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 0935544D6B2; Tue, 16 Jun 2026 15:56:53 +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=1781625414; cv=none; b=QoeZ/5Tb1zln8T03E9FINon37ltn2KFtCfA91EBYCFGIWR1sxh6tHR7ptN3MTOEsCHSscENMJdoo4LRANusEFyElz68zga+agqD/mN5ZHTwqDNLqY76GaPORE35aU4cMwLXvSAwK/idh/5Giqp3H0qk7oSJaDExVNwvs8qwIGFk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781625414; c=relaxed/simple; bh=AxG7eSlGqnXnbX9seGYurrK4oKrAJpSjYGaUclvLtG4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=b7+60N5J6lxx25o//Zj8rJT0fu7e9YNrG/6sZ4L3/rtDmOLJVK016+Zmr6EOS0vk471A53NQSX1PKRc0ZG8dJzHU4aiaFGgDlN5uyfYSlNAkaQEIogYo4qiEoYiRiLwsy/pYL24D8MHjXB7UUSC9qmQ2KAnlnLEybgabGmvRh6w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Pr7cfQeA; 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="Pr7cfQeA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EDE3D1F000E9; Tue, 16 Jun 2026 15:56:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781625412; bh=kYF3UEmZvp5kwfiAfx6zspGMk89drcopvQ19A+GDTMQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Pr7cfQeASWpvwFn6HtmVUre4g49p89QUgGYRtahj2+6qk4uVhM3+BpnS4/bUxCPq1 ZfWDMpsNRkUFht4lV4RTbc5l8XiEBqcv5iWZRQunqFy/J05Jf+Jv5T1X1mtqkcRNoY euJK7PusaP37xkZUfWYUWyfEzTJ2cvqXWzdS0pkg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jian Zhou , David Ahern , Ido Schimmel , Paolo Abeni , Sasha Levin Subject: [PATCH 6.18 137/325] ipv6: Fix a potential NPD in cleanup_prefix_route() Date: Tue, 16 Jun 2026 20:28:53 +0530 Message-ID: <20260616145104.556888083@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145057.827196531@linuxfoundation.org> References: <20260616145057.827196531@linuxfoundation.org> User-Agent: quilt/0.69 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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ido Schimmel [ Upstream commit b70c687b7cf267fb08586667a3946c8851cad672 ] addrconf_get_prefix_route() can return the fib6_null_entry sentinel entry which has a NULL fib6_table pointer. Therefore, before setting the route's expiration time, check that we are not working with this entry, as otherwise a NPD will be triggered [1]. Note that the other callers of addrconf_get_prefix_route() are not susceptible to this bug: 1. addrconf_prefix_rcv(): Requests a route with the 'RTF_ADDRCONF | RTF_PREFIX_RT' flags which are not set on fib6_null_entry. 2. modify_prefix_route(): Fixed by commit a747e02430df ("ipv6: avoid possible NULL deref in modify_prefix_route()"). 3. __ipv6_ifa_notify(): Calls ip6_del_rt() which specifically checks for fib6_null_entry and returns an error. [1] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] [...] Call Trace: __kasan_check_byte (mm/kasan/common.c:573) lock_acquire.part.0 (kernel/locking/lockdep.c:5842 (discriminator 1)) _raw_spin_lock_bh (kernel/locking/spinlock.c:182 (discriminator 1)) cleanup_prefix_route (net/ipv6/addrconf.c:1280) ipv6_del_addr (net/ipv6/addrconf.c:1342) inet6_addr_del.isra.0 (net/ipv6/addrconf.c:3119) inet6_rtm_deladdr (net/ipv6/addrconf.c:4812) rtnetlink_rcv_msg (net/core/rtnetlink.c:6997) netlink_rcv_skb (net/netlink/af_netlink.c:2555) netlink_unicast (net/netlink/af_netlink.c:1344) netlink_sendmsg (net/netlink/af_netlink.c:1899) __sock_sendmsg (net/socket.c:802 (discriminator 4)) ____sys_sendmsg (net/socket.c:2698) ___sys_sendmsg (net/socket.c:2752) __sys_sendmsg (net/socket.c:2784) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Fixes: 5eb902b8e719 ("net/ipv6: Remove expired routes with a separated list of routes.") Reported-by: Ji'an Zhou Reviewed-by: David Ahern Signed-off-by: Ido Schimmel Link: https://patch.msgid.link/20260609145448.768318-1-idosch@nvidia.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/ipv6/addrconf.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 2d4c3d9c1a2a51..b2e1328371d3f6 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -1265,6 +1265,7 @@ static void cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long expires, bool del_rt, bool del_peer) { + struct net *net = dev_net(ifp->idev->dev); struct fib6_table *table; struct fib6_info *f6i; @@ -1273,9 +1274,10 @@ cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long expires, ifp->idev->dev, 0, RTF_DEFAULT, true); if (f6i) { if (del_rt) - ip6_del_rt(dev_net(ifp->idev->dev), f6i, false); + ip6_del_rt(net, f6i, false); else { - if (!(f6i->fib6_flags & RTF_EXPIRES)) { + if (f6i != net->ipv6.fib6_null_entry && + !(f6i->fib6_flags & RTF_EXPIRES)) { table = f6i->fib6_table; spin_lock_bh(&table->tb6_lock); -- 2.53.0