1// SPDX-License-Identifier: AGPL-3.0-or-later
2
3package app
4
5import (
6 "context"
7 "errors"
8 "net/http"
9 "net/netip"
10 "net/url"
11 "strings"
12 "time"
13
14 "github.com/bnema/zerowrap"
15
16 "bnema.dev/ermite/internal/adapters/httpserver"
17 "bnema.dev/ermite/internal/adapters/web"
18 "bnema.dev/ermite/internal/clientlimit"
19 "bnema.dev/ermite/internal/config"
20 "bnema.dev/ermite/internal/domain"
21 "bnema.dev/ermite/internal/ports"
22 "bnema.dev/ermite/internal/usecase"
23)
24
25// newWeb builds the web pages on the use cases of this process, through the
26// ports (ADR 0020), like the API and Git over HTTP.
27//
28// The owner's session cookie turns a request into the owner's (web.Server
29// checks it with sessions); every other request is anonymous. The web passes
30// the principal of the request to each use case call itself.
31func newWeb(cfg config.Config, f *forge, limiter *clientlimit.Limiter) (http.Handler, error) {
32 // A nil *usecase.Passkeys must not become a non-nil interface (the web
33 // tests for nil to leave the passkey routes out).
34 var passkeys ports.WebPasskeyService
35 if f.Passkeys != nil {
36 passkeys = webPasskeys{f.Passkeys}
37 }
38 return web.New(web.Config{
39 Repos: f.Repos,
40 Browse: f.Browse,
41 MergeRequests: f.MergeRequests,
42 Runs: f.CI,
43 Events: f.EventLog,
44 PublicURL: cfg.PublicURL,
45 SourceURL: cfg.SourceURL,
46 Version: serverVersion(),
47
48 Sessions: webSessions{f.Sessions},
49 Passkeys: passkeys,
50 Limiter: limiter,
51 TrustedProxies: cfg.TrustedProxies,
52 })
53}
54
55// sessionsNeedHTTPS reports whether browser sign-in cannot work on this public
56// URL: the session cookie is Secure (and __Host-), which a browser keeps only
57// from https, except on a loopback host (localhost, 127.0.0.0/8, ::1), where
58// browsers treat http as secure.
59func sessionsNeedHTTPS(publicURL string) bool {
60 u, err := url.Parse(publicURL)
61 if err != nil || !strings.EqualFold(u.Scheme, "http") {
62 return false
63 }
64 host := strings.ToLower(u.Hostname())
65 if host == "localhost" {
66 return false
67 }
68 ip, err := netip.ParseAddr(host)
69 return err != nil || !ip.Unmap().IsLoopback()
70}
71
72// passkeysAvailable reports whether passkeys can work on this public URL, and
73// if not, why. WebAuthn needs a secure context (https, or localhost) and a
74// relying party ID that is a DNS name, not an IP address, so a server on
75// http://127.0.0.1 starts without passkeys. A sign-in needs the session
76// cookie, hence the same https rule as sessionsNeedHTTPS.
77func passkeysAvailable(publicURL string) (ok bool, reason string) {
78 if sessionsNeedHTTPS(publicURL) {
79 return false, "needs https"
80 }
81 u, err := url.Parse(publicURL)
82 if err != nil || u.Hostname() == "" {
83 return false, "public URL has no host"
84 }
85 if _, err := netip.ParseAddr(strings.ToLower(u.Hostname())); err == nil {
86 return false, "public URL host is an IP address"
87 }
88 return true, ""
89}
90
91// warnSessionsNeedHTTPS tells the operator, at startup, that web sign-in will
92// not work on an http public URL. It does not stop the server: the pages,
93// the API and Git do not need the cookie.
94func warnSessionsNeedHTTPS(ctx context.Context, publicURL string) {
95 if !sessionsNeedHTTPS(publicURL) {
96 return
97 }
98 log := zerowrap.FromCtx(ctx)
99 log.Warn().Str("public_url", publicURL).Msg(
100 "browser sign-in cannot work: " + config.EnvPublicURL + " is http:// on a host that is not loopback, " +
101 "and the session cookie is Secure (__Host-), so browsers drop it; serve the site over https")
102}
103
104// warnSharedClientKey tells the operator, at startup, that without trusted
105// proxies every request is attributed to the address of its TCP peer. Behind a
106// reverse proxy that is the proxy: all the clients then share one key, and so
107// one cap on the Git backends running at once (maxPerClient) and one budget of
108// failed authentications. The keying is unchanged; the fix is to list the
109// proxy networks.
