[PATCH] Disallow empty section and variable names

[Libor Pechacek <lpechacek@suse.cz>]

It is possible to break you repository config by creating an invalid config
option.  The config parser in turn chokes on it.

$ git init
Initialized empty Git repository in /tmp/gittest/.git/
$ git config .foo false
$ git config .foo
fatal: bad config file line 6 in .git/config

This patch makes git-config reject keys which start or end with a dot.  The fix
also revealed a typo in t5526-fetch-submodules, which is fixed by this patch as
well.

Signed-off-by: Libor Pechacek <lpechacek@suse.cz>
---

Applies on top "Sanity-check config variable names".

 config.c                    |    7 ++++++-
 t/t5526-fetch-submodules.sh |    2 +-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/config.c b/config.c
index c976544..81a0705 100644
--- a/config.c
+++ b/config.c
@@ -1119,7 +1119,7 @@ int git_config_parse_key(const char *key, char **store_key, int *baselen_)
 	 * key name separated by a dot, we have to know where the dot is.
 	 */
 
-	if (last_dot == NULL) {
+	if (last_dot == NULL || *key == '.') {
 		error("key does not contain a section: %s", key);
 		return -2;
 	}
@@ -1156,6 +1156,11 @@ int git_config_parse_key(const char *key, char **store_key, int *baselen_)
 	if (store_key)
 		(*store_key)[i] = 0;
 
+	if (key[i-1] == '.') {
+		error("key does not contain variable name: %s", key);
+		goto out_free_ret_1;
+	}
+
 	return 0;
 
 out_free_ret_1:
diff --git a/t/t5526-fetch-submodules.sh b/t/t5526-fetch-submodules.sh
index 884a5e5..7106c6c 100755
--- a/t/t5526-fetch-submodules.sh
+++ b/t/t5526-fetch-submodules.sh
@@ -124,7 +124,7 @@ test_expect_success "--recurse-submodules overrides fetchRecurseSubmodules setti
 	(
 		cd downstream &&
 		git fetch --recurse-submodules >../actual.out 2>../actual.err &&
-		git config -f --unset .gitmodules submodule.submodule.fetchRecurseSubmodules true &&
+		git config -f .gitmodules --unset submodule.submodule.fetchRecurseSubmodules true &&
 		git config --unset submodule.submodule.fetchRecurseSubmodules
 	) &&
 	test_cmp expect.out actual.out &&
-- 
1.7.4.rc3.3.g8b2bfe