We made sure that save_env_before_alias() does not skip saving the
environment when asked to (which led to use-after-free of orig_cwd
in restore_env() in the buggy version) with the previous step.
Protect against future breakage where somebody adds new callers of
these functions in an unbalanced fashion.
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
---
git.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/git.c b/git.c
index a57a4cb..e39b972 100644
--- a/git.c
+++ b/git.c
@@ -26,11 +26,15 @@ static const char *env_names[] = {
};
static char *orig_env[4];
static int saved_env_before_alias;
+static int save_restore_env_balance;
static void save_env_before_alias(void)
{
int i;
saved_env_before_alias = 1;
+
+ assert(save_restore_env_balance == 0);
+ save_restore_env_balance = 1;
orig_cwd = xgetcwd();
for (i = 0; i < ARRAY_SIZE(env_names); i++) {
orig_env[i] = getenv(env_names[i]);
@@ -42,6 +46,9 @@ static void save_env_before_alias(void)
static void restore_env(int external_alias)
{
int i;
+
+ assert(save_restore_env_balance == 1);
+ save_restore_env_balance = 0;
if (!external_alias && orig_cwd && chdir(orig_cwd))
die_errno("could not move to %s", orig_cwd);
free(orig_cwd);
--
2.7.0-391-gcd29568
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