| 1 | package home |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "encoding/base64" |
| 6 | "net/http" |
| 7 | "strings" |
| 8 | "time" |
| 9 | |
| 10 | "amadan.net/oficina/home/internal/home/directorydata" |
| 11 | "amadan.net/oficina/home/roster" |
| 12 | ) |
| 13 | |
| 14 | const rosterPath = "/roster" |
| 15 | |
| 16 | type rosterReadSource interface { |
| 17 | Read(context.Context, directorydata.RosterRequest, time.Time) (roster.Page, int, error) |
| 18 | } |
| 19 | type rosterHandler struct { |
| 20 | runtime rosterRuntime |
| 21 | directory string |
| 22 | source rosterReadSource |
| 23 | now func() time.Time |
| 24 | } |
| 25 | |
| 26 | func newRosterHandler(cfg Runtime, source rosterReadSource) (*rosterHandler, error) { |
| 27 | if cfg.role != "directory" || !cfg.roster.valid(cfg.role, cfg.keys) || !directorydata.ValidOrigin(cfg.origins.Directory) || (cfg.roster.mode == "serve") != (source != nil) { |
| 28 | return nil, errExchangeConfig |
| 29 | } |
| 30 | return &rosterHandler{runtime: cfg.roster, directory: cfg.origins.Directory, source: source, now: time.Now}, nil |
| 31 | } |
| 32 | func rosterFailure(w http.ResponseWriter, status int) { |
| 33 | code := "unavailable" |
| 34 | switch status { |
| 35 | case 400: |
| 36 | code = "bad_request" |
| 37 | case 401: |
| 38 | code = "unauthorized" |
| 39 | case 404: |
| 40 | code = "not_found" |
| 41 | case 405: |
| 42 | code = "method_not_allowed" |
| 43 | default: |
| 44 | status = 503 |
| 45 | } |
| 46 | w.WriteHeader(status) |
| 47 | _, _ = w.Write([]byte(`{"error":"` + code + `"}`)) |
| 48 | } |
| 49 | func rosterQuery(r *http.Request, directory string) (directorydata.RosterRequest, bool) { |
| 50 | var req directorydata.RosterRequest |
| 51 | if r.URL.EscapedPath() != rosterPath || r.URL.IsAbs() || r.URL.Fragment != "" || r.ContentLength != 0 || len(r.TransferEncoding) != 0 || len(r.RequestURI) > 4096 || len(directory)+len(rosterPath)+1+len(r.URL.RawQuery) > 4096 { |
| 52 | return req, false |
| 53 | } |
| 54 | fields := strings.Split(r.URL.RawQuery, "&") |
| 55 | if len(fields) != 2 && len(fields) != 3 { |
| 56 | return req, false |
| 57 | } |
| 58 | seen := map[string]bool{} |
| 59 | for _, field := range fields { |
| 60 | name, value, ok := strings.Cut(field, "=") |
| 61 | if !ok || value == "" || seen[name] { |
| 62 | return req, false |
| 63 | } |
| 64 | seen[name] = true |
| 65 | switch name { |
| 66 | case "team": |
| 67 | if len(value) > 64 { |
| 68 | return req, false |
| 69 | } |
| 70 | for _, c := range value { |
| 71 | if !(c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z' || c >= '0' && c <= '9') { |
| 72 | return req, false |
| 73 | } |
| 74 | } |
| 75 | req.Team = value |
| 76 | case "fetch": |
| 77 | if !roster.ValidChallenge(value) { |
| 78 | return req, false |
| 79 | } |
| 80 | req.Fetch = value |
| 81 | case "cursor": |
| 82 | if len(value) > roster.CursorLimit { |
| 83 | return req, false |
| 84 | } |
| 85 | b, e := base64.RawURLEncoding.Strict().DecodeString(value) |
| 86 | if e != nil || base64.RawURLEncoding.EncodeToString(b) != value { |
| 87 | return req, false |
| 88 | } |
| 89 | req.Cursor = value |
| 90 | default: |
| 91 | return req, false |
| 92 | } |
| 93 | } |
| 94 | return req, seen["team"] && seen["fetch"] |
| 95 | } |
| 96 | func rosterBearer(headers http.Header) (string, bool) { |
| 97 | var values []string |
| 98 | for name, v := range headers { |
| 99 | if strings.EqualFold(name, "Authorization") { |
| 100 | values = append(values, v...) |
| 101 | } |
| 102 | } |
| 103 | if len(values) != 1 || !strings.HasPrefix(values[0], "Bearer ") { |
| 104 | return "", false |
| 105 | } |
| 106 | token := strings.TrimPrefix(values[0], "Bearer ") |
| 107 | return token, roster.ValidChallenge(token) |
| 108 | } |
| 109 | func (h *rosterHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { |
| 110 | w.Header().Set("Cache-Control", "no-store, no-transform") |
| 111 | w.Header().Set("Content-Type", "application/json") |
| 112 | w.Header().Set("X-Content-Type-Options", "nosniff") |
| 113 | if r.Host != strings.TrimPrefix(h.directory, "https://") { |
| 114 | rosterFailure(w, 404) |
| 115 | return |
| 116 | } |
| 117 | if r.Method != http.MethodGet { |
| 118 | w.Header().Set("Allow", "GET") |
| 119 | rosterFailure(w, 405) |
| 120 | return |
| 121 | } |
| 122 | if h.runtime.mode != "serve" { |
| 123 | rosterFailure(w, 503) |
| 124 | return |
| 125 | } |
| 126 | req, ok := rosterQuery(r, h.directory) |
| 127 | if !ok { |
| 128 | rosterFailure(w, 400) |
| 129 | return |
| 130 | } |
| 131 | req.Token, ok = rosterBearer(r.Header) |
| 132 | if !ok { |
| 133 | rosterFailure(w, 401) |
| 134 | return |
| 135 | } |
| 136 | now := h.now() |
| 137 | if now.Unix() <= 0 { |
| 138 | rosterFailure(w, 503) |
| 139 | return |
| 140 | } |
| 141 | ctx, cancel := context.WithTimeout(r.Context(), 5*time.Second) |
| 142 | defer cancel() |
| 143 | page, status, err := h.source.Read(ctx, req, now) |
| 144 | if err != nil { |
| 145 | if !(status == 400 && err == directorydata.ErrRosterBadRequest || status == 401 && err == directorydata.ErrRosterUnauthorized || status == 404 && err == directorydata.ErrRosterNotFound || status == 503 && err == directorydata.ErrUnavailable) { |
| 146 | status = 503 |
| 147 | } |
| 148 | rosterFailure(w, status) |
| 149 | return |
| 150 | } |
| 151 | if !(status == 200 && page.Type == "page" || status == 409 && page.Type == "stale-cursor") { |
| 152 | rosterFailure(w, 503) |
| 153 | return |
| 154 | } |
| 155 | wire, err := roster.SignPage(h.runtime.signer, h.runtime.keyID, page) |
| 156 | if err != nil || len(wire) > roster.BodyLimit { |
| 157 | rosterFailure(w, 503) |
| 158 | return |
| 159 | } |
| 160 | w.WriteHeader(status) |
| 161 | _, _ = w.Write(wire) |
| 162 | } |
| 163 | |
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