diff --git a/share/man/man4/ktls.4 b/share/man/man4/ktls.4 index 21e1a1bdb6ca..648eeaedfa6a 100644 --- a/share/man/man4/ktls.4 +++ b/share/man/man4/ktls.4 @@ -1,267 +1,267 @@ .\" Copyright (c) 2020, Chelsio Inc .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions are met: .\" .\" 1. Redistributions of source code must retain the above copyright notice, .\" this list of conditions and the following disclaimer. .\" .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" 3. Neither the name of the Chelsio Inc nor the names of its .\" contributors may be used to endorse or promote products derived from .\" this software without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" .\" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE .\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF .\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS .\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN .\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE .\" POSSIBILITY OF SUCH DAMAGE. .\" .\" * Other names and brands may be claimed as the property of others. .\" .\" $FreeBSD$ .\" -.Dd February 8, 2021 +.Dd March 8, 2021 .Dt KTLS 4 .Os .Sh NAME .Nm ktls .Nd kernel Transport Layer Security .Sh SYNOPSIS .Cd options KERN_TLS .Sh DESCRIPTION The .Nm facility allows the kernel to perform Transport Layer Security (TLS) framing on TCP sockets. With .Nm , the initial handshake for a socket using TLS is performed in userland. Once the session keys are negotiated, they are provided to the kernel via the .Dv TCP_TXTLS_ENABLE and .Dv TCP_RXTLS_ENABLE socket options. Both socket options accept a -.Vt struct tls_so_enable +.Vt struct tls_enable structure as their argument. The members of this structure describe the cipher suite used for the TLS session and provide the session keys used for the respective direction. .Pp .Nm only permits the session keys to be set once in each direction. As a result, applications must disable rekeying when using .Nm . .Ss Modes .Nm can operate in different modes. A given socket may use different modes for transmit and receive, or a socket may only offload a single direction. The available modes are: .Bl -tag -width "Dv TCP_TLS_MODE_IFNET" .It Dv TCP_TLS_MODE_NONE .Nm is not enabled. .It Dv TCP_TLS_MODE_SW TLS records are encrypted or decrypted in the kernel in the socket layer. Typically the encryption or decryption is performed in software, but it may also be performed by co-processors via .Xr crypto 9 . .It Dv TCP_TLS_MODE_IFNET TLS records are encrypted or decrypted by the network interface card (NIC). In this mode, the network stack does not work with encrypted data. Instead, the NIC encrypts TLS records as they are being transmitted, or decrypts received TLS records before providing them to the host. .Pp Network interfaces which support this feature will advertise the .Dv TXTLS4 (for IPv4) and/or .Dv TXTLS6 (for IPv6) capabilities as reported by .Xr ifconfig 8 . These capabilities can also be controlled by .Xr ifconfig 8 . .Pp If a network interface supports rate limiting (also known as packet pacing) for TLS offload, the interface will advertise the .Dv TXTLS_RTLMT capability. .It Dv TCP_TLS_MODE_TOE TLS records are encrypted by the NIC using a TCP offload engine (TOE). This is similar to .Dv TCP_TLS_MODE_IFNET in that the network stack does not work with encrypted data. However, this mode works in tandem with a TOE to handle interactions between TCP and TLS. .El .Ss Transmit Once TLS transmit is enabled by a successful set of the .Dv TCP_TXTLS_ENABLE socket option, all data written on the socket is stored in TLS records and encrypted. Most data is transmitted in application layer TLS records, and the kernel chooses how to partition data among TLS records. Individual TLS records with a fixed length and record type can be sent by .Xr sendmsg 2 with the TLS record type set in a .Dv TLS_SET_RECORD_TYPE control message. The payload of