From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f194.google.com (mail-pg1-f194.google.com [209.85.215.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D66EE402B9C for ; Mon, 11 May 2026 15:52:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.194 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778514756; cv=none; b=deMLHmP00mZk/etbJtNLrCJ+kqn81NCw2EF2ttLFCh7/8F2p+xkwSRTu3cB3KYUxCmlKnWluLrgLqZJe0XLm7CnJzXqSTOfYvHpGehZG/eTDbQG+h5Y+r77piwW5BlZ5oe215AE0kOKXTxJ5X6rfh/9dGzKPjTMZ6lseSen6Qk4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778514756; c=relaxed/simple; bh=DTFUEU2OuJNVmNPfMe4YoHyZOAvET9nfa33vgjgsZ7g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=u/7ZdxIJXZK9LfAMdoqFlHCbGYXqMn1rJssbYTMEZ0CpRjcpSoz0SfH7eikQ95Tk0AhCs/79Z2hyBzNIDjl7ONe5J8XH6wHUeqEvUKuy5ddULoHqJ1kTAF8+18QRNQpBDhPA9vYceCdVkuPW1nIy0nFjgezH/W/wJ0Oa2wely/U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=maKVNWf1; arc=none smtp.client-ip=209.85.215.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="maKVNWf1" Received: by mail-pg1-f194.google.com with SMTP id 41be03b00d2f7-c80227c9572so1983780a12.2 for ; Mon, 11 May 2026 08:52:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1778514754; x=1779119554; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=ZY7jXeM4i67pdCLJbWB9EBFnm7uOeoT6zFaMpTbtsOY=; b=maKVNWf1mJzHhaEeiuyuZWckH3Qr84UFyQ/JfdsCVyPgpiP4ln95izCR2on6W9dYFI obCH8V8ylJC0I9ADel0qt/Chk9cL1Kk/8S7QIHFFo4S9PoeWWrHi8HiS6rqh2JyQGzDn ELBdgCqUfWxrKpa6CiFX66vUd6B8bFJzBkDqy0crgM2WPB4N8FYbAtLlJmEgxVvqQGdW 3vo01TMvKuQgL/L/53QgdioqDUTTd5h8hu2nzJCc33acg62g46BFofsGwXGPXUd3Fs3E KHOS8wllHWKMYRxNc0gKZyTpYXFnFvwfjx8jwCot8dTdzlFsY/K/Dms1HZWNqrvV9wy0 z4Pg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778514754; x=1779119554; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=ZY7jXeM4i67pdCLJbWB9EBFnm7uOeoT6zFaMpTbtsOY=; b=YkM7drv/UbTguk3aIV69nZ/EKeOYJ9CqgJGZT4AyhlGrvpo600QzAGl0gwTYpbxFg2 fqE9/yMcvpR5py6Kkc/WVBqaCfauLSCvtQI702kh89LTpVeV0N2XbEgsNs8EdQJ4iQ+y U9VD3hAke0QGiACjErxC7Rhzjr4fOW+0p6Z787a5D+aGuNYp5de1XHH33Gg45GPc+NHV qNeRm+ObjSzajFBGY6y6685H/6tLorkMJojEOWeVKQ5lUslL75K0bQfqAK6kpTcOLUhm ZxiTg7cu4EWbiWr6wru1X7ktDwHg4FkW7m/Lgs9wIyGS79tXQSCkmpadAHWD/2AGdmxE uD5g== X-Forwarded-Encrypted: i=1; AFNElJ/iucI3bXTEUimzno6KSB8uNo/8g9QYshpIA6Zq4H/qRTwA9S/ImK/YXe7ye+6O3hu3ay2riYY=@vger.kernel.org X-Gm-Message-State: AOJu0YztX+8UasfXI8aEzOUT79ZupRnP6B4HGr2exQIMzbsx4gpPwII6 96N2zgwAbWHk4kVKlzNJ2E4upFSugc/RRLaPUi3+QGvGXWJP2xa9NkGn X-Gm-Gg: Acq92OE/CoUWw6ETD3bG1WLUu22lAkWXoQfDZZapGxnAGurfD4yGKqLGD98IsXibVZ3 GwA+Mo9sJGgww10pkovUDQAJxNnc9FBC+8k72fygcU++69rmSHQs4+qmJSt0uL7P8e/UKkqqKDV 8ryJhY2MlDot0gZeCkXA6P/LkpHQVav38se+BIYVR7ctKZqabyEt28eza4BL+ZABT1BpuWzv1k2 KPveb1E3IZ2LR6MWeNpoFnPauiDcMeQZC/JaUJu3hmIp+HkORnsJJk8iTn5lRT7Jkqbc8K2TW0g N9SSTCbX0GZuAuR32SKnkO3ZoEfiuvhofPkcoKik24mk/UHI/TyjO/Zk/XhZ4IP5IV9K31RzO+M taBzdIA0sTvewySiZI1s6k+m3fhhS4TxwbLz4NshnkX62Diw3OatZYwz6wJPS93yyrnRH7EKGyS F7k85KheaPirN7K2UvlCaUVxA+h3lSbEnB4/E= X-Received: by 2002:a17:903:64f:b0:2b0:41bf:ca83 with SMTP id d9443c01a7336-2ba798c27a9mr170300155ad.23.1778514754024; Mon, 11 May 2026 08:52:34 -0700 (PDT) Received: from fedora.localdomain ([222.20.193.20]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2baf1e78c6csm112117885ad.60.2026.05.11.08.52.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 May 2026 08:52:33 -0700 (PDT) From: Xingwang Xiang To: john.fastabend@gmail.com Cc: kuba@kernel.org, jakub@cloudflare.com, sd@queasysnail.net, davem@davemloft.net, pabeni@redhat.com, horms@kernel.org, netdev@vger.kernel.org, mrpre@163.com, Xingwang Xiang Subject: [PATCH net v4 2/2] selftests: bpf: add test for KTLS+sockmap reverse-order UAF Date: Tue, 12 May 2026 00:52:09 +0900 Message-ID: <20260511155210.32926-3-v3rdant.xiang@gmail.