Git 2.31.5

Signed-off-by: Taylor Blau <me@ttaylorr.com>

Documentation/RelNotes/2.30.5.txt

@@ -0,0 +1,12 @@
+Git v2.30.5 Release Notes
+=========================
+
+This release contains minor fix-ups for the changes that went into
+Git 2.30.3 and 2.30.4, addressing CVE-2022-29187.
+
+ * The safety check that verifies a safe ownership of the Git
+   worktree is now extended to also cover the ownership of the Git
+   directory (and the `.git` file, if there is any).
+
+Carlo Marcelo Arenas Belón (1):
+      setup: tighten ownership checks post CVE-2022-24765

Documentation/RelNotes/2.30.6.txt

@@ -0,0 +1,60 @@
+Git v2.30.6 Release Notes
+=========================
+
+This release addresses the security issues CVE-2022-39253 and
+CVE-2022-39260.
+
+Fixes since v2.30.5
+-------------------
+
+ * CVE-2022-39253:
+   When relying on the `--local` clone optimization, Git dereferences
+   symbolic links in the source repository before creating hardlinks
+   (or copies) of the dereferenced link in the destination repository.
+   This can lead to surprising behavior where arbitrary files are
+   present in a repository's `$GIT_DIR` when cloning from a malicious
+   repository.
+
+   Git will no longer dereference symbolic links via the `--local`
+   clone mechanism, and will instead refuse to clone repositories that
+   have symbolic links present in the `$GIT_DIR/objects` directory.
+
+   Additionally, the value of `protocol.file.allow` is changed to be
+   "user" by default.
+
+ * CVE-2022-39260:
+   An overly-long command string given to `git shell` can result in
+   overflow in `split_cmdline()`, leading to arbitrary heap writes and
+   remote code execution when `git shell` is exposed and the directory
+   `$HOME/git-shell-commands` exists.
+
+   `git shell` is taught to refuse interactive commands that are
+   longer than 4MiB in size. `split_cmdline()` is hardened to reject
+   inputs larger than 2GiB.
+
+Credit for finding CVE-2022-39253 goes to Cory Snider of Mirantis. The
+fix was authored by Taylor Blau, with help from Johannes Schindelin.
+
+Credit for finding CVE-2022-39260 goes to Kevin Backhouse of GitHub.
+The fix was authored by Kevin Backhouse, Jeff King, and Taylor Blau.
+
+
+Jeff King (2):
+      shell: add basic tests
+      shell: limit size of interactive commands
+
+Kevin Backhouse (1):
+      alias.c: reject too-long cmdline strings in split_cmdline()
+
+Taylor Blau (11):
+      builtin/clone.c: disallow `--local` clones with symlinks
+      t/lib-submodule-update.sh: allow local submodules
+      t/t1NNN: allow local submodules
+      t/2NNNN: allow local submodules
+      t/t3NNN: allow local submodules
+      t/t4NNN: allow local submodules
+      t/t5NNN: allow local submodules
+      t/t6NNN: allow local submodules
+      t/t7NNN: allow local submodules
+      t/t9NNN: allow local submodules
+      transport: make `protocol.file.allow` be "user" by default

Documentation/RelNotes/2.31.4.txt

@@ -0,0 +1,6 @@
+Git v2.31.4 Release Notes
+=========================
+
+This release merges up the fixes that appear in v2.30.5 to address
+the security issue CVE-2022-29187; see the release notes for that
+version for details.

Documentation/RelNotes/2.31.5.txt

@@ -0,0 +1,5 @@
+Git v2.31.5 Release Notes
+=========================
+
+This release merges the security fix that appears in v2.30.6; see
+the release notes for that version for details.

Documentation/config/protocol.txt

@@ -1,10 +1,10 @@
 protocol.allow::
 	If set, provide a user defined default policy for all protocols which
 	don't explicitly have a policy (`protocol.<name>.allow`).  By default,
-	if unset, known-safe protocols (http, https, git, ssh, file) have a
+	if unset, known-safe protocols (http, https, git, ssh) have a
 	default policy of `always`, known-dangerous protocols (ext) have a
-	default policy of `never`, and all other protocols have a default
-	policy of `user`.  Supported policies:
+	default policy of `never`, and all other protocols (including file)
+	have a default policy of `user`.  Supported policies:
 +
 --
 

Documentation/config/safe.txt

@@ -26,3 +26,17 @@ directory was listed in the `safe.directory` list. If `safe.directory=*`
 is set in system config and you want to re-enable this protection, then
 initialize your list with an empty value before listing the repositories
 that you deem safe.
++
+As explained, Git only allows you to access repositories owned by
+yourself, i.e. the user who is running Git, by default.  When Git
+is running as 'root' in a non Windows platform that provides sudo,
+however, git checks the SUDO_UID environment variable that sudo creates
+and will allow access to the uid recorded as its value in addition to
+the id from 'root'.
+This is to make it easy to perform a common sequence during installation
+"make && sudo make install".  A git process running under 'sudo' runs as
+'root' but the 'sudo' command exports the environment variable to record
+which id the original user has.
+If that is not what you would prefer and want git to only trust
+repositories that are owned by root instead, then you can remove
+the `SUDO_UID` variable from root's environment before invoking git.

GIT-VERSION-GEN

@@ -1,7 +1,7 @@
 #!/bin/sh
 
 GVF=GIT-VERSION-FILE
-DEF_VER=v2.31.3
+DEF_VER=v2.31.5
 
 LF='
 '

RelNotes

@@ -1 +1 @@
-Documentation/RelNotes/2.31.3.txt
+Documentation/RelNotes/2.31.5.txt

alias.c

@@ -46,14 +46,16 @@ void list_aliases(struct string_list *list)
 
 #define SPLIT_CMDLINE_BAD_ENDING 1
 #define SPLIT_CMDLINE_UNCLOSED_QUOTE 2
+#define SPLIT_CMDLINE_ARGC_OVERFLOW 3
 static const char *split_cmdline_errors[] = {
 	N_("cmdline ends with \\"),
-	N_("unclosed quote")
+	N_("unclosed quote"),
+	N_("too many arguments"),
 };
 
 int split_cmdline(char *cmdline, const char ***argv)
 {
-	int src, dst, count = 0, size = 16;
+	size_t src, dst, count = 0, size = 16;
 	char quoted = 0;
 
 	ALLOC_ARRAY(*argv, size);
@@ -96,6 +98,11 @@ int split_cmdline(char *cmdline, const char ***argv)
 		return -SPLIT_CMDLINE_UNCLOSED_QUOTE;
 	}
 