110func warnSharedClientKey(ctx context.Context, trusted []netip.Prefix, maxPerClient int) {
111 if len(trusted) > 0 || maxPerClient <= 0 {
112 return
113 }
114 log := zerowrap.FromCtx(ctx)
115 log.Warn().Int("max_git_backends_per_client", maxPerClient).Msg(
116 config.EnvTrustedProxies + " is not set: clients are told apart by their TCP peer address only. " +
117 "Behind a reverse proxy, all clients share the proxy's address, so one cap of concurrent Git " +
118 "requests and one budget of failed authentications; set it to the proxy networks")
119}
120
121// webSessions adapts the session use cases to ports.WebSessionService: a valid
122// token gives the owner, the principal the web passes to the use cases for
123// that request.
124type webSessions struct{ *usecase.Sessions }
125
126var _ ports.WebSessionService = webSessions{}
127
128func (s webSessions) Login(ctx context.Context, nonce string) (string, time.Duration, error) {
129 token, expiresAt, err := s.Sessions.Login(ctx, nonce)
130 if errors.Is(err, domain.ErrUnauthenticated) {
131 return "", 0, ports.ErrLinkRejected
132 }
133 if err != nil {
134 return "", 0, err
135 }
136 lifetime, ok := cookieLifetime(expiresAt)
137 if !ok {
138 return "", 0, ports.ErrLinkRejected
139 }
140 return token, lifetime, nil
141}
142
143// cookieLifetime is how long the session cookie lasts for a session that
144// expires at expiresAt: as long as the session, which the expiry of the token
145// that made a login link may cut short. The session token carries its own
146// expiry, so a cookie that outlives it by under a second is harmless. The
147// expiry is truncated to the second, hence the slack on the full TTL. ok is
148// false when under a second is left: there is no session to give.
149func cookieLifetime(expiresAt time.Time) (lifetime time.Duration, ok bool) {
150 lifetime = usecase.SessionTTL
151 if d := time.Until(expiresAt); d < usecase.SessionTTL-time.Second {
152 lifetime = d.Round(time.Second)
153 }
154 return lifetime, lifetime >= time.Second
155}
156
157func (s webSessions) Verify(ctx context.Context, token string) (domain.Principal, bool, error) {
158 p, err := s.Sessions.Verify(ctx, token)
159 if errors.Is(err, domain.ErrUnauthenticated) {
160 return domain.Anonymous(), false, nil
161 }
162 if err != nil {
163 return domain.Anonymous(), false, err
164 }
165 return p, true, nil
166}
167
168// webPasskeys adapts the passkey use cases to ports.WebPasskeyService. Only
169// FinishLogin differs from *usecase.Passkeys: the session a passkey sign-in
170// opens is given to the web as a token and a lifetime, like webSessions.Login
171// does for a link, and a refusal is ports.ErrLinkRejected.
172type webPasskeys struct{ *usecase.Passkeys }
173
174var _ ports.WebPasskeyService = webPasskeys{}
175
176func (p webPasskeys) FinishLogin(ctx context.Context, ceremony string, response []byte) (string, time.Duration, error) {
177 token, expiresAt, err := p.Passkeys.FinishLogin(ctx, ceremony, response)
178 if errors.Is(err, domain.ErrUnauthenticated) {
179 return "", 0, ports.ErrLinkRejected
180 }
181 if err != nil {
182 return "", 0, err
183 }
184 lifetime, ok := cookieLifetime(expiresAt)
185 if !ok {
186 return "", 0, ports.ErrLinkRejected
187 }
188 return token, lifetime, nil
189}
190
191// webRoutes mounts the web on the patterns it serves.
192func webRoutes(h http.Handler) []httpserver.Route {
193 routes := make([]httpserver.Route, 0, len(web.Patterns))
194 for _, p := range web.Patterns {
195 routes = append(routes, httpserver.Route{Pattern: p, Handler: h})
196 }
197 return routes
198}