this control message is a single byte holding the desired TLS record type. This can be used to send TLS records with a type other than application data (for example, handshake messages) or to send application data records with specific contents (for example, empty fragments). .Pp TLS transmit requires the use of unmapped mbufs. Unmapped mbufs are not enabled by default, but can be enabled by setting the .Va kern.ipc.mb_use_ext_pgs sysctl node to 1. .Pp The current TLS transmit mode of a socket can be queried via the .Dv TCP_TXTLS_MODE socket option. A socket using TLS transmit offload can also set the .Dv TCP_TXTLS_MODE socket option to toggle between .Dv TCP_TLS_MODE_SW and .Dv TCP_TLS_MODE_IFNET . .Ss Receive Once TLS receive is enabled by a successful set of the .Dv TCP_RXTLS_ENABLE socket option, all data read from the socket is returned as decrypted TLS records. Each received TLS record must be read from the socket using .Xr recvmsg 2 . Each received TLS record will contain a .Dv TLS_GET_RECORD control message along with the decrypted payload. The control message contains a .Vt struct tls_get_record which includes fields from the TLS record header. If an invalid or corrupted TLS record is received, .Xr recvmsg 2 will fail with one of the following errors: .Bl -tag -width Er .It Bq Er EINVAL The version fields in a TLS record's header did not match the version required by the -.Vt struct tls_so_enable +.Vt struct tls_enable structure used to enable in-kernel TLS. .It Bq Er EMSGSIZE A TLS record's length was either too small or too large. .It Bq Er EMSGSIZE The connection was closed after sending a truncated TLS record. .It Bq Er EBADMSG The TLS record failed to match the included authentication tag. .El .Pp The current TLS receive mode of a socket can be queried via the .Dv TCP_RXTLS_MODE socket option. At present, the mode cannot be changed. .Ss Sysctl Nodes .Nm uses several sysctl nodes under the .Va kern.ipc.tls node. A few of them are described below: .Bl -tag -width ".Va kern.ipc.tls.cbc_enable" .It Va kern.ipc.tls.enable Determines if new kernel TLS sessions can be created. .It Va kern.ipc.tls.cbc_enable Determines if new kernel TLS sessions with a cipher suite using AES-CBC can be created. .It Va kern.ipc.tls.sw A tree of nodes containing statistics for TLS sessions using .Dv TCP_TLS_MODE_SW . .It Va kern.ipc.tls.ifnet A tree of nodes containing statistics for TLS sessions using .Dv TCP_TLS_MODE_IFNET . .It Va kern.ipc.tls.toe A tree of nodes containing statistics for TLS sessions using .Dv TCP_TLS_MODE_TOE . .It Va kern.ipc.tls.stats A tree of nodes containing various kernel TLS statistics. .El .Ss Backends The base system includes a software backend for the .Dv TCP_TLS_MODE_SW mode which uses .Xr crypto 9 to encrypt and decrypt TLS records. This backend can be enabled by loading the .Pa ktls_ocf.ko kernel module. .Pp The .Xr cxgbe 4 and .Xr mlx5en 4 drivers include support for the .Dv TCP_TLS_MODE_IFNET mode. .Pp The .Xr cxgbe 4 driver includes support for the .Dv TCP_TLS_MODE_TOE mode. .Ss Supported Libraries OpenSSL 3.0 and later include support for .Nm . The .Fa devel/openssl port may also be built with support for .Nm by enabling the .Dv KTLS option. OpenSSL in the base system includes KTLS support when built with .Dv WITH_OPENSSL_KTLS . .Pp Applications using a supported library should generally work with .Nm without any changes provided they use standard interfaces such as .Xr SSL_read 3 and .Xr SSL_write 3 . Additional performance may be gained by the use of .Xr SSL_sendfile 3 . .Sh IMPLEMENTATION NOTES .Nm assumes the presence of a direct map of physical memory when performing software encryption and decryption. As a result, it is only supported on architectures with a direct map. .Sh SEE ALSO .Xr cxgbe 4 , .Xr mlx5en 4 , .Xr tcp 4 , .Xr src.conf 5 , .Xr ifconfig 8 , .Xr sysctl 8 , .Xr crypto 9 .Sh HISTORY Kernel TLS first appeared in .Fx 13.0 .