Commit Graph

2686 Commits

Author SHA1 Message Date
Linus Torvalds 3822a7c409 - Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
   memfd creation time, with the option of sealing the state of the X bit.
 
 - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
   thread-safe for pmd unshare") which addresses a rare race condition
   related to PMD unsharing.
 
 - Several folioification patch serieses from Matthew Wilcox, Vishal
   Moola, Sidhartha Kumar and Lorenzo Stoakes
 
 - Johannes Weiner has a series ("mm: push down lock_page_memcg()") which
   does perform some memcg maintenance and cleanup work.
 
 - SeongJae Park has added DAMOS filtering to DAMON, with the series
   "mm/damon/core: implement damos filter".  These filters provide users
   with finer-grained control over DAMOS's actions.  SeongJae has also done
   some DAMON cleanup work.
 
 - Kairui Song adds a series ("Clean up and fixes for swap").
 
 - Vernon Yang contributed the series "Clean up and refinement for maple
   tree".
 
 - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series.  It
   adds to MGLRU an LRU of memcgs, to improve the scalability of global
   reclaim.
 
 - David Hildenbrand has added some userfaultfd cleanup work in the
   series "mm: uffd-wp + change_protection() cleanups".
 
 - Christoph Hellwig has removed the generic_writepages() library
   function in the series "remove generic_writepages".
 
 - Baolin Wang has performed some maintenance on the compaction code in
   his series "Some small improvements for compaction".
 
 - Sidhartha Kumar is doing some maintenance work on struct page in his
   series "Get rid of tail page fields".
 
 - David Hildenbrand contributed some cleanup, bugfixing and
   generalization of pte management and of pte debugging in his series "mm:
   support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap
   PTEs".
 
 - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
   flag in the series "Discard __GFP_ATOMIC".
 
 - Sergey Senozhatsky has improved zsmalloc's memory utilization with his
   series "zsmalloc: make zspage chain size configurable".
 
 - Joey Gouly has added prctl() support for prohibiting the creation of
   writeable+executable mappings.  The previous BPF-based approach had
   shortcomings.  See "mm: In-kernel support for memory-deny-write-execute
   (MDWE)".
 
 - Waiman Long did some kmemleak cleanup and bugfixing in the series
   "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
 
 - T.J.  Alumbaugh has contributed some MGLRU cleanup work in his series
   "mm: multi-gen LRU: improve".
 
 - Jiaqi Yan has provided some enhancements to our memory error
   statistics reporting, mainly by presenting the statistics on a per-node
   basis.  See the series "Introduce per NUMA node memory error
   statistics".
 
 - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
   regression in compaction via his series "Fix excessive CPU usage during
   compaction".
 
 - Christoph Hellwig does some vmalloc maintenance work in the series
   "cleanup vfree and vunmap".
 
 - Christoph Hellwig has removed block_device_operations.rw_page() in ths
   series "remove ->rw_page".
 
 - We get some maple_tree improvements and cleanups in Liam Howlett's
   series "VMA tree type safety and remove __vma_adjust()".
 
 - Suren Baghdasaryan has done some work on the maintainability of our
   vm_flags handling in the series "introduce vm_flags modifier functions".
 
 - Some pagemap cleanup and generalization work in Mike Rapoport's series
   "mm, arch: add generic implementation of pfn_valid() for FLATMEM" and
   "fixups for generic implementation of pfn_valid()"
 
 - Baoquan He has done some work to make /proc/vmallocinfo and
   /proc/kcore better represent the real state of things in his series
   "mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
 
 - Jason Gunthorpe rationalized the GUP system's interface to the rest of
   the kernel in the series "Simplify the external interface for GUP".
 
 - SeongJae Park wishes to migrate people from DAMON's debugfs interface
   over to its sysfs interface.  To support this, we'll temporarily be
   printing warnings when people use the debugfs interface.  See the series
   "mm/damon: deprecate DAMON debugfs interface".
 
 - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
   and clean-ups" series.
 
 - Huang Ying has provided a dramatic reduction in migration's TLB flush
   IPI rates with the series "migrate_pages(): batch TLB flushing".
 
 - Arnd Bergmann has some objtool fixups in "objtool warning fixes".
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Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - Daniel Verkamp has contributed a memfd series ("mm/memfd: add
   F_SEAL_EXEC") which permits the setting of the memfd execute bit at
   memfd creation time, with the option of sealing the state of the X
   bit.

 - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
   thread-safe for pmd unshare") which addresses a rare race condition
   related to PMD unsharing.

 - Several folioification patch serieses from Matthew Wilcox, Vishal
   Moola, Sidhartha Kumar and Lorenzo Stoakes

 - Johannes Weiner has a series ("mm: push down lock_page_memcg()")
   which does perform some memcg maintenance and cleanup work.

 - SeongJae Park has added DAMOS filtering to DAMON, with the series
   "mm/damon/core: implement damos filter".

   These filters provide users with finer-grained control over DAMOS's
   actions. SeongJae has also done some DAMON cleanup work.

 - Kairui Song adds a series ("Clean up and fixes for swap").

 - Vernon Yang contributed the series "Clean up and refinement for maple
   tree".

 - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
   adds to MGLRU an LRU of memcgs, to improve the scalability of global
   reclaim.

 - David Hildenbrand has added some userfaultfd cleanup work in the
   series "mm: uffd-wp + change_protection() cleanups".

 - Christoph Hellwig has removed the generic_writepages() library
   function in the series "remove generic_writepages".

 - Baolin Wang has performed some maintenance on the compaction code in
   his series "Some small improvements for compaction".

 - Sidhartha Kumar is doing some maintenance work on struct page in his
   series "Get rid of tail page fields".

 - David Hildenbrand contributed some cleanup, bugfixing and
   generalization of pte management and of pte debugging in his series
   "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
   swap PTEs".

 - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
   flag in the series "Discard __GFP_ATOMIC".

 - Sergey Senozhatsky has improved zsmalloc's memory utilization with
   his series "zsmalloc: make zspage chain size configurable".

 - Joey Gouly has added prctl() support for prohibiting the creation of
   writeable+executable mappings.

   The previous BPF-based approach had shortcomings. See "mm: In-kernel
   support for memory-deny-write-execute (MDWE)".

 - Waiman Long did some kmemleak cleanup and bugfixing in the series
   "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".

 - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
   "mm: multi-gen LRU: improve".

 - Jiaqi Yan has provided some enhancements to our memory error
   statistics reporting, mainly by presenting the statistics on a
   per-node basis. See the series "Introduce per NUMA node memory error
   statistics".

 - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
   regression in compaction via his series "Fix excessive CPU usage
   during compaction".

 - Christoph Hellwig does some vmalloc maintenance work in the series
   "cleanup vfree and vunmap".

 - Christoph Hellwig has removed block_device_operations.rw_page() in
   ths series "remove ->rw_page".

 - We get some maple_tree improvements and cleanups in Liam Howlett's
   series "VMA tree type safety and remove __vma_adjust()".

 - Suren Baghdasaryan has done some work on the maintainability of our
   vm_flags handling in the series "introduce vm_flags modifier
   functions".

 - Some pagemap cleanup and generalization work in Mike Rapoport's
   series "mm, arch: add generic implementation of pfn_valid() for
   FLATMEM" and "fixups for generic implementation of pfn_valid()"

 - Baoquan He has done some work to make /proc/vmallocinfo and
   /proc/kcore better represent the real state of things in his series
   "mm/vmalloc.c: allow vread() to read out vm_map_ram areas".

 - Jason Gunthorpe rationalized the GUP system's interface to the rest
   of the kernel in the series "Simplify the external interface for
   GUP".

 - SeongJae Park wishes to migrate people from DAMON's debugfs interface
   over to its sysfs interface. To support this, we'll temporarily be
   printing warnings when people use the debugfs interface. See the
   series "mm/damon: deprecate DAMON debugfs interface".

 - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
   and clean-ups" series.

 - Huang Ying has provided a dramatic reduction in migration's TLB flush
   IPI rates with the series "migrate_pages(): batch TLB flushing".

 - Arnd Bergmann has some objtool fixups in "objtool warning fixes".

* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
  include/linux/migrate.h: remove unneeded externs
  mm/memory_hotplug: cleanup return value handing in do_migrate_range()
  mm/uffd: fix comment in handling pte markers
  mm: change to return bool for isolate_movable_page()
  mm: hugetlb: change to return bool for isolate_hugetlb()
  mm: change to return bool for isolate_lru_page()
  mm: change to return bool for folio_isolate_lru()
  objtool: add UACCESS exceptions for __tsan_volatile_read/write
  kmsan: disable ftrace in kmsan core code
  kasan: mark addr_has_metadata __always_inline
  mm: memcontrol: rename memcg_kmem_enabled()
  sh: initialize max_mapnr
  m68k/nommu: add missing definition of ARCH_PFN_OFFSET
  mm: percpu: fix incorrect size in pcpu_obj_full_size()
  maple_tree: reduce stack usage with gcc-9 and earlier
  mm: page_alloc: call panic() when memoryless node allocation fails
  mm: multi-gen LRU: avoid futile retries
  migrate_pages: move THP/hugetlb migration support check to simplify code
  migrate_pages: batch flushing TLB
  migrate_pages: share more code between _unmap and _move
  ...
2023-02-23 17:09:35 -08:00
Linus Torvalds f3dd0c5337 bpf: add missing header file include
Commit 74e19ef0ff ("uaccess: Add speculation barrier to
copy_from_user()") built fine on x86-64 and arm64, and that's the extent
of my local build testing.

It turns out those got the <linux/nospec.h> include incidentally through
other header files (<linux/kvm_host.h> in particular), but that was not
true of other architectures, resulting in build errors

  kernel/bpf/core.c: In function ‘___bpf_prog_run’:
  kernel/bpf/core.c:1913:3: error: implicit declaration of function ‘barrier_nospec’

so just make sure to explicitly include the proper <linux/nospec.h>
header file to make everybody see it.

Fixes: 74e19ef0ff ("uaccess: Add speculation barrier to copy_from_user()")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Viresh Kumar <viresh.kumar@linaro.org>
Reported-by: Huacai Chen <chenhuacai@loongson.cn>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-02-22 09:52:32 -08:00
Linus Torvalds 5b7c4cabbb Networking changes for 6.3.
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):
      - enetc: support XDP_REDIRECT for XDP non-linear buffers
      - enetc: improve reconfig, avoid link flap and waiting for idle
      - enetc: 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.
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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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().
  ...
2023-02-21 18:24:12 -08:00
Dave Hansen 74e19ef0ff uaccess: Add speculation barrier to copy_from_user()
The results of "access_ok()" can be mis-speculated.  The result is that
you can end speculatively:

	if (access_ok(from, size))
		// Right here

even for bad from/size combinations.  On first glance, it would be ideal
to just add a speculation barrier to "access_ok()" so that its results
can never be mis-speculated.

But there are lots of system calls just doing access_ok() via
"copy_to_user()" and friends (example: fstat() and friends).  Those are
generally not problematic because they do not _consume_ data from
userspace other than the pointer.  They are also very quick and common
system calls that should not be needlessly slowed down.

"copy_from_user()" on the other hand uses a user-controller pointer and
is frequently followed up with code that might affect caches.  Take
something like this:

	if (!copy_from_user(&kernelvar, uptr, size))
		do_something_with(kernelvar);

If userspace passes in an evil 'uptr' that *actually* points to a kernel
addresses, and then do_something_with() has cache (or other)
side-effects, it could allow userspace to infer kernel data values.

Add a barrier to the common copy_from_user() code to prevent
mis-speculated values which happen after the copy.

Also add a stub for architectures that do not define barrier_nospec().
This makes the macro usable in generic code.

Since the barrier is now usable in generic code, the x86 #ifdef in the
BPF code can also go away.

Reported-by: Jordy Zomer <jordyzomer@google.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>   # BPF bits
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-02-21 14:45:22 -08:00
Linus Torvalds 05e6295f7b fs.idmapped.v6.3
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Merge tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

Pull vfs idmapping updates from Christian Brauner:

 - Last cycle we introduced the dedicated struct mnt_idmap type for
   mount idmapping and the required infrastucture in 256c8aed2b ("fs:
   introduce dedicated idmap type for mounts"). As promised in last
   cycle's pull request message this converts everything to rely on
   struct mnt_idmap.

   Currently we still pass around the plain namespace that was attached
   to a mount. This is in general pretty convenient but it makes it easy
   to conflate namespaces that are relevant on the filesystem with
   namespaces that are relevant on the mount level. Especially for
   non-vfs developers without detailed knowledge in this area this was a
   potential source for bugs.

   This finishes the conversion. Instead of passing the plain namespace
   around this updates all places that currently take a pointer to a
   mnt_userns with a pointer to struct mnt_idmap.

   Now that the conversion is done all helpers down to the really
   low-level helpers only accept a struct mnt_idmap argument instead of
   two namespace arguments.

   Conflating mount and other idmappings will now cause the compiler to
   complain loudly thus eliminating the possibility of any bugs. This
   makes it impossible for filesystem developers to mix up mount and
   filesystem idmappings as they are two distinct types and require
   distinct helpers that cannot be used interchangeably.

   Everything associated with struct mnt_idmap is moved into a single
   separate file. With that change no code can poke around in struct
   mnt_idmap. It can only be interacted with through dedicated helpers.
   That means all filesystems are and all of the vfs is completely
   oblivious to the actual implementation of idmappings.

   We are now also able to extend struct mnt_idmap as we see fit. For
   example, we can decouple it completely from namespaces for users that
   don't require or don't want to use them at all. We can also extend
   the concept of idmappings so we can cover filesystem specific
   requirements.

   In combination with the vfs{g,u}id_t work we finished in v6.2 this
   makes this feature substantially more robust and thus difficult to
   implement wrong by a given filesystem and also protects the vfs.

 - Enable idmapped mounts for tmpfs and fulfill a longstanding request.

   A long-standing request from users had been to make it possible to
   create idmapped mounts for tmpfs. For example, to share the host's
   tmpfs mount between multiple sandboxes. This is a prerequisite for
   some advanced Kubernetes cases. Systemd also has a range of use-cases
   to increase service isolation. And there are more users of this.

   However, with all of the other work going on this was way down on the
   priority list but luckily someone other than ourselves picked this
   up.

   As usual the patch is tiny as all the infrastructure work had been
   done multiple kernel releases ago. In addition to all the tests that
   we already have I requested that Rodrigo add a dedicated tmpfs
   testsuite for idmapped mounts to xfstests. It is to be included into
   xfstests during the v6.3 development cycle. This should add a slew of
   additional tests.

* tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits)
  shmem: support idmapped mounts for tmpfs
  fs: move mnt_idmap
  fs: port vfs{g,u}id helpers to mnt_idmap
  fs: port fs{g,u}id helpers to mnt_idmap
  fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
  fs: port i_{g,u}id_{needs_}update() to mnt_idmap
  quota: port to mnt_idmap
  fs: port privilege checking helpers to mnt_idmap
  fs: port inode_owner_or_capable() to mnt_idmap
  fs: port inode_init_owner() to mnt_idmap
  fs: port acl to mnt_idmap
  fs: port xattr to mnt_idmap
  fs: port ->permission() to pass mnt_idmap
  fs: port ->fileattr_set() to pass mnt_idmap
  fs: port ->set_acl() to pass mnt_idmap
  fs: port ->get_acl() to pass mnt_idmap
  fs: port ->tmpfile() to pass mnt_idmap
  fs: port ->rename() to pass mnt_idmap
  fs: port ->mknod() to pass mnt_idmap
  fs: port ->mkdir() to pass mnt_idmap
  ...
2023-02-20 11:53:11 -08:00
Andrii Nakryiko d384dce281 bpf: Fix global subprog context argument resolution logic
KPROBE program's user-facing context type is defined as typedef
bpf_user_pt_regs_t. This leads to a problem when trying to passing
kprobe/uprobe/usdt context argument into global subprog, as kernel
always strip away mods and typedefs of user-supplied type, but takes
expected type from bpf_ctx_convert as is, which causes mismatch.

