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 // Without artifacts (ERMITE_CI_ARTIFACTS=0) the run page has no section
39 // for them and no download route.
40 var artifacts ports.ArtifactService
41 if cfg.CIArtifacts {
42 artifacts = f.CI
43 }
44 return web.New(web.Config{
45 Repos: f.Repos,
46 Browse: f.Browse,
47 MergeRequests: f.MergeRequests,
48 Issues: f.Issues,
49 IssueNumbers: f.Issues,
50 Inbox: f.Inbox,
51 IssueForm: f.IssueSubmissions,
52 Moderation: f.IssueModeration,
53 Runs: f.CI,
54 Artifacts: artifacts,
55 Events: f.EventLog,
56 Owner: cfg.Owner,
57 PublicURL: cfg.PublicURL,
58 SourceURL: cfg.SourceURL,
59 Version: serverVersion(),
60
61 Sessions: webSessions{f.Sessions},
62 Passkeys: passkeys,
63 Limiter: limiter,
64 TrustedProxies: cfg.TrustedProxies,
65 })
66}
67
68// sessionsNeedHTTPS reports whether browser sign-in cannot work on this public
69// URL: the session cookie is Secure (and __Host-), which a browser keeps only
70// from https, except on a loopback host (localhost, 127.0.0.0/8, ::1), where
71// browsers treat http as secure.
72func sessionsNeedHTTPS(publicURL string) bool {
73 u, err := url.Parse(publicURL)
74 if err != nil || !strings.EqualFold(u.Scheme, "http") {
75 return false
76 }
77 host := strings.ToLower(u.Hostname())
78 if host == "localhost" {
79 return false
80 }
81 ip, err := netip.ParseAddr(host)
82 return err != nil || !ip.Unmap().IsLoopback()
83}
84
85// passkeysAvailable reports whether passkeys can work on this public URL, and
86// if not, why. WebAuthn needs a secure context (https, or localhost) and a
87// relying party ID that is a DNS name, not an IP address, so a server on
88// http://127.0.0.1 starts without passkeys. A sign-in needs the session
89// cookie, hence the same https rule as sessionsNeedHTTPS.
90func passkeysAvailable(publicURL string) (ok bool, reason string) {
91 if sessionsNeedHTTPS(publicURL) {
92 return false, "needs https"
93 }
94 u, err := url.Parse(publicURL)
95 if err != nil || u.Hostname() == "" {
96 return false, "public URL has no host"
97 }
98 if _, err := netip.ParseAddr(strings.ToLower(u.Hostname())); err == nil {
99 return false, "public URL host is an IP address"
100 }
101 return true, ""
102}
103
104// warnSessionsNeedHTTPS tells the operator, at startup, that web sign-in will
105// not work on an http public URL. It does not stop the server: the pages,
106// the API and Git do not need the cookie.
107func warnSessionsNeedHTTPS(ctx context.Context, publicURL string) {
108 if !sessionsNeedHTTPS(publicURL) {
109 return
110 }
111 log := zerowrap.FromCtx(ctx)
112 log.Warn().Str("public_url", publicURL).Msg(
113 "browser sign-in cannot work: " + config.EnvPublicURL + " is http:// on a host that is not loopback, " +
114 "and the session cookie is Secure (__Host-), so browsers drop it; serve the site over https")
115}
116
117// warnSharedClientKey tells the operator, at startup, that without trusted
118// proxies every request is attributed to the address of its TCP peer. Behind a
119// reverse proxy that is the proxy: all the clients then share one key, and so
120// one cap on the Git backends running at once (maxPerClient) and one budget of
121// failed authentications. The keying is unchanged; the fix is to list the
122// proxy networks.
123func warnSharedClientKey(ctx context.Context, trusted []netip.Prefix, maxPerClient int) {
124 if len(trusted) > 0 || maxPerClient <= 0 {
125 return
126 }
127 log := zerowrap.FromCtx(ctx)
128 log.Warn().Int("max_git_backends_per_client", maxPerClient).Msg(
129 config.EnvTrustedProxies + " is not set: clients are told apart by their TCP peer address only. " +
130 "Behind a reverse proxy, all clients share the proxy's address, so one cap of concurrent Git " +
131 "requests and one budget of failed authentications; set it to the proxy networks")
132}
133
134// webSessions adapts the session use cases to ports.WebSessionService: a valid
135// token gives the owner, the principal the web passes to the use cases for
136// that request.
137type webSessions struct{ *usecase.Sessions }
138
139var _ ports.WebSessionService = webSessions{}
140
141func (s webSessions) Login(ctx context.Context, nonce string) (string, time.Duration, error) {
142 token, expiresAt, err := s.Sessions.Login(ctx, nonce)
143 if errors.Is(err, domain.ErrUnauthenticated) {
144 return "", 0, ports.ErrLinkRejected
145 }
146 if err != nil {
147 return "", 0, err
148 }
149 lifetime, ok := cookieLifetime(expiresAt)
150 if !ok {
151 return "", 0, ports.ErrLinkRejected
152 }
153 return token, lifetime, nil
154}
155
156// cookieLifetime is how long the session cookie lasts for a session that
157// expires at expiresAt: as long as the session, which the expiry of the token
158// that made a login link may cut short. The session token carries its own
159// expiry, so a cookie that outlives it by under a second is harmless. The
160// expiry is truncated to the second, hence the slack on the full TTL. ok is
161// false when under a second is left: there is no session to give.
162func cookieLifetime(expiresAt time.Time) (lifetime time.Duration, ok bool) {
163 lifetime = usecase.SessionTTL
164 if d := time.Until(expiresAt); d < usecase.SessionTTL-time.Second {
165 lifetime = d.Round(time.Second)
166 }
167 return lifetime, lifetime >= time.Second
168}
169
170func (s webSessions) Verify(ctx context.Context, token string) (domain.Principal, bool, error) {
171 p, err := s.Sessions.Verify(ctx, token)
172 if errors.Is(err, domain.ErrUnauthenticated) {
173 return domain.Anonymous(), false, nil
174 }
175 if err != nil {
176 return domain.Anonymous(), false, err
177 }
178 return p, true, nil
179}
180
181// webPasskeys adapts the passkey use cases to ports.WebPasskeyService. Only
182// FinishLogin differs from *usecase.Passkeys: the session a passkey sign-in
183// opens is given to the web as a token and a lifetime, like webSessions.Login
184// does for a link, and a refusal is ports.ErrLinkRejected.
185type webPasskeys struct{ *usecase.Passkeys }
186
187var _ ports.WebPasskeyService = webPasskeys{}
188
189func (p webPasskeys) FinishLogin(ctx context.Context, ceremony string, response []byte) (string, time.Duration, error) {
190 token, expiresAt, err := p.Passkeys.FinishLogin(ctx, ceremony, response)
191 if errors.Is(err, domain.ErrUnauthenticated) {
192 return "", 0, ports.ErrLinkRejected
193 }
194 if err != nil {
195 return "", 0, err
196 }
197 lifetime, ok := cookieLifetime(expiresAt)
198 if !ok {
199 return "", 0, ports.ErrLinkRejected
200 }
201 return token, lifetime, nil
202}
203
204// webRoutes mounts the web on the patterns it serves.
205func webRoutes(h http.Handler) []httpserver.Route {
206 routes := make([]httpserver.Route, 0, len(web.Patterns))
207 for _, p := range web.Patterns {
208 routes = append(routes, httpserver.Route{Pattern: p, Handler: h})
209 }
210 return routes
211}