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 BF6993CF1E4; Wed, 7 Oct 2026 19:49:47 +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=1791402589; cv=none; b=YXJFxq9APpDMcBzlOd8Omdr+lVsPWjnPPZOi6aDpfpXZkjcgQXetHiNEehwUrTOdxY7WQhWc2FxJsjEwJjLvFmQp2xNHbZIU+2MqZ5rwAEH9i7O+eWhSPMG/i8l1u6n1a15HLqV1PB9hTOaiYLvHVYc1mkdZER8SWGW9HY1065A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791402589; c=relaxed/simple; bh=c1VopkM7IUVLIk93aABQYe9KjIRNYiwyejP96Ne6OTE=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=QD72ahncYhOaApo5JnGG/qDbNDp8US9ZXxY+t/i1ojy9mfzmzkQXPa9AcUdeizFnvjKwGhpnTW64x2N9pY5YAZcIvbpRuf7Q7P3AmCTy/y0+/2O6jI8kFLXutKSCubJY1QayHAV2upjVfBYEMasm/sF0KWTO5r802xmV5VszOeM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KRuMv19n; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KRuMv19n" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55CAA1F000FF; Wed, 7 Oct 2026 19:49:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791402587; bh=RCwrViG08gG1Wt4WrfkXXu0M9wkCYS/dAGqLxWSwyxw=; h=From:Subject:Date:To:Cc; b=KRuMv19nD3Y4niLIo5RKg0+kZSfWAFd5UdQ8UEEhHB30bFv+2BGRzmlXsIyplUzSu h1lpRDl4Tz6eesZuxFyo306qOLUzrBvWNgZIaEomuDWfk3JKf1ATs5JSr7nyv493bL mszE//+ydrRHaA5KRDVnQKrIh7qVZenpGk7uzNn08Cs74U1oIBj+e0eqg+zLYPLVF1 kuuuZT9l8Dq9XvVU11K2AcHnCSYdRw+A2s5eiTZWFm6NJPbCYspiA8SWKLN3kPQTlO wYYxmEMNi/LrcSDgewnVVCwGpwnQBqkAyU9u/Lmyt1brV26OYiExX3YFHVA1EVbkRu H71tQM5e/GxbQ== From: Chuck Lever Subject: [PATCH net-next v3 0/9] net/tls: Receive-path fixes for zero-length data records Date: Wed, 07 Oct 2026 15:49:29 -0400 Message-Id: <20261007-tls-follow-on-v3-0-6d52d98389b3@kernel.org> 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: 7bit X-B4-Tracking: v=1; b=H4sIAAAAAAAC/3WOzQ6CMBCEX4X07GpbCT+efA/joVsWqWJr2ooYw 7sLGE008Tg7883OgwXyhgLbJA/mqTPBODuK9SJhulH2QGCqUTPJZcZzmUFsA9Subd0NnIW0yGq BqkBEzkbm4qk2/dy3Y5YiWOoj27+ccMUj6TjVTVlUgQC9srqZTu/06qyMnfzGhOj8fZ7Wibnxz 4pOAIeyxDrVWuhcltsTeUvt0vnD/LyTH1xwLn5xOeKyqkSZ5ohZKr/wYRieU3iDRyYBAAA= X-Change-ID: 20260726-tls-follow-on-486f1ba8bbb0 To: John Fastabend , Jakub Kicinski , Sabrina Dubroca , "David S. Miller" , Paolo Abeni , Simon Horman , Chuck Lever , Dave Watson , Shuah Khan , Qingfang Deng , Eric Dumazet Cc: netdev@vger.kernel.org, linux-kselftest@vger.kernel.org, sashiko-bot , sashiko-bot X-Mailer: b4 0.16-dev-da966 X-Developer-Signature: v=1; a=openpgp-sha256; l=4967; i=cel@kernel.org; h=from:subject:message-id; bh=c1VopkM7IUVLIk93aABQYe9KjIRNYiwyejP96Ne6OTE=; b=owEBbQKS/ZANAwAKATNqszNvZn+XAcsmYgBqxqJOxv22DTqcrs2DoxlmQRbmwoNPB8YUErIM7 3xFaKioHBaJAjMEAAEKAB0WIQQosuWwEobfJDzyPv4zarMzb2Z/lwUCasaiTgAKCRAzarMzb2Z/ l7ifEACnCMCnFaf7LKOxx36qNf2uMHuYFOa2NbtMjvEYUYDi4lMHtDZSufL+zFXWEM4FxAG4zks minFyoFnGci/ysAVC21wZqZC4O/6LzepwSF+81f5Vjvp3NmqgcuD+F9HM82fDN8aiV3eJV2r7gf A1sBmbN+Nzax3/5jUadgojwIMpgi7YzIq0ykhdARRD4UAEUbrbuKorWEn4x2pGynJR9I1jDhNEG +Kr3y9MWfiF7rAgf3vk5CfFgjXL1ZlzDOfy+dYJfrFNazYzPlzlVMpP9+r8YMVB6VnUQBhQ8xh3 HiDccD3s46DGXtjW21ZHTYDFrL/Iov58Ol2gDMVETcXhwkBXTq7Tbc8tV1NrAY2eNw/UzDUGyWn srcsTuddrxEdEhlVsasutX3m/ghGgJ7zKQGXZ08u7Gk+xwAN+mssaGlOdOPxIl1s9vIFnMGUONz 5G8QPNy9p1U2jPJBMp5WeL2ilInygZfYdjcfZlniuJ5Dey+4E5Gwdpk9zvZGvZ2pHu/SC2hpoG2 XQz2B4t8S7xMs8DwdEWXzjr0c10yfyMox0w5UyZh8XPcuu5FnVsAKU+4PdLgJZj0NJqnXEKL7+w uA6LQEGoJvW8U604AJ/AUlk7WKQ0pOEZt2P9kxBUqTLtT1SOopV1VAPPuqLYftnf26WUlSb1Nxw LnVoIVCZ5oqorSA== X-Developer-Key: i=cel@kernel.org; a=openpgp; fpr=28B2E5B01286DF243CF23EFE336AB3336F667F97 Commit 3be28e2c9cd0 ("net/tls: Consume empty data records in tls_sw_read_sock()") fixed one reader. TLS 1.2 and TLS 1.3 both permit a zero-length application_data record as a traffic-analysis countermeasure (RFC 5246, Section 6.2.1; RFC 8446, Section 5.1), so a peer that pads its stream emits them by design. The other two software readers still mishandle them. splice(2) reports an empty record as EOF, and the caller tears down a connection that is still live. recvmsg(2) makes no progress on one, so a peer that streams them holds the caller in the kernel past SIGKILL. With MSG_PEEK or async decryption, each record is also queued on rx_list, which grows without