+	if (count >= INT_MAX) {
+		FREE_AND_NULL(*argv);
+		return -SPLIT_CMDLINE_ARGC_OVERFLOW;
+	}
+
 	ALLOC_GROW(*argv, count + 1, size);
 	(*argv)[count] = NULL;
 

builtin/clone.c

@@ -420,13 +420,11 @@ static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest,
 	int src_len, dest_len;
 	struct dir_iterator *iter;
 	int iter_status;
-	unsigned int flags;
 	struct strbuf realpath = STRBUF_INIT;
 
 	mkdir_if_missing(dest->buf, 0777);
 
-	flags = DIR_ITERATOR_PEDANTIC | DIR_ITERATOR_FOLLOW_SYMLINKS;
-	iter = dir_iterator_begin(src->buf, flags);
+	iter = dir_iterator_begin(src->buf, DIR_ITERATOR_PEDANTIC);
 
 	if (!iter)
 		die_errno(_("failed to start iterator over '%s'"), src->buf);
@@ -442,6 +440,10 @@ static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest,
 		strbuf_setlen(dest, dest_len);
 		strbuf_addstr(dest, iter->relative_path);
 
+		if (S_ISLNK(iter->st.st_mode))
+			die(_("symlink '%s' exists, refusing to clone with --local"),
+			    iter->relative_path);
+
 		if (S_ISDIR(iter->st.st_mode)) {
 			mkdir_if_missing(dest->buf, 0777);
 			continue;

git-compat-util.h

@@ -393,12 +393,68 @@ static inline int git_offset_1st_component(const char *path)
 #endif
 
 #ifndef is_path_owned_by_current_user
+
+#ifdef __TANDEM
+#define ROOT_UID 65535
+#else
+#define ROOT_UID 0
+#endif
+
+/*
+ * Do not use this function when
+ * (1) geteuid() did not say we are running as 'root', or
+ * (2) using this function will compromise the system.
+ *
+ * PORTABILITY WARNING:
+ * This code assumes uid_t is unsigned because that is what sudo does.
+ * If your uid_t type is signed and all your ids are positive then it
+ * should all work fine.
+ * If your version of sudo uses negative values for uid_t or it is
+ * buggy and return an overflowed value in SUDO_UID, then git might
+ * fail to grant access to your repository properly or even mistakenly
+ * grant access to someone else.
+ * In the unlikely scenario this happened to you, and that is how you
+ * got to this message, we would like to know about it; so sent us an
+ * email to git@vger.kernel.org indicating which platform you are
+ * using and which version of sudo, so we can improve this logic and
+ * maybe provide you with a patch that would prevent this issue again
+ * in the future.
+ */
+static inline void extract_id_from_env(const char *env, uid_t *id)
+{
+	const char *real_uid = getenv(env);
+
+	/* discard anything empty to avoid a more complex check below */
+	if (real_uid && *real_uid) {
+		char *endptr = NULL;
+		unsigned long env_id;
+
+		errno = 0;
+		/* silent overflow errors could trigger a bug here */
+		env_id = strtoul(real_uid, &endptr, 10);
+		if (!*endptr && !errno)
+			*id = env_id;
+	}
+}
+
 static inline int is_path_owned_by_current_uid(const char *path)
 {
 	struct stat st;
+	uid_t euid;
+
 	if (lstat(path, &st))
 		return 0;
-	return st.st_uid == geteuid();
+
+	euid = geteuid();
+	if (euid == ROOT_UID)
+	{
+		if (st.st_uid == ROOT_UID)
+			return 1;
+		else
+			extract_id_from_env("SUDO_UID", &euid);
+	}
+
+	return st.st_uid == euid;
 }
 
 #define is_path_owned_by_current_user is_path_owned_by_current_uid

setup.c

@@ -1054,14 +1054,32 @@ static int safe_directory_cb(const char *key, const char *value, void *d)
 	return 0;
 }
 
-static int ensure_valid_ownership(const char *path)
+/*
+ * Check if a repository is safe, by verifying the ownership of the
+ * worktree (if any), the git directory, and the gitfile (if any).
+ *
+ * Exemptions for known-safe repositories can be added via `safe.directory`
+ * config settings; for non-bare repositories, their worktree needs to be
+ * added, for bare ones their git directory.
+ */
+static int ensure_valid_ownership(const char *gitfile,
+				const char *worktree, const char *gitdir)
 {
-	struct safe_directory_data data = { .path = path };
+	struct safe_directory_data data = {
+		.path = worktree ? worktree : gitdir
+	};
 
 	if (!git_env_bool("GIT_TEST_ASSUME_DIFFERENT_OWNER", 0) &&
-	    is_path_owned_by_current_user(path))
+	   (!gitfile || is_path_owned_by_current_user(gitfile)) &&
+	   (!worktree || is_path_owned_by_current_user(worktree)) &&
+	   (!gitdir || is_path_owned_by_current_user(gitdir)))
 		return 1;
 
+	/*
+	 * data.path is the "path" that identifies the repository and it is
+	 * constant regardless of what failed above. data.is_safe should be
+	 * initialized to false, and might be changed by the callback.
+	 */
 	read_very_early_config(safe_directory_cb, &data);
 
 	return data.is_safe;
@@ -1149,6 +1167,8 @@ static enum discovery_result setup_git_directory_gently_1(struct strbuf *dir,
 		current_device = get_device_or_die(dir->buf, NULL, 0);
 	for (;;) {
 		int offset = dir->len, error_code = 0;
+		char *gitdir_path = NULL;
+		char *gitfile = NULL;
 
