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 780D04749F6; Fri, 7 Aug 2026 15:00:05 +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=1786114806; cv=none; b=g6u51iEkteepMGBU/9mfoRRTFLD8i4CLUswawAWSpEgnVXO0L9h52Uq5byhrPRyZN6EJn27akR7pLy+wNlirEsGjkEZ4zco4ypOIyPoUiso/Zzu9UzKCz6m3ayxTxjAjwkEOlObPKcz9gZRKiY08vv0TXkJmYwFzHfW5E0lfqVA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786114806; c=relaxed/simple; bh=ruRAQA9emKV/Bigx3xwbI0CJIrVZyks2um9Q9+DrRf0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=shl8IT7/k6YiR3nA1QfGwIPiwBYkp3gFga/tJYA/HBR0JeD5bna9EIcICYL2joNPoBFoAPY/1KcKjFVZ/riVvWzl6YzHO45qoOgDsc0TSidndxniFCRdUQkLQxHbKlWRLP7VCgq5wlzG0QAclXelbc1hDj4CXZbNisqMhB5Kyec= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kwq8vks2; 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="kwq8vks2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2D4F1F000E9; Fri, 7 Aug 2026 15:00:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786114805; bh=fYsuw3PTSmQP9K43kveO++4gL5+NfAWdrIpZzoh7zqk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kwq8vks2iSjrEauMmrM/9OXmBuzpWxalXlrc8SocHuOrsXDRd7w8PWLR8FrW8bUKZ fmud7uKswUKZa2chw+1ZKCdJfyohmY1xJLyVxj8zBlintJrSApxiJ4ZriFAo7hdKP0 WanZTkP4ZPzIdJFgDY/1eoLRtUtmOb4vVMnf0Phc= 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 6.18 055/396] rds: tcp: hold the RCU lock across ipv6_chk_addr() in rds_tcp_laddr_check() Date: Fri, 7 Aug 2026 16:33:35 +0200 Message-ID: <20260807143425.456378646@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807143424.272339768@linuxfoundation.org> References: <20260807143424.272339768@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: 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 87e6ab0e93b71..1980a197034ba 100644 --- a/net/rds/tcp.c +++ b/net/rds/tcp.c @@ -331,23 +331,25 @@ 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