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 7CAD72F656A; Fri, 21 Nov 2025 13:20:30 +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=1763731230; cv=none; b=iVOH1zm3+HmqGh/Jjwc7qVrhCkM/HCKhYVYIDBy81UZsBE2iU4PP11b1WtdQSVf2uY26KzFonXwlcOeML43mfoVIIyFtkIwaqm8Z9rhwqNaFZJGdjb4EjWj+5dKAJ8u9DJNDKps0Wx0fd8LfW3Ky5yYb4krdEXcFSHbjM1ZZO3Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763731230; c=relaxed/simple; bh=dHvqEBwe+3XnTSwAxQBATdpqTEMoXyrYMIypLuGrRls=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UM5RcH9NRRAz3M6x8LHP3cU09RP+NlWr84j/nT6w8gujIUXYlLV+1tZkq09zYjE7K3KzB8tqJPkG/fvGelRpBWM1gKOfb5foZuJaTlS4xywPYlzDhyGbkQP0rl7JAb4FAUxPHLJZHVpPspmd/jwBtp4sWH1OGfofDXv+sHj55g0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FHrUktem; 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="FHrUktem" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB40DC4CEF1; Fri, 21 Nov 2025 13:20:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1763731230; bh=dHvqEBwe+3XnTSwAxQBATdpqTEMoXyrYMIypLuGrRls=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FHrUktemyEbpIG71GzyWGolVf1oGEPjygT8lQIoYJDIDYDOn89tsqCbHo1jGO2hl+ ZaltvZBsufNLmZgqQxCQoX5BNBl7TSl6rzp5/0uoXcQID1TZO9QUJ/bSYNoPPMTv60 W85FdEIqrbbCCDrsILKCmJI6pH0lYwZd8BR1VigM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot , Eric Dumazet , Martin KaFai Lau , Victor Nogueira , Jamal Hadi Salim , Sasha Levin Subject: [PATCH 6.17 118/247] bpf: Add bpf_prog_run_data_pointers() Date: Fri, 21 Nov 2025 14:11:05 +0100 Message-ID: <20251121130158.817836984@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251121130154.587656062@linuxfoundation.org> References: <20251121130154.587656062@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 6.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 4ef92743625818932b9c320152b58274c05e5053 ] syzbot found that cls_bpf_classify() is able to change tc_skb_cb(skb)->drop_reason triggering a warning in sk_skb_reason_drop(). WARNING: CPU: 0 PID: 5965 at net/core/skbuff.c:1192 __sk_skb_reason_drop net/core/skbuff.c:1189 [inline] WARNING: CPU: 0 PID: 5965 at net/core/skbuff.c:1192 sk_skb_reason_drop+0x76/0x170 net/core/skbuff.c:1214 struct tc_skb_cb has been added in commit ec624fe740b4 ("net/sched: Extend qdisc control block with tc control block"), which added a wrong interaction with db58ba459202 ("bpf: wire in data and data_end for cls_act_bpf"). drop_reason was added later. Add bpf_prog_run_data_pointers() helper to save/restore the net_sched storage colliding with BPF data_meta/data_end. Fixes: ec624fe740b4 ("net/sched: Extend qdisc control block with tc control block") Reported-by: syzbot Closes: https://lore.kernel.org/netdev/6913437c.a70a0220.22f260.013b.GAE@google.com/ Signed-off-by: Eric Dumazet Signed-off-by: Martin KaFai Lau Reviewed-by: Victor Nogueira Acked-by: Jamal Hadi Salim Link: https://patch.msgid.link/20251112125516.1563021-1-edumazet@google.com Signed-off-by: Sasha Levin --- include/linux/filter.h | 20 ++++++++++++++++++++ net/sched/act_bpf.c | 6 ++---- net/sched/cls_bpf.c | 6 ++---- 3 files changed, 24 insertions(+), 8 deletions(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 52fecb7a1fe36..152f2fc7b65a3 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -898,6 +898,26 @@ static inline void bpf_compute_data_pointers(struct sk_buff *skb) cb->data_end = skb->data + skb_headlen(skb); } +static inline int bpf_prog_run_data_pointers( + const struct bpf_prog *prog, + struct sk_buff *skb) +{ + struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb; + void *save_data_meta, *save_data_end; + int res; + + save_data_meta = cb->data_meta; + save_data_end = cb->data_end; + + bpf_compute_data_pointers(skb); + res = bpf_prog_run(prog, skb); + + cb->data_meta = save_data_meta; + cb->data_end = save_data_end; + + return res; +} + /* Similar to bpf_compute_data_pointers(), except that save orginal * data in cb->data and cb->meta_data for restore. */ diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c index 396b576390d00..c2b5bc19e0911 100644 --- a/net/sched/act_bpf.c +++ b/net/sched/act_bpf.c @@ -47,12 +47,10 @@ TC_INDIRECT_SCOPE int tcf_bpf_act(struct sk_buff *skb, filter = rcu_dereference(prog->filter); if (at_ingress) { __skb_push(skb, skb->mac_len); - bpf_compute_data_pointers(skb); - filter_res = bpf_prog_run(filter, skb); + filter_res = bpf_prog_run_data_pointers(filter, skb); __skb_pull(skb, skb->mac_len); } else { - bpf_compute_data_pointers(skb); - filter_res = bpf_prog_run(filter, skb); + filter_res = bpf_prog_run_data_pointers(filter, skb); } if (unlikely(!skb->tstamp && skb->tstamp_type)) skb->tstamp_type = SKB_CLOCK_REALTIME; diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c index 7fbe42f0e5c2b..a32754a2658bb 100644 --- a/net/sched/cls_bpf.c +++ b/net/sched/cls_bpf.c @@ -97,12 +97,10 @@ TC_INDIRECT_SCOPE int cls_bpf_classify(struct sk_buff *skb, } else if (at_ingress) { /* It is safe to push/pull even if skb_shared() */ __skb_push(skb, skb->mac_len); - bpf_compute_data_pointers(skb); - filter_res = bpf_prog_run(prog->filter, skb); + filter_res = bpf_prog_run_data_pointers(prog->filter, skb); __skb_pull(skb, skb->mac_len); } else { - bpf_compute_data_pointers(skb); - filter_res = bpf_prog_run(prog->filter, skb); + filter_res = bpf_prog_run_data_pointers(prog->filter, skb); } if (unlikely(!skb->tstamp && skb->tstamp_type)) skb->tstamp_type = SKB_CLOCK_REALTIME; -- 2.51.0