Enforce Gitea environment for pushes (#8982)

* Enforce Gitea environment for pushes

* Update custom/conf/app.ini.sample

Co-Authored-By: Antoine GIRARD <sapk@users.noreply.github.com>

cmd/hook.go

 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/private"
+	"code.gitea.io/gitea/modules/setting"
 
 	"github.com/urfave/cli"
 )
 
 func runHookPreReceive(c *cli.Context) error {
 	if len(os.Getenv("SSH_ORIGINAL_COMMAND")) == 0 {
-		return nil
+		if setting.OnlyAllowPushIfGiteaEnvironmentSet {
+			fail(`Rejecting changes as Gitea environment not set.
+If you are pushing over SSH you must push with a key managed by
+Gitea or set your environment appropriately.`, "")
+		} else {
+			return nil
+		}
 	}
 
 	setup("hooks/pre-receive.log")
 
 func runHookUpdate(c *cli.Context) error {
 	if len(os.Getenv("SSH_ORIGINAL_COMMAND")) == 0 {
-		return nil
+		if setting.OnlyAllowPushIfGiteaEnvironmentSet {
+			fail(`Rejecting changes as Gitea environment not set.
+If you are pushing over SSH you must push with a key managed by
+Gitea or set your environment appropriately.`, "")
+		} else {
+			return nil
+		}
 	}
 
 	setup("hooks/update.log")
 
 func runHookPostReceive(c *cli.Context) error {
 	if len(os.Getenv("SSH_ORIGINAL_COMMAND")) == 0 {
-		return nil
+		if setting.OnlyAllowPushIfGiteaEnvironmentSet {
+			fail(`Rejecting changes as Gitea environment not set.
+If you are pushing over SSH you must push with a key managed by
+Gitea or set your environment appropriately.`, "")
+		} else {
+			return nil
+		}
 	}
 
 	setup("hooks/post-receive.log")

custom/conf/app.ini.sample

 DOMAIN = localhost
 ROOT_URL = %(PROTOCOL)s://%(DOMAIN)s:%(HTTP_PORT)s/
 ; when STATIC_URL_PREFIX is empty it will follow APP_URL
-STATIC_URL_PREFIX = 
+STATIC_URL_PREFIX =
 ; The address to listen on. Either a IPv4/IPv6 address or the path to a unix socket.
 HTTP_ADDR = 0.0.0.0
 HTTP_PORT = 3000
 IMPORT_LOCAL_PATHS = false
 ; Set to true to prevent all users (including admin) from creating custom git hooks
 DISABLE_GIT_HOOKS = false
+; Set to false to allow pushes to gitea repositories despite having an incomplete environment - NOT RECOMMENDED
+ONLY_ALLOW_PUSH_IF_GITEA_ENVIRONMENT_SET = true
 ;Comma separated list of character classes required to pass minimum complexity.
 ;If left empty or no valid values are specified, the default values ("lower,upper,digit,spec") will be used.
 ;Use "off" to disable checking.
 ; Number of history information in each page
 PAGING_NUM = 10
 ; Proxy server URL, support http://, https//, socks://, blank will follow environment http_proxy/https_proxy
-PROXY_URL = 
+PROXY_URL =
 ; Comma separated list of host names requiring proxy. Glob patterns (*) are accepted; use ** to match all hosts.
-PROXY_HOSTS = 
+PROXY_HOSTS =
 
 [mailer]
 ENABLED = false

docs/content/doc/advanced/config-cheat-sheet.en-us.md

    authentication provided email.
 - `DISABLE_GIT_HOOKS`: **false**: Set to `true` to prevent all users (including admin) from creating custom
    git hooks.
+- `ONLY_ALLOW_PUSH_IF_GITEA_ENVIRONMENT_SET`: **true**: Set to `false` to allow local users to push to gitea-repositories without setting up the Gitea environment. This is not recommended and if you want local users to push to gitea repositories you should set the environment appropriately.
 - `IMPORT_LOCAL_PATHS`: **false**: Set to `false` to prevent all users (including admin) from importing local path on server.
 - `INTERNAL_TOKEN`: **\<random at every install if no uri set\>**: Secret used to validate communication within Gitea binary.
 - `INTERNAL_TOKEN_URI`: **<empty>**: Instead of defining internal token in the configuration, this configuration option can be used to give Gitea a path to a file that contains the internal token (example value: `file:/etc/gitea/internal_token`)

modules/setting/setting.go

 	}
 
 	// Security settings
-	InstallLock           bool
-	SecretKey             string
-	LogInRememberDays     int
-	CookieUserName        string
-	CookieRememberName    string
-	ReverseProxyAuthUser  string
-	ReverseProxyAuthEmail string
-	MinPasswordLength     int
-	ImportLocalPaths      bool
-	DisableGitHooks       bool
-	PasswordComplexity    []string
-	PasswordHashAlgo      string
+	InstallLock                        bool
+	SecretKey                          string
+	LogInRememberDays                  int
+	CookieUserName                     string
+	CookieRememberName                 string
+	ReverseProxyAuthUser               string
+	ReverseProxyAuthEmail              string
+	MinPasswordLength                  int
+	ImportLocalPaths                   bool
+	DisableGitHooks                    bool
+	OnlyAllowPushIfGiteaEnvironmentSet bool
+	PasswordComplexity                 []string
+	PasswordHashAlgo                   string
 
 	// UI settings
 	UI = struct {
 	MinPasswordLength = sec.Key("MIN_PASSWORD_LENGTH").MustInt(6)
 	ImportLocalPaths = sec.Key("IMPORT_LOCAL_PATHS").MustBool(false)
 	DisableGitHooks = sec.Key("DISABLE_GIT_HOOKS").MustBool(false)
+	OnlyAllowPushIfGiteaEnvironmentSet = sec.Key("ONLY_ALLOW_PUSH_IF_GITEA_ENVIRONMENT_SET").MustBool(true)
 	PasswordHashAlgo = sec.Key("PASSWORD_HASH_ALGO").MustString("pbkdf2")
 	CSRFCookieHTTPOnly = sec.Key("CSRF_COOKIE_HTTP_ONLY").MustBool(true)