From 1b356361196fe3095717c91b669976bb91e998ec Mon Sep 17 00:00:00 2001 From: jhb Date: Tue, 27 Aug 2019 00:01:56 +0000 Subject: [PATCH] Add kernel-side support for in-kernel TLS. KTLS adds support for in-kernel framing and encryption of Transport Layer Security (1.0-1.2) data on TCP sockets. KTLS only supports offload of TLS for transmitted data. Key negotation must still be performed in userland. Once completed, transmit session keys for a connection are provided to the kernel via a new TCP_TXTLS_ENABLE socket option. All subsequent data transmitted on the socket is placed into TLS frames and encrypted using the supplied keys. Any data written to a KTLS-enabled socket via write(2), aio_write(2), or sendfile(2) is assumed to be application data and is encoded in TLS frames with an application data type. Individual records can be sent with a custom type (e.g. handshake messages) via sendmsg(2) with a new control message (TLS_SET_RECORD_TYPE) specifying the record type. At present, rekeying is not supported though the in-kernel framework should support rekeying. KTLS makes use of the recently added unmapped mbufs to store TLS frames in the socket buffer. Each TLS frame is described by a single ext_pgs mbuf. The ext_pgs structure contains the header of the TLS record (and trailer for encrypted records) as well as references to the associated TLS session. KTLS supports two primary methods of encrypting TLS frames: software TLS and ifnet TLS. Software TLS marks mbufs holding socket data as not ready via M_NOTREADY similar to sendfile(2) when TLS framing information is added to an unmapped mbuf in ktls_frame(). ktls_enqueue() is then called to schedule TLS frames for encryption. In the case of sendfile_iodone() calls ktls_enqueue() instead of pru_ready() leaving the mbufs marked M_NOTREADY until encryption is completed. For other writes (vn_sendfile when pages are available, write(2), etc.), the PRUS_NOTREADY is set when invoking pru_send() along with invoking ktls_enqueue(). A pool of worker threads (the "KTLS" kernel process) encrypts TLS frames queued via ktls_enqueue(). Each TLS frame is temporarily mapped using the direct map and passed to a software encryption backend to perform the actual encryption. (Note: The use of PHYS_TO_DMAP could be replaced with sf_bufs if someone wished to make this work on architectures without a direct map.) KTLS supports pluggable software encryption backends. Internally, Netflix uses proprietary pure-software backends. This commit includes a simple backend in a new ktls_ocf.ko module that uses the kernel's OpenCrypto framework to provide AES-GCM encryption of TLS frames. As a result, software TLS is now a bit of a misnomer as it can make use of hardware crypto accelerators. Once software encryption has finished, the TLS frame mbufs are marked ready via pru_ready(). At this point, the encrypted data appears as regular payload to the TCP stack stored in unmapped mbufs. ifnet TLS permits a NIC to offload the TLS encryption and TCP segmentation. In this mode, a new send tag type (IF_SND_TAG_TYPE_TLS) is allocated on the interface a socket is routed over and associated with a TLS session. TLS records for a TLS session using ifnet TLS are not marked M_NOTREADY but are passed down the stack unencrypted. The ip_output_send() and ip6_output_send() helper functions that apply send tags to outbound IP packets verify that the send tag of the TLS record matches the outbound interface. If so, the packet is tagged with the TLS send tag and sent to the interface. The NIC device driver must recognize packets with the TLS send tag and schedule them for TLS encryption and TCP segmentation. If the the outbound interface does not match the interface in the TLS send tag, the packet is dropped. In addition, a task is scheduled to refresh the TLS send tag for the TLS session. If a new TLS send tag cannot be allocated, the connection is dropped. If a new TLS send tag is allocated, however, subsequent packets will be tagged with the correct TLS send tag. (This latter case has been tested by configuring both ports of a Chelsio T6 in a lagg and failing over from one