[PATCH 3/8] Revert "core.hooksPath: add some protection while cloning"

From: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
Date: May 17, 2024, 23:15 UTC
Message-ID: <57db89a14977bdff01f8f82cb4d6f85cc49d4b55.1715987756.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.1732.git.1715987756.gitgitgadget@gmail.com>

From: Johannes Schindelin <johannes.schindelin@gmx.de>

This defense-in-depth was intended to protect the clone operation against future escalations where bugs in `git clone` would allow attackers to write arbitrary files in the `.git/` directory would allow for Remote Code Execution attacks via maliciously-placed hooks.

However, it turns out that the `core.hooksPath` protection has unintentional side effects so severe that they do not justify the benefit of the protections. For example, it has been reported in https://lore.kernel.org/git/FAFA34CB-9732-4A0A-87FB-BDB272E6AEE8@alchemists.io/ that the following invocation, which is intended to make `git clone` safer, is itself broken by that protective measure:

	git clone --config core.hooksPath=/dev/null <url>

Since it turns out that the benefit does not justify the cost, let's revert 20f3588efc6 (core.hooksPath: add some protection while cloning, 2024-03-30).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 config.c        | 13 +------------
 t/t1800-hook.sh | 15 ---------------
 2 files changed, 1 insertion(+), 27 deletions(-)

diff --git a/config.c b/config.c
index 85b37f2ee09..8c1c4071f0d 100644
--- a/config.c
+++ b/config.c
@@ -1525,19 +1525,8 @@ static int git_default_core_config(const char *var, const char *value, void *cb)
 	if (!strcmp(var, "core.attributesfile"))
 		return git_config_pathname(&git_attributes_file, var, value);
 
-	if (!strcmp(var, "core.hookspath")) {
-		if (current_config_scope() == CONFIG_SCOPE_LOCAL &&
-		    git_env_bool("GIT_CLONE_PROTECTION_ACTIVE", 0))
-			die(_("active `core.hooksPath` found in the local "
-			      "repository config:\n\t%s\nFor security "
-			      "reasons, this is disallowed by default.\nIf "
-			      "this is intentional and the hook should "
-			      "actually be run, please\nrun the command "
-			      "again with "
-			      "`GIT_CLONE_PROTECTION_ACTIVE=false`"),
-			    value);
+	if (!strcmp(var, "core.hookspath"))
 		return git_config_pathname(&git_hooks_path, var, value);
-	}
 
 	if (!strcmp(var, "core.bare")) {
 		is_bare_repository_cfg = git_config_bool(var, value);
diff --git a/t/t1800-hook.sh b/t/t1800-hook.sh
index 7ee12e6f48a..2ef3579fa7c 100755
--- a/t/t1800-hook.sh
+++ b/t/t1800-hook.sh
@@ -177,19 +177,4 @@ test_expect_success 'git hook run a hook with a bad shebang' '
 	test_cmp expect actual
 '
 
-test_expect_success 'clone protections' '
-	test_config core.hooksPath "$(pwd)/my-hooks" &&
-	mkdir -p my-hooks &&
-	write_script my-hooks/test-hook <<-\EOF &&
-	echo Hook ran $1
-	EOF
-
-	git hook run test-hook 2>err &&
-	grep "Hook ran" err &&
-	test_must_fail env GIT_CLONE_PROTECTION_ACTIVE=true \
-		git hook run test-hook 2>err &&
-	grep "active .core.hooksPath" err &&
-	! grep "Hook ran" err
-'
-
 test_done

-- 
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