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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /Documentation/x86/intel_txt.rst
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Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ...
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+=====================
+Intel(R) TXT Overview
+=====================
+
+Intel's technology for safer computing, Intel(R) Trusted Execution
+Technology (Intel(R) TXT), defines platform-level enhancements that
+provide the building blocks for creating trusted platforms.
+
+Intel TXT was formerly known by the code name LaGrande Technology (LT).
+
+Intel TXT in Brief:
+
+- Provides dynamic root of trust for measurement (DRTM)
+- Data protection in case of improper shutdown
+- Measurement and verification of launched environment
+
+Intel TXT is part of the vPro(TM) brand and is also available some
+non-vPro systems. It is currently available on desktop systems
+based on the Q35, X38, Q45, and Q43 Express chipsets (e.g. Dell
+Optiplex 755, HP dc7800, etc.) and mobile systems based on the GM45,
+PM45, and GS45 Express chipsets.
+
+For more information, see http://www.intel.com/technology/security/.
+This site also has a link to the Intel TXT MLE Developers Manual,
+which has been updated for the new released platforms.
+
+Intel TXT has been presented at various events over the past few
+years, some of which are:
+
+ - LinuxTAG 2008:
+ http://www.linuxtag.org/2008/en/conf/events/vp-donnerstag.html
+
+ - TRUST2008:
+ http://www.trust-conference.eu/downloads/Keynote-Speakers/
+ 3_David-Grawrock_The-Front-Door-of-Trusted-Computing.pdf
+
+ - IDF, Shanghai:
+ http://www.prcidf.com.cn/index_en.html
+
+ - IDFs 2006, 2007
+ (I'm not sure if/where they are online)
+
+Trusted Boot Project Overview
+=============================
+
+Trusted Boot (tboot) is an open source, pre-kernel/VMM module that
+uses Intel TXT to perform a measured and verified launch of an OS
+kernel/VMM.
+
+It is hosted on SourceForge at http://sourceforge.net/projects/tboot.
+The mercurial source repo is available at http://www.bughost.org/
+repos.hg/tboot.hg.
+
+Tboot currently supports launching Xen (open source VMM/hypervisor
+w/ TXT support since v3.2), and now Linux kernels.
+
+
+Value Proposition for Linux or "Why should you care?"
+=====================================================
+
+While there are many products and technologies that attempt to
+measure or protect the integrity of a running kernel, they all
+assume the kernel is "good" to begin with. The Integrity
+Measurement Architecture (IMA) and Linux Integrity Module interface
+are examples of such solutions.
+
+To get trust in the initial kernel without using Intel TXT, a
+static root of trust must be used. This bases trust in BIOS
+starting at system reset and requires measurement of all code
+executed between system reset through the completion of the kernel
+boot as well as data objects used by that code. In the case of a
+Linux kernel, this means all of BIOS, any option ROMs, the
+bootloader and the boot config. In practice, this is a lot of
+code/data, much of which is subject to change from boot to boot
+(e.g. changing NICs may change option ROMs). Without reference
+hashes, these measurement changes are difficult to assess or
+confirm as benign. This process also does not provide DMA
+protection, memory configuration/alias checks and locks, crash
+protection, or policy support.
+
+By using the hardware-based root of trust that Intel TXT provides,
+many of these issues can be mitigated. Specifically: many
+pre-launch components can be removed from the trust chain, DMA
+protection is provided to all launched components, a large number
+of platform configuration checks are performed and values locked,
+protection is provided for any data in the event of an improper
+shutdown, and there is support for policy-based execution/verification.
+This provides a more stable measurement and a higher assurance of
+system configuration and initial state than would be otherwise
+possible. Since the tboot project is open source, source code for
+almost all parts of the trust chain is available (excepting SMM and
+Intel-provided firmware).
+
+How Does it Work?
+=================
+
+- Tboot is an executable that is launched by the bootloader as
+ the "kernel" (the binary the bootloader executes).
+- It performs all of the work necessary to determine if the
+ platform supports Intel TXT and, if so, executes the GETSEC[SENTER]
+ processor instruction that initiates the dynamic root of trust.
+
+ - If tboot determines that the system does not support Intel TXT
+ or is not configured correctly (e.g. the SINIT AC Module was
+ incorrect), it will directly launch the kernel with no changes
+ to any state.
+ - Tboot will output various information about its progress to the
+ terminal, serial port, and/or an in-memory log; the output
+ locations can be configured with a command line switch.
+
+- The GETSEC[SENTER] instruction will return control to tboot and
+ tboot then verifies certain aspects of the environment (e.g. TPM NV
+ lock, e820 table does not have invalid entries, etc.).
+- It will wake the APs from the special sleep state the GETSEC[SENTER]
+ instruction had put them in and place them into a wait-for-SIPI
+ state.