 		if (offset > min_offset)
 			strbuf_addch(dir, '/');
@@ -1159,21 +1179,50 @@ static enum discovery_result setup_git_directory_gently_1(struct strbuf *dir,
 			if (die_on_error ||
 			    error_code == READ_GITFILE_ERR_NOT_A_FILE) {
 				/* NEEDSWORK: fail if .git is not file nor dir */
-				if (is_git_directory(dir->buf))
+				if (is_git_directory(dir->buf)) {
 					gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
+					gitdir_path = xstrdup(dir->buf);
+				}
 			} else if (error_code != READ_GITFILE_ERR_STAT_FAILED)
 				return GIT_DIR_INVALID_GITFILE;
-		}
+		} else
+			gitfile = xstrdup(dir->buf);
+		/*
+		 * Earlier, we tentatively added DEFAULT_GIT_DIR_ENVIRONMENT
+		 * to check that directory for a repository.
+		 * Now trim that tentative addition away, because we want to
+		 * focus on the real directory we are in.
+		 */
 		strbuf_setlen(dir, offset);
 		if (gitdirenv) {
-			if (!ensure_valid_ownership(dir->buf))
-				return GIT_DIR_INVALID_OWNERSHIP;
+			enum discovery_result ret;
+
+			if (ensure_valid_ownership(gitfile,
+						 dir->buf,
+				 (gitdir_path ? gitdir_path : gitdirenv))) {
 				strbuf_addstr(gitdir, gitdirenv);
-			return GIT_DIR_DISCOVERED;
+				ret = GIT_DIR_DISCOVERED;
+			} else
+				ret = GIT_DIR_INVALID_OWNERSHIP;
+
+			/*
+			 * Earlier, during discovery, we might have allocated
+			 * string copies for gitdir_path or gitfile so make
+			 * sure we don't leak by freeing them now, before
+			 * leaving the loop and function.
+			 *
+			 * Note: gitdirenv will be non-NULL whenever these are
+			 * allocated, therefore we need not take care of releasing
+			 * them outside of this conditional block.
+			 */
+			free(gitdir_path);
+			free(gitfile);
+
+			return ret;
 		}
 
 		if (is_git_directory(dir->buf)) {
-			if (!ensure_valid_ownership(dir->buf))
+			if (!ensure_valid_ownership(NULL, NULL, dir->buf))
 				return GIT_DIR_INVALID_OWNERSHIP;
 			strbuf_addstr(gitdir, ".");
 			return GIT_DIR_BARE;
@@ -1306,7 +1355,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 			struct strbuf quoted = STRBUF_INIT;
 
 			sq_quote_buf_pretty(&quoted, dir.buf);
-			die(_("unsafe repository ('%s' is owned by someone else)\n"
+			die(_("detected dubious ownership in repository at '%s'\n"
 			      "To add an exception for this directory, call:\n"
 			      "\n"
 			      "\tgit config --global --add safe.directory %s"),

shell.c

@@ -47,6 +47,8 @@ static void cd_to_homedir(void)
 		die("could not chdir to user's home directory");
 }
 
+#define MAX_INTERACTIVE_COMMAND (4*1024*1024)
+
 static void run_shell(void)
 {
 	int done = 0;
@@ -67,22 +69,46 @@ static void run_shell(void)
 	run_command_v_opt(help_argv, RUN_SILENT_EXEC_FAILURE);
 
 	do {
-		struct strbuf line = STRBUF_INIT;
 		const char *prog;
 		char *full_cmd;
 		char *rawargs;
+		size_t len;
 		char *split_args;
 		const char **argv;
 		int code;
 		int count;
 
 		fprintf(stderr, "git> ");
-		if (git_read_line_interactively(&line) == EOF) {
+
+		/*
+		 * Avoid using a strbuf or git_read_line_interactively() here.
+		 * We don't want to allocate arbitrary amounts of memory on
+		 * behalf of a possibly untrusted client, and we're subject to
+		 * OS limits on command length anyway.
+		 */
+		fflush(stdout);
+		rawargs = xmalloc(MAX_INTERACTIVE_COMMAND);
+		if (!fgets(rawargs, MAX_INTERACTIVE_COMMAND, stdin)) {
 			fprintf(stderr, "\n");
-			strbuf_release(&line);
+			free(rawargs);
 			break;
 		}
-		rawargs = strbuf_detach(&line, NULL);
+		len = strlen(rawargs);
+
+		/*
+		 * If we truncated due to our input buffer size, reject the
+		 * command. That's better than running bogus input, and
+		 * there's a good chance it's just malicious garbage anyway.
+		 */
+		if (len >= MAX_INTERACTIVE_COMMAND - 1)
+			die("invalid command format: input too long");
+
+		if (len > 0 && rawargs[len - 1] == '\n') {
+			if (--len > 0 && rawargs[len - 1] == '\r')
+				--len;
+			rawargs[len] = '\0';
+		}
+
 		split_args = xstrdup(rawargs);
 		count = split_cmdline(split_args, &argv);
 		if (count < 0) {

t/lib-submodule-update.sh

@@ -196,6 +196,7 @@ test_git_directory_exists () {
 # the submodule repo if it doesn't exist and configures the most problematic
 # settings for diff.ignoreSubmodules.
 prolog () {
+	test_config_global protocol.file.allow always &&
 	(test -d submodule_update_repo || create_lib_submodule_repo) &&
 	test_config_global diff.ignoreSubmodules all &&
 	test_config diff.ignoreSubmodules all

t/lib-sudo.sh

@@ -0,0 +1,15 @@
+# Helpers for running git commands under sudo.
+
+# Runs a scriplet passed through stdin under sudo.
+run_with_sudo () {
+	local ret
+	local RUN="$TEST_DIRECTORY/$$.sh"
+	write_script "$RUN" "$TEST_SHELL_PATH"
+	# avoid calling "$RUN" directly so sudo doesn't get a chance to
+	# override the shell, add aditional restrictions or even reject
+	# running the script because its security policy deem it unsafe
+	sudo "$TEST_SHELL_PATH" -c "\"$RUN\""
+	ret=$?
+	rm -f "$RUN"
+	return $ret
+}

t/t0034-root-safe-directory.sh

@@ -0,0 +1,93 @@
+#!/bin/sh
+
+test_description='verify safe.directory checks while running as root'
+
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-sudo.sh
+
+if [ "$GIT_TEST_ALLOW_SUDO" != "YES" ]
+then
+	skip_all="You must set env var GIT_TEST_ALLOW_SUDO=YES in order to run this test"
+	test_done
+fi
+
+if ! test_have_prereq NOT_ROOT
+then
+	skip_all="These tests do not support running as root"
+	test_done
+fi
+
+test_lazy_prereq SUDO '
+	sudo -n id -u >u &&
+	id -u root >r &&
+	test_cmp u r &&
+	command -v git >u &&
+	sudo command -v git >r &&
+	test_cmp u r
+'
+
+if ! test_have_prereq SUDO
+then
+	skip_all="Your sudo/system configuration is either too strict or unsupported"
+	test_done
+fi
+
+test_expect_success SUDO 'setup' '
+	sudo rm -rf root &&
+	mkdir -p root/r &&
+	(
+		cd root/r &&
+		git init
+	)
+'
+
+test_expect_success SUDO 'sudo git status as original owner' '
+	(
+		cd root/r &&
+		git status &&
+		sudo git status
+	)
+'
+
+test_expect_success SUDO 'setup root owned repository' '
+	sudo mkdir -p root/p &&
+	sudo git init root/p
+'
+
+test_expect_success 'cannot access if owned by root' '
+	(
+		cd root/p &&
+		test_must_fail git status
+	)
+'
+
+test_expect_success 'can access if addressed explicitly' '
+	(
+		cd root/p &&
+		GIT_DIR=.git GIT_WORK_TREE=. git status
+	)
+'
+
+test_expect_success SUDO 'can access with sudo if root' '
+	(
+		cd root/p &&
+		sudo git status
+	)
+'
+
+test_expect_success SUDO 'can access with sudo if root by removing SUDO_UID' '
+	(
+		cd root/p &&
+		run_with_sudo <<-END
+			unset SUDO_UID &&
+			git status
+		END
+	)
+'
+
+# this MUST be always the last test
+test_expect_success SUDO 'cleanup' '
+	sudo rm -rf root
+'
+
+test_done

