fix(git)!: use internal proxy for all git operations (#39426)

Introduces gitproxy module which spawns a small forward proxy as scanner
for git calls
Replaces hostmatcher with matchlist which supports port rules
Deprecates ALLOWED_DOMAINS/BLOCKED_DOMAINS and ALLOW_LOCALNETWORKS
settings in migration in favor of full names we have in security
configs.
Removes `external` preset in favor of lax/strict modes, strict mode
requiring explicit ports if they aren't standard http/s ones.

Breaking changes:
- `external` preset no longer works as deny rule. To enforce that, use
`strict` mode and allow ranges to connect to
- Wildcards are no longer accepted in IP addresses
- `*` is no longer allowed as entry in lists
- domain rules now use curl like syntax `*.example.com` matching
subdomains but not `example.com`, `example.com` matching itself and all
subdomains. `example.*` is not a valid rule
- In the default `lax` mode, `[security] ALLOWED_HOST_LIST` no longer
restricts public hosts, set `EGRESS_MODE = strict` to keep an exclusive
list. A startup warning flags this
- Invalid list entries are logged at startup, invalid
`BLOCKED_HOST_LIST`/`BLOCKED_DOMAINS` entries stop it

Docs: https://gitea.com/gitea/docs/pulls/557
Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: bircni <bircni@icloud.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/git/repo_test.go

@@ -4,10 +4,7 @@
 package git
 
 import (
-	"net/http"
-	"net/http/httptest"
 	"path/filepath"
-	"sync/atomic"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -22,24 +19,3 @@ func TestRepoIsEmpty(t *testing.T) {
 	assert.NoError(t, err)
 	assert.True(t, isEmpty)
 }
-
-// TestCloneRefusesRedirects ensures Clone never follows HTTP redirects, so a remote
-// cannot redirect to an otherwise-blocked address (SSRF, e.g. during migration).
-func TestCloneRefusesRedirects(t *testing.T) {
-	t.Skip("FIXME: GIT-CLONE-HTTP-REDIRECT-SSRF: need a complete solution in the future")
-	var targetHit atomic.Bool
-	target := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		targetHit.Store(true)
-		w.WriteHeader(http.StatusNotFound)
-	}))
-	defer target.Close()
-
-	redirect := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		http.Redirect(w, r, target.URL+r.URL.Path, http.StatusFound)
-	}))
-	defer redirect.Close()
-
-	err := Clone(t.Context(), redirect.URL, filepath.Join(t.TempDir(), "dst"), CloneRepoOptions{})
-	assert.Error(t, err)
-	assert.False(t, targetHit.Load(), "git must not follow the redirect to the target")
-}