From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8C38C1DDC23; Wed, 7 May 2025 18:48:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746643713; cv=none; b=Dwms3KbxhTcdH6fAy9olplJESgVuwi0MsmpVifVdZd0kODEt1kSDZ0LQtUzNvvn465cv+0TipGiaUe64i14v7O4rmeQhGpnN1wLSAMi89mCkf924CmYBacz8JuK2GEl+ECTJSsuGPaoK5ewI183eLQRlnR9phzVsDbUauaYK/4U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746643713; c=relaxed/simple; bh=mjtA3xYBHrfjqIFyVNWC9NgQUFD8/N8KBaZmXykPuAY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fg7AQh0jbcqGlGwFg4NF/c+Wz3LgHb7qb/6rTYzJZXFVrTzlB46+OTkVtEWt7t5ey9JtIoAaKyKDjyiKWnEt29eOlXz2IiF/41ncUuOP5/FlzY/6OptPoo4b94t+YvS+IwKNCOmhViJimGNTSsWlac+IuHlikL6G8hHDuviO3zg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IJ7j1Wcu; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="IJ7j1Wcu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DAAF5C4CEF0; Wed, 7 May 2025 18:48:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1746643713; bh=mjtA3xYBHrfjqIFyVNWC9NgQUFD8/N8KBaZmXykPuAY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IJ7j1WcuRTJQW3zkksPwYOqQuUOdIcSoBveJJhQzexU0wikn8aivPyEwprhS7kS4X x5mGJ+sr+b3s0zYO+38bH6yck9gJiCSj13mWP0TfFBRKkGOPQZ/Km3uQPOOoiWdirM 3lBBsWP57PHBB+bLumoCsqPUFSxGO6GjgQqfoGgM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Gerrard Tai , Jamal Hadi Salim , Victor Nogueira , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 51/97] net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc Date: Wed, 7 May 2025 20:39:26 +0200 Message-ID: <20250507183809.055726978@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250507183806.987408728@linuxfoundation.org> References: <20250507183806.987408728@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Victor Nogueira [ Upstream commit 141d34391abbb315d68556b7c67ad97885407547 ] As described in Gerrard's report [1], we have a UAF case when an hfsc class has a netem child qdisc. The crux of the issue is that hfsc is assuming that checking for cl->qdisc->q.qlen == 0 guarantees that it hasn't inserted the class in the vttree or eltree (which is not true for the netem duplicate case). This patch checks the n_active class variable to make sure that the code won't insert the class in the vttree or eltree twice, catering for the reentrant case. [1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/ Fixes: 37d9cf1a3ce3 ("sched: Fix detection of empty queues in child qdiscs") Reported-by: Gerrard Tai Acked-by: Jamal Hadi Salim Signed-off-by: Victor Nogueira Link: https://patch.msgid.link/20250425220710.3964791-3-victor@mojatatu.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sched/sch_hfsc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c index dbed490aafd3d..4b9f323845b91 100644 --- a/net/sched/sch_hfsc.c +++ b/net/sched/sch_hfsc.c @@ -1564,7 +1564,7 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) return err; } - if (first) { + if (first && !cl->cl_nactive) { if (cl->cl_flags & HFSC_RSC) init_ed(cl, len); if (cl->cl_flags & HFSC_FSC) -- 2.39.5