip the global --json flag wherever it appears, before any
199 // refusal below: a scripted caller needs the envelope most when it is
200 // being told no (#109).
201 args := rest[:0:0]
202 for _, a := range rest {
203 if a == "--json" {
204 c.JSON = true
205 continue
206 }
207 args = append(args, a)
208 }
209 c.Argv = args
210 code := runChecked(c, cmd, args)
211 if !cmd.ReadOnly {
212 switch code {
213 case protocol.ExitOK:
214 // Every successful mutating command lands in the audit log.
215 c.Store.Audit(c.User.ID, "cmd "+joinPath(cmd.Path), map[string]any{"argv": auditArgs(args), "source": c.Source})
216 case protocol.ExitDenied, protocol.ExitNotFound:
217 // So does every refused one: probing leaves a trace.
218 AuditRefused(c.Store, c.User.ID, "refused "+joinPath(cmd.Path),
219 map[string]any{"argv": refusalArgs(args), "source": c.Source, "exit": code})
220 }
221 }
222 return code
223}
224
225// runChecked applies the dispatcher's own gates, then runs the command.
226func runChecked(c *Ctx, cmd Command, args []string) int {
227 // A runner-scoped key reaches the runner protocol and nothing else, so
228 // the key a CI host holds cannot administer the instance.
229 if c.Scope != "full" && !(c.Scope == "runner" && cmd.Path[0] == "runner") {
230 return c.fail(protocol.ExitDenied, "this key's scope (%s) does not allow control commands; use a key added with --scope full", c.Scope)
231 }
232 if c.ReadOnly && !cmd.ReadOnly {
233 return c.fail(protocol.ExitDenied, "this token is read-only; %s modifies state — mint one with --scope full", joinPath(cmd.Path))
234 }
235 // What an expiring credential creates would outlive it (#257).
236 if cmd.MintsCredential && c.Expires != nil {
237 return c.fail(protocol.ExitDenied,
238 "%s creates a credential, and the one this request came with expires; use a token or key without an expiry", joinPath(cmd.Path))
239 }
240 // The SSH listener refuses a disabled account before it gets here; the
241 // API and the web reach Dispatch directly, so the check lives here too.
242 if c.User.Disabled {
243 return c.fail(protocol.ExitDenied, "this account is disabled; ask an instance admin to enable it")
244 }
245 if cmd.NeedsRecentSignIn && c.Source == SourceWeb && staleSignIn(c.User.SignedInAt, time.Now()) {
246 return c.fail(protocol.ExitDenied, "%s", ReauthRefusal)
247 }
248 // The admin noun is gated here as well as in each handler, so a new
249 // admin command that forgets requireInstanceAdmin is still refused.
250 if cmd.Path[0] == "admin" && !c.User.IsAdmin {
251 return c.fail(protocol.ExitDenied, "admin commands are for instance admins; ask one")
252 }
253 if c.User.Pending && !pendingAllowed(cmd.Path) {
254 return c.fail(protocol.ExitDenied,
255 "your account is not active yet: verify your email first (email verify <code>, or ask for the mail again with email add)")
256 }
257 if code := limitWrites(c, cmd); code >= 0 {
258 return code
259 }
260 if !cmd.ReadsStdin {
261 c.Stdin = emptyReader{}
262 }
263 return cmd.Run(c, args)
264}
265
266// auditArgs is argv with flag values dropped. Secrets never reach argv —
267// they travel on stdin — but prose does: `issue create a/b --title x
268// --body <the whole issue>` used to store the body verbatim, in a table
269// nothing pruned, for a repository that may be private. The identifiers
270// are positional, so keeping those and the flag names says what was done
271// without copying what was written (#122).
272func auditArgs(args []string) []string {
273 out := make([]string, 0, len(args))
274 for i := 0; i < len(args); i++ {
275 a := args[i]
276 if !strings.HasPrefix(a, "--") {
277 out = append(out, a)
278 continue
279 }
280 // A gate refuses before parseFlags runs, so a "--name=value"
281 // token reaches here whole; only the name is kept.
282 name, _, _ := strings.Cut(a, "=")
283 out = append(out, name)
284 // "--" ends flag parsing; everything after it is positional.
285 if a == "--" {
286 out = append(out, args[i+1:]...)
287 break
288 }
289 // A flag's value is the next argument unless that is itself a
290 // flag, which is how a switch is told from one that takes a value
291 // without consulting the command's spec.
292 if i+1 < len(args) && !strings.HasPrefix(args[i+1], "--") {
293 i++
294 }
295 }
296 return out
297}
298
299// refusalArgs is what a refusal row keeps of argv: the flag names and the
300// first positional, which names the target. A gate refuses before the
301// handler checks its arguments, so later positionals may be anything the
302// caller typed, a value meant for stdin included.