t/t1091-sparse-checkout-builtin.sh

@@ -452,7 +452,8 @@ test_expect_success 'interaction with submodules' '
 	(
 		cd super &&
 		mkdir modules &&
-		git submodule add ../repo modules/child &&
+		git -c protocol.file.allow=always \
+			submodule add ../repo modules/child &&
 		git add . &&
 		git commit -m "add submodule" &&
 		git sparse-checkout init --cone &&

t/t1500-rev-parse.sh

@@ -221,7 +221,8 @@ test_expect_success 'showing the superproject correctly' '
 	test_commit -C super test_commit &&
 	test_create_repo sub &&
 	test_commit -C sub test_commit &&
-	git -C super submodule add ../sub dir/sub &&
+	git -c protocol.file.allow=always \
+		-C super submodule add ../sub dir/sub &&
 	echo $(pwd)/super >expect  &&
 	git -C super/dir/sub rev-parse --show-superproject-working-tree >out &&
 	test_cmp expect out &&

t/t2400-worktree-add.sh

@@ -600,6 +600,7 @@ test_expect_success '"add" should not fail because of another bad worktree' '
 '
 
 test_expect_success '"add" with uninitialized submodule, with submodule.recurse unset' '
+	test_config_global protocol.file.allow always &&
 	test_create_repo submodule &&
 	test_commit -C submodule first &&
 	test_create_repo project &&
@@ -615,6 +616,7 @@ test_expect_success '"add" with uninitialized submodule, with submodule.recurse
 '
 
 test_expect_success '"add" with initialized submodule, with submodule.recurse unset' '
+	test_config_global protocol.file.allow always &&
 	git -C project-clone submodule update --init &&
 	git -C project-clone worktree add ../project-4
 '

t/t2403-worktree-move.sh

@@ -138,7 +138,8 @@ test_expect_success 'move a repo with uninitialized submodule' '
 	(
 		cd withsub &&
 		test_commit initial &&
-		git submodule add "$PWD"/.git sub &&
+		git -c protocol.file.allow=always \
+			submodule add "$PWD"/.git sub &&
 		git commit -m withsub &&
 		git worktree add second HEAD &&
 		git worktree move second third
@@ -148,7 +149,7 @@ test_expect_success 'move a repo with uninitialized submodule' '
 test_expect_success 'not move a repo with initialized submodule' '
 	(
 		cd withsub &&
-		git -C third submodule update &&
+		git -c protocol.file.allow=always -C third submodule update &&
 		test_must_fail git worktree move third forth
 	)
 '
@@ -227,6 +228,7 @@ test_expect_success 'remove cleans up .git/worktrees when empty' '
 '
 
 test_expect_success 'remove a repo with uninitialized submodule' '
+	test_config_global protocol.file.allow always &&
 	(
 		cd withsub &&
 		git worktree add to-remove HEAD &&
@@ -235,6 +237,7 @@ test_expect_success 'remove a repo with uninitialized submodule' '
 '
 
 test_expect_success 'not remove a repo with initialized submodule' '
+	test_config_global protocol.file.allow always &&
 	(
 		cd withsub &&
 		git worktree add to-remove HEAD &&

t/t2405-worktree-submodule.sh

@@ -10,6 +10,7 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 base_path=$(pwd -P)
 
 test_expect_success 'setup: create origin repos'  '
+	git config --global protocol.file.allow always &&
 	git init origin/sub &&
 	test_commit -C origin/sub file1 &&
 	git init origin/main &&

t/t3200-branch.sh

@@ -282,6 +282,7 @@ test_expect_success 'deleting checked-out branch from repo that is a submodule'
 	git init repo1 &&
 	git init repo1/sub &&
 	test_commit -C repo1/sub x &&
+	test_config_global protocol.file.allow always &&
 	git -C repo1 submodule add ./sub &&
 	git -C repo1 commit -m "adding sub" &&
 

t/t3420-rebase-autostash.sh

@@ -310,7 +310,7 @@ test_expect_success 'autostash is saved on editor failure with conflict' '
 test_expect_success 'autostash with dirty submodules' '
 	test_when_finished "git reset --hard && git checkout main" &&
 	git checkout -b with-submodule &&
-	git submodule add ./ sub &&
+	git -c protocol.file.allow=always submodule add ./ sub &&
 	test_tick &&
 	git commit -m add-submodule &&
 	echo changed >sub/file0 &&

t/t3426-rebase-submodule.sh

@@ -47,7 +47,8 @@ test_expect_success 'rebase interactive ignores modified submodules' '
 	git init sub &&
 	git -C sub commit --allow-empty -m "Initial commit" &&
 	git init super &&
-	git -C super submodule add ../sub &&
+	git -c protocol.file.allow=always \
+		-C super submodule add ../sub &&
 	git -C super config submodule.sub.ignore dirty &&
 	>super/foo &&
 	git -C super add foo &&

t/t3512-cherry-pick-submodule.sh

@@ -13,6 +13,8 @@ KNOWN_FAILURE_NOFF_MERGE_ATTEMPTS_TO_MERGE_REMOVED_SUBMODULE_FILES=1
 test_submodule_switch "cherry-pick"
 
 test_expect_success 'unrelated submodule/file conflict is ignored' '
+	test_config_global protocol.file.allow always &&
+
 	test_create_repo sub &&
 
 	touch sub/file &&

t/t3600-rm.sh

@@ -336,7 +336,7 @@ test_expect_success 'rm removes empty submodules from work tree' '
 
