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 435FF4156D0; Mon, 17 Aug 2026 14:34:03 +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=1786977244; cv=none; b=Gxod45fk+hX/0c5St1C05CTTD/Cm1fTl598DCyvIGFEVSSovQKza1heNQCP0L4vvU2PqBuvVYbiZFPj8Ir+bbU3QI1qdEXG/+XvM0YNpCUpIu1EUobVk+XoqdLRQA9Wb+QEzmyrXP14ctiu+ZM4EbI7ziLwJgo6c0pqoiUS8Mtk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786977244; c=relaxed/simple; bh=fIR8TfNJF7iNY7oZ5BCToyCOFMo06DkJIq+upTqz+lc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=P7/nuiX1wL7xo/VJ7fDQKYsTGcXjNrhwblYjvZI1yg+hYqPZv/LhtRu2swBNhIqn4kIUJpGefOhxITiDQ4nURWVxH/yYDkkq5Hq/tMRyBeoJVl6Lu1TH/GPA+22Eg3YF3FWjFtRreb05/0/L7qVgT5N9jziwkPqT7ZOIcU/hLQI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ufGwN+3H; 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="ufGwN+3H" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 97C4D1F000E9; Mon, 17 Aug 2026 14:34:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786977243; bh=Qnt8YQD4/yUVk8Je4cikyqeyHo8cZtZShwhCFs7n2QM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ufGwN+3Hr4XZ0x9FR7H7MlP9p/LoMfrrvNFSoKarNqVe3RWhUPhgI65MFjOIwfWvw r8tfT45KnU/4fd72Zlk0PufB8GWirGqH3Y6KZmuk4GI/2oBYhbkibgX1khIP0jbtHQ 7uaP0I2TA7CsmG3ZzxqKfMcT5e8oQZctHxddY09c= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Weiming Shi , Xiang Mei , Allison Henderson , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 261/456] rds: tcp: hold the RCU lock across ipv6_chk_addr() in rds_tcp_laddr_check() Date: Mon, 17 Aug 2026 15:30:51 +0200 Message-ID: <20260817132550.223206129@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132539.792407575@linuxfoundation.org> References: <20260817132539.792407575@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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei [ Upstream commit 78f75d632f74b8de0f081a128588f7c37d0d1164 ] rds_tcp_laddr_check() looks up a scoped IPv6 interface with dev_get_by_index_rcu(), drops the RCU read-side lock, and only then passes the bare struct net_device * into ipv6_chk_addr(). dev_get_by_index_rcu() only keeps the device alive within the same RCU read-side section. After rcu_read_unlock(), a concurrent RTM_DELLINK can free the net_device; ipv6_chk_addr() then dereferences the stale pointer in __ipv6_chk_addr_and_flags() (e.g. l3mdev_master_dev_rcu(dev)), reading freed memory. Keep the RCU read-side lock held across the ipv6_chk_addr() call instead of dropping it right after the lookup, so the device cannot be freed while it is in use. BUG: KASAN: slab-use-after-free in __ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998) Read of size 8 at addr ffff8880106ec000 by task exploit/153 Call Trace: ... kasan_report (mm/kasan/report.c:595) __ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998) ipv6_chk_addr (net/ipv6/addrconf.c:2031 net/ipv6/addrconf.c:1972) rds_tcp_laddr_check (net/rds/tcp.c:370) rds_bind (net/rds/bind.c:248) __sys_bind (net/socket.c:1920) __x64_sys_bind (net/socket.c:1956) do_syscall_64 (arch/x86/entry/syscall_64.c:63) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Fixes: eee2fa6ab322 ("rds: Changing IP address internal representation to struct in6_addr") Reported-by: Weiming Shi Signed-off-by: Xiang Mei Reviewed-by: Allison Henderson Link: https://patch.msgid.link/20260722210203.565803-1-xmei5@asu.edu Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/rds/tcp.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/rds/tcp.c b/net/rds/tcp.c index 071f2a2f514ff..f66cbf0b9895f 100644 --- a/net/rds/tcp.c +++ b/net/rds/tcp.c @@ -330,23 +330,25 @@ int rds_tcp_laddr_check(struct net *net, const struct in6_addr *addr, /* If the scope_id is specified, check only those addresses * hosted on the specified interface. */ + rcu_read_lock(); if (scope_id != 0) { - rcu_read_lock(); dev = dev_get_by_index_rcu(net, scope_id); /* scope_id is not valid... */ if (!dev) { rcu_read_unlock(); return -EADDRNOTAVAIL; } - rcu_read_unlock(); } #if IS_ENABLED(CONFIG_IPV6) if (ipv6_mod_enabled()) { ret = ipv6_chk_addr(net, addr, dev, 0); - if (ret) + if (ret) { + rcu_read_unlock(); return 0; + } } #endif + rcu_read_unlock(); return -EADDRNOTAVAIL; } -- 2.53.0