From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1804835DA40; Sat, 12 Sep 2026 18:33:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789238026; cv=none; b=WzxhMU0LwmLUVM1jmSXt/KRxr4W1cujJYKi2oDul5nTyGEREcO7Q1huj7lDZ26YhcDHknZd4C2Fek2PtMmISBp6IlK2DRG0QPmAN0KrScMrGQBjNvdAqkQ81KiVbUJbAd3SE/8Q38/BGn0eJpC+yiF9txcWC55Hg9WvWt256a6Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789238026; c=relaxed/simple; bh=3y4Kll/ih3htJEjDPYH2mdIwLNeVTS7XJmah34Zi1Zc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nI48SHCLVjQ9y1TJkzcXmIB7zTz9wcMqL7cVCVf8HR58gVw/kWcrLn1h7egpNLJw+sagHzkRjGjO/ysklxajdObPjfaLO3lZISRrtGevpgi7WoCKuW7T/aL0nOtBFt0AjZieDycdSfJJ3/sFsTFPKxhlPCCuqLCqRjX6eYtt7x8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RKVcQuOZ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RKVcQuOZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE45F1F000FF; Sat, 12 Sep 2026 18:33:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789238024; bh=xsLletF1DIZ+lyyZq+x5VThDZvRhqcx6bWlZIYmPc78=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RKVcQuOZtlDwohnKBlOXJ5Ld+tazpQSIcKZ8ZToODAKLK6Sir1VUmOak+gBRsHmBA Mx3alTrDoGfLWk/pxcE4uezNTUVyVOhO0RHP1NYG2Uov/8uvF/g6Z6A2d2PID3a5NP NaH35wM7ejmeUvKk9SHZ9BjLfnUYueTfjtjpD1b8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Duoming Zhou , Simon Horman , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 378/935] ax25: fix use-after-free bugs caused by ax25_ds_del_timer Date: Sat, 12 Sep 2026 08:56:48 +0200 Message-ID: <20260912065535.487247911@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065526.833703348@linuxfoundation.org> References: <20260912065526.833703348@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Duoming Zhou [ Upstream commit fd819ad3ecf6f3c232a06b27423ce9ed8c20da89 ] When the ax25 device is detaching, the ax25_dev_device_down() calls ax25_ds_del_timer() to cleanup the slave_timer. When the timer handler is running, the ax25_ds_del_timer() that calls del_timer() in it will return directly. As a result, the use-after-free bugs could happen, one of the scenarios is shown below: (Thread 1) | (Thread 2) | ax25_ds_timeout() ax25_dev_device_down() | ax25_ds_del_timer() | del_timer() | ax25_dev_put() //FREE | | ax25_dev-> //USE In order to mitigate bugs, when the device is detaching, use timer_shutdown_sync() to stop the timer. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Duoming Zhou Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20240329015023.9223-1-duoming@zju.edu.cn Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ax25/ax25_dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c index d2e0cc67d91a7..d1d8d8a21ddd5 100644 --- a/net/ax25/ax25_dev.c +++ b/net/ax25/ax25_dev.c @@ -103,7 +103,7 @@ void ax25_dev_device_down(struct net_device *dev) spin_lock_bh(&ax25_dev_lock); #ifdef CONFIG_AX25_DAMA_SLAVE - ax25_ds_del_timer(ax25_dev); + timer_shutdown_sync(&ax25_dev->dama.slave_timer); #endif /* -- 2.53.0