From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [91.216.245.30]) (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 653583E16B0; Tue, 30 Jun 2026 04:53:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.216.245.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782795208; cv=none; b=ENpBpDD47fJ3j4xE4PO99/LZVeznP3+6wXInx5YKgFOSt7HrGCRkwMaDw85XYFDhmVqoerFJlMbEuShiVKyUC06l8QLwd2gO4ZD82bl+IE5xiediiMmEklcb713oAxYCTzPlNUuOD6XsDRzeWL15GxyLWv21kM/CggJHtMZ5C4k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782795208; c=relaxed/simple; bh=b/V7Z3z9DnLJITbrn7BnDEdgmDhy9mb8Z0HhJpC6OUY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=j+qORSKwAv5o8rBQAChKC9Dy9/vtZtZrNvvMNqe0XQ3gDE6DMrz2yzFHUBvUopRFoOFo0M5wRoG2UX1qMhoGMae1xKszlmZ1XjB8I/TVCxmWGTC4fqcVbZFDuN8ylvNuYEF4vMfzA1lOk550GZCWt43KkfWeKKRR4cEGoLfmN5E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc; arc=none smtp.client-ip=91.216.245.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc Received: by Chamillionaire.breakpoint.cc (Postfix, from userid 1003) id D73486032C; Tue, 30 Jun 2026 06:53:25 +0200 (CEST) From: Florian Westphal To: Cc: Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , , pablo@netfilter.org Subject: [PATCH net 3/9] netfilter: ipset: fix race between dump and ip_set_list resize Date: Tue, 30 Jun 2026 06:52:37 +0200 Message-ID: <20260630045243.2657-4-fw@strlen.de> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260630045243.2657-1-fw@strlen.de> References: <20260630045243.2657-1-fw@strlen.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Xiang Mei The release path of ip_set_dump_do() and ip_set_dump_done() read inst->ip_set_list via ip_set_ref_netlink(), a plain rcu_dereference_raw() of the array pointer. These run from netlink_recvmsg() without the nfnl mutex and without an RCU read-side critical section. A concurrent ip_set_create() can grow the array: it publishes the new array, calls synchronize_net() and then kvfree()s the old one. Since the dump paths read the array outside any RCU reader, synchronize_net() does not wait for them and the old array can be freed while they still index into it, causing a use-after-free. The dumped set itself stays pinned via set->ref_netlink, so only the array load needs protecting. Take rcu_read_lock() around it, matching ip_set_get_byname() and __ip_set_put_byindex(). BUG: KASAN: slab-use-after-free in ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697) Read of size 8 at addr ffff88800b5c4018 by task exploit/150 Call Trace: ... kasan_report (mm/kasan/report.c:595) ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697) netlink_dump (net/netlink/af_netlink.c:2325) netlink_recvmsg (net/netlink/af_netlink.c:1976) sock_recvmsg (net/socket.c:1159) __sys_recvfrom (net/socket.c:2315) ... Oops: general protection fault, probably for non-canonical address ... KASAN NOPTI KASAN: maybe wild-memory-access in range [0x02d6...d0-0x02d6...d7] RIP: 0010:ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1698) Kernel panic - not syncing: Fatal exception Fixes: 8a02bdd50b2e ("netfilter: ipset: Fix calling ip_set() macro at dumping") Cc: stable@vger.kernel.org Reported-by: Weiming Shi Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Xiang Mei Acked-by: Jozsef Kadlecsik Signed-off-by: Florian Westphal --- net/netfilter/ipset/ip_set_core.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c index a531b654b8d9..6cfad152d7d1 100644 --- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -1480,7 +1480,11 @@ ip_set_dump_done(struct netlink_callback *cb) struct ip_set_net *inst = (struct ip_set_net *)cb->args[IPSET_CB_NET]; ip_set_id_t index = (ip_set_id_t)cb->args[IPSET_CB_INDEX]; - struct ip_set *set = ip_set_ref_netlink(inst, index); + struct ip_set *set; + + rcu_read_lock(); + set = ip_set_ref_netlink(inst, index); + rcu_read_unlock(); if (set->variant->uref) set->variant->uref(set, cb, false); @@ -1686,7 +1690,9 @@ ip_set_dump_do(struct sk_buff *skb, struct netlink_callback *cb) release_refcount: /* If there was an error or set is done, release set */ if (ret || !cb->args[IPSET_CB_ARG0]) { + rcu_read_lock(); set = ip_set_ref_netlink(inst, index); + rcu_read_unlock(); if (set->variant->uref) set->variant->uref(set, cb, false); pr_debug("release set %s\n", set->name); -- 2.53.0