veryroundbird.house
1package knotserver
2
3import (
4 "compress/gzip"
5 "fmt"
6 "io"
7 "net/http"
8 "path/filepath"
9 "strings"
10
11 securejoin "github.com/cyphar/filepath-securejoin"
12 "github.com/go-chi/chi/v5"
13 "tangled.sh/tangled.sh/core/knotserver/git/service"
14)
15
16func (d *Knot) InfoRefs(w http.ResponseWriter, r *http.Request) {
17 did := chi.URLParam(r, "did")
18 name := chi.URLParam(r, "name")
19 repoName, err := securejoin.SecureJoin(did, name)
20 if err != nil {
21 gitError(w, "repository not found", http.StatusNotFound)
22 d.l.Error("git: failed to secure join repo path", "handler", "InfoRefs", "error", err)
23 return
24 }
25
26 repoPath, err := securejoin.SecureJoin(d.c.Repo.ScanPath, repoName)
27 if err != nil {
28 gitError(w, "repository not found", http.StatusNotFound)
29 d.l.Error("git: failed to secure join repo path", "handler", "InfoRefs", "error", err)
30 return
31 }
32
33 cmd := service.ServiceCommand{
34 GitProtocol: r.Header.Get("Git-Protocol"),
35 Dir: repoPath,
36 Stdout: w,
37 }
38
39 serviceName := r.URL.Query().Get("service")
40 switch serviceName {
41 case "git-upload-pack":
42 w.Header().Set("Content-Type", "application/x-git-upload-pack-advertisement")
43 w.Header().Set("Connection", "Keep-Alive")
44 w.Header().Set("Cache-Control", "no-cache, max-age=0, must-revalidate")
45 w.WriteHeader(http.StatusOK)
46
47 if err := cmd.InfoRefs(); err != nil {
48 gitError(w, err.Error(), http.StatusInternalServerError)
49 d.l.Error("git: process failed", "handler", "InfoRefs", "service", serviceName, "error", err)
50 return
51 }
52 case "git-receive-pack":
53 d.RejectPush(w, r, name)
54 default:
55 gitError(w, fmt.Sprintf("service unsupported: '%s'", serviceName), http.StatusForbidden)
56 }
57}
58
59func (d *Knot) UploadPack(w http.ResponseWriter, r *http.Request) {
60 did := chi.URLParam(r, "did")
61 name := chi.URLParam(r, "name")
62 repo, err := securejoin.SecureJoin(d.c.Repo.ScanPath, filepath.Join(did, name))
63 if err != nil {
64 gitError(w, err.Error(), http.StatusInternalServerError)
65 d.l.Error("git: failed to secure join repo path", "handler", "UploadPack", "error", err)
66 return
67 }
68
69 const expectedContentType = "application/x-git-upload-pack-request"
70 contentType := r.Header.Get("Content-Type")
71 if contentType != expectedContentType {
72 gitError(w, fmt.Sprintf("Expected Content-Type: '%s', but received '%s'.", expectedContentType, contentType), http.StatusUnsupportedMediaType)
73 }
74
75 var bodyReader io.ReadCloser = r.Body
76 if r.Header.Get("Content-Encoding") == "gzip" {
77 gzipReader, err := gzip.NewReader(r.Body)
78 if err != nil {
79 gitError(w, err.Error(), http.StatusInternalServerError)
80 d.l.Error("git: failed to create gzip reader", "handler", "UploadPack", "error", err)
81 return
82 }
83 defer gzipReader.Close()
84 bodyReader = gzipReader
85 }
86
87 w.Header().Set("Content-Type", "application/x-git-upload-pack-result")
88 w.Header().Set("Connection", "Keep-Alive")
89 w.Header().Set("Cache-Control", "no-cache, max-age=0, must-revalidate")
90
91 d.l.Info("git: executing git-upload-pack", "handler", "UploadPack", "repo", repo)
92
93 cmd := service.ServiceCommand{
94 GitProtocol: r.Header.Get("Git-Protocol"),
95 Dir: repo,
96 Stdout: w,
97 Stdin: bodyReader,
98 }
99
100 w.WriteHeader(http.StatusOK)
101
102 if err := cmd.UploadPack(); err != nil {
103 d.l.Error("git: failed to execute git-upload-pack", "handler", "UploadPack", "error", err)
104 return
105 }
106}
107
108func (d *Knot) ReceivePack(w http.ResponseWriter, r *http.Request) {
109 did := chi.URLParam(r, "did")
110 name := chi.URLParam(r, "name")
111 _, err := securejoin.SecureJoin(d.c.Repo.ScanPath, filepath.Join(did, name))
112 if err != nil {
113 gitError(w, err.Error(), http.StatusForbidden)
114 d.l.Error("git: failed to secure join repo path", "handler", "ReceivePack", "error", err)
115 return
116 }
117
118 d.RejectPush(w, r, name)
119}
120
121func (d *Knot) RejectPush(w http.ResponseWriter, r *http.Request, unqualifiedRepoName string) {
122 // A text/plain response will cause git to print each line of the body
123 // prefixed with "remote: ".
124 w.Header().Set("content-type", "text/plain; charset=UTF-8")
125 w.WriteHeader(http.StatusForbidden)
126
127 fmt.Fprintf(w, "Pushes are only supported over SSH.")
128
129 // If the appview gave us the repository owner's handle we can attempt to
130 // construct the correct ssh url.
131 ownerHandle := r.Header.Get("x-tangled-repo-owner-handle")
132 ownerHandle = strings.TrimPrefix(ownerHandle, "@")
133 if ownerHandle != "" && !strings.ContainsAny(ownerHandle, ":") {
134 hostname := d.c.Server.Hostname
135 if strings.Contains(hostname, ":") {
136 hostname = strings.Split(hostname, ":")[0]
137 }
138
139 if hostname == "knot1.tangled.sh" {
140 hostname = "tangled.sh"
141 }
142
143 fmt.Fprintf(w, " Try:\ngit remote set-url --push origin git@%s:%s/%s\n\n... and push again.", hostname, ownerHandle, unqualifiedRepoName)
144 }
145 fmt.Fprintf(w, "\n\n")
146}
147
148func gitError(w http.ResponseWriter, msg string, status int) {
149 w.Header().Set("content-type", "text/plain; charset=UTF-8")
150 w.WriteHeader(status)
151 fmt.Fprintf(w, "%s\n", msg)
152}