 test_expect_success 'rm removes removed submodule from index and .gitmodules' '
 	git reset --hard &&
-	git submodule update &&
+	git -c protocol.file.allow=always submodule update &&
 	rm -rf submod &&
 	git rm submod &&
 	git status -s -uno --ignore-submodules=none >actual &&
@@ -642,6 +642,7 @@ cat >expect.deepmodified <<EOF
 EOF
 
 test_expect_success 'setup subsubmodule' '
+	test_config_global protocol.file.allow always &&
 	git reset --hard &&
 	git submodule update &&
 	(

t/t3906-stash-submodule.sh

@@ -36,7 +36,7 @@ setup_basic () {
 	git init main &&
 	(
 		cd main &&
-		git submodule add ../sub &&
+		git -c protocol.file.allow=always submodule add ../sub &&
 		test_commit main_file
 	)
 }

t/t4059-diff-submodule-not-initialized.sh

@@ -49,7 +49,7 @@ test_expect_success 'setup - submodules' '
 '
 
 test_expect_success 'setup - git submodule add' '
-	git submodule add ./sm2 sm1 &&
+	git -c protocol.file.allow=always submodule add ./sm2 sm1 &&
 	commit_file sm1 .gitmodules &&
 	git diff-tree -p --no-commit-id --submodule=log HEAD -- sm1 >actual &&
 	cat >expected <<-EOF &&

t/t4060-diff-submodule-option-diff-format.sh

@@ -759,9 +759,9 @@ test_expect_success 'diff --submodule=diff with .git file' '
 '
 
 test_expect_success 'setup nested submodule' '
-	git submodule add -f ./sm2 &&
+	git -c protocol.file.allow=always submodule add -f ./sm2 &&
 	git commit -a -m "add sm2" &&
-	git -C sm2 submodule add ../sm2 nested &&
+	git -c protocol.file.allow=always -C sm2 submodule add ../sm2 nested &&
 	git -C sm2 commit -a -m "nested sub" &&
 	head10=$(git -C sm2 rev-parse --short --verify HEAD)
 '

t/t4067-diff-partial-clone.sh

@@ -77,6 +77,7 @@ test_expect_success 'diff skips same-OID blobs' '
 
 test_expect_success 'when fetching missing objects, diff skips GITLINKs' '
 	test_when_finished "rm -rf sub server client trace" &&
+	test_config_global protocol.file.allow always &&
 
 	test_create_repo sub &&
 	test_commit -C sub first &&

t/t4208-log-magic-pathspec.sh

@@ -124,6 +124,7 @@ test_expect_success 'command line pathspec parsing for "git log"' '
 
 test_expect_success 'tree_entry_interesting does not match past submodule boundaries' '
 	test_when_finished "rm -rf repo submodule" &&
+	test_config_global protocol.file.allow always &&
 	git init submodule &&
 	test_commit -C submodule initial &&
 	git init repo &&

t/t5510-fetch.sh

@@ -782,6 +782,7 @@ test_expect_success 'fetch.writeCommitGraph' '
 '
 
 test_expect_success 'fetch.writeCommitGraph with submodules' '
+	test_config_global protocol.file.allow always &&
 	git clone dups super &&
 	(
 		cd super &&

t/t5526-fetch-submodules.sh

@@ -38,6 +38,7 @@ add_upstream_commit() {
 }
 
 test_expect_success setup '
+	git config --global protocol.file.allow always &&
 	mkdir deepsubmodule &&
 	(
 		cd deepsubmodule &&

t/t5545-push-options.sh

@@ -116,6 +116,7 @@ test_expect_success 'push options and submodules' '
 	test_commit -C parent one &&
 	git -C parent push --mirror up &&
 
+	test_config_global protocol.file.allow always &&
 	git -C parent submodule add ../upstream workbench &&
 	git -C parent/workbench remote add up ../../upstream &&
 	git -C parent commit -m "add submodule" &&

t/t5572-pull-submodule.sh

@@ -46,6 +46,10 @@ KNOWN_FAILURE_NOFF_MERGE_DOESNT_CREATE_EMPTY_SUBMODULE_DIR=1
 KNOWN_FAILURE_NOFF_MERGE_ATTEMPTS_TO_MERGE_REMOVED_SUBMODULE_FILES=1
 test_submodule_switch_func "git_pull_noff"
 
+test_expect_success 'setup' '
+	git config --global protocol.file.allow always
+'
+
 test_expect_success 'pull --recurse-submodule setup' '
 	test_create_repo child &&
 	test_commit -C child bar &&

t/t5601-clone.sh

@@ -741,6 +741,7 @@ test_expect_success 'batch missing blob request does not inadvertently try to fe
 	echo aa >server/a &&
 	echo bb >server/b &&
 	# Also add a gitlink pointing to an arbitrary repository
+	test_config_global protocol.file.allow always &&
 	git -C server submodule add "$(pwd)/repo_for_submodule" c &&
 	git -C server add a b c &&
 	git -C server commit -m x &&

t/t5604-clone-reference.sh

@@ -303,8 +303,6 @@ test_expect_success SYMLINKS 'setup repo with manually symlinked or unknown file
 		ln -s ../an-object $obj &&
 
 		cd ../ &&
-		find . -type f | sort >../../../T.objects-files.raw &&
-		find . -type l | sort >../../../T.objects-symlinks.raw &&
 		echo unknown_content >unknown_file
 	) &&
 	git -C T fsck &&
@@ -313,19 +311,27 @@ test_expect_success SYMLINKS 'setup repo with manually symlinked or unknown file
 
 
 test_expect_success SYMLINKS 'clone repo with symlinked or unknown files at objects/' '
-	for option in --local --no-hardlinks --shared --dissociate
+	# None of these options work when cloning locally, since T has
+	# symlinks in its `$GIT_DIR/objects` directory
+	for option in --local --no-hardlinks --dissociate
 	do
-		git clone $option T T$option || return 1 &&
-		git -C T$option fsck || return 1 &&
-		git -C T$option rev-list --all --objects >T$option.objects &&
-		test_cmp T.objects T$option.objects &&
-		(
-			cd T$option/.git/objects &&
-			find . -type f | sort >../../../T$option.objects-files.raw &&
-			find . -type l | sort >../../../T$option.objects-symlinks.raw
-		)
+		test_must_fail git clone $option T T$option 2>err || return 1 &&
+		test_i18ngrep "symlink.*exists" err || return 1
 	done &&
 