bound. This series supersedes "[PATCH net] tls: skip empty data records in tls_sw_splice_read()", which fixes the splice case alone: https://lore.kernel.org/netdev/20260930052636.166007-1-qingfang.deng@linux.dev/ Which fix a reader gets depends on its caller. splice(2) and recvmsg(2) are system calls, so consuming the record and testing signal_pending() is enough. A signal ends the call. An in-kernel caller of sock_recvmsg() cannot take a signal, so a flood holds that caller as it does today. Only tls_sw_read_sock() gets a bound of its own. Its callers hold the socket lock across the whole call and cannot act on a signal, so nothing else can stop the loop. A count of consecutive records that deliver no bytes supplies the bound (patch 1). The count is scoped to read_sock deliberately. A flood on the other two paths costs the caller CPU time and nothing else. The series changes user-visible behavior. splice(2) on a nonblocking socket, and sendfile(2) from one, now return -EAGAIN where they used to block, as they do on a plain TCP socket. A splice that reaches a control record behind an empty one now returns -EINVAL rather than the zero that was the false EOF. A nonblocking recvmsg(2) or splice(2) that has copied nothing and finds a signal pending after an empty record returns -EINTR. A recvmsg(2) that has copied data now returns at an empty record rather than reading the records that follow. SO_RCVTIMEO does not bound these calls. It is applied at the reader lock and again on each call to tls_rx_rec_wait(), so a call that keeps retrying can wait past it. recvmsg(2) behaves this way today. The retry added to splice(2) extends the same behavior to that path. Tested on x86_64. The tls selftest suite passes, 937 tests with no skips. --- Changes in v3: - Run the consumer's sk_data_ready() from a work item (sashiko). - Move the sync decrypt of empty records to the signal patch (sashiko). - Put the O_NONBLOCK patch before the splice retry patch (sashiko). - Reword the O_NONBLOCK patch description to match (sashiko). - Say that the recvmsg patch does not bound the receive loop (sashiko). - Add a patch that returns copied data ahead of empty records (sashiko). - Put the zero_len skip patch before the coverage patch (sashiko). - Use poll() to check for records left on rx_list (sashiko). - Link to v2: https://patch.msgid.link/20261001-tls-follow-on-v2-0-2dd1947bb642@kernel.org Changes in v2: - Bound no-data records by count, not elapsed time (Jakub). - Drop the tls_rx_empty_data_rec() helper (Sabrina). - Keep the strparser anchor out of tls_sw.c comments (Sabrina). - Split the recvmsg signal test into its own patch. - Drop tls_rx_intr_errno(); a nonblocking reader now gets -EINTR. - Say why do_splice() misses the socket's O_NONBLOCK (Sabrina). - Point the recvmsg patch's Fixes: at the commit that added rx_list. - Reuse the new zero_len helpers in the existing fixture (Sabrina). - Check errno unconditionally in the zero_len tests (Sabrina). - Split the splice crypto-error fix and its test out (Jakub): https://patch.msgid.link/20260806-tls-splice-crypto-fix-v1-0-a2624005a286@kernel.org - Link to v1: https://patch.msgid.link/20260726-tls-follow-on-v1-0-99bf4cc1c729@kernel.org --- Chuck Lever (9): tls: Bound consecutive no-data records in tls_sw_read_sock() tls: Check for a pending signal after an empty record tls: Honor O_NONBLOCK in tls_sw_splice_read() tls: Consume empty data records in tls_sw_splice_read() tls: Consume empty data records in tls_sw_recvmsg() tls: Return copied data ahead of a run of empty records selftests: tls: Skip the zero_len tests when TLS is unavailable selftests: tls: Add peek and splice coverage for zero-length records selftests: tls: Cover splice on a nonblocking socket include/net/tls.h | 1 + net/tls/tls_sw.c | 98 +++++++++++++-- tools/testing/selftests/net/tls.c | 256 +++++++++++++++++++++++++++++++++++--- 3 files changed, 328 insertions(+), 27 deletions(-) --- base-commit: a5e7d8e446af9803e37a3b6a4d416fb41178348f change-id: 20260726-tls-follow-on-486f1ba8bbb0 Best regards, -- Chuck Lever