Current way to work around this is to define a fake struct with the same
name as expected typedef:

  struct bpf_user_pt_regs_t {};

  __noinline my_global_subprog(struct bpf_user_pt_regs_t *ctx) { ... }

This patch fixes the issue by resolving expected type, if it's not
a struct. It still leaves the above work-around working for backwards
compatibility.

Fixes: 91cc1a9974 ("bpf: Annotate context types")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230216045954.3002473-2-andrii@kernel.org
2023-02-17 21:20:44 +01:00
Hou Tao 997849c4b9 bpf: Zeroing allocated object from slab in bpf memory allocator
Currently the freed element in bpf memory allocator may be immediately
reused, for htab map the reuse will reinitialize special fields in map
value (e.g., bpf_spin_lock), but lookup procedure may still access
these special fields, and it may lead to hard-lockup as shown below:

 NMI backtrace for cpu 16
 CPU: 16 PID: 2574 Comm: htab.bin Tainted: G             L     6.1.0+ #1
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
 RIP: 0010:queued_spin_lock_slowpath+0x283/0x2c0
 ......
 Call Trace:
  <TASK>
  copy_map_value_locked+0xb7/0x170
  bpf_map_copy_value+0x113/0x3c0
  __sys_bpf+0x1c67/0x2780
  __x64_sys_bpf+0x1c/0x20
  do_syscall_64+0x30/0x60
  entry_SYSCALL_64_after_hwframe+0x46/0xb0
 ......
  </TASK>

For htab map, just like the preallocated case, these is no need to
initialize these special fields in map value again once these fields
have been initialized. For preallocated htab map, these fields are
initialized through __GFP_ZERO in bpf_map_area_alloc(), so do the
similar thing for non-preallocated htab in bpf memory allocator. And
there is no need to use __GFP_ZERO for per-cpu bpf memory allocator,
because __alloc_percpu_gfp() does it implicitly.

Fixes: 0fd7c5d433 ("bpf: Optimize call_rcu in non-preallocated hash map.")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20230215082132.3856544-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-15 15:40:06 -08:00
Eduard Zingerman 31ff213512 bpf: BPF_ST with variable offset should preserve STACK_ZERO marks
BPF_STX instruction preserves STACK_ZERO marks for variable offset
writes in situations like below:

  *(u64*)(r10 - 8) = 0   ; STACK_ZERO marks for fp[-8]
  r0 = random(-7, -1)    ; some random number in range of [-7, -1]
  r0 += r10              ; r0 is now a variable offset pointer to stack
  r1 = 0
  *(u8*)(r0) = r1        ; BPF_STX writing zero, STACK_ZERO mark for
                         ; fp[-8] is preserved

This commit updates verifier.c:check_stack_write_var_off() to process
BPF_ST in a similar manner, e.g. the following example:

  *(u64*)(r10 - 8) = 0   ; STACK_ZERO marks for fp[-8]
  r0 = random(-7, -1)    ; some random number in range of [-7, -1]
  r0 += r10              ; r0 is now variable offset pointer to stack
  *(u8*)(r0) = 0         ; BPF_ST writing zero, STACK_ZERO mark for
                         ; fp[-8] is preserved

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230214232030.1502829-4-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-15 11:48:47 -08:00
Eduard Zingerman ecdf985d76 bpf: track immediate values written to stack by BPF_ST instruction
For aligned stack writes using BPF_ST instruction track stored values
in a same way BPF_STX is handled, e.g. make sure that the following
commands produce similar verifier knowledge:

  fp[-8] = 42;             r1 = 42;
                       fp[-8] = r1;

This covers two cases:
 - non-null values written to stack are stored as spill of fake
   registers;
 - null values written to stack are stored as STACK_ZERO marks.

Previously both cases above used STACK_MISC marks instead.

Some verifier test cases relied on the old logic to obtain STACK_MISC
marks for some stack values. These test cases are updated in the same
commit to avoid failures during bisect.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230214232030.1502829-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-15 11:48:47 -08:00
Dave Marchevsky a40d363243 bpf: Special verifier handling for bpf_rbtree_{remove, first}
Newly-added bpf_rbtree_{remove,first} kfuncs have some special properties
that require handling in the verifier:

  * both bpf_rbtree_remove and bpf_rbtree_first return the type containing
    the bpf_rb_node field, with the offset set to that field's offset,
    instead of a struct bpf_rb_node *
    * mark_reg_graph_node helper added in previous patch generalizes
      this logic, use it

  * bpf_rbtree_remove's node input is a node that's been inserted
    in the tree - a non-owning reference.

  * bpf_rbtree_remove must invalidate non-owning references in order to
    avoid aliasing issue. Use previously-added
    invalidate_non_owning_refs helper to mark this function as a
    non-owning ref invalidation point.

  * Unlike other functions, which convert one of their input arg regs to
    non-owning reference, bpf_rbtree_first takes no arguments and just
    returns a non-owning reference (possibly null)
    * For now verifier logic for this is special-cased instead of
      adding new kfunc flag.

This patch, along with the previous one, complete special verifier
handling for all rbtree API functions added in this series.

With functional verifier handling of rbtree_remove, under current
non-owning reference scheme, a node type with both bpf_{list,rb}_node
fields could cause the verifier to accept programs which remove such
nodes from collections they haven't been added to.

In order to prevent this, this patch adds a check to btf_parse_fields
which rejects structs with both bpf_{list,rb}_node fields. This is a
temporary measure that can be removed after "collection identity"
followup. See comment added in btf_parse_fields. A linked_list BTF test
exercising the new check is added in this patch as well.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-6-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-13 19:40:53 -08:00
Dave Marchevsky 5d92ddc3de bpf: Add callback validation to kfunc verifier logic
Some BPF helpers take a callback function which the helper calls. For
each helper that takes such a callback, there's a special call to
__check_func_call with a callback-state-setting callback that sets up
verifier bpf_func_state for the callback's frame.

kfuncs don't have any of this infrastructure yet, so let's add it in
this patch, following existing helper pattern as much as possible. To
validate functionality of this added plumbing, this patch adds
callback handling for the bpf_rbtree_add kfunc and hopes to lay
groundwork for future graph datastructure callbacks.

In the "general plumbing" category we have:

  * check_kfunc_call doing callback verification right before clearing
    CALLER_SAVED_REGS, exactly like check_helper_call
  * recognition of func_ptr BTF types in kfunc args as
    KF_ARG_PTR_TO_CALLBACK + propagation of subprogno for this arg type

In the "rbtree_add / graph datastructure-specific plumbing" category:

  * Since bpf_rbtree_add must be called while the spin_lock associated
    with the tree is held, don't complain when callback's func_state
    doesn't unlock it by frame exit
  * Mark rbtree_add callback's args with ref_set_non_owning
    to prevent rbtree api functions from being called in the callback.
    Semantically this makes sense, as less() takes no ownership of its
    args when determining which comes first.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-5-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-13 19:40:53 -08:00
Dave Marchevsky cd6791b4b6 bpf: Add support for bpf_rb_root and bpf_rb_node in kfunc args
Now that we find bpf_rb_root and bpf_rb_node in structs, let's give args
that contain those types special classification and properly handle
these types when checking kfunc args.

"Properly handling" these types largely requires generalizing similar
handling for bpf_list_{head,node}, with little new logic added in this
patch.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-4-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-13 19:40:53 -08:00
Dave Marchevsky bd1279ae8a bpf: Add bpf_rbtree_{add,remove,first} kfuncs
This patch adds implementations of bpf_rbtree_{add,remove,first}
and teaches verifier about their BTF_IDs as well as those of
bpf_rb_{root,node}.

All three kfuncs have some nonstandard component to their verification
that needs to be addressed in future patches before programs can
properly use them:

  * bpf_rbtree_add:     Takes 'less' callback, need to verify it

  * bpf_rbtree_first:   Returns ptr_to_node_type(off=rb_node_off) instead
                        of ptr_to_rb_node(off=0). Return value ref is
			non-owning.

