From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 69B694418E3; Wed, 29 Apr 2026 22:30:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777501806; cv=none; b=UsajA3lictjYViKU9iaQQ5mhInGj4gn8mGhIwnUnRCKnhoFzcC/Au64TIZcntgzzq59bsrDLxHU98nDLTayH+EY3qEApnsX05FeKUhpAKssET9F/aW30iux6YPcEBr2FIr3VET85/3T+TvsO9CgGzhyHTxNaf0SuiLpIcLFo7SE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777501806; c=relaxed/simple; bh=KLo8GwQQAN017DwDhaIw9VW4z9RqVNldHinrlyKtg2o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KV1fM5NwDAyIzEaYNWetCUt2z5P5eQJ5C8GQ3LPkADOT/ZUI/bhkhENkhhbIT1U3NhaovCOByGSZvjah3wOGmnTWx317wtL57V2fhARLCKZ1E2MYqh+o34SehikaTH7dCB7Btkr9HlV4BwgRKspcAYVWb1kOR9SEq3EJPG+YunQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZPwGILz4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZPwGILz4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F96DC19425; Wed, 29 Apr 2026 22:30:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777501806; bh=KLo8GwQQAN017DwDhaIw9VW4z9RqVNldHinrlyKtg2o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZPwGILz4aiMPP+PKxU73i1CA7Q7+y1euk2NrZ9sXPskDNjSRcpWDf7ziFnbCwMx6b hKaiUvZ5Myponoo9cfZGoRLbt0SD7J/ba3mnZDpsJ6x+gh3To8HhwLqFJJkULPcUEE h+u3TPPBOwRTKLHZ8ZDEefDm5wHLmQSEpZpDj/Lhrx5e41/+Cv2NYKABAb1jYXKjJ5 RfihHrrdINeCC8SxaaeKsRgU2EhOOQx9zMFyrwuzBjpAFShzCqM/8+vomAPsptrQg0 HOkQJ9fU7cH0xilvyWUHcRGJRpbMY1xlWdfHFo2yqLc6Mg26Z2rv3YLIn72mIreiPl 3yxb4HQVJwdJA== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, bpf@vger.kernel.org, john.fastabend@gmail.com, sd@queasysnail.net, linux-kselftest@vger.kernel.org, Jakub Kicinski , ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, memxor@gmail.com, song@kernel.org, yonghong.song@linux.dev, jolsa@kernel.org, shuah@kernel.org, jiayuan.chen@linux.dev, isolodrai@meta.com Subject: [PATCH net 5/7] selftests: bpf: cover wrapped sk_msg ring chaining in ktls TX path Date: Wed, 29 Apr 2026 15:29:42 -0700 Message-ID: <20260429222944.2139041-6-kuba@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260429222944.2139041-1-kuba@kernel.org> References: <20260429222944.2139041-1-kuba@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add a regression test for the off-by-one in tls_push_record() where the sg_chain() entry count was MAX_SKB_FRAGS instead of NR_MSG_FRAG_IDS, causing the chain pointer to overwrite a live ring slot when an sk_msg scatterlist ring wrapped (sg.end < sg.start). The new "tls tx wrapped sg chain" subtest: 1. attaches an SK_MSG program (prog_sk_policy_drop) that drops the first N bytes of a message via bpf_msg_apply_bytes() + SK_DROP, 2. splices 17 single-byte frags through a kTLS TX socket so the ring fills to sg.start=16, sg.end=17, 3. removes the socket from the sockmap and sends one more byte, which wraps sg.end to 0 and exercises the wrap branch in tls_push_record(). Without the fix the kernel hangs on the wrapping send (the corrupted chain pointer leaves the sg traversal stuck); with the fix the test completes cleanly. Signed-off-by: Jakub Kicinski --- CC: ast@kernel.org CC: daniel@iogearbox.net CC: andrii@kernel.org CC: martin.lau@linux.dev CC: eddyz87@gmail.com CC: memxor@gmail.com CC: song@kernel.org CC: yonghong.song@linux.dev CC: jolsa@kernel.org CC: shuah@kernel.org CC: john.fastabend@gmail.com CC: jiayuan.chen@linux.dev CC: isolodrai@meta.com CC: bpf@vger.kernel.org CC: