netdev - [PATCH 2/2] batman-adv: Improve exception handling in batadv_throw

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Message-ID: <d2ce9337-e1a4-4213-ad6f-926c085dc17f@web.de>
Date: Tue, 2 Jan 2024 08:12:56 +0100
From: Markus Elfring <Markus.Elfring@....de>
To: b.a.t.m.a.n@...ts.open-mesh.org, netdev@...r.kernel.org,
 kernel-janitors@...r.kernel.org, Antonio Quartulli <a@...table.cc>,
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>, Marek Lindner
 <mareklindner@...mailbox.ch>, Paolo Abeni <pabeni@...hat.com>,
 Simon Wunderlich <sw@...onwunderlich.de>, Sven Eckelmann <sven@...fation.org>
Cc: LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] batman-adv: Improve exception handling in
 batadv_throw_uevent()

From: Markus Elfring <elfring@...rs.sourceforge.net>
Date: Tue, 2 Jan 2024 07:52:21 +0100

The kfree() function was called in up to three cases by
the batadv_throw_uevent() function during error handling
even if the passed variable contained a null pointer.
This issue was detected by using the Coccinelle software.

* Thus adjust jump targets.

* Reorder kfree() calls at the end.

Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
---
 net/batman-adv/main.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 5fc754b0b3f7..75119f1ffccc 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -691,29 +691,31 @@ int batadv_throw_uevent(struct batadv_priv *bat_priv, enum batadv_uev_type type,
 				  "%s%s", BATADV_UEV_TYPE_VAR,
 				  batadv_uev_type_str[type]);
 	if (!uevent_env[0])
-		goto out;
+		goto report_error;

 	uevent_env[1] = kasprintf(GFP_ATOMIC,
 				  "%s%s", BATADV_UEV_ACTION_VAR,
 				  batadv_uev_action_str[action]);
 	if (!uevent_env[1])
-		goto out;
+		goto free_first_env;

 	/* If the event is DEL, ignore the data field */
 	if (action != BATADV_UEV_DEL) {
 		uevent_env[2] = kasprintf(GFP_ATOMIC,
 					  "%s%s", BATADV_UEV_DATA_VAR, data);
 		if (!uevent_env[2])
-			goto out;
+			goto free_second_env;
 	}

 	ret = kobject_uevent_env(bat_kobj, KOBJ_CHANGE, uevent_env);
-out:
-	kfree(uevent_env[0]);
-	kfree(uevent_env[1]);
 	kfree(uevent_env[2]);
+free_second_env:
+	kfree(uevent_env[1]);
+free_first_env:
+	kfree(uevent_env[0]);

 	if (ret)
+report_error:
 		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
 			   "Impossible to send uevent for (%s,%s,%s) event (err: %d)\n",
 			   batadv_uev_type_str[type],
--
2.43.0