  * bpf_rbtree_remove:  Returns ptr_to_node_type(off=rb_node_off) instead
                        of ptr_to_rb_node(off=0). 2nd arg (node) is a
			non-owning reference.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-3-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-13 19:40:48 -08:00
Dave Marchevsky 9c395c1b99 bpf: Add basic bpf_rb_{root,node} support
This patch adds special BPF_RB_{ROOT,NODE} btf_field_types similar to
BPF_LIST_{HEAD,NODE}, adds the necessary plumbing to detect the new
types, and adds bpf_rb_root_free function for freeing bpf_rb_root in
map_values.

structs bpf_rb_root and bpf_rb_node are opaque types meant to
obscure structs rb_root_cached rb_node, respectively.

btf_struct_access will prevent BPF programs from touching these special
fields automatically now that they're recognized.

btf_check_and_fixup_fields now groups list_head and rb_root together as
"graph root" fields and {list,rb}_node as "graph node", and does same
ownership cycle checking as before. Note that this function does _not_
prevent ownership type mixups (e.g. rb_root owning list_node) - that's
handled by btf_parse_graph_root.

After this patch, a bpf program can have a struct bpf_rb_root in a
map_value, but not add anything to nor do anything useful with it.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-13 19:31:13 -08:00
Dave Marchevsky 6a3cd3318f bpf: Migrate release_on_unlock logic to non-owning ref semantics
This patch introduces non-owning reference semantics to the verifier,
specifically linked_list API kfunc handling. release_on_unlock logic for
refs is refactored - with small functional changes - to implement these
semantics, and bpf_list_push_{front,back} are migrated to use them.

When a list node is pushed to a list, the program still has a pointer to
the node:

  n = bpf_obj_new(typeof(*n));

  bpf_spin_lock(&l);
  bpf_list_push_back(&l, n);
  /* n still points to the just-added node */
  bpf_spin_unlock(&l);

What the verifier considers n to be after the push, and thus what can be
done with n, are changed by this patch.

Common properties both before/after this patch:
  * After push, n is only a valid reference to the node until end of
    critical section
  * After push, n cannot be pushed to any list
  * After push, the program can read the node's fields using n

Before:
  * After push, n retains the ref_obj_id which it received on
    bpf_obj_new, but the associated bpf_reference_state's
    release_on_unlock field is set to true
    * release_on_unlock field and associated logic is used to implement
      "n is only a valid ref until end of critical section"
  * After push, n cannot be written to, the node must be removed from
    the list before writing to its fields
  * After push, n is marked PTR_UNTRUSTED

After:
  * After push, n's ref is released and ref_obj_id set to 0. NON_OWN_REF
    type flag is added to reg's type, indicating that it's a non-owning
    reference.
    * NON_OWN_REF flag and logic is used to implement "n is only a
      valid ref until end of critical section"
  * n can be written to (except for special fields e.g. bpf_list_node,
    timer, ...)

Summary of specific implementation changes to achieve the above:

  * release_on_unlock field, ref_set_release_on_unlock helper, and logic
    to "release on unlock" based on that field are removed

  * The anonymous active_lock struct used by bpf_verifier_state is
    pulled out into a named struct bpf_active_lock.

  * NON_OWN_REF type flag is introduced along with verifier logic
    changes to handle non-owning refs

  * Helpers are added to use NON_OWN_REF flag to implement non-owning
    ref semantics as described above
    * invalidate_non_owning_refs - helper to clobber all non-owning refs
      matching a particular bpf_active_lock identity. Replaces
      release_on_unlock logic in process_spin_lock.
    * ref_set_non_owning - set NON_OWN_REF type flag after doing some
      sanity checking
    * ref_convert_owning_non_owning - convert owning reference w/
      specified ref_obj_id to non-owning references. Set NON_OWN_REF
      flag for each reg with that ref_obj_id and 0-out its ref_obj_id

  * Update linked_list selftests to account for minor semantic
    differences introduced by this patch
    * Writes to a release_on_unlock node ref are not allowed, while
      writes to non-owning reference pointees are. As a result the
      linked_list "write after push" failure tests are no longer scenarios
      that should fail.
    * The test##missing_lock##op and test##incorrect_lock##op
      macro-generated failure tests need to have a valid node argument in
      order to have the same error output as before. Otherwise
      verification will fail early and the expected error output won't be seen.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230212092715.1422619-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-13 13:37:37 -08:00
Yafang Shao bf39650824 bpf: allow to disable bpf prog memory accounting
We can simply disable the bpf prog memory accouting by not setting the
GFP_ACCOUNT.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-5-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-10 18:59:57 -08:00
Yafang Shao ee53cbfb1e bpf: allow to disable bpf map memory accounting
We can simply set root memcg as the map's memcg to disable bpf memory
accounting. bpf_map_area_alloc is a little special as it gets the memcg
from current rather than from the map, so we need to disable GFP_ACCOUNT
specifically for it.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-4-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-10 18:59:57 -08:00
Yafang Shao ddef81b5fd bpf: use bpf_map_kvcalloc in bpf_local_storage
Introduce new helper bpf_map_kvcalloc() for the memory allocation in
bpf_local_storage(). Then the allocation will charge the memory from the
map instead of from current, though currently they are the same thing as
it is only used in map creation path now. By charging map's memory into
the memcg from the map, it will be more clear.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-3-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-10 18:59:56 -08:00
Jakub Kicinski de42873367 bpf-next-for-netdev
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Daniel Borkmann says:

====================
pull-request: bpf-next 2023-02-11

We've added 96 non-merge commits during the last 14 day(s) which contain
a total of 152 files changed, 4884 insertions(+), 962 deletions(-).

There is a minor conflict in drivers/net/ethernet/intel/ice/ice_main.c
between commit 5b246e533d ("ice: split probe into smaller functions")
from the net-next tree and commit 66c0e13ad2 ("drivers: net: turn on
XDP features") from the bpf-next tree. Remove the hunk given ice_cfg_netdev()
is otherwise there a 2nd time, and add XDP features to the existing
ice_cfg_netdev() one:

        [...]
        ice_set_netdev_features(netdev);
        netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
                               NETDEV_XDP_ACT_XSK_ZEROCOPY;
        ice_set_ops(netdev);
        [...]

Stephen's merge conflict mail:
https://lore.kernel.org/bpf/20230207101951.21a114fa@canb.auug.org.au/

The main changes are:

1) Add support for BPF trampoline on s390x which finally allows to remove many
   test cases from the BPF CI's DENYLIST.s390x, from Ilya Leoshkevich.

2) Add multi-buffer XDP support to ice driver, from Maciej Fijalkowski.

3) Add capability to export the XDP features supported by the NIC.
   Along with that, add a XDP compliance test tool,
   from Lorenzo Bianconi & Marek Majtyka.

4) Add __bpf_kfunc tag for marking kernel functions as kfuncs,
   from David Vernet.

5) Add a deep dive documentation about the verifier's register
   liveness tracking algorithm, from Eduard Zingerman.

6) Fix and follow-up cleanups for resolve_btfids to be compiled
   as a host program to avoid cross compile issues,
   from Jiri Olsa & Ian Rogers.

7) Batch of fixes to the BPF selftest for xdp_hw_metadata which resulted
   when testing on different NICs, from Jesper Dangaard Brouer.

8) Fix libbpf to better detect kernel version code on Debian, from Hao Xiang.

9) Extend libbpf to add an option for when the perf buffer should
   wake up, from Jon Doron.

10) Follow-up fix on xdp_metadata selftest to just consume on TX
    completion, from Stanislav Fomichev.

11) Extend the kfuncs.rst document with description on kfunc
    lifecycle & stability expectations, from David Vernet.

12) Fix bpftool prog profile to skip attaching to offline CPUs,
    from Tonghao Zhang.

====================

Link: https://lore.kernel.org/r/20230211002037.8489-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-02-10 17:51:27 -08:00
Jakub Kicinski 025a785ff0 net: skbuff: drop the word head from skb cache
skbuff_head_cache is misnamed (perhaps for historical reasons?)
because it does not hold heads. Head is the buffer which skb->data
points to, and also where shinfo lives. struct sk_buff is a metadata
structure, not the head.

Eric recently added skb_small_head_cache (which allocates actual
head buffers), let that serve as an excuse to finally clean this up :)

Leave the user-space visible name intact, it could possibly be uAPI.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-02-10 09:10:28 +00:00
Suren Baghdasaryan 1c71222e5f mm: replace vma->vm_flags direct modifications with modifier calls
Replace direct modifications to vma->vm_flags with calls to modifier
functions to be able to track flag changes and to keep vma locking
correctness.