+	# But `--shared` clones should still work, even when specifying
+	# a local path *and* that repository has symlinks present in its
+	# `$GIT_DIR/objects` directory.
+	git clone --shared T T--shared &&
+	git -C T--shared fsck &&
+	git -C T--shared rev-list --all --objects >T--shared.objects &&
+	test_cmp T.objects T--shared.objects &&
+	(
+		cd T--shared/.git/objects &&
+		find . -type f | sort >../../../T--shared.objects-files.raw &&
+		find . -type l | sort >../../../T--shared.objects-symlinks.raw
+	) &&
+
 	for raw in $(ls T*.raw)
 	do
 		sed -e "s!/../!/Y/!; s![0-9a-f]\{38,\}!Z!" -e "/commit-graph/d" \
@@ -333,26 +339,6 @@ test_expect_success SYMLINKS 'clone repo with symlinked or unknown files at obje
 		sort $raw.de-sha-1 >$raw.de-sha || return 1
 	done &&
 
-	cat >expected-files <<-EOF &&
-	./Y/Z
-	./Y/Z
-	./Y/Z
-	./a-loose-dir/Z
-	./an-object
-	./info/packs
-	./pack/pack-Z.idx
-	./pack/pack-Z.pack
-	./packs/pack-Z.idx
-	./packs/pack-Z.pack
-	./unknown_file
-	EOF
-
-	for option in --local --no-hardlinks --dissociate
-	do
-		test_cmp expected-files T$option.objects-files.raw.de-sha || return 1 &&
-		test_must_be_empty T$option.objects-symlinks.raw.de-sha || return 1
-	done &&
-
 	echo ./info/alternates >expected-files &&
 	test_cmp expected-files T--shared.objects-files.raw &&
 	test_must_be_empty T--shared.objects-symlinks.raw

t/t5614-clone-submodules-shallow.sh

@@ -24,6 +24,7 @@ test_expect_success 'setup' '
 
 test_expect_success 'nonshallow clone implies nonshallow submodule' '
 	test_when_finished "rm -rf super_clone" &&
+	test_config_global protocol.file.allow always &&
 	git clone --recurse-submodules "file://$pwd/." super_clone &&
 	git -C super_clone log --oneline >lines &&
 	test_line_count = 3 lines &&
@@ -33,6 +34,7 @@ test_expect_success 'nonshallow clone implies nonshallow submodule' '
 
 test_expect_success 'shallow clone with shallow submodule' '
 	test_when_finished "rm -rf super_clone" &&
+	test_config_global protocol.file.allow always &&
 	git clone --recurse-submodules --depth 2 --shallow-submodules "file://$pwd/." super_clone &&
 	git -C super_clone log --oneline >lines &&
 	test_line_count = 2 lines &&
@@ -42,6 +44,7 @@ test_expect_success 'shallow clone with shallow submodule' '
 
 test_expect_success 'shallow clone does not imply shallow submodule' '
 	test_when_finished "rm -rf super_clone" &&
+	test_config_global protocol.file.allow always &&
 	git clone --recurse-submodules --depth 2 "file://$pwd/." super_clone &&
 	git -C super_clone log --oneline >lines &&
 	test_line_count = 2 lines &&
@@ -51,6 +54,7 @@ test_expect_success 'shallow clone does not imply shallow submodule' '
 
 test_expect_success 'shallow clone with non shallow submodule' '
 	test_when_finished "rm -rf super_clone" &&
+	test_config_global protocol.file.allow always &&
 	git clone --recurse-submodules --depth 2 --no-shallow-submodules "file://$pwd/." super_clone &&
 	git -C super_clone log --oneline >lines &&
 	test_line_count = 2 lines &&
@@ -60,6 +64,7 @@ test_expect_success 'shallow clone with non shallow submodule' '
 
 test_expect_success 'non shallow clone with shallow submodule' '
 	test_when_finished "rm -rf super_clone" &&
+	test_config_global protocol.file.allow always &&
 	git clone --recurse-submodules --no-local --shallow-submodules "file://$pwd/." super_clone &&
 	git -C super_clone log --oneline >lines &&
 	test_line_count = 3 lines &&
@@ -69,6 +74,7 @@ test_expect_success 'non shallow clone with shallow submodule' '
 
 test_expect_success 'clone follows shallow recommendation' '
 	test_when_finished "rm -rf super_clone" &&
+	test_config_global protocol.file.allow always &&
 	git config -f .gitmodules submodule.sub.shallow true &&
 	git add .gitmodules &&
 	git commit -m "recommend shallow for sub" &&
@@ -87,6 +93,7 @@ test_expect_success 'clone follows shallow recommendation' '
 
 test_expect_success 'get unshallow recommended shallow submodule' '
 	test_when_finished "rm -rf super_clone" &&
+	test_config_global protocol.file.allow always &&
 	git clone --no-local "file://$pwd/." super_clone &&
 	(
 		cd super_clone &&
@@ -103,6 +110,7 @@ test_expect_success 'get unshallow recommended shallow submodule' '
 
 test_expect_success 'clone follows non shallow recommendation' '
 	test_when_finished "rm -rf super_clone" &&
+	test_config_global protocol.file.allow always &&
 	git config -f .gitmodules submodule.sub.shallow false &&
 	git add .gitmodules &&
 	git commit -m "recommend non shallow for sub" &&

t/t5616-partial-clone.sh

@@ -174,6 +174,8 @@ test_expect_success 'partial clone with transfer.fsckobjects=1 works with submod
 	test_config -C src_with_sub uploadpack.allowfilter 1 &&
 	test_config -C src_with_sub uploadpack.allowanysha1inwant 1 &&
 
+	test_config_global protocol.file.allow always &&
+
 	git -C src_with_sub submodule add "file://$(pwd)/submodule" mysub &&
 	git -C src_with_sub commit -m "commit with submodule" &&
 

t/t5617-clone-submodules-remote.sh

@@ -10,6 +10,7 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 pwd=$(pwd)
 
 test_expect_success 'setup' '
+	git config --global protocol.file.allow always &&
 	git checkout -b main &&
 	test_commit commit1 &&
 	mkdir sub &&

t/t6008-rev-list-submodule.sh

@@ -26,7 +26,7 @@ test_expect_success 'setup' '
 
