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 941C52144C1; Wed, 7 May 2025 19:10:19 +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=1746645019; cv=none; b=BzvQzfVAf68oavTDSpf0eOCHfQ55atsP8SqiCDD6Kez72ilRCrOOiSLKse/qLiZS60ziKGQl+SxoAb6LJNOqqB1KtvUPpesOPgrY80N/uKDzSQLh+OqNRr9fzd6IwqsG5TPmpS5iubTRfiK56+3DZsa921ssCMinXYKzwfqxrTU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746645019; c=relaxed/simple; bh=LOAm3oT3089Y73TaQuLl63N86/3Nprm6+kasIZr+Ll0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Fns/UuXWpI2K41HnDm7ws0EuEfmTXnKf23ZCfJT6DVGc3oATNMkHOoHD255Er85C5G2o0PdJzEzYJswJBziHCRnkUjCJoc+Rg0uiCdt+3mItYmAUTVE3qPbU7TGXL7QCmTh4BCQK+BHs7R/D9+tsGa6meOELAVy93E6PJ7vBB2Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Vb0jl+6D; 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="Vb0jl+6D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2FEDC4CEE2; Wed, 7 May 2025 19:10:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1746645019; bh=LOAm3oT3089Y73TaQuLl63N86/3Nprm6+kasIZr+Ll0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vb0jl+6DaQVk+21poO8aH8dnnOq64y7nleZpNuU8BiRNB/F1J2u/cVL5WfulnDJxh z7JAH97CrWUsHjIW4J/aW/Esa+oi2OpyIahZzvNMVdMdWv2gk40E7wvCKGaO51+8DZ 7/vYDx861u8tX00z6/DkiSkOGI4MrSIXBcKEfRiM= 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 6.6 069/129] net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc Date: Wed, 7 May 2025 20:40:05 +0200 Message-ID: <20250507183816.318007866@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250507183813.500572371@linuxfoundation.org> References: <20250507183813.500572371@linuxfoundation.org> User-Agent: quilt/0.68 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 6.6-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 371255e624332..4be8760b8bc3c 100644 --- a/net/sched/sch_hfsc.c +++ b/net/sched/sch_hfsc.c @@ -1566,7 +1566,7 @@ 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