From: Junio C Hamano <gitster@pobox•com>
To: "Nguyễn Thái Ngọc Duy" <pclouds@gmail•com>
Cc: git@vger•kernel.org, git@drmicha•warpmail.net
Subject: [PATCH v2 2/3] git: protect against unbalanced calls to {save,restore}_env()
Date: Wed, 27 Jan 2016 15:19:49 -0800 [thread overview]
Message-ID: <xmqqtwly625m.fsf_-_@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <xmqq7fiva53g.fsf_-_@gitster.mtv.corp.google.com> (Junio C. Hamano's message of "Tue, 26 Jan 2016 22:50:27 -0800")
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@pobox•com>
---
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);
--
2.7.0-368-gb6e04f9
next prev parent reply other threads:[~2016-01-27 23:19 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-26 7:37 [BUG] typo DWIMery with alias broken (cd to random dir) Michael J Gruber
2016-01-26 12:50 ` Duy Nguyen
2016-01-26 13:26 ` [PATCH] git.c: fix help.autocorrect after 57ea712 breaks it Nguyễn Thái Ngọc Duy
2016-01-26 14:39 ` Michael J Gruber
2016-01-26 17:44 ` Junio C Hamano
2016-01-26 19:02 ` Junio C Hamano
2016-01-26 20:11 ` Junio C Hamano
2016-01-27 6:49 ` Junio C Hamano
2016-01-27 6:50 ` [PATCH 2/3] git: protect against unbalanced calls to {save,restore}_env() Junio C Hamano
2016-01-27 23:19 ` Junio C Hamano [this message]
2016-01-27 6:52 ` [PATCH 3/3] git: simplify environment save/restore logic Junio C Hamano
2016-01-27 23:22 ` [PATCH v2 " Junio C Hamano
2016-01-27 23:47 ` Junio C Hamano
2016-01-27 9:14 ` [PATCH] git.c: fix help.autocorrect after 57ea712 breaks it Duy Nguyen
2016-01-27 12:01 ` Junio C Hamano
2016-01-27 23:18 ` [PATCH v2 1/3] git: remove an early return from save_env_before_alias() Junio C Hamano
2016-02-02 23:47 ` [PATCH v3 1/4] " Junio C Hamano
2016-02-02 23:47 ` [PATCH v3 2/4] git: protect against unbalanced calls to {save,restore}_env() Junio C Hamano
2016-02-02 23:48 ` [PATCH v3 3/4] git: simplify environment save/restore logic Junio C Hamano
2016-02-02 23:50 ` [PATCH v3 4/4] restore_env(): free the saved environment variable once we are done Junio C Hamano
2016-02-03 1:47 ` Eric Sunshine
2016-02-03 2:19 ` Junio C Hamano
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