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 8A351344D99; Mon, 20 Apr 2026 16:11:28 +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=1776701488; cv=none; b=ik2YWYhKqly63KWSxwsx/w1Yv5Qtk69H0HEwbzMHYItjsa7gUH0uITkRodcImhArKdAeuT/WMUNbNliQEKANTD1nlrL5om3juZ3ZnRLp3JZIeizUOGqlJfgYn/bLQOc+nm79GBIHTI4vrYf8MsEZSx5kwzU067oLsDx577EzUEU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776701488; c=relaxed/simple; bh=c051yRc6US0Wg2ZMh33U0U3DkPicb+1J4oaX6wcrHDA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uuC8UulfGpFYwsy/xfjekU5zJgyYghEVQEqtsFCuiKjnfwxzNMJpK77tV3880hC7XVUZco5Wi7O0Qj49lEQkmCBSVVHIp4FFuu+fOY9KVGOiWtPGG30xYebacnnr/zcvLgbnHYO5ywmzEIoarF8wyeOsTuX/HFLIbavLKpUC3sI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GW1P4XG6; 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="GW1P4XG6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E23DAC2BCB6; Mon, 20 Apr 2026 16:11:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776701488; bh=c051yRc6US0Wg2ZMh33U0U3DkPicb+1J4oaX6wcrHDA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GW1P4XG6yLC304wUOMV6AlYJjzy+wzA7ElJ38vJ/1PBhrVK42MvJ3REETD3KMMBW/ QfuAtfJSnXWIYY0Hj+QH6CxixlCH11Cpms+mnByP5MxEsOMhFzB/9ZnMDWo6hfjqcE OjRWPTwR0rTYNStIEzGdikiLys9EUwKusRyfq4LU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+f3a497f02c389d86ef16@syzkaller.appspotmail.com, Eric Dumazet , Jamal Hadi Salim , Jakub Kicinski , Chelsy Ratnawat , Sasha Levin Subject: [PATCH 6.12 134/162] net: sched: fix TCF_LAYER_TRANSPORT handling in tcf_get_base_ptr() Date: Mon, 20 Apr 2026 17:42:46 +0200 Message-ID: <20260420153931.899955161@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420153927.006696811@linuxfoundation.org> References: <20260420153927.006696811@linuxfoundation.org> User-Agent: quilt/0.69 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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [Upstream commit 4fe5a00ec70717a7f1002d8913ec6143582b3c8e] syzbot reported that tcf_get_base_ptr() can be called while transport header is not set [1]. Instead of returning a dangling pointer, return NULL. Fix tcf_get_base_ptr() callers to handle this NULL value. [1] WARNING: CPU: 1 PID: 6019 at ./include/linux/skbuff.h:3071 skb_transport_header include/linux/skbuff.h:3071 [inline] WARNING: CPU: 1 PID: 6019 at ./include/linux/skbuff.h:3071 tcf_get_base_ptr include/net/pkt_cls.h:539 [inline] WARNING: CPU: 1 PID: 6019 at ./include/linux/skbuff.h:3071 em_nbyte_match+0x2d8/0x3f0 net/sched/em_nbyte.c:43 Modules linked in: CPU: 1 UID: 0 PID: 6019 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Call Trace: tcf_em_match net/sched/ematch.c:494 [inline] __tcf_em_tree_match+0x1ac/0x770 net/sched/ematch.c:520 tcf_em_tree_match include/net/pkt_cls.h:512 [inline] basic_classify+0x115/0x2d0 net/sched/cls_basic.c:50 tc_classify include/net/tc_wrapper.h:197 [inline] __tcf_classify net/sched/cls_api.c:1764 [inline] tcf_classify+0x4cf/0x1140 net/sched/cls_api.c:1860 multiq_classify net/sched/sch_multiq.c:39 [inline] multiq_enqueue+0xfd/0x4c0 net/sched/sch_multiq.c:66 dev_qdisc_enqueue+0x4e/0x260 