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260511155210.32926-1-v3rdant.xiang@gmail.com> References: <20260511155210.32926-1-v3rdant.xiang@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a selftest that reproduces the use-after-free triggered when a TCP socket is inserted into a sockmap *before* TLS RX is configured on it (the reverse of the order that is already blocked by the kernel). Vulnerable sequence: 1. bpf_map_update_elem(sockmap, server_fd) -> sk->sk_data_ready = sk_psock_verdict_data_ready 2. setsockopt(server_fd, SOL_TLS, TLS_RX, ...) -> tls_sw_strparser_arm() saves sk_psock_verdict_data_ready as rx_ctx->saved_data_ready, then sets sk->sk_data_ready = tls_data_ready When data arrives: tls_data_ready -> tls_strp_data_ready -> tls_rx_msg_ready -> saved_data_ready() [= sk_psock_verdict_data_ready] -> tcp_read_skb() drains sk_receive_queue via __skb_unlink() without calling tcp_eat_skb(), so copied_seq is never advanced. tls_strp_msg_load() then finds tcp_inq() >= full_len (stale), calls tcp_recv_skb() on an empty queue, hits WARN_ON_ONCE(!first), and returns with frag_list still pointing at the now psock-owned (or already freed) skb. tls_decrypt_sg() subsequently walks that stale frag_list: a use-after-free. The new BPF program (prog_skb_verdict_pass, sk_skb/verdict) returns SK_PASS, which is the specific verdict that triggers the missing tcp_eat_skb() call inside sk_psock_verdict_recv(). The test drives the full setup in the vulnerable order and then attempts a send+recv. After a correct fix the kernel either: (a) rejects setsockopt(TLS_RX) with EBUSY/EINVAL when the socket is already owned by a psock, or (b) completes the data transfer without corruption or kernel warnings. Signed-off-by: Xingwang Xiang --- .../selftests/bpf/prog_tests/sockmap_ktls.c | 109 ++++++++++++++++++ .../selftests/bpf/progs/test_sockmap_ktls.c | 21 ++++ 2 files changed, 130 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c b/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c index b87e7f39e..e71e6561b 100644 --- a/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c @@ -417,6 +417,113 @@ static void run_tests(int family, enum bpf_map_type map_type) close(map); } +/* + * Regression test for the KTLS + sockmap reverse-order frag_list UAF. + * + * Vulnerable sequence: + * 1. Insert receiver socket into sockmap (sets sk_data_ready = + * sk_psock_verdict_data_ready) + * 2. Configure TLS RX on the same socket: tls_sw_strparser_arm() saves + * sk_psock_verdict_data_ready as rx_ctx->saved_data_ready and replaces + * sk_data_ready with tls_data_ready. + * + * When data arrives, tls_rx_msg_ready() calls saved_data_ready(), which is + * sk_psock_verdict_data_ready(). That drains sk_receive_queue via + * tcp_read_skb() / __skb_unlink() without advancing copied_seq. + * tls_strp_msg_load() then finds an empty queue while tcp_inq() is still + * non-zero, hits WARN_ON_ONCE(!first), and leaves a dangling frag_list + * pointer that tls_decrypt_sg() walks — a use-after-free. + * + * After the fix the kernel either: + * (a) rejects setsockopt(TLS_RX) with EBUSY/EINVAL when the socket is + * already owned by a psock, or + * (b) correctly handles the data path so recv() returns the right data. + */ +static void test_sockmap_ktls_reverse_order_tls(int family, int sotype) +{ + struct tls12_crypto_info_aes_gcm_128 crypto_info = {}; + char send_buf[] = "hello ktls sockmap reverse order"; + char recv_buf[sizeof(send_buf)] = {}; + struct test_sockmap_ktls *skel; + int c = -1, p = -1, zero = 0; + int prog_fd, map_fd; + ssize_t n; + int err; + + skel = test_sockmap_ktls__open_and_load(); + if (!ASSERT_TRUE(skel, "open_and_load")) + return; + + err = create_pair(family, sotype, &c, &p); + if (!ASSERT_OK(err, "create_pair")) + goto out; + + prog_fd = bpf_program__fd(skel->progs.prog_skb_verdict_pass); + map_fd = bpf_map__fd(skel->maps.sock_map_verdict); + + err = bpf_prog_attach(prog_fd, map_fd, BPF_SK_SKB_VERDICT, 0); + if (!ASSERT_OK(err, "bpf_prog_attach sk_skb verdict")) + goto out; + + /* Configure TLS TX on the sender (normal order, no sockmap) */ + err = setsockopt(c, IPPROTO_TCP, TCP_ULP, "tls", strlen("tls")); + if (!ASSERT_OK(err, "setsockopt(TCP_ULP) client")) + goto out; + + crypto_info.info.version = TLS_1_2_VERSION; + crypto_info.info.cipher_type = TLS_CIPHER_AES_GCM_128; + memset(crypto_info.key, 0x01, sizeof(crypto_info.key)); + memset(crypto_info.salt, 0x02, sizeof(crypto_info.salt)); + + err = setsockopt(c, SOL_TLS, TLS_TX, &crypto_info, sizeof(crypto_info)); + if (!ASSERT_OK(err, "setsockopt(TLS_TX)")) + goto out; + + /* Insert receiver into sockmap BEFORE TLS RX — the vulnerable ordering */ + err = bpf_map_update_elem(map_fd, &zero, &p, BPF_NOEXIST); + if (!ASSERT_OK(err, "bpf_map_update_elem server")) + goto out; + + /* Attempt TLS RX setup AFTER sockmap insertion */ + err = setsockopt(p, IPPROTO_TCP, TCP_ULP, "tls", strlen("tls")); + if (err) { + /* Kernel correctly rejected TLS ULP on a psock-owned socket */ + ASSERT_TRUE(errno == EINVAL || errno == EBUSY, + "expected EINVAL or EBUSY for TCP_ULP on sockmap socket"); + goto out; + } + + err = setsockopt(p, SOL_TLS, TLS_RX, &crypto_info, sizeof(crypto_info)); + if (err) { + /* Kernel correctly rejected TLS RX after sockmap insertion */ + ASSERT_TRUE(errno == EINVAL || errno == EBUSY || errno == EOPNOTSUPP, + "expected rejection of TLS_RX on sockmap socket"); + goto out; + } + + /* + * Setup was allowed — verify data transfer is correct. + * A buggy kernel hits WARN_ON_ONCE in tls_strp_load_anchor_with_queue + * and may UAF in tls_decrypt_sg when walking the stale frag_list. + */ + n = send(c, send_buf, sizeof(send_buf), 0); + if (!ASSERT_EQ(n, (ssize_t)sizeof(send_buf), "send")) + goto out; + + n = recv_timeout(p, recv_buf, sizeof(recv_buf), 0, 5); + if (!ASSERT_EQ(n, (ssize_t)sizeof(send_buf), "recv")) + goto out; + + ASSERT_OK(memcmp(send_buf, recv_buf, sizeof(send_buf)), "data integrity"); + +out: + if (c != -1) + close(c); + if (p != -1) + close(p); + test_sockmap_ktls__destroy(skel); +} + static void run_ktls_test(int family, int sotype) { if (test__start_subtest("tls simple offload")) @@ -429,6 +536,8 @@ static void run_ktls_test(int family, int sotype) test_sockmap_ktls_tx_no_buf(family, sotype, true); if (test__start_subtest("tls tx with pop")) test_sockmap_ktls_tx_pop(family, sotype); + if (test__start_subtest("tls rx after sockmap insert")) + test_sockmap_ktls_reverse_order_tls(family, sotype); } void test_sockmap_ktls(void) diff --git a/tools/testing/selftests/bpf/progs/test_sockmap_ktls.c b/tools/testing/selftests/bpf/progs/test_sockmap_ktls.c index 83df4919c..facafeaf4 100644 --- a/tools/testing/selftests/bpf/progs/test_sockmap_ktls.c +++ b/tools/testing/selftests/bpf/progs/test_sockmap_ktls.c @@ -17,6 +17,13 @@ struct { __type(value, int); } sock_map SEC(".maps"); +struct { + __uint(type, BPF_MAP_TYPE_SOCKMAP); + __uint(max_entries, 2); + __type(key, int); + __type(value, int); +} sock_map_verdict SEC(".maps"); + SEC("sk_msg") int prog_sk_policy(struct sk_msg_md *msg) { @@ -38,3 +45,17 @@ int prog_sk_policy_redir(struct sk_msg_md *msg) bpf_msg_apply_bytes(msg, apply_bytes); return bpf_msg_redirect_map(msg, &sock_map, two, 0); } + +/* + * Verdict program for the reverse-order TLS/sockmap regression test. + * Returns SK_PASS so tcp_read_skb() drains the receive queue via + * sk_psock_verdict_recv() without calling tcp_eat_skb(), which is + * the precondition for the KTLS strparser frag_list UAF. + */ +SEC("sk_skb/verdict") +int prog_skb_verdict_pass(struct __sk_buff *skb) +{ + return SK_PASS; +} + +char _license[] SEC("license") = "GPL"; -- 2.54.0