[akpm@linux-foundation.org: fix drivers/misc/open-dice.c, per Hyeonggon Yoo]
Link: https://lkml.kernel.org/r/20230126193752.297968-5-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Oskolkov <posk@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-02-09 16:51:39 -08:00
Lorenzo Bianconi b9d460c924 bpf: devmap: check XDP features in __xdp_enqueue routine
Check if the destination device implements ndo_xdp_xmit callback relying
on NETDEV_XDP_ACT_NDO_XMIT flags. Moreover, check if the destination device
supports XDP non-linear frame in __xdp_enqueue and is_valid_dst routines.
This patch allows to perform XDP_REDIRECT on non-linear XDP buffers.

Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/26a94c33520c0bfba021b3fbb2cb8c1e69bf53b8.1675245258.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-02 20:48:24 -08:00
Tobias Klauser 158e5e9eea bpf: Drop always true do_idr_lock parameter to bpf_map_free_id
The do_idr_lock parameter to bpf_map_free_id was introduced by commit
bd5f5f4ecb ("bpf: Add BPF_MAP_GET_FD_BY_ID"). However, all callers set
do_idr_lock = true since commit 1e0bd5a091 ("bpf: Switch bpf_map ref
counter to atomic64_t so bpf_map_inc() never fails").

While at it also inline __bpf_map_put into its only caller bpf_map_put
now that do_idr_lock can be dropped from its signature.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Link: https://lore.kernel.org/r/20230202141921.4424-1-tklauser@distanz.ch
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-02 20:26:12 -08:00
Jakub Kicinski 82b4a9412b Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
net/core/gro.c
  7d2c89b325 ("skb: Do mix page pool and page referenced frags in GRO")
  b1a78b9b98 ("net: add support for ipv4 big tcp")
https://lore.kernel.org/all/20230203094454.5766f160@canb.auug.org.au/

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-02-02 14:49:55 -08:00
David Vernet 400031e05a bpf: Add __bpf_kfunc tag to all kfuncs
Now that we have the __bpf_kfunc tag, we should use add it to all
existing kfuncs to ensure that they'll never be elided in LTO builds.

Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230201173016.342758-4-void@manifault.com
2023-02-02 00:25:14 +01:00
Ilya Leoshkevich 49f67f393f bpf: btf: Add BTF_FMODEL_SIGNED_ARG flag
s390x eBPF JIT needs to know whether a function return value is signed
and which function arguments are signed, in order to generate code
compliant with the s390x ABI.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230128000650.1516334-26-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-28 12:45:15 -08:00
Ilya Leoshkevich 0f0e5f5bd5 bpf: iterators: Split iterators.lskel.h into little- and big- endian versions
iterators.lskel.h is little-endian, therefore bpf iterator is currently
broken on big-endian systems. Introduce a big-endian version and add
instructions regarding its generation. Unfortunately bpftool's
cross-endianness capabilities are limited to BTF right now, so the
procedure requires access to a big-endian machine or a configured
emulator.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230128000650.1516334-25-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-28 12:45:15 -08:00
David Vernet cb4a21ea59 bpf: Build-time assert that cpumask offset is zero
The first element of a struct bpf_cpumask is a cpumask_t. This is done
to allow struct bpf_cpumask to be cast to a struct cpumask. If this
element were ever moved to another field, any BPF program passing a
struct bpf_cpumask * to a kfunc expecting a const struct cpumask * would
immediately fail to load. Add a build-time assertion so this is
assumption is captured and verified.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230128141537.100777-1-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-28 12:21:40 -08:00
Jakub Kicinski 2d104c390f bpf-next-for-netdev
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Daniel Borkmann says:

====================
bpf-next 2023-01-28

We've added 124 non-merge commits during the last 22 day(s) which contain
a total of 124 files changed, 6386 insertions(+), 1827 deletions(-).

The main changes are:

1) Implement XDP hints via kfuncs with initial support for RX hash and
   timestamp metadata kfuncs, from Stanislav Fomichev and
   Toke Høiland-Jørgensen.
   Measurements on overhead: https://lore.kernel.org/bpf/875yellcx6.fsf@toke.dk

2) Extend libbpf's bpf_tracing.h support for tracing arguments of
   kprobes/uprobes and syscall as a special case, from Andrii Nakryiko.

3) Significantly reduce the search time for module symbols by livepatch
   and BPF, from Jiri Olsa and Zhen Lei.

4) 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, from David Vernet.

5) Fix several issues in the dynptr processing such as stack slot liveness
   propagation, missing checks for PTR_TO_STACK variable offset, etc,
   from Kumar Kartikeya Dwivedi.

6) Various performance improvements, fixes, and introduction of more
   than just one XDP program to XSK selftests, from Magnus Karlsson.

7) Big batch to BPF samples to reduce deprecated functionality,
   from Daniel T. Lee.

8) Enable struct_ops programs to be sleepable in verifier,
   from David Vernet.

9) Reduce pr_warn() noise on BTF mismatches when they are expected under
   the CONFIG_MODULE_ALLOW_BTF_MISMATCH config anyway, from Connor O'Brien.

10) Describe modulo and division by zero behavior of the BPF runtime
    in BPF's instruction specification document, from Dave Thaler.

11) Several improvements to libbpf API documentation in libbpf.h,
    from Grant Seltzer.

12) Improve resolve_btfids header dependencies related to subcmd and add
    proper support for HOSTCC, from Ian Rogers.

13) Add ipip6 and ip6ip decapsulation support for bpf_skb_adjust_room()
    helper along with BPF selftests, from Ziyang Xuan.

14) Simplify the parsing logic of structure parameters for BPF trampoline
    in the x86-64 JIT compiler, from Pu Lehui.

15) Get BTF working for kernels with CONFIG_RUST enabled by excluding
    Rust compilation units with pahole, from Martin Rodriguez Reboredo.

16) Get bpf_setsockopt() working for kTLS on top of TCP sockets,
    from Kui-Feng Lee.

17) Disable stack protection for BPF objects in bpftool given BPF backends
    don't support it, from Holger Hoffstätte.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (124 commits)
  selftest/bpf: Make crashes more debuggable in test_progs
  libbpf: Add documentation to map pinning API functions
  libbpf: Fix malformed documentation formatting
  selftests/bpf: Properly enable hwtstamp in xdp_hw_metadata
  selftests/bpf: Calls bpf_setsockopt() on a ktls enabled socket.
  bpf: Check the protocol of a sock to agree the calls to bpf_setsockopt().
  bpf/selftests: Verify struct_ops prog sleepable behavior
  bpf: Pass const struct bpf_prog * to .check_member
  libbpf: Support sleepable struct_ops.s section
  bpf: Allow BPF_PROG_TYPE_STRUCT_OPS programs to be sleepable
  selftests/bpf: Fix vmtest static compilation error
  tools/resolve_btfids: Alter how HOSTCC is forced
  tools/resolve_btfids: Install subcmd headers
  bpf/docs: Document the nocast aliasing behavior of ___init
  bpf/docs: Document how nested trusted fields may be defined
  bpf/docs: Document cpumask kfuncs in a new file
  selftests/bpf: Add selftest suite for cpumask kfuncs
  selftests/bpf: Add nested trust selftests suite
  bpf: Enable cpumasks to be queried and used as kptrs
  bpf: Disallow NULLable pointers for trusted kfuncs
  ...
====================

Link: https://lore.kernel.org/r/20230128004827.21371-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-01-28 00:00:14 -08:00
Kui-Feng Lee 5416c9aea8 bpf: Fix the kernel crash caused by bpf_setsockopt().
The kernel crash was caused by a BPF program attached to the
"lsm_cgroup/socket_sock_rcv_skb" hook, which performed a call to
`bpf_setsockopt()` in order to set the TCP_NODELAY flag as an
example. Flags like TCP_NODELAY can prompt the kernel to flush a
socket's outgoing queue, and this hook
"lsm_cgroup/socket_sock_rcv_skb" is frequently triggered by
softirqs. The issue was that in certain circumstances, when
`tcp_write_xmit()` was called to flush the queue, it would also allow
BH (bottom-half) to run. This could lead to our program attempting to
flush the same socket recursively, which caused a `skbuff` to be
unlinked twice.

