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 1B63446C4A2; Mon, 12 Oct 2026 15:30:05 +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=1791819006; cv=none; b=MVMrzkiiijhhhwCr3mb0LYFnzeYyHtuQH598p4pRVLOe8KPeeYM8byQJIudvPhulbvZ0DMFEXgQTCc3s1/YlON6fBnCHSa94ihSwrRYffrOeEzlkA0nYlEL906gNP7doKIkDVv3qcWjXDdZ1k+KZt9UnjJIt17+c69MjqEQS2DQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791819006; c=relaxed/simple; bh=AzQS5tb1ZscGG3jWsdkTaNmde+f98oNCiULD+M9ePAI=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=CqGrsvfh4phZjueFaKXzBPRigEs/JqJHmRx5pMNGFap0IYoBNzUOcwA+t4bqwKHBYENbqkfIwGZSpD0x7h5atkh9Nf2JFAv++YNdYNueWudJ1rXD3ygvx77WcUJ/4LK/F+EpZR+1gv5nW01kWnLPgQMVcnimh/yUv4ixs17fMT4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=To00rTU7; 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="To00rTU7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B7BFC1F0089B; Mon, 12 Oct 2026 15:30:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791819004; bh=+JL7KlwxoHKKUvRbn3u7ffVTeigoRO2Pbhx9b07QL3s=; h=From:Subject:Date:To:Cc; b=To00rTU7Eod3/dTyuA+ont2/VxwQ+mvydxbttCzrXXaSxfr2QpexaUt7nMgtfCVsp qVRQY5xZjzPkMoTTDlyXCZf3DWyMud+NpecQDYY0SPdkJzNTzj6Ugl7sro22qgslgB QZp2QVrAHX2Nl4hrV2k3wQs9xHU27R1YfsbJI7wgBuSB+5yRxuc2XPZyr5EndpaWQJ 7WDU/rbFvb0fRVQt92mJXaM67KG4W4OMd1Vlep3ZzSesnpId0QnQ1GfyCYWkqV4FP3 fPLVAB6dD8YsrkAjeCM9R9xmaxxuNbb2c/kFccOPZEI6aXNy7kvn4IV3kwR0tmt8vU /Cm7uKyltoYUQ== From: Chuck Lever Subject: [PATCH net-next v4 0/9] net/tls: Receive-path fixes for zero-length data records Date: Mon, 12 Oct 2026 11:29:48 -0400 Message-Id: <20261012-tls-follow-on-v4-0-8cea429565da@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/3XOzVLDIBAH8FfpcBYFQknoqe/R8cDCpkFT6ADGO p28uyQdHa3jcT9+/90ryZg8ZrLbXEnCyWcfQy3kw4bYwYQjUu9qTQQTirVC0TJm2sdxjO80Bio 71XMwHQAwUs05Ye8va96BBCw04KWQ59skv8EL2rLELbtgMlJIJthhaX1tP52MD8t88LnE9LG+N vE18Z8vJk4Z1Rp6aS23rdD7V0wBx8eYjuvxSXxzzhi/56Jy4RzXsgVQUvzhzU/e3vOmcuW2wum u6TQ0v/g8z5+X2UHNZQEAAA== 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=5299; i=cel@kernel.org; h=from:subject:message-id; bh=AzQS5tb1ZscGG3jWsdkTaNmde+f98oNCiULD+M9ePAI=; b=owEBbQKS/ZANAwAKATNqszNvZn+XAcsmYgBqzPzwrFDNUcOL5AWOQHWAa0tjKPJdm9VYUnGbY FRWVI9xhReJAjMEAAEKAB0WIQQosuWwEobfJDzyPv4zarMzb2Z/lwUCasz88AAKCRAzarMzb2Z/ l0fXEACuovkDMbIFEh2RP6N/avRR03Kcz6ANLvTLNlbxz3CN/FyFRtx042nN1AOIcYhF1WVCDVJ s3tq72dDkAlzYRsmyKowixFdvulSG6WUysLZdndUAMnyr6mBT1gDwpKPljltOum9Xzy5y9q/vKX m4pyRW7Xts3W4CHm3j5E+lrjwJH4VbsC4eHc7G08LnbcTUlmp755wVWJ84aH89JuznpQw4KgUtm +8ywzhwFWkexowTWM4Pzti3pE2iaWXkqoGkEyB4DAHEisg2r2i03couRGK/tKTNH2nyMdt9SK0e xnHZ3v2DG8W7RU3TSGlHhqCf9A9KaEVAdrqfmdfZxdyM5NnERUbCe42yZ3EgmEFw8r3e4ueN0rg xKm5YCpxe3U44QEalhiW9v8omKn06t5exeADlP2G6XZzev5eYE74YM5BIqvj1ubqfC2H3ybSk5T +HY+1hVJObVM7budJDjjlCdbgHe4zJPBiQwxVkVtuTsQEUNjxgSGrUpPFBwlxehuzVlxeyuBB8X XJH6/btop4Xi0peRxr9uia9/DQ1NUfghvkmo0kqQe3oB9bSMB67naK8dCqu1U6lEjmosPeVGKVQ rGNcZC5pE5douxkajemaYQYZqCQRsf+V6Nd5dkDQXXAQEyjq9mK22aTv7jOuyt6c4fLKS4TImpO VZjuQ8liT7Y5xiw== 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 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 net/tls/tls_sw.c | 87 +++++++++++-- tools/testing/selftests/net/tls.c | 262 +++++++++++++++++++++++++++++++++++--- 2 files changed, 322 insertions(+), 27 deletions(-) --- base-commit: 29f144016f03608abfddcd6ebaeabafd7aeaadd2 change-id: 20260726-tls-follow-on-486f1ba8bbb0 Best regards, -- Chuck Lever