net/core/dev.c:4118 __dev_xmit_skb net/core/dev.c:4214 [inline] __dev_queue_xmit+0xe83/0x3b50 net/core/dev.c:4729 packet_snd net/packet/af_packet.c:3076 [inline] packet_sendmsg+0x3e33/0x5080 net/packet/af_packet.c:3108 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x505/0x830 net/socket.c:2630 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+f3a497f02c389d86ef16@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6920855a.a70a0220.2ea503.0058.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Reviewed-by: Jamal Hadi Salim Link: https://patch.msgid.link/20251121154100.1616228-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Chelsy Ratnawat Signed-off-by: Sasha Levin --- include/net/pkt_cls.h | 2 ++ net/sched/em_cmp.c | 5 ++++- net/sched/em_nbyte.c | 2 ++ net/sched/em_text.c | 11 +++++++++-- 4 files changed, 17 insertions(+), 3 deletions(-) diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h index 4229e4fcd2a9e..ea2c69fdc8396 100644 --- a/include/net/pkt_cls.h +++ b/include/net/pkt_cls.h @@ -536,6 +536,8 @@ static inline unsigned char * tcf_get_base_ptr(struct sk_buff *skb, int layer) case TCF_LAYER_NETWORK: return skb_network_header(skb); case TCF_LAYER_TRANSPORT: + if (!skb_transport_header_was_set(skb)) + break; return skb_transport_header(skb); } diff --git a/net/sched/em_cmp.c b/net/sched/em_cmp.c index 64b637f18bc7d..48c1bce74f498 100644 --- a/net/sched/em_cmp.c +++ b/net/sched/em_cmp.c @@ -22,9 +22,12 @@ static int em_cmp_match(struct sk_buff *skb, struct tcf_ematch *em, struct tcf_pkt_info *info) { struct tcf_em_cmp *cmp = (struct tcf_em_cmp *) em->data; - unsigned char *ptr = tcf_get_base_ptr(skb, cmp->layer) + cmp->off; + unsigned char *ptr = tcf_get_base_ptr(skb, cmp->layer); u32 val = 0; + if (!ptr) + return 0; + ptr += cmp->off; if (!tcf_valid_offset(skb, ptr, cmp->align)) return 0; diff --git a/net/sched/em_nbyte.c b/net/sched/em_nbyte.c index 4f9f21a05d5e4..c65ffa5fff946 100644 --- a/net/sched/em_nbyte.c +++ b/net/sched/em_nbyte.c @@ -42,6 +42,8 @@ static int em_nbyte_match(struct sk_buff *skb, struct tcf_ematch *em, struct nbyte_data *nbyte = (struct nbyte_data *) em->data; unsigned char *ptr = tcf_get_base_ptr(skb, nbyte->hdr.layer); + if (!ptr) + return 0; ptr += nbyte->hdr.off; if (!tcf_valid_offset(skb, ptr, nbyte->hdr.len)) diff --git a/net/sched/em_text.c b/net/sched/em_text.c index 420c66203b177..8331f38eadc60 100644 --- a/net/sched/em_text.c +++ b/net/sched/em_text.c @@ -29,12 +29,19 @@ static int em_text_match(struct sk_buff *skb, struct tcf_ematch *m, struct tcf_pkt_info *info) { struct text_match *tm = EM_TEXT_PRIV(m); + unsigned char *ptr; int from, to; - from = tcf_get_base_ptr(skb, tm->from_layer) - skb->data; + ptr = tcf_get_base_ptr(skb, tm->from_layer); + if (!ptr) + return 0; + from = ptr - skb->data; from += tm->from_offset; - to = tcf_get_base_ptr(skb, tm->to_layer) - skb->data; + ptr = tcf_get_base_ptr(skb, tm->to_layer); + if (!ptr) + return 0; + to = ptr - skb->data; to += tm->to_offset; return skb_find_text(skb, from, to, tm->config) != UINT_MAX; -- 2.53.0