`security_sock_rcv_skb()` is triggered by `tcp_filter()`. This occurs
before the sock ownership is checked in `tcp_v4_rcv()`. Consequently,
if a bpf program runs on `security_sock_rcv_skb()` while under softirq
conditions, it may not possess the lock needed for `bpf_setsockopt()`,
thus presenting an issue.

The patch fixes this issue by ensuring that a BPF program attached to
the "lsm_cgroup/socket_sock_rcv_skb" hook is not allowed to call
`bpf_setsockopt()`.

The differences from v1 are
 - changing commit log to explain holding the lock of the sock,
 - emphasizing that TCP_NODELAY is not the only flag, and
 - adding the fixes tag.

v1: https://lore.kernel.org/bpf/20230125000244.1109228-1-kuifeng@meta.com/

Signed-off-by: Kui-Feng Lee <kuifeng@meta.com>
Fixes: 9113d7e48e ("bpf: expose bpf_{g,s}etsockopt to lsm cgroup")
Link: https://lore.kernel.org/r/20230127001732.4162630-1-kuifeng@meta.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-01-26 23:26:40 -08:00
David Vernet 51a52a29eb bpf: Pass const struct bpf_prog * to .check_member
The .check_member field of struct bpf_struct_ops is currently passed the
member's btf_type via const struct btf_type *t, and a const struct
btf_member *member. This allows the struct_ops implementation to check
whether e.g. an ops is supported, but it would be useful to also enforce
that the struct_ops prog being loaded for that member has other
qualities, like being sleepable (or not). This patch therefore updates
the .check_member() callback to also take a const struct bpf_prog *prog
argument.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125164735.785732-4-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-25 10:25:57 -08:00
David Vernet 1e12d3ef47 bpf: Allow BPF_PROG_TYPE_STRUCT_OPS programs to be sleepable
BPF struct_ops programs currently cannot be marked as sleepable. This
need not be the case -- struct_ops programs can be sleepable, and e.g.
invoke kfuncs that export the KF_SLEEPABLE flag. So as to allow future
struct_ops programs to invoke such kfuncs, this patch updates the
verifier to allow struct_ops programs to be sleepable. A follow-on patch
will add support to libbpf for specifying struct_ops.s as a sleepable
struct_ops program, and then another patch will add testcases to the
dummy_st_ops selftest suite which test sleepable struct_ops behavior.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125164735.785732-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-25 10:25:57 -08:00
David Vernet bdbda39584 bpf/docs: Document cpumask kfuncs in a new file
Now that we've added a series of new cpumask kfuncs, we should document
them so users can easily use them. This patch adds a new cpumasks.rst
file to document them.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125143816.721952-6-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-25 07:57:50 -08:00
David Vernet 516f4d3397 bpf: Enable cpumasks to be queried and used as kptrs
Certain programs may wish to be able to query cpumasks. For example, if
a program that is tracing percpu operations wishes to track which tasks
end up running on which CPUs, it could be useful to associate that with
the tasks' cpumasks. Similarly, programs tracking NUMA allocations, CPU
scheduling domains, etc, could potentially benefit from being able to
see which CPUs a task could be migrated to.

This patch enables these types of use cases by introducing a series of
bpf_cpumask_* kfuncs. Amongst these kfuncs, there are two separate
"classes" of operations:

1. kfuncs which allow the caller to allocate and mutate their own
   cpumask kptrs in the form of a struct bpf_cpumask * object. Such
   kfuncs include e.g. bpf_cpumask_create() to allocate the cpumask, and
   bpf_cpumask_or() to mutate it. "Regular" cpumasks such as p->cpus_ptr
   may not be passed to these kfuncs, and the verifier will ensure this
   is the case by comparing BTF IDs.

2. Read-only operations which operate on const struct cpumask *
   arguments. For example, bpf_cpumask_test_cpu(), which tests whether a
   CPU is set in the cpumask. Any trusted struct cpumask * or struct
   bpf_cpumask * may be passed to these kfuncs. The verifier allows
   struct bpf_cpumask * even though the kfunc is defined with struct
   cpumask * because the first element of a struct bpf_cpumask is a
   cpumask_t, so it is safe to cast.

A follow-on patch will add selftests which validate these kfuncs, and
another will document them.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125143816.721952-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-25 07:57:49 -08:00
David Vernet caf713c338 bpf: Disallow NULLable pointers for trusted kfuncs
KF_TRUSTED_ARGS kfuncs currently have a subtle and insidious bug in
validating pointers to scalars. Say that you have a kfunc like the
following, which takes an array as the first argument:

bool bpf_cpumask_empty(const struct cpumask *cpumask)
{
	return cpumask_empty(cpumask);
}

...
BTF_ID_FLAGS(func, bpf_cpumask_empty, KF_TRUSTED_ARGS)
...

If a BPF program were to invoke the kfunc with a NULL argument, it would
crash the kernel. The reason is that struct cpumask is defined as a
bitmap, which is itself defined as an array, and is accessed as a memory
address by bitmap operations. So when the verifier analyzes the
register, it interprets it as a pointer to a scalar struct, which is an
array of size 8. check_mem_reg() then sees that the register is NULL and
returns 0, and the kfunc crashes when it passes it down to the cpumask
wrappers.

To fix this, this patch adds a check for KF_ARG_PTR_TO_MEM which
verifies that the register doesn't contain a possibly-NULL pointer if
the kfunc is KF_TRUSTED_ARGS.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230125143816.721952-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-25 07:57:49 -08:00
David Vernet b613d335a7 bpf: Allow trusted args to walk struct when checking BTF IDs
When validating BTF types for KF_TRUSTED_ARGS kfuncs, the verifier
currently enforces that the top-level type must match when calling
the kfunc. In other words, the verifier does not allow the BPF program
to pass a bitwise equivalent struct, despite it being allowed according
to the C standard.

For example, if you have the following type:

struct  nf_conn___init {
	struct nf_conn ct;
};

The C standard stipulates that it would be safe to pass a struct
nf_conn___init to a kfunc expecting a struct nf_conn. The verifier
currently disallows this, however, as semantically kfuncs may want to
enforce that structs that have equivalent types according to the C
standard, but have different BTF IDs, are not able to be passed to
kfuncs expecting one or the other. For example, struct nf_conn___init
may not be queried / looked up, as it is allocated but may not yet be
fully initialized.

On the other hand, being able to pass types that are equivalent
according to the C standard will be useful for other types of kfunc /
kptrs enabled by BPF.  For example, in a follow-on patch, a series of
kfuncs will be added which allow programs to do bitwise queries on
cpumasks that are either allocated by the program (in which case they'll
be a 'struct bpf_cpumask' type that wraps a cpumask_t as its first
element), or a cpumask that was allocated by the main kernel (in which
case it will just be a straight cpumask_t, as in task->cpus_ptr).

Having the two types of cpumasks allows us to distinguish between the
two for when a cpumask is read-only vs. mutatable. A struct bpf_cpumask
can be mutated by e.g. bpf_cpumask_clear(), whereas a regular cpumask_t
cannot be. On the other hand, a struct bpf_cpumask can of course be
queried in the exact same manner as a cpumask_t, with e.g.
bpf_cpumask_test_cpu().

If we were to enforce that top level types match, then a user that's
passing a struct bpf_cpumask to a read-only cpumask_t argument would
have to cast with something like bpf_cast_to_kern_ctx() (which itself
would need to be updated to expect the alias, and currently it only
accommodates a single alias per prog type). Additionally, not specifying
KF_TRUSTED_ARGS is not an option, as some kfuncs take one argument as a
struct bpf_cpumask *, and another as a struct cpumask *
(i.e. cpumask_t).

In order to enable this, this patch relaxes the constraint that a
KF_TRUSTED_ARGS kfunc must have strict type matching, and instead only
enforces strict type matching if a type is observed to be a "no-cast
alias" (i.e., that the type names are equivalent, but one is suffixed
with ___init).

