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 4CF0F22259B; Mon, 2 Jun 2025 14:28:19 +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=1748874499; cv=none; b=swP84LoZfb9tNFJOsVB+utViG86zXWvo5u7KXoIx/uR9fo/fYkhjNftIitkKueN45H0pc6ltlFtuhMs/s/DVgFomMJ/o2NAwQvi/p4Pz8udlvAPX00V2bO6/c594R2bNzqQsybuPV4NAHLrR/skmAkulM+cJt2lMrzAhOzMHUSE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748874499; c=relaxed/simple; bh=FgSHl9GFibSVUmQ7cc96r6+jinGzY4qB2HZFFkp7hlw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fjmhSvTJw3GmZClTEfx5+et0pzGuu2pZ4iu7hiANMAbmTSYV9aHIZYTHvL0TD27JMmdF2UVqiHEEIUrGOLrNjhpGNflx9CVDFHCDx4aTqqVU7vxqnBSlDtSwH/7YwZ7p0QUq70blWRjSdUijqwUEMGK6csand2phLslWqxznlQ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Xx5JE2Rg; 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="Xx5JE2Rg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB96DC4CEF0; Mon, 2 Jun 2025 14:28:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1748874499; bh=FgSHl9GFibSVUmQ7cc96r6+jinGzY4qB2HZFFkp7hlw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Xx5JE2Rg/NOXsudyb1nDE+G1AEDbdacjKdIqjqB4r+ORJSGtO3puR6KAE8Klgf8Dd LQ016O3BJfyswFLh6VAE+CFriEWkVeZ9EdFZr0xQyaStZ3qo7+KK/B98Qnf2SHgiv0 8Xe5XaHlDndxdWQVPVApJtN4Jsvk3LDP2QHU5HB8= 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 5.4 012/204] net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc Date: Mon, 2 Jun 2025 15:45:45 +0200 Message-ID: <20250602134255.970665884@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250602134255.449974357@linuxfoundation.org> References: <20250602134255.449974357@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 5.4-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 79c63c4610d3a..5d73d02b8dce7 100644 --- a/net/sched/sch_hfsc.c +++ b/net/sched/sch_hfsc.c @@ -1573,7 +1573,7 @@ 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