From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792428931; b=X2AB7WdCrRL0OK5fLP5MoppMyQrtQIDvRAB1oa59vLQ5NgjkV6Xa3kYeAGr/pXsEKAsq +BSLdhwejq8urJ34Xi7+STnznr27N4dFJuh1Cn88d1RTYmRzmHSB6pprHyQYMwrtvIYxR ls49xVeJiK3uyLkOi/u8xk4DZ62PfI2YjoNy28TxsIaIxod7nStyC09H15COkPAWu5BqH mQ1TGB9zHxOlvDDTnHKXMpAut2IRCaWI3legtCmhHghl/edwxwHqdnuPbkLXpIa7by0vX En9YypHiXYy+Y/Pd/zP2JxTedPOXjpqoGN6PlUkQcsjQ3iQd7luM7w+0FrygDLyNljg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792428931; h=Received:DKIM-Signature:From:Subject:Date:Message-Id:MIME-Version: Content-Type:Content-Transfer-Encoding:X-B4-Tracking:X-Change-ID:To: Cc:X-Mailer:X-Developer-Signature:X-Developer-Key; bh=Ci8Cm2jw1ezjETTeikEr3zJn3zOORrt6gyC+LSBdgIE=; b=3oypXIWiROA8/IdA5z3vw3LXSZT7GeeKtLpKnUHln5vB6gDESm9VYsjym4859d9AAhC/ a1jAEqRGeR9yJzoJ0qG/U9KPv9jfn2gZrQLndEkl4bp44ir5u2y6UaPMp+Izf5DF+n0DT /o8KWPq2SoRB7z5grkQSMW2K4uTLy9Gm+tfBEEdiMVEaH40p1rjRNW4fyKJK57R5vkNW7 wzzBATX+3ZhnjZKZFlZwl+Flt1HaerTsA4exSYPdogoZ/wm1hvO6UHRli4o4qQtdcij5s B9hSdhV61U/DXOFLRLFKStObpbz34T+L0XfnqY5S9qscxClWOY2AbuhILrKxBPAeiMA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=T+8R+CY4; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 92953606A31B; Mon, 19 Oct 2026 16:55:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=T+8R+CY4 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AF7F1F000C4; Mon, 19 Oct 2026 16:55:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792428931; bh=Ci8Cm2jw1ezjETTeikEr3zJn3zOORrt6gyC+LSBdgIE=; h=From:Subject:Date:To:Cc; b=T+8R+CY49guUWL4uT+cq9SPD+Yy3NLolKGNaqz2ZmG3JEYHrGflL486sWxJE5+4N1 wata7+QNhKp3nixfX188EgIZMUZPTvI5fdFcA6NA3k02BYvlKHSpo86qqevlKtbN6W RZnvCZHaDKWbIKUeolDuvjXUnBwHFp71vyjY/B7jnCnjupB4VfaAqL5aoSs8YFaiMF sPJ0DlUHdMMNoj+ldaBQUWVV9ZW4zLHCpoHMS0GQlRfSn2LhZnA/oE2GZ0ok9h/LVd 7ojqcFGtyCQqtzfhjRtTnKg2SRvEeEWZVpqpboLfX43UrNgoVyH+Dib9IKaXNwzrFP lY+EduNCSVB0A== From: Chuck Lever Subject: [PATCH net-next v6 0/9] net/tls: Receive-path fixes for zero-length data records Date: Mon, 19 Oct 2026 12:55:16 -0400 Message-Id: <20261019-tls-follow-on-v6-0-ab01c4ecca0c@kernel.org> X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAAAAAAAC/3XOy07FIBAG4Fc5YS0KFGhx5XsYF1ymp2gFA1iPO em7S2s0tY3LuXz/zBVlSB4yuj9dUYLJZx9DLeTNCdlBhzNg72qNGGGStEziMmbcx3GMHzgGzDv ZU6M7YwxB1bwl6P1lzXtEAQoOcCno6XuS380z2LLELbtGZ8Am6WCHpfWzffeqfVjmg88lps/1t Ymuif98MVFMsFKm59ZS2zL18AIpwHgb03k9PrFfTgmhe84qZ85RxVtjJGcH3mx5u+dN5dIJ5lT XdMo0B843nLI955V3FjRnSkjh9IGLLed7LiqHVtqGUMd7Iv7weZ6/ABqCo8jjAQAA 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 0.17-dev-9c833 X-Developer-Signature: v=1; a=openpgp-sha256; l=6515; i=cel@kernel.org; h=from:subject:message-id; bh=Sh1mWDuUw2qFcpb4nVpa3/uH3MCwKiKo+z9qMCLkCiw=; b=kA0DAAoBM2qzM29mf5cByyZiAGrWS3nISENHJ/+UaZrUnbDb0XhpuEnGFF2hQUsfhOo8+fkRZ 