Additionally, in order to try and be conservative and match existing
behavior / expectations, this patch also enforces strict type checking
for acquire kfuncs. We were already enforcing it for release kfuncs, so
this should also improve the consistency of the semantics for kfuncs.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230120192523.3650503-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-24 20:15:13 -08:00
David Vernet 57539b1c0a bpf: Enable annotating trusted nested pointers
In kfuncs, a "trusted" pointer is a pointer that the kfunc can assume is
safe, and which the verifier will allow to be passed to a
KF_TRUSTED_ARGS kfunc. Currently, a KF_TRUSTED_ARGS kfunc disallows any
pointer to be passed at a nonzero offset, but sometimes this is in fact
safe if the "nested" pointer's lifetime is inherited from its parent.
For example, the const cpumask_t *cpus_ptr field in a struct task_struct
will remain valid until the task itself is destroyed, and thus would
also be safe to pass to a KF_TRUSTED_ARGS kfunc.

While it would be conceptually simple to enable this by using BTF tags,
gcc unfortunately does not yet support this. In the interim, this patch
enables support for this by using a type-naming convention. A new
BTF_TYPE_SAFE_NESTED macro is defined in verifier.c which allows a
developer to specify the nested fields of a type which are considered
trusted if its parent is also trusted. The verifier is also updated to
account for this. A patch with selftests will be added in a follow-on
change, along with documentation for this feature.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230120192523.3650503-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-24 20:15:01 -08:00
Toke Høiland-Jørgensen fd7c211d68 bpf: Support consuming XDP HW metadata from fext programs
Instead of rejecting the attaching of PROG_TYPE_EXT programs to XDP
programs that consume HW metadata, implement support for propagating the
offload information. The extension program doesn't need to set a flag or
ifindex, these will just be propagated from the target by the verifier.
We need to create a separate offload object for the extension program,
though, since it can be reattached to a different program later (which
means we can't just inherit the offload information from the target).

An additional check is added on attach that the new target is compatible
with the offload information in the extension prog.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-9-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-01-23 09:38:11 -08:00
Stanislav Fomichev 3d76a4d3d4 bpf: XDP metadata RX kfuncs
Define a new kfunc set (xdp_metadata_kfunc_ids) which implements all possible
XDP metatada kfuncs. Not all devices have to implement them. If kfunc is not
supported by the target device, the default implementation is called instead.
The verifier, at load time, replaces a call to the generic kfunc with a call
to the per-device one. Per-device kfunc pointers are stored in separate
struct xdp_metadata_ops.

Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-8-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-01-23 09:38:11 -08:00
Stanislav Fomichev 2b3486bc2d bpf: Introduce device-bound XDP programs
New flag BPF_F_XDP_DEV_BOUND_ONLY plus all the infra to have a way
to associate a netdev with a BPF program at load time.

netdevsim checks are dropped in favor of generic check in dev_xdp_attach.

Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-6-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-01-23 09:38:10 -08:00
Stanislav Fomichev 89bbc53a4d bpf: Reshuffle some parts of bpf/offload.c
To avoid adding forward declarations in the main patch, shuffle
some code around. No functional changes.

Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-5-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-01-23 09:38:10 -08:00
Stanislav Fomichev f1fc43d039 bpf: Move offload initialization into late_initcall
So we don't have to initialize it manually from several paths.

Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-4-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-01-23 09:38:10 -08:00
Stanislav Fomichev 9d03ebc71a bpf: Rename bpf_{prog,map}_is_dev_bound to is_offloaded
BPF offloading infra will be reused to implement
bound-but-not-offloaded bpf programs. Rename existing
helpers for clarity. No functional changes.

Cc: John Fastabend <john.fastabend@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Anatoly Burakov <anatoly.burakov@intel.com>
Cc: Alexander Lobakin <alexandr.lobakin@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@gmail.com>
Cc: Maryam Tahhan <mtahhan@redhat.com>
Cc: xdp-hints@xdp-project.net
Cc: netdev@vger.kernel.org
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230119221536.3349901-3-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-01-23 09:38:10 -08:00
Kumar Kartikeya Dwivedi 1ee72bcbe4 bpf: Avoid recomputing spi in process_dynptr_func
Currently, process_dynptr_func first calls dynptr_get_spi and then
is_dynptr_reg_valid_init and is_dynptr_reg_valid_uninit have to call it
again to obtain the spi value. Instead of doing this twice, reuse the
already obtained value (which is by default 0, and is only set for
PTR_TO_STACK, and only used in that case in aforementioned functions).
The input value for these two functions will either be -ERANGE or >= 1,
and can either be permitted or rejected based on the respective check.

Suggested-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-8-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-20 17:55:03 -08:00
Kumar Kartikeya Dwivedi f5b625e5f8 bpf: Combine dynptr_get_spi and is_spi_bounds_valid
Currently, a check on spi resides in dynptr_get_spi, while others
checking its validity for being within the allocated stack slots happens
in is_spi_bounds_valid. Almost always barring a couple of cases (where
being beyond allocated stack slots is not an error as stack slots need
to be populated), both are used together to make checks. Hence, subsume
the is_spi_bounds_valid check in dynptr_get_spi, and return -ERANGE to
specially distinguish the case where spi is valid but not within
allocated slots in the stack state.

The is_spi_bounds_valid function is still kept around as it is a generic
helper that will be useful for other objects on stack similar to dynptr
in the future.

Suggested-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-20 17:55:03 -08:00
Kumar Kartikeya Dwivedi 379d4ba831 bpf: Allow reinitializing unreferenced dynptr stack slots
Consider a program like below:

void prog(void)
{
	{
		struct bpf_dynptr ptr;
		bpf_dynptr_from_mem(...);
	}
	...
	{
		struct bpf_dynptr ptr;
		bpf_dynptr_from_mem(...);
	}
}

Here, the C compiler based on lifetime rules in the C standard would be
well within in its rights to share stack storage for dynptr 'ptr' as
their lifetimes do not overlap in the two distinct scopes. Currently,
such an example would be rejected by the verifier, but this is too
strict. Instead, we should allow reinitializing over dynptr stack slots
and forget information about the old dynptr object.

The destroy_if_dynptr_stack_slot function already makes necessary checks
to avoid overwriting referenced dynptr slots. This is done to present a
better error message instead of forgetting dynptr information on stack
and preserving reference state, leading to an inevitable but
undecipherable error at the end about an unreleased reference which has
to be associated back to its allocating call instruction to make any
sense to the user.

Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-20 17:55:03 -08:00
Kumar Kartikeya Dwivedi f8064ab90d bpf: Invalidate slices on destruction of dynptrs on stack
The previous commit implemented destroy_if_dynptr_stack_slot. It
destroys the dynptr which given spi belongs to, but still doesn't
invalidate the slices that belong to such a dynptr. While for the case
of referenced dynptr, we don't allow their overwrite and return an error
early, we still allow it and destroy the dynptr for unreferenced dynptr.

To be able to enable precise and scoped invalidation of dynptr slices in
this case, we must be able to associate the source dynptr of slices that
have been obtained using bpf_dynptr_data. When doing destruction, only
slices belonging to the dynptr being destructed should be invalidated,
and nothing else. Currently, dynptr slices belonging to different
dynptrs are indistinguishible.

Hence, allocate a unique id to each dynptr (CONST_PTR_TO_DYNPTR and
those on stack). This will be stored as part of reg->id. Whenever using
bpf_dynptr_data, transfer this unique dynptr id to the returned
PTR_TO_MEM_OR_NULL slice pointer, and store it in a new per-PTR_TO_MEM
dynptr_id register state member.

Finally, after establishing such a relationship between dynptrs and
their slices, implement precise invalidation logic that only invalidates
slices belong to the destroyed dynptr in destroy_if_dynptr_stack_slot.

Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-20 17:55:03 -08:00
Kumar Kartikeya Dwivedi ef8fc7a07c bpf: Fix partial dynptr stack slot reads/writes
Currently, while reads are disallowed for dynptr stack slots, writes are
not. Reads don't work from both direct access and helpers, while writes
do work in both cases, but have the effect of overwriting the slot_type.

While this is fine, handling for a few edge cases is missing. Firstly,
a user can overwrite the stack slots of dynptr partially.

