From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8809E40DB55 for ; Mon, 31 Aug 2026 12:59:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788181155; cv=none; b=mYc860GpFDBqkWMcIWJtVD0STfoL7pLEWqz4KunSTaUdRiMf9pIFdef4oghAvte+3hqCbj2PNg0vKFQ/xWUzdw3Z8VeF0CbokYaA/NMYiEsl7ElETQAJBdelABZhyqXGI3nz829B+ETmWjzOcX0l8BTqxLJU9610BrzabtHc6Vs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788181155; c=relaxed/simple; bh=DaOWfdXBS4UvLCY1RggxTEiA1JtrZm04/5nq9cAK3PM=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=r5/Bs1Egmca65Pg86Dv294cVuoaatdSM19/6DWjt9wLjbkpPQe4Jcy2WaSqo1xFyjbWOHJGbNhZ2ArP7TfWmCC1gZ709b8CUciE6PRfxw1Obh35ywpnP8EtXujS+bInzg5QbCfJA6afv3uvMc86VEI9dd/bNHTyuWgsTecM/GTc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PoJ322OP; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="PoJ322OP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2BDC1F00A3F; Mon, 31 Aug 2026 12:59:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788181154; bh=eUkXeuiHyifMr02evJSqvEapkjLT0rSGzSqhenknkc0=; h=Subject:To:Cc:From:Date; b=PoJ322OPIe2FrkFXVzfs/gXZJxGv2AixxKFWiTYQ10Y2chlfaVUpQ/QzsWqow35LX dTcvqO/WmZjnDfpbDyUrRUpB0S6XSpoi8DSck4G1BY8kcP9LRS01N15wPd03oa+xz6 M0ziNmOgTbLmkUMhxRrTd10SpHWqR8iAm7V1M6Bs= Subject: FAILED: patch "[PATCH] netfilter: nf_tables: don't queue packet path object" failed to apply to 5.15-stable tree To: littleddfu@gmail.com,corvus@tencent.com,fouriezhang@tencent.com,pablo@netfilter.org Cc: From: Date: Mon, 31 Aug 2026 14:58:58 +0200 Message-ID: <2026083158-undecided-swear-7f28@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 7904b94768e983bcb2be34a8d6d1f3450f5b838b # git commit -s git send-email --to '' --in-reply-to '2026083158-undecided-swear-7f28@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 7904b94768e983bcb2be34a8d6d1f3450f5b838b Mon Sep 17 00:00:00 2001 From: Fourie Zhang Date: Mon, 10 Aug 2026 19:35:01 +0800 Subject: [PATCH] netfilter: nf_tables: don't queue packet path object notifications All file:line references below are against v7.2-rc4 (ac5b0e5651b1). The trace was captured on 7.2.0-rc6-kasan72rc6 (075b74841bd0), where the same lines apply. nft_obj_notify() is exported and reached from the packet path. Its only in-tree caller is nft_quota_obj_eval() (net/netfilter/nft_quota.c:68), which notifies with GFP_ATOMIC while evaluating a rule for a transiting packet, holding no mutex. Since commit 67cc570edaa0 ("netfilter: nf_tables: coalesce multiple notifications into one skbuff") that notification is no longer sent immediately. __nft_obj_notify() queues it onto nft_net->notify_list via nft_notify_enqueue() (net/netfilter/nf_tables_api.c:1211), which is a bare list_add_tail(). notify_list has no lock of its own (include/net/netfilter/nf_tables.h:1951), it is serialised by commit_mutex: the six other enqueue sites all run inside a netlink transaction, and the drain in nft_commit_notify() (net/netfilter/nf_tables_api.c:10746) does list_del() + kfree_skb() from nf_tables_commit() with commit_mutex held. Sending packets through a chain that references a depleted quota object therefore races an unlocked list_add_tail() against list_del() + kfree_skb() on another CPU. The WRITE_ONCE(prev->next, new) in __list_add() then stores through an sk_buff that has already been freed: BUG: KASAN: slab-use-after-free in __nft_obj_notify+0x2c5/0x2d0 Write of size 8 at addr ff110001047183c0 by task poc/76 CPU: 0 UID: 1000 PID: 76 Comm: poc Tainted: G W 7.2.0-rc6-kasan72rc6 #4 Call Trace: __nft_obj_notify (include/linux/list.h:164 include/linux/list.h:191 net/netfilter/nf_tables_api.c:1211 net/netfilter/nf_tables_api.c:8743) nft_quota_obj_eval (net/netfilter/nft_quota.c:68) nft_do_chain_inet nf_hook_slow __ip_local_out ip_push_pending_frames udp_send_skb udp_sendmsg __x64_sys_sendto Allocated by task 77: __alloc_skb (net/core/skbuff.c:704) __nft_obj_notify (include/net/netlink.h:1055 