 	: > super-file &&
 	git add super-file &&
-	git submodule add "$(pwd)" sub &&
+	git -c protocol.file.allow=always submodule add "$(pwd)" sub &&
 	git symbolic-ref HEAD refs/heads/super &&
 	test_tick &&
 	git commit -m super-initial &&

t/t6134-pathspec-in-submodule.sh

@@ -9,7 +9,7 @@ test_expect_success 'setup a submodule' '
 	: >pretzel/a &&
 	git -C pretzel add a &&
 	git -C pretzel commit -m "add a file" -- a &&
-	git submodule add ./pretzel sub &&
+	git -c protocol.file.allow=always submodule add ./pretzel sub &&
 	git commit -a -m "add submodule" &&
 	git submodule deinit --all
 '

t/t7001-mv.sh

@@ -304,6 +304,7 @@ test_expect_success SYMLINKS 'check moved symlink' '
 rm -f moved symlink
 
 test_expect_success 'setup submodule' '
+	test_config_global protocol.file.allow always &&
 	git commit -m initial &&
 	git reset --hard &&
 	git submodule add ./. sub &&
@@ -489,6 +490,7 @@ test_expect_success 'moving a submodule in nested directories' '
 '
 
 test_expect_success 'moving nested submodules' '
+	test_config_global protocol.file.allow always &&
 	git commit -am "cleanup commit" &&
 	mkdir sub_nested_nested &&
 	(

t/t7064-wtstatus-pv2.sh

@@ -465,6 +465,7 @@ test_expect_success 'create and add submodule, submodule appears clean (A. S...)
 	git checkout initial-branch &&
 	git clone . sub_repo &&
 	git clone . super_repo &&
+	test_config_global protocol.file.allow always &&
 	(	cd super_repo &&
 		git submodule add ../sub_repo sub1 &&
 

t/t7300-clean.sh

@@ -480,6 +480,7 @@ test_expect_success 'should not clean submodules' '
 		git init &&
 		test_commit msg hello.world
 	) &&
+	test_config_global protocol.file.allow always &&
 	git submodule add ./repo/.git sub1 &&
 	git commit -m "sub1" &&
 	git branch before_sub2 &&

t/t7400-submodule-basic.sh

@@ -14,6 +14,10 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 . ./test-lib.sh
 
+test_expect_success 'setup - enable local submodules' '
+	git config --global protocol.file.allow always
+'
+
 test_expect_success 'submodule deinit works on empty repository' '
 	git submodule deinit --all
 '

t/t7403-submodule-sync.sh

@@ -14,6 +14,8 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 . ./test-lib.sh
 
 test_expect_success setup '
+	git config --global protocol.file.allow always &&
+
 	echo file >file &&
 	git add file &&
 	test_tick &&

t/t7406-submodule-update.sh

@@ -25,6 +25,7 @@ compare_head()
 
 
 test_expect_success 'setup a submodule tree' '
+	git config --global protocol.file.allow always &&
 	echo file > file &&
 	git add file &&
 	test_tick &&

t/t7407-submodule-foreach.sh

@@ -16,6 +16,7 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 
 test_expect_success 'setup a submodule tree' '
+	git config --global protocol.file.allow always &&
 	echo file > file &&
 	git add file &&
 	test_tick &&

t/t7408-submodule-reference.sh

@@ -17,6 +17,10 @@ test_alternate_is_used () {
 	test_cmp expect actual
 }
 
+test_expect_success 'setup' '
+	git config --global protocol.file.allow always
+'
+
 test_expect_success 'preparing first repository' '
 	test_create_repo A &&
 	(

t/t7409-submodule-detached-work-tree.sh

@@ -15,6 +15,10 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 . ./test-lib.sh
 
+test_expect_success 'setup' '
+	git config --global protocol.file.allow always
+'
+
 test_expect_success 'submodule on detached working tree' '
 	git init --bare remote &&
 	test_create_repo bundle1 &&

t/t7411-submodule-config.sh

@@ -12,6 +12,9 @@ from the database and from the worktree works.
 TEST_NO_CREATE_REPO=1
 . ./test-lib.sh
 
+test_expect_success 'setup' '
+	git config --global protocol.file.allow always
+'
 test_expect_success 'submodule config cache setup' '
 	mkdir submodule &&
 	(cd submodule &&

t/t7413-submodule-is-active.sh

@@ -9,6 +9,7 @@ submodules which are "active" and interesting to the user.
 . ./test-lib.sh
 
 test_expect_success 'setup' '
+	git config --global protocol.file.allow always &&
 	git init sub &&
 	test_commit -C sub initial &&
 	git init super &&

t/t7414-submodule-mistakes.sh

@@ -30,7 +30,8 @@ test_expect_success 'no warning when updating entry' '
 
 test_expect_success 'submodule add does not warn' '
 	test_when_finished "git rm -rf submodule .gitmodules" &&
-	git submodule add ./embed submodule 2>stderr &&
+	git -c protocol.file.allow=always \
+		submodule add ./embed submodule 2>stderr &&
 	test_i18ngrep ! warning stderr
 '
 

t/t7415-submodule-names.sh

@@ -8,6 +8,10 @@ real-world setup that confirms we catch this in practice.
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-pack.sh
 
+test_expect_success 'setup' '
+	git config --global protocol.file.allow always
+'
+
 test_expect_success 'check names' '
 	cat >expect <<-\EOF &&
 	valid

t/t7416-submodule-dash-url.sh

@@ -3,6 +3,10 @@
 test_description='check handling of disallowed .gitmodule urls'
 . ./test-lib.sh
 
+test_expect_success 'setup' '
+	git config --global protocol.file.allow always
+'
+
 test_expect_success 'create submodule with protected dash in url' '
 	git init upstream &&
 	git -C upstream commit --allow-empty -m base &&

t/t7417-submodule-path-url.sh

@@ -6,6 +6,10 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 . ./test-lib.sh
 
+test_expect_success 'setup' '
+	git config --global protocol.file.allow always
+'
+
 test_expect_success 'create submodule with dash in path' '
 	git init upstream &&
 	git -C upstream commit --allow-empty -m base &&

t/t7418-submodule-sparse-gitmodules.sh

@@ -14,6 +14,10 @@ also by committing .gitmodules and then just removing it from the filesystem.
 