Consider the following layout:
spi: [d][d][?]
      2  1  0

First slot is at spi 2, second at spi 1.
Now, do a write of 1 to 8 bytes for spi 1.

This will essentially either write STACK_MISC for all slot_types or
STACK_MISC and STACK_ZERO (in case of size < BPF_REG_SIZE partial write
of zeroes). The end result is that slot is scrubbed.

Now, the layout is:
spi: [d][m][?]
      2  1  0

Suppose if user initializes spi = 1 as dynptr.
We get:
spi: [d][d][d]
      2  1  0

But this time, both spi 2 and spi 1 have first_slot = true.

Now, when passing spi 2 to dynptr helper, it will consider it as
initialized as it does not check whether second slot has first_slot ==
false. And spi 1 should already work as normal.

This effectively replaced size + offset of first dynptr, hence allowing
invalid OOB reads and writes.

Make a few changes to protect against this:
When writing to PTR_TO_STACK using BPF insns, when we touch spi of a
STACK_DYNPTR type, mark both first and second slot (regardless of which
slot we touch) as STACK_INVALID. Reads are already prevented.

Second, prevent writing	to stack memory from helpers if the range may
contain any STACK_DYNPTR slots. Reads are already prevented.

For helpers, we cannot allow it to destroy dynptrs from the writes as
depending on arguments, helper may take uninit_mem and dynptr both at
the same time. This would mean that helper may write to uninit_mem
before it reads the dynptr, which would be bad.

PTR_TO_MEM: [?????dd]

Depending on the code inside the helper, it may end up overwriting the
dynptr contents first and then read those as the dynptr argument.

Verifier would only simulate destruction when it does byte by byte
access simulation in check_helper_call for meta.access_size, and
fail to catch this case, as it happens after argument checks.

The same would need to be done for any other non-trivial objects created
on the stack in the future, such as bpf_list_head on stack, or
bpf_rb_root on stack.

A common misunderstanding in the current code is that MEM_UNINIT means
writes, but note that writes may also be performed even without
MEM_UNINIT in case of helpers, in that case the code after handling meta
&& meta->raw_mode will complain when it sees STACK_DYNPTR. So that
invalid read case also covers writes to potential STACK_DYNPTR slots.
The only loophole was in case of meta->raw_mode which simulated writes
through instructions which could overwrite them.

A future series sequenced after this will focus on the clean up of
helper access checks and bugs around that.

Fixes: 97e03f5210 ("bpf: Add verifier support for dynptrs")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-20 17:55:03 -08:00
Kumar Kartikeya Dwivedi 79168a669d bpf: Fix missing var_off check for ARG_PTR_TO_DYNPTR
Currently, the dynptr function is not checking the variable offset part
of PTR_TO_STACK that it needs to check. The fixed offset is considered
when computing the stack pointer index, but if the variable offset was
not a constant (such that it could not be accumulated in reg->off), we
will end up a discrepency where runtime pointer does not point to the
actual stack slot we mark as STACK_DYNPTR.

It is impossible to precisely track dynptr state when variable offset is
not constant, hence, just like bpf_timer, kptr, bpf_spin_lock, etc.
simply reject the case where reg->var_off is not constant. Then,
consider both reg->off and reg->var_off.value when computing the stack
pointer index.

A new helper dynptr_get_spi is introduced to hide over these details
since the dynptr needs to be located in multiple places outside the
process_dynptr_func checks, hence once we know it's a PTR_TO_STACK, we
need to enforce these checks in all places.

Note that it is disallowed for unprivileged users to have a non-constant
var_off, so this problem should only be possible to trigger from
programs having CAP_PERFMON. However, its effects can vary.

Without the fix, it is possible to replace the contents of the dynptr
arbitrarily by making verifier mark different stack slots than actual
location and then doing writes to the actual stack address of dynptr at
runtime.

Fixes: 97e03f5210 ("bpf: Add verifier support for dynptrs")
Acked-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-20 17:55:02 -08:00
Kumar Kartikeya Dwivedi d6fefa1105 bpf: Fix state pruning for STACK_DYNPTR stack slots
The root of the problem is missing liveness marking for STACK_DYNPTR
slots. This leads to all kinds of problems inside stacksafe.

The verifier by default inside stacksafe ignores spilled_ptr in stack
slots which do not have REG_LIVE_READ marks. Since this is being checked
in the 'old' explored state, it must have already done clean_live_states
for this old bpf_func_state. Hence, it won't be receiving any more
liveness marks from to be explored insns (it has received REG_LIVE_DONE
marking from liveness point of view).

What this means is that verifier considers that it's safe to not compare
the stack slot if was never read by children states. While liveness
marks are usually propagated correctly following the parentage chain for
spilled registers (SCALAR_VALUE and PTR_* types), the same is not the
case for STACK_DYNPTR.

clean_live_states hence simply rewrites these stack slots to the type
STACK_INVALID since it sees no REG_LIVE_READ marks.

The end result is that we will never see STACK_DYNPTR slots in explored
state. Even if verifier was conservatively matching !REG_LIVE_READ
slots, very next check continuing the stacksafe loop on seeing
STACK_INVALID would again prevent further checks.

Now as long as verifier stores an explored state which we can compare to
when reaching a pruning point, we can abuse this bug to make verifier
prune search for obviously unsafe paths using STACK_DYNPTR slots
thinking they are never used hence safe.

Doing this in unprivileged mode is a bit challenging. add_new_state is
only set when seeing BPF_F_TEST_STATE_FREQ (which requires privileges)
or when jmps_processed difference is >= 2 and insn_processed difference
is >= 8. So coming up with the unprivileged case requires a little more
work, but it is still totally possible. The test case being discussed
below triggers the heuristic even in unprivileged mode.

However, it no longer works since commit
8addbfc7b3 ("bpf: Gate dynptr API behind CAP_BPF").

Let's try to study the test step by step.

Consider the following program (C style BPF ASM):

0  r0 = 0;
1  r6 = &ringbuf_map;
3  r1 = r6;
4  r2 = 8;
5  r3 = 0;
6  r4 = r10;
7  r4 -= -16;
8  call bpf_ringbuf_reserve_dynptr;
9  if r0 == 0 goto pc+1;
10 goto pc+1;
11 *(r10 - 16) = 0xeB9F;
12 r1 = r10;
13 r1 -= -16;
14 r2 = 0;
15 call bpf_ringbuf_discard_dynptr;
16 r0 = 0;
17 exit;

We know that insn 12 will be a pruning point, hence if we force
add_new_state for it, it will first verify the following path as
safe in straight line exploration:
0 1 3 4 5 6 7 8 9 -> 10 -> (12) 13 14 15 16 17

Then, when we arrive at insn 12 from the following path:
0 1 3 4 5 6 7 8 9 -> 11 (12)

We will find a state that has been verified as safe already at insn 12.
Since register state is same at this point, regsafe will pass. Next, in
stacksafe, for spi = 0 and spi = 1 (location of our dynptr) is skipped
seeing !REG_LIVE_READ. The rest matches, so stacksafe returns true.
Next, refsafe is also true as reference state is unchanged in both
states.

The states are considered equivalent and search is pruned.

Hence, we are able to construct a dynptr with arbitrary contents and use
the dynptr API to operate on this arbitrary pointer and arbitrary size +
offset.

To fix this, first define a mark_dynptr_read function that propagates
liveness marks whenever a valid initialized dynptr is accessed by dynptr
helpers. REG_LIVE_WRITTEN is marked whenever we initialize an
uninitialized dynptr. This is done in mark_stack_slots_dynptr. It allows
screening off mark_reg_read and not propagating marks upwards from that
point.

This ensures that we either set REG_LIVE_READ64 on both dynptr slots, or
none, so clean_live_states either sets both slots to STACK_INVALID or
none of them. This is the invariant the checks inside stacksafe rely on.

Next, do a complete comparison of both stack slots whenever they have
STACK_DYNPTR. Compare the dynptr type stored in the spilled_ptr, and
also whether both form the same first_slot. Only then is the later path
safe.

Fixes: 97e03f5210 ("bpf: Add verifier support for dynptrs")
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230121002241.2113993-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-20 17:55:02 -08:00