net/netfilter/nf_tables_api.c:8731) nft_quota_obj_eval (net/netfilter/nft_quota.c:68) nft_do_chain Freed by task 79: nf_tables_commit (include/linux/skbuff.h:1332 net/netfilter/nf_tables_api.c:10759 net/netfilter/nf_tables_api.c:11185) nfnetlink_rcv_batch (net/netfilter/nfnetlink.c:574) netlink_unicast netlink_sendmsg The buggy address belongs to the cache skbuff_head_cache of size 232 Queueing from the packet path is wrong even leaving the race aside: notify_list is only drained by nft_commit_notify() from nf_tables_commit() (:11185), so a notification enqueued outside a transaction is not sent until some later netlink batch commits, if one ever does. The gfp argument that nft_obj_notify() still takes is a leftover of the pre-67cc570edaa0 behaviour, where this path called nfnetlink_send() directly. Restore that: split the message construction out into nft_obj_notify_alloc() and let each caller decide what to do with the skb. nft_obj_notify(), the exported one reached from the packet path, sends it straight away; nf_tables_obj_notify(), which runs under commit_mutex, keeps queueing it, so transaction notifications are still coalesced. Fixes: 67cc570edaa0 ("netfilter: nf_tables: coalesce multiple notifications into one skbuff") Cc: stable@kernel.org Reported-by: TencentOS Corvus AI Assisted-by: tencentos-corvus-ai:kimi-k3 Signed-off-by: Fourie Zhang Signed-off-by: Pablo Neira Ayuso diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index af357f6c5070..3a7c8f7a6304 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -8715,18 +8715,17 @@ static int nf_tables_delobj(struct sk_buff *skb, const struct nfnl_info *info, return nft_delobj(&ctx, obj); } -static void -__nft_obj_notify(struct net *net, const struct nft_table *table, - struct nft_object *obj, u32 portid, u32 seq, int event, - u16 flags, int family, int report, gfp_t gfp) +static struct sk_buff * +nft_obj_notify_alloc(struct net *net, const struct nft_table *table, + struct nft_object *obj, u32 portid, u32 seq, int event, + u16 flags, int family, int report, gfp_t gfp) { - struct nftables_pernet *nft_net = nft_pernet(net); struct sk_buff *skb; int err; if (!report && !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES)) - return; + return NULL; skb = nlmsg_new(NLMSG_GOODSIZE, gfp); if (skb == NULL) @@ -8740,10 +8739,10 @@ __nft_obj_notify(struct net *net, const struct nft_table *table, goto err; } - nft_notify_enqueue(skb, report, &nft_net->notify_list); - return; + return skb; err: nfnetlink_set_err(net, portid, NFNLGRP_NFTABLES, -ENOBUFS); + return NULL; } void nft_obj_notify(struct net *net, const struct nft_table *table, @@ -8752,6 +8751,7 @@ void nft_obj_notify(struct net *net, const struct nft_table *table, { char *buf = kasprintf(gfp, "%s:%u", table->name, nft_base_seq(net)); + struct sk_buff *skb; audit_log_nfcfg(buf, family, @@ -8762,17 +8762,27 @@ void nft_obj_notify(struct net *net, const struct nft_table *table, gfp); kfree(buf); - __nft_obj_notify(net, table, obj, portid, seq, event, - flags, family, report, gfp); + /* Called from the packet path, holding no mutex: notify_list is + * serialised by commit_mutex, so send this notification directly. + */ + skb = nft_obj_notify_alloc(net, table, obj, portid, seq, event, + flags, family, report, gfp); + if (skb) + nfnetlink_send(skb, net, portid, NFNLGRP_NFTABLES, report, gfp); } EXPORT_SYMBOL_GPL(nft_obj_notify); static void nf_tables_obj_notify(const struct nft_ctx *ctx, struct nft_object *obj, int event) { - __nft_obj_notify(ctx->net, ctx->table, obj, ctx->portid, - ctx->seq, event, ctx->flags, ctx->family, - ctx->report, GFP_KERNEL); + struct nftables_pernet *nft_net = nft_pernet(ctx->net); + struct sk_buff *skb; + + skb = nft_obj_notify_alloc(ctx->net, ctx->table, obj, ctx->portid, + ctx->seq, event, ctx->flags, ctx->family, + ctx->report, GFP_KERNEL); + if (skb) + nft_notify_enqueue(skb, ctx->report, &nft_net->notify_list); } /*