4kCMwQAAQoAHRYhBCiy5bASht8kPPI+/jNqszNvZn+XBQJq1kt5AAoJEDNqszNvZn+XflcP/RdK 4o8S/aKHCRURDRQx1FlucX5Xn7OSu8Qxwcjb4qwIlgEL0XTbAhOMpEXuTw3EeRxH4P9J2hW/qtH SLio3SPbkE+D3CCsPhCIQJf9TwkXzTjMzj+jM59Jk9Jx8v226SOtvFvj7XWLeh29b5BzTncFkDK 3BAHZKzH6mLshDGw/BP7FnkuzevTvIcaooSqHqV6EUw6ItMNtKb0MIyOLqVZL/OTbJ3Tr5cvUeK UsQE5BsVRaopI8cNuPVJ0aZWd47aIvlMs9jm7YteGxoFkarN7H506Sm2+1598bVswwbdM5whb9M O3t3dkCK2lW4a2tz3Dvib0a76Qs/SjZebJjoA39gloEcu+hIGk7a7QbsK2eXEEnEwfLG/Mae0vZ xDD8Fnowib9Er6TL0aDp7iVDskkNPPEiPGNUbCGtz1UXd2x3qXLyTgZmWurAPEnNL0xYIxQ+DsU XNcN8uT7v4XgiA3ocFbUEipZmA8uMQVBxCuOzQXKPv9HlvmzIEg6SanbDkK16GODbJz+VHJO3IX 8aQfYrOcIJ0SCwKPrq+kO6lsR3KhQUjKtn0vSNhV8SFvRTZNi989IuvahFWpleH6RlKAKhR4XZc WhRxwtJbNuEuvQbbOmevRxnmd9F2zW0aHr9uJMsjdTiUv7+HjTrkv7RZpnJHFpi6Xrdpbj14ZVG 0bF3P 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, 940 tests with no skips. --- Changes in v6: - Drop the empty-record cap from tls_sw_splice_read() (sashiko). - Drop the zero_len_splice variant that reached the cap. - State why the read_sock consumer cannot bound the run (sashiko). - Name the later patches the O_NONBLOCK description relies on (sashiko). - Note the MSG_EOR change under MSG_PEEK in the recvmsg patch (sashiko). - Link to v5: https://patch.msgid.link/20261014-tls-follow-on-v5-0-e76c301d4f05@kernel.org Changes in v5: - Restore the v3 data_ready work item in tls_sw_read_sock() (sashiko). - Queue the work item on tls_strp_wq, not system_wq (sashiko). - Queue the work item only when a record is left parsed at the break. - Skip the work item's callback once the strparser is stopped. - Reword the signal patch: -EAGAIN needs a pending signal (sashiko). - Cap consecutive empty records in tls_sw_splice_read() (sashiko). - Define TLS_RX_NODATA_LIMIT above tls_sw_splice_read(). - Add a zero_len_splice variant that reaches the cap. - Link to v4: https://patch.msgid.link/20261012-tls-follow-on-v4-0-8cea429565da@kernel.org Changes in v4: - Drop the data_ready work item; the reader release announces (sashiko). - Return -EAGAIN to a nonblocking reader with a signal pending (sashiko). - Add a Fixes: tag to the low-water mark patch (sashiko). - Add a zero_len variant that pins the low-water mark patch's behavior. - Link to v3: https://patch.msgid.link/20261007-tls-follow-on-v3-0-6d52d98389b3@kernel.org 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: Extend coverage for zero-length records selftests: tls: Cover splice on a nonblocking socket include/net/tls.h | 1 + net/tls/tls.h | 2 + net/tls/tls_strp.c | 2 +- net/tls/tls_sw.c | 98 +++++++++++++- tools/testing/selftests/net/tls.c | 261 +++++++++++++++++++++++++++++++++++--- 5 files changed, 340 insertions(+), 24 deletions(-) --- base-commit: 05b5019b01fb9443b09ae4ed34af1135a80a84c8 change-id: 20260726-tls-follow-on-486f1ba8bbb0 Best regards, -- Chuck Lever