From patchwork Mon Aug 5 13:51:45 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Antipov X-Patchwork-Id: 13753648 X-Patchwork-Delegate: kuba@kernel.org Received: from forward202d.mail.yandex.net (forward202d.mail.yandex.net [178.154.239.219]) (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 AC88141C6C for ; Mon, 5 Aug 2024 13:52:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.154.239.219 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722865933; cv=none; b=h7VzDNJ2hxrnVHkwWHfTwUXRVO5+HogmPqIhfcFydBUGtDcdTQRQ9CNDZOBk2NcgyCn1FJFTwC3xOG60Xd8Do4abvfsIHZPDTAqsPa8EtW0twYrG46VZ4pdaoonQAth090vCSVSzUEhriX4/US5hzJPr4A9uUnbgq2zmz9I+5mc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722865933; c=relaxed/simple; bh=r/xcw4mkfLvHrB7PfXQuHyAeZI0Y0vdAmcw8mBFA1B8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=cojSTdqW6+tTnbeqPzSfbcuoLqs6VZTx7Uuv/nqENrlqvb4+o8uxuTN/zcJZrZRNgEDhSabnPIet2sKwDrz+Cfqbt4KZG7Rj3SsEpikXP094j03fiZZQz3OotNJGvYeRGd7ocNVJp49mVWltMcYakfuVXgFo3syrswhirzbVWJw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=yandex.ru; spf=pass smtp.mailfrom=yandex.ru; dkim=pass (1024-bit key) header.d=yandex.ru header.i=@yandex.ru header.b=BBwrH1/x; arc=none smtp.client-ip=178.154.239.219 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=yandex.ru Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=yandex.ru Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=yandex.ru header.i=@yandex.ru header.b="BBwrH1/x" Received: from forward101d.mail.yandex.net (forward101d.mail.yandex.net [IPv6:2a02:6b8:c41:1300:1:45:d181:d101]) by forward202d.mail.yandex.net (Yandex) with ESMTPS id B554B65523 for ; Mon, 5 Aug 2024 16:52:01 +0300 (MSK) Received: from mail-nwsmtp-smtp-production-main-35.klg.yp-c.yandex.net (mail-nwsmtp-smtp-production-main-35.klg.yp-c.yandex.net [IPv6:2a02:6b8:c42:2345:0:640:1ce6:0]) by forward101d.mail.yandex.net (Yandex) with ESMTPS id 2B545609DE; Mon, 5 Aug 2024 16:51:54 +0300 (MSK) Received: by mail-nwsmtp-smtp-production-main-35.klg.yp-c.yandex.net (smtp/Yandex) with ESMTPSA id ppbqS4Fc2Os0-o2PMHSwf; Mon, 05 Aug 2024 16:51:53 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1722865913; bh=AF4nlcPDOOqSXjDCWCvo6NX6QZUE6FVV55e/YuwK8Nc=; h=Message-ID:Date:Cc:Subject:To:From; b=BBwrH1/xKiqW9c6rTaYlOEUCPICod2PbOD8AS9trdsIxI79QPmeyGS3j6Tl2O9LwO ocpA5DLSxlOA7civdg9IMycMDlbp1tsNOEJBd4Aj+wMDQxdJxLJTBnEFi9N0TbWy19 TzKTTM55BGt3LZKiogytjI8AHuqXQ1o+tlF3Z/C0= Authentication-Results: mail-nwsmtp-smtp-production-main-35.klg.yp-c.yandex.net; dkim=pass header.i=@yandex.ru From: Dmitry Antipov To: Vinicius Costa Gomes Cc: Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, lvc-project@linuxtesting.org, Dmitry Antipov , syzbot+b65e0af58423fc8a73aa@syzkaller.appspotmail.com Subject: [PATCH] net: sched: fix use-after-free in taprio_change() Date: Mon, 5 Aug 2024 16:51:45 +0300 Message-ID: <20240805135145.37604-1-dmantipov@yandex.ru> X-Mailer: git-send-email 2.45.2 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org In 'taprio_change()', 'admin' pointer may become dangling due to sched switch / removal caused by 'advance_sched()', and critical section protected by 'q->current_entry_lock' is too small to prevent from such a scenario (which causes use-after-free detected by KASAN). Fix this by prefer 'rcu_replace_pointer()' over 'rcu_assign_pointer()' to update 'admin' immediately before an attempt to schedule freeing. Fixes: a3d43c0d56f1 ("taprio: Add support adding an admin schedule") Reported-by: syzbot+b65e0af58423fc8a73aa@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b65e0af58423fc8a73aa Signed-off-by: Dmitry Antipov Acked-by: Vinicius Costa Gomes --- net/sched/sch_taprio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index cc2df9f8c14a..59fad74d5ff9 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1963,7 +1963,8 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, taprio_start_sched(sch, start, new_admin); - rcu_assign_pointer(q->admin_sched, new_admin); + admin = rcu_replace_pointer(q->admin_sched, new_admin, + lockdep_rtnl_is_held()); if (admin) call_rcu(&admin->rcu, taprio_free_sched_cb);