linux-kselftest@vger.kernel.org --- .../selftests/bpf/prog_tests/sockmap_ktls.c | 83 +++++++++++++++++++ .../selftests/bpf/progs/test_sockmap_ktls.c | 8 ++ 2 files changed, 91 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c b/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c index b87e7f39e15a..8ab7f4cdc614 100644 --- a/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_ktls.c @@ -4,6 +4,7 @@ * Tests for sockmap/sockhash holding kTLS sockets. */ #include +#include #include #include #include "test_progs.h" @@ -403,6 +404,86 @@ static void test_sockmap_ktls_tx_pop(int family, int sotype) test_sockmap_ktls__destroy(skel); } +static void test_sockmap_ktls_tx_wrapped_chain(int family, int sotype) +{ + int c = -1, p = -1, one = 1, prog_fd, map_fd; + int pipefd[2] = { -1, -1 }; + struct test_sockmap_ktls *skel; + char byte; + ssize_t n; + int err, i; + + skel = test_sockmap_ktls__open_and_load(); + if (!ASSERT_TRUE(skel, "open ktls skel")) + return; + + err = create_pair(family, sotype, &c, &p); + if (!ASSERT_OK(err, "create_pair()")) + goto out; + + prog_fd = bpf_program__fd(skel->progs.prog_sk_policy_drop); + map_fd = bpf_map__fd(skel->maps.sock_map); + + err = bpf_prog_attach(prog_fd, map_fd, BPF_SK_MSG_VERDICT, 0); + if (!ASSERT_OK(err, "bpf_prog_attach sk msg")) + goto out; + + err = bpf_map_update_elem(map_fd, &one, &c, BPF_NOEXIST); + if (!ASSERT_OK(err, "bpf_map_update_elem(c)")) + goto out; + + err = init_ktls_pairs(c, p); + if (!ASSERT_OK(err, "init_ktls_pairs(c, p)")) + goto out; + + /* packetized pipe so each splice frag becomes its own sg entry */ + err = pipe2(pipefd, O_DIRECT); + if (!ASSERT_OK(err, "pipe2")) + goto out; + err = fcntl(pipefd[0], F_SETPIPE_SZ, 17 * 4096); + if (!ASSERT_GE(err, 17 * 4096, "F_SETPIPE_SZ")) + goto out; + + for (i = 0; i < 17; i++) { + byte = 'A' + i; + if (!ASSERT_EQ(write(pipefd[1], &byte, 1), 1, "write to pipe")) + goto out; + } + + /* drop the first 16 bytes so sg.start advances to 16 */ + skel->bss->apply_bytes = 16; + + n = splice(pipefd[0], NULL, c, NULL, 17, 0); + if (n < 0) + ASSERT_EQ(errno, EACCES, "splice errno"); + + err = bpf_map_delete_elem(map_fd, &one); + if (!ASSERT_OK(err, "bpf_map_delete_elem")) + goto out; + usleep(50000); + + while (recv(p, &byte, 1, MSG_DONTWAIT) > 0) + ; + + /* this send wraps sg.end to 0 and trips the wrap branch */ + byte = 'X'; + n = send(c, &byte, 1, MSG_DONTWAIT); + if (n < 0) + ASSERT_TRUE(errno == EAGAIN || errno == EACCES || errno == EPIPE, + "send errno"); + +out: + if (pipefd[0] != -1) + close(pipefd[0]); + if (pipefd[1] != -1) + close(pipefd[1]); + if (c != -1) + close(c); + if (p != -1) + close(p); + test_sockmap_ktls__destroy(skel); +} + static void run_tests(int family, enum bpf_map_type map_type) { int map; @@ -429,6 +510,8 @@ 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 tx wrapped sg chain")) + test_sockmap_ktls_tx_wrapped_chain(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 83df4919c224..18de4d7cd816 100644 --- a/tools/testing/selftests/bpf/progs/test_sockmap_ktls.c +++ b/tools/testing/selftests/bpf/progs/test_sockmap_ktls.c @@ -38,3 +38,11 @@ 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); } + +SEC("sk_msg") +int prog_sk_policy_drop(struct sk_msg_md *msg) +{ + if (apply_bytes > 0) + bpf_msg_apply_bytes(msg, apply_bytes); + return SK_DROP; +} -- 2.54.0