 . ./test-lib.sh
 
+test_expect_success 'setup' '
+	git config --global protocol.file.allow always
+'
+
 test_expect_success 'sparse checkout setup which hides .gitmodules' '
 	git init upstream &&
 	git init submodule &&

t/t7419-submodule-set-branch.sh

@@ -12,6 +12,10 @@ as expected.
 TEST_NO_CREATE_REPO=1
 . ./test-lib.sh
 
+test_expect_success 'setup' '
+	git config --global protocol.file.allow always
+'
+
 test_expect_success 'submodule config cache setup' '
 	mkdir submodule &&
 	(cd submodule &&

t/t7420-submodule-set-url.sh

@@ -12,6 +12,10 @@ as expected.
 TEST_NO_CREATE_REPO=1
 . ./test-lib.sh
 
+test_expect_success 'setup' '
+	git config --global protocol.file.allow always
+'
+
 test_expect_success 'submodule config cache setup' '
 	mkdir submodule &&
 	(

t/t7421-submodule-summary-add.sh

@@ -12,6 +12,10 @@ while making sure to add submodules using `git submodule add` instead of
 
 . ./test-lib.sh
 
+test_expect_success 'setup' '
+	git config --global protocol.file.allow always
+'
+
 test_expect_success 'summary test environment setup' '
 	git init sm &&
 	test_commit -C sm "add file" file file-content file-tag &&

t/t7506-status-submodule.sh

@@ -251,6 +251,7 @@ test_expect_success 'status with merge conflict in .gitmodules' '
 	test_create_repo_with_commit sub1 &&
 	test_tick &&
 	test_create_repo_with_commit sub2 &&
+	test_config_global protocol.file.allow always &&
 	(
 		cd super &&
 		prev=$(git rev-parse HEAD) &&
@@ -326,6 +327,7 @@ test_expect_success 'diff --submodule with merge conflict in .gitmodules' '
 # sub2 will have an untracked file
 # sub3 will have an untracked repository
 test_expect_success 'setup superproject with untracked file in nested submodule' '
+	test_config_global protocol.file.allow always &&
 	(
 		cd super &&
 		git clean -dfx &&

t/t7507-commit-verbose.sh

@@ -74,6 +74,7 @@ test_expect_success 'diff in message is retained with -v' '
 
 test_expect_success 'submodule log is stripped out too with -v' '
 	git config diff.submodule log &&
+	test_config_global protocol.file.allow always &&
 	git submodule add ./. sub &&
 	git commit -m "sub added" &&
 	(

t/t7800-difftool.sh

@@ -629,6 +629,7 @@ test_expect_success 'difftool --no-symlinks detects conflict ' '
 
 test_expect_success 'difftool properly honors gitlink and core.worktree' '
 	test_when_finished rm -rf submod/ule &&
+	test_config_global protocol.file.allow always &&
 	git submodule add ./. submod/ule &&
 	test_config -C submod/ule diff.tool checktrees &&
 	test_config -C submod/ule difftool.checktrees.cmd '\''

t/t7814-grep-recurse-submodules.sh

@@ -193,6 +193,7 @@ test_expect_success !MINGW 'grep recurse submodule colon in name' '
 	git -C "su:b" commit -m "add fi:le" &&
 	test_tick &&
 
+	test_config_global protocol.file.allow always &&
 	git -C parent submodule add "../su:b" "su:b" &&
 	git -C parent commit -m "add submodule" &&
 	test_tick &&
@@ -227,6 +228,7 @@ test_expect_success 'grep history with moved submoules' '
 	git -C sub commit -m "add file" &&
 	test_tick &&
 
+	test_config_global protocol.file.allow always &&
 	git -C parent submodule add ../sub dir/sub &&
 	git -C parent commit -m "add submodule" &&
 	test_tick &&
@@ -271,6 +273,7 @@ test_expect_success 'grep using relative path' '
 	mkdir parent/src &&
 	echo "(1|2)d(3|4)" >parent/src/file2 &&
 	git -C parent add src/file2 &&
+	test_config_global protocol.file.allow always &&
 	git -C parent submodule add ../sub &&
 	git -C parent commit -m "add files and submodule" &&
 	test_tick &&
@@ -313,6 +316,7 @@ test_expect_success 'grep from a subdir' '
 	mkdir parent/src &&
 	echo "(1|2)d(3|4)" >parent/src/file &&
 	git -C parent add src/file &&
+	test_config_global protocol.file.allow always &&
 	git -C parent submodule add ../sub src/sub &&
 	git -C parent submodule add ../sub sub &&
 	git -C parent commit -m "add files and submodules" &&

t/t9304-fast-import-marks.sh

@@ -25,6 +25,7 @@ test_expect_success 'import with large marks file' '
 '
 
 test_expect_success 'setup dump with submodule' '
+	test_config_global protocol.file.allow always &&
 	git submodule add "$PWD" sub &&
 	git commit -m "add submodule" &&
 	git fast-export HEAD >dump

t/t9350-fast-export.sh

@@ -268,6 +268,7 @@ test_expect_success 'signed-tags=warn-strip' '
 
 test_expect_success 'setup submodule' '
 
+	test_config_global protocol.file.allow always &&
 	git checkout -f main &&
 	mkdir sub &&
 	(
@@ -293,6 +294,7 @@ test_expect_success 'setup submodule' '
 
 test_expect_success 'submodule fast-export | fast-import' '
 
+	test_config_global protocol.file.allow always &&
 	SUBENT1=$(git ls-tree main^ sub) &&
 	SUBENT2=$(git ls-tree main sub) &&
 	rm -rf new &&

t/t9850-shell.sh

@@ -0,0 +1,37 @@
+#!/bin/sh
+
+test_description='git shell tests'
+. ./test-lib.sh
+
+test_expect_success 'shell allows upload-pack' '
+	printf 0000 >input &&
+	git upload-pack . <input >expect &&
+	git shell -c "git-upload-pack $SQ.$SQ" <input >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'shell forbids other commands' '
+	test_must_fail git shell -c "git config foo.bar baz"
+'
+
+test_expect_success 'shell forbids interactive use by default' '
+	test_must_fail git shell
+'
+
+test_expect_success 'shell allows interactive command' '
+	mkdir git-shell-commands &&
+	write_script git-shell-commands/ping <<-\EOF &&
+	echo pong
+	EOF
+	echo pong >expect &&
+	echo ping | git shell >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'shell complains of overlong commands' '
+	perl -e "print \"a\" x 2**12 for (0..2**19)" |
+	test_must_fail git shell 2>err &&
+	grep "too long" err
+'
+
+test_done

transport.c

@@ -964,8 +964,7 @@ static enum protocol_allow_config get_protocol_config(const char *type)
 	if (!strcmp(type, "http") ||
 	    !strcmp(type, "https") ||
 	    !strcmp(type, "git") ||
-	    !strcmp(type, "ssh") ||
-	    !strcmp(type, "file"))
+	    !strcmp(type, "ssh"))
 		return PROTOCOL_ALLOW_ALWAYS;
 
 	/* known scary; err on the side of caution */