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/gitcmd/command.go

@@ -255,10 +255,14 @@ func commonBaseEnvs() []string {
 
 // CommonGitCmdEnvs returns the common environment variables for a "git" command.
 func CommonGitCmdEnvs() []string {
-	return append(commonBaseEnvs(), []string{
+	envs := append(commonBaseEnvs(), []string{
 		"LC_ALL=C",              // ensure git output is in English, error messages are parsed in English
 		"GIT_TERMINAL_PROMPT=0", // avoid prompting for credentials interactively, supported since git v2.3
 	}...)
+	if extra := extraEnvs.Load(); extra != nil {
+		envs = append(envs, *extra...)
+	}
+	return envs
 }
 
 // CommonCmdServEnvs is like CommonGitCmdEnvs, but it only returns minimal required environment variables for the "gitea serv" command

modules/git/gitcmd/env.go

@@ -6,6 +6,7 @@ package gitcmd
 import (
 	"fmt"
 	"os/exec"
+	"sync/atomic"
 
 	"gitea.dev/modules/log"
 	"gitea.dev/modules/setting"
@@ -13,6 +14,13 @@ import (
 
 var GitExecutable = "git" // the command name of git, will be updated to an absolute path during initialization
 
+var extraEnvs atomic.Pointer[[]string]
+
+// SetExtraEnvs adds envs to every git command, the git proxy routes git's network remotes with them
+func SetExtraEnvs(envs []string) {
+	extraEnvs.Store(&envs)
+}
+
 // SetExecutablePath changes the path of git executable and checks the file permission and version.
 func SetExecutablePath(path string) error {
 	// If path is empty, we use the default value of GitExecutable "git" to search for the location of git.