port to another. As the connections migrated to the new port, new TLS send tags were allocated for the new port and connections resumed without being dropped.) ifnet TLS can be enabled and disabled on supported network interfaces via new '[-]txtls[46]' options to ifconfig(8). ifnet TLS is supported across both vlan devices and lagg interfaces using failover, lacp with flowid enabled, or lacp with flowid enabled. Applications may request the current KTLS mode of a connection via a new TCP_TXTLS_MODE socket option. They can also use this socket option to toggle between software and ifnet TLS modes. In addition, a testing tool is available in tools/tools/switch_tls. This is modeled on tcpdrop and uses similar syntax. However, instead of dropping connections, -s is used to force KTLS connections to switch to software TLS and -i is used to switch to ifnet TLS. Various sysctls and counters are available under the kern.ipc.tls sysctl node. The kern.ipc.tls.enable node must be set to true to enable KTLS (it is off by default). The use of unmapped mbufs must also be enabled via kern.ipc.mb_use_ext_pgs to enable KTLS. KTLS is enabled via the KERN_TLS kernel option. This patch is the culmination of years of work by several folks including Scott Long and Randall Stewart for the original design and implementation; Drew Gallatin for several optimizations including the use of ext_pgs mbufs, the M_NOTREADY mechanism for TLS records awaiting software encryption, and pluggable software crypto backends; and John Baldwin for modifications to support hardware TLS offload. Reviewed by: gallatin, hselasky, rrs Obtained from: Netflix Sponsored by: Netflix, Chelsio Communications Differential Revision: https://reviews.freebsd.org/D21277 --- newlib/libc/sys/rtems/include/net/if.h | 3 +++ newlib/libc/sys/rtems/include/netinet/tcp.h | 14 +++++++++++++- 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/newlib/libc/sys/rtems/include/net/if.h b/newlib/libc/sys/rtems/include/net/if.h index a60374d54..a5539bdcd 100644 --- a/newlib/libc/sys/rtems/include/net/if.h +++ b/newlib/libc/sys/rtems/include/net/if.h @@ -247,6 +247,8 @@ struct if_data { #define IFCAP_TXRTLMT 0x1000000 /* hardware supports TX rate limiting */ #define IFCAP_HWRXTSTMP 0x2000000 /* hardware rx timestamping */ #define IFCAP_NOMAP 0x4000000 /* can TX unmapped mbufs */ +#define IFCAP_TXTLS4 0x8000000 /* can do TLS encryption and segmentation for TCP */ +#define IFCAP_TXTLS6 0x10000000 /* can do TLS encryption and segmentation for TCP6 */ #define IFCAP_HWCSUM_IPV6 (IFCAP_RXCSUM_IPV6 | IFCAP_TXCSUM_IPV6) @@ -254,6 +256,7 @@ struct if_data { #define IFCAP_TSO (IFCAP_TSO4 | IFCAP_TSO6) #define IFCAP_WOL (IFCAP_WOL_UCAST | IFCAP_WOL_MCAST | IFCAP_WOL_MAGIC) #define IFCAP_TOE (IFCAP_TOE4 | IFCAP_TOE6) +#define IFCAP_TXTLS (IFCAP_TXTLS4 | IFCAP_TXTLS6) #define IFCAP_CANTCHANGE (IFCAP_NETMAP) diff --git a/newlib/libc/sys/rtems/include/netinet/tcp.h b/newlib/libc/sys/rtems/include/netinet/tcp.h index 37cf35caa..bce1d59c6 100644 --- a/newlib/libc/sys/rtems/include/netinet/tcp.h +++ b/newlib/libc/sys/rtems/include/netinet/tcp.h @@ -29,7 +29,7 @@ * SUCH DAMAGE. * * @(#)tcp.h 8.1 (Berkeley) 6/10/93 - * $FreeBSD: head/sys/netinet/tcp.h 334804 2018-06-07 18:18:13Z rrs $ + * $FreeBSD: head/sys/netinet/tcp.h 351522 2019-08-27 00:01:56Z jhb $ */ #ifndef _NETINET_TCP_H_ @@ -174,6 +174,8 @@ struct tcphdr { #define TCP_LOGDUMP 37 /* dump connection log events to device */ #define TCP_LOGDUMPID 38 /* dump events from connections with same ID to device */ +#define TCP_TXTLS_ENABLE 39 /* TLS framing and encryption for transmit */ +#define TCP_TXTLS_MODE 40 /* Transmit TLS mode */ #define TCP_CONGESTION 64 /* get/set congestion control algorithm */ #define TCP_CCALGOOPT 65 /* get/set cc algorithm specific options */ #define TCP_DELACK 72 /* socket option for delayed ack */ @@ -350,4 +352,14 @@ struct tcp_function_set { uint32_t pcbcnt; }; +/* TLS modes for TCP_TXTLS_MODE */ +#define TCP_TLS_MODE_NONE 0 +#define TCP_TLS_MODE_SW 1 +#define TCP_TLS_MODE_IFNET 2 + +/* + * TCP Control message types + */ +#define TLS_SET_RECORD_TYPE 1 + #endif /* !_NETINET_TCP_H_ */