From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 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(). ... --- Documentation/bpf/prog_cgroup_sysctl.rst | 125 +++++++++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 Documentation/bpf/prog_cgroup_sysctl.rst (limited to 'Documentation/bpf/prog_cgroup_sysctl.rst') diff --git a/Documentation/bpf/prog_cgroup_sysctl.rst b/Documentation/bpf/prog_cgroup_sysctl.rst new file mode 100644 index 000000000..677d6c637 --- /dev/null +++ b/Documentation/bpf/prog_cgroup_sysctl.rst @@ -0,0 +1,125 @@ +.. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +=========================== +BPF_PROG_TYPE_CGROUP_SYSCTL +=========================== + +This document describes ``BPF_PROG_TYPE_CGROUP_SYSCTL`` program type that +provides cgroup-bpf hook for sysctl. + +The hook has to be attached to a cgroup and will be called every time a +process inside that cgroup tries to read from or write to sysctl knob in proc. + +1. Attach type +************** + +``BPF_CGROUP_SYSCTL`` attach type has to be used to attach +``BPF_PROG_TYPE_CGROUP_SYSCTL`` program to a cgroup. + +2. Context +********** + +``BPF_PROG_TYPE_CGROUP_SYSCTL`` provides access to the following context from +BPF program:: + + struct bpf_sysctl { + __u32 write; + __u32 file_pos; + }; + +* ``write`` indicates whether sysctl value is being read (``0``) or written + (``1``). This field is read-only. + +* ``file_pos`` indicates file position sysctl is being accessed at, read + or written. This field is read-write. Writing to the field sets the starting + position in sysctl proc file ``read(2)`` will be reading from or ``write(2)`` + will be writing to. Writing zero to the field can be used e.g. to override + whole sysctl value by ``bpf_sysctl_set_new_value()`` on ``write(2)`` even + when it's called by user space on ``file_pos > 0``. Writing non-zero + value to the field can be used to access part of sysctl value starting from + specified ``file_pos``. Not all sysctl support access with ``file_pos != + 0``, e.g. writes to numeric sysctl entries must always be at file position + ``0``. See also ``kernel.sysctl_writes_strict`` sysctl. + +See `linux/bpf.h`_ for more details on how context field can be accessed. + +3. Return code +************** + +``BPF_PROG_TYPE_CGROUP_SYSCTL`` program must return one of the following +return codes: + +* ``0`` means "reject access to sysctl"; +* ``1`` means "proceed with access". + +If program returns ``0`` user space will get ``-1`` from ``read(2)`` or +``write(2)`` and ``errno`` will be set to ``EPERM``. + +4. Helpers +********** + +Since sysctl knob is represented by a name and a value, sysctl specific BPF +helpers focus on providing access to these properties: + +* ``bpf_sysctl_get_name()`` to get sysctl name as it is visible in + ``/proc/sys`` into provided by BPF program buffer; + +* ``bpf_sysctl_get_current_value()`` to get string value currently held by + sysctl into provided by BPF program buffer. This helper is available on both + ``read(2)`` from and ``write(2)`` to sysctl; + +* ``bpf_sysctl_get_new_value()`` to get new string value currently being + written to sysctl before actual write happens. This helper can be used only + on ``ctx->write == 1``; + +* ``bpf_sysctl_set_new_value()`` to override new string value currently being + written to sysctl before actual write happens. Sysctl value will be + overridden starting from the current ``ctx->file_pos``. If the whole value + has to be overridden BPF program can set ``file_pos`` to zero before calling + to the helper. This helper can be used only on ``ctx->write == 1``. New + string value set by the helper is treated and verified by kernel same way as + an equivalent string passed by user space. + +BPF program sees sysctl value same way as user space does in proc filesystem, +i.e. as a string. Since many sysctl values represent an integer or a vector +of integers, the following helpers can be used to get numeric value from the +string: + +* ``bpf_strtol()`` to convert initial part of the string to long integer + similar to user space `strtol(3)`_; +* ``bpf_strtoul()`` to convert initial part of the string to unsigned long + integer similar to user space `strtoul(3)`_; + +See `linux/bpf.h`_ for more details on helpers described here. + +5. Examples +*********** + +See `test_sysctl_prog.c`_ for an example of BPF program in C that access +sysctl name and value, parses string value to get vector of integers and uses +the result to make decision whether to allow or deny access to sysctl. + +6. Notes +******** + +``BPF_PROG_TYPE_CGROUP_SYSCTL`` is intended to be used in **trusted** root +environment, for example to monitor sysctl usage or catch unreasonable values +an application, running as root in a separate cgroup, is trying to set. + +Since `task_dfl_cgroup(current)` is called at `sys_read` / `sys_write` time it +may return results different from that at `sys_open` time, i.e. process that +opened sysctl file in proc filesystem may differ from process that is trying +to read from / write to it and two such processes may run in different +cgroups, what means ``BPF_PROG_TYPE_CGROUP_SYSCTL`` should not be used as a +security mechanism to limit sysctl usage. + +As with any cgroup-bpf program additional care should be taken if an +application running as root in a cgroup should not be allowed to +detach/replace BPF program attached by administrator. + +.. Links +.. _linux/bpf.h: ../../include/uapi/linux/bpf.h +.. _strtol(3): http://man7.org/linux/man-pages/man3/strtol.3p.html +.. _strtoul(3): http://man7.org/linux/man-pages/man3/strtoul.3p.html +.. _test_sysctl_prog.c: + ../../tools/testing/selftests/bpf/progs/test_sysctl_prog.c -- cgit v1.2.3