+
+ - Because the processors will not respond to an INIT or SIPI when
+ in the TXT environment, it is necessary to create a small VT-x
+ guest for the APs. When they run in this guest, they will
+ simply wait for the INIT-SIPI-SIPI sequence, which will cause
+ VMEXITs, and then disable VT and jump to the SIPI vector. This
+ approach seemed like a better choice than having to insert
+ special code into the kernel's MP wakeup sequence.
+
+- Tboot then applies an (optional) user-defined launch policy to
+ verify the kernel and initrd.
+
+ - This policy is rooted in TPM NV and is described in the tboot
+ project. The tboot project also contains code for tools to
+ create and provision the policy.
+ - Policies are completely under user control and if not present
+ then any kernel will be launched.
+ - Policy action is flexible and can include halting on failures
+ or simply logging them and continuing.
+
+- Tboot adjusts the e820 table provided by the bootloader to reserve
+ its own location in memory as well as to reserve certain other
+ TXT-related regions.
+- As part of its launch, tboot DMA protects all of RAM (using the
+ VT-d PMRs). Thus, the kernel must be booted with 'intel_iommu=on'
+ in order to remove this blanket protection and use VT-d's
+ page-level protection.
+- Tboot will populate a shared page with some data about itself and
+ pass this to the Linux kernel as it transfers control.
+
+ - The location of the shared page is passed via the boot_params
+ struct as a physical address.
+
+- The kernel will look for the tboot shared page address and, if it
+ exists, map it.
+- As one of the checks/protections provided by TXT, it makes a copy
+ of the VT-d DMARs in a DMA-protected region of memory and verifies
+ them for correctness. The VT-d code will detect if the kernel was
+ launched with tboot and use this copy instead of the one in the
+ ACPI table.
+- At this point, tboot and TXT are out of the picture until a
+ shutdown (S<n>)
+- In order to put a system into any of the sleep states after a TXT
+ launch, TXT must first be exited. This is to prevent attacks that
+ attempt to crash the system to gain control on reboot and steal
+ data left in memory.
+
+ - The kernel will perform all of its sleep preparation and
+ populate the shared page with the ACPI data needed to put the
+ platform in the desired sleep state.
+ - Then the kernel jumps into tboot via the vector specified in the
+ shared page.
+ - Tboot will clean up the environment and disable TXT, then use the
+ kernel-provided ACPI information to actually place the platform
+ into the desired sleep state.
+ - In the case of S3, tboot will also register itself as the resume
+ vector. This is necessary because it must re-establish the
+ measured environment upon resume. Once the TXT environment
+ has been restored, it will restore the TPM PCRs and then
+ transfer control back to the kernel's S3 resume vector.
+ In order to preserve system integrity across S3, the kernel
+ provides tboot with a set of memory ranges (RAM and RESERVED_KERN
+ in the e820 table, but not any memory that BIOS might alter over
+ the S3 transition) that tboot will calculate a MAC (message
+ authentication code) over and then seal with the TPM. On resume
+ and once the measured environment has been re-established, tboot
+ will re-calculate the MAC and verify it against the sealed value.
+ Tboot's policy determines what happens if the verification fails.
+ Note that the c/s 194 of tboot which has the new MAC code supports
+ this.
+
+That's pretty much it for TXT support.
+
+
+Configuring the System
+======================
+
+This code works with 32bit, 32bit PAE, and 64bit (x86_64) kernels.
+
+In BIOS, the user must enable: TPM, TXT, VT-x, VT-d. Not all BIOSes
+allow these to be individually enabled/disabled and the screens in
+which to find them are BIOS-specific.
+
+grub.conf needs to be modified as follows::
+
+ title Linux 2.6.29-tip w/ tboot
+ root (hd0,0)
+ kernel /tboot.gz logging=serial,vga,memory
+ module /vmlinuz-2.6.29-tip intel_iommu=on ro
+ root=LABEL=/ rhgb console=ttyS0,115200 3
+ module /initrd-2.6.29-tip.img
+ module /Q35_SINIT_17.BIN
+
+The kernel option for enabling Intel TXT support is found under the
+Security top-level menu and is called "Enable Intel(R) Trusted
+Execution Technology (TXT)". It is considered EXPERIMENTAL and
+depends on the generic x86 support (to allow maximum flexibility in
+kernel build options), since the tboot code will detect whether the
+platform actually supports Intel TXT and thus whether any of the
+kernel code is executed.
+
+The Q35_SINIT_17.BIN file is what Intel TXT refers to as an
+Authenticated Code Module. It is specific to the chipset in the
+system and can also be found on the Trusted Boot site. It is an
+(unencrypted) module signed by Intel that is used as part of the
+DRTM process to verify and configure the system. It is signed
+because it operates at a higher privilege level in the system than
+any other macrocode and its correct operation is critical to the
+establishment of the DRTM. The process for determining the correct
+SINIT ACM for a system is documented in the SINIT-guide.txt file
+that is on the tboot SourceForge site under the SINIT ACM downloads.