Override safe.bareRepository for git remotes

Fix using git remotes that are bare when git is configured
with safe.bareRepository = explicit

Sponsored-by: Dartmouth College's DANDI project

CHANGELOG

@@ -3,6 +3,8 @@ git-annex (10.20230829) UNRELEASED; urgency=medium
   * Fix more breakage caused by git's fix for CVE-2022-24765, this time
     involving a remote (either local or ssh) that is a repository not owned
     by the current user.
+  * Fix using git remotes that are bare when git is configured with 
+    safe.bareRepository = explicit.
   * Removed the vendored git-lfs and the GitLfs build flag.
   * Fix linker optimisation in linux standalone tarballs.
 

CmdLine/GitAnnexShell.hs

@@ -124,11 +124,7 @@ builtin cmd dir params = do
 	mkrepo = do
 		r <- Git.Construct.repoAbsPath (toRawFilePath dir)
 			>>= Git.Construct.fromAbsPath
-		{- Since the path to the repository was specified
+		let r' = r { repoPathSpecifiedExplicitly = True }
-		 - explicitly, CVE-2022-24765 is not a concern,
-		 - so tell git to treat the repository directory as safe.
-		 -}
-		let r' = r { safeDirectory = True }
 		Git.Config.read r'
 			`catchIO` \_ -> do
 				hn <- fromMaybe "unknown" <$> getHostname

Git/Config.hs

@@ -72,18 +72,21 @@ read' repo = go repo
 	go _ = assertLocal repo $ error "internal"
 	git_config addparams d = withCreateProcess p (git_config' p)
 	  where
-		params = addparams ++ safedirparam 
+		params = addparams ++ explicitrepoparams
 			++ ["config", "--null", "--list"]
 		p = (proc "git" params)
 			{ cwd = Just (fromRawFilePath d)
 			, env = gitEnv repo
 			, std_out = CreatePipe 
 			}
-		safedirparam = if safeDirectory repo 
+		explicitrepoparams = if repoPathSpecifiedExplicitly repo 
-			-- Use * rather than d, because git treats
+			then 
-			-- "dir/" differently than "dir" when comparing for
+				-- Use * rather than d, because git treats
-			-- safe.directory purposes.
+				-- "dir/" differently than "dir" when comparing
-			then ["-c", "safe.directory=*"]
+				-- for safe.directory purposes.
+				[ "-c", "safe.directory=*"
+				, "-c", "safe.bareRepository=all" 
+				]
 			else []
 	git_config' p _ (Just hout) _ pid = 
 		forceSuccessProcess p pid

Git/Construct.hs

@@ -287,6 +287,6 @@ newFrom l = Repo
 	, gitEnvOverridesGitDir = False
 	, gitGlobalOpts = []
 	, gitDirSpecifiedExplicitly = False
-	, safeDirectory = False
+	, repoPathSpecifiedExplicitly = False
 	}
 

Git/Types.hs

@@ -53,8 +53,11 @@ data Repo = Repo
 	, gitGlobalOpts :: [CommandParam]
 	-- True only when --git-dir or GIT_DIR was used
 	, gitDirSpecifiedExplicitly :: Bool
-	-- Set -c safe.directory when using this repository.
+	-- Use when the path to the repository was specified explicitly,
-	, safeDirectory :: Bool
+	-- eg in a git remote, and so it's safe to set 
+	-- -c safe.directory=* and -c safe.bareRepository=all 
+	-- when using this repository.
+	, repoPathSpecifiedExplicitly :: Bool
 	} deriving (Show, Eq, Ord)
 
 newtype ConfigKey = ConfigKey S.ByteString

Remote/Git.hs

@@ -339,11 +339,7 @@ tryGitConfigRead autoinit r hasuuid
 				warning $ UnquotedString $ "Remote " ++ Git.repoDescribe r ++
 					": "  ++ show e
 			Annex.getState Annex.repo
-		{- Since the path to the repository was specified
+		let r' = r { Git.repoPathSpecifiedExplicitly = True }
-		 - explicitly, CVE-2022-24765 is not a concern,
-		 - so tell git to treat the repository directory as safe.
-		 -}
-		let r' = r { Git.safeDirectory = True }
 		s <- newLocal r'
 		liftIO $ Annex.eval s $ check
 			`finally` quiesce True

doc/bugs/enableremote_fails_with___34__wrong_reason__34___stated/comment_4_c7a5c3dfaca25fad2edf9575f65629e8._comment

@@ -0,0 +1,18 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 4"""
+ date="2023-09-07T18:36:37Z"
+ content="""
+Another related case is when git has been configured with
+safe.bareRepository=explicit and the remote (either ssh or local)
+is a bare repo. git-annex-shell will fail with the same misleading message,
+and for a local repo, git-annex will also display the same misleading
+message.
+
+I think it also ought to override safe.bareRepository for such remotes,
+because eg git pull works with such remotes. The point of 
+safe.bareRepository=explicit is not to prevent using bare remotes, but to
+prevent things like shell prompts to accidentially use bare repos that are
+eg, committed by a malicious attacker to a git repository, to avoid using
+git configs that allow running arbitrary code.
+"""]]