303func refusalArgs(args []string) []string {
304 out := []string{}
305 target := false
306 for _, a := range auditArgs(args) {
307 if a == "--" {
308 break
309 }
310 if strings.HasPrefix(a, "--") {
311 out = append(out, a)
312 } else if !target {
313 out = append(out, a)
314 target = true
315 }
316 }
317 return out
318}
319
320// pendingAllowed lists what an unverified self-registered account may do.
321// limitWrites spends one token of the account's write budget, and refuses
322// with the wait when it is empty. Returns -1 when the command may run.
323//
324// Exempt: read-only commands, which cost the instance nothing to serve
325// twice; the runner protocol, which streams a build's log in many small
326// writes and would throttle CI; and the host CLI on the server, which has
327// no account to key on and is already root-equivalent.
328func limitWrites(c *Ctx, cmd Command) int {
329 if cmd.ReadOnly || cmd.Path[0] == "runner" || c.Source == "host" || c.User.ID == 0 {
330 return -1
331 }
332 perMinute := c.Cfg.Limits.WriteRate
333 if perMinute == 0 {
334 perMinute = config.DefaultWriteRate
335 }
336 if perMinute < 0 {
337 return -1
338 }
339 if ok, wait := writes.allow(c.User.ID, perMinute); !ok {
340 return c.fail(protocol.ExitDenied,
341 "too many writes: %d a minute per account; try again in %s",
342 perMinute, wait.Round(time.Second))
343 }
344 return -1
345}
346
347func pendingAllowed(path []string) bool {
348 key := joinPath(path)
349 return key == "email verify" || key == "email add" || key == "whoami" || key == "help"
350}
351
352type emptyReader struct{}
353
354func (emptyReader) Read([]byte) (int, error) { return 0, io.EOF }
355
356// emit writes data as the command result: a JSON envelope under --json,
357// otherwise via the plain formatter.
358func (c *Ctx) emit(data any, plain func(w io.Writer)) int {
359 // A nil slice would serialize as null; consumers should see [].
360 v := reflect.ValueOf(data)
361 if v.Kind() == reflect.Slice && v.IsNil() {
362 data = reflect.MakeSlice(v.Type(), 0, 0).Interface()
363 }
364 // An empty list prints nothing a script would read; the person at
365 // the terminal hears about it on stderr.
366 if !c.JSON && v.Kind() == reflect.Slice && v.Len() == 0 {
367 fmt.Fprintln(c.Stderr, "nothing to list")
368 return protocol.ExitOK
369 }
370 if c.JSON {
371 enc := json.NewEncoder(c.Stdout)
372 enc.SetEscapeHTML(false)
373 if err := enc.Encode(protocol.Envelope{ProtocolVersion: protocol.Version, Data: data}); err != nil {
374 return protocol.ExitFailure
375 }
376 return protocol.ExitOK
377 }
378 plain(c.Stdout)
379 return protocol.ExitOK
380}
381
382// failErr reports an error from a store call: not-found is not-found,
383// and anything else — the database failing, a duplicate, a state that
384// does not allow the change — is a failure. An error about the caller's
385// own arguments goes through failInput instead; this used to default to
386// usage, which turned every refusal into exit 2 (#211).
387func (c *Ctx) failErr(err error) int {
388 if errors.Is(err, store.ErrNotFound) {
389 return c.fail(protocol.ExitNotFound, "%v", err)
390 }
391 return c.fail(protocol.ExitFailure, "%v", err)
392}
393
394// failInput reports an error about the caller's input — a name that does
395// not validate, a flag value out of range, a body that could not be read
396// — as a usage error, unless the database or I/O failed underneath it.
397// A SQLite I/O error used to be a usage error and an HTTP 400 (#107).
398func (c *Ctx) failInput(err error) int {
399 switch {
400 case errors.Is(err, store.ErrNotFound):
401 return c.fail(protocol.ExitNotFound, "%v", err)
402 case store.IsInternal(err):
403 return c.fail(protocol.ExitFailure, "%v", err)
404 }
405 return c.fail(protocol.ExitUsage, "%v", err)
406}
407
408func (c *Ctx) fail(code int, format string, args ...any) int {
409 msg := fmt.Sprintf(format, args...)
410 if c.JSON {
411 enc := json.NewEncoder(c.Stdout)
412 enc.SetEscapeHTML(false)
413 enc.Encode(protocol.Envelope{ProtocolVersion: protocol.Version, Error: msg})
414 } else {
415 fmt.Fprintln(c.Stderr, msg)
416 }
417 return code
418}
419
420func joinPath(p []string) string {
421 out := ""
422 for i, s := range p {
423 if i > 0 {
424 out += " "
425 }
426 out += s
427 }
428 return out
429}