pm24.git/kernel/bpf/core.c, branch v5.2-rc4

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman

bpf: fix out of bounds backwards jmps due to dead code removal

2019-05-11T01:49:27Z

systemtap folks reported the following splat recently: [ 7790.862212] WARNING: CPU: 3 PID: 26759 at arch/x86/kernel/kprobes/core.c:1022 kprobe_fault_handler+0xec/0xf0 [...] [ 7790.864113] CPU: 3 PID: 26759 Comm: sshd Not tainted 5.1.0-0.rc7.git1.1.fc31.x86_64 #1 [ 7790.864198] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS[...] [ 7790.864314] RIP: 0010:kprobe_fault_handler+0xec/0xf0 [ 7790.864375] Code: 48 8b 50 [...] [ 7790.864714] RSP: 0018:ffffc06800bdbb48 EFLAGS: 00010082 [ 7790.864812] RAX: ffff9e2b75a16320 RBX: 0000000000000000 RCX: 0000000000000000 [ 7790.865306] RDX: ffffffffffffffff RSI: 000000000000000e RDI: ffffc06800bdbbf8 [ 7790.865514] RBP: ffffc06800bdbbf8 R08: 0000000000000000 R09: 0000000000000000 [ 7790.865960] R10: 0000000000000000 R11: 0000000000000000 R12: ffffc06800bdbbf8 [ 7790.866037] R13: ffff9e2ab56a0418 R14: ffff9e2b6d0bb400 R15: ffff9e2b6d268000 [ 7790.866114] FS: 00007fde49937d80(0000) GS:ffff9e2b75a00000(0000) knlGS:0000000000000000 [ 7790.866193] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 7790.866318] CR2: 0000000000000000 CR3: 000000012f312000 CR4: 00000000000006e0 [ 7790.866419] Call Trace: [ 7790.866677] do_user_addr_fault+0x64/0x480 [ 7790.867513] do_page_fault+0x33/0x210 [ 7790.868002] async_page_fault+0x1e/0x30 [ 7790.868071] RIP: 0010: (null) [ 7790.868144] Code: Bad RIP value. [ 7790.868229] RSP: 0018:ffffc06800bdbca8 EFLAGS: 00010282 [ 7790.868362] RAX: ffff9e2b598b60f8 RBX: ffffc06800bdbe48 RCX: 0000000000000004 [ 7790.868629] RDX: 0000000000000004 RSI: ffffc06800bdbc6c RDI: ffff9e2b598b60f0 [ 7790.868834] RBP: ffffc06800bdbcf8 R08: 0000000000000000 R09: 0000000000000004 [ 7790.870432] R10: 00000000ff6f7a03 R11: 0000000000000000 R12: 0000000000000001 [ 7790.871859] R13: ffffc06800bdbcb8 R14: 0000000000000000 R15: ffff9e2acd0a5310 [ 7790.873455] ? vfs_read+0x5/0x170 [ 7790.874639] ? vfs_read+0x1/0x170 [ 7790.875834] ? trace_call_bpf+0xf6/0x260 [ 7790.877044] ? vfs_read+0x1/0x170 [ 7790.878208] ? vfs_read+0x5/0x170 [ 7790.879345] ? kprobe_perf_func+0x233/0x260 [ 7790.880503] ? vfs_read+0x1/0x170 [ 7790.881632] ? vfs_read+0x5/0x170 [ 7790.882751] ? kprobe_ftrace_handler+0x92/0xf0 [ 7790.883926] ? __vfs_read+0x30/0x30 [ 7790.885050] ? ftrace_ops_assist_func+0x94/0x100 [ 7790.886183] ? vfs_read+0x1/0x170 [ 7790.887283] ? vfs_read+0x5/0x170 [ 7790.888348] ? ksys_read+0x5a/0xe0 [ 7790.889389] ? do_syscall_64+0x5c/0xa0 [ 7790.890401] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe After some debugging, turns out that the logic in 2cbd95a5c4fb ("bpf: change parameters of call/branch offset adjustment") has a bug that is exposed after 52875a04f4b2 ("bpf: verifier: remove dead code") in that we miss some of the jump offset adjustments after code patching when we remove dead code, more concretely, upon backward jump spanning over the area that is being removed. BPF insns of a case that was hit pre 52875a04f4b2: [...] 676: (85) call bpf_perf_event_output#-47616 677: (05) goto pc-636 678: (62) *(u32 *)(r10 -64) = 0 679: (bf) r7 = r10 680: (07) r7 += -64 681: (05) goto pc-44 682: (05) goto pc-1 683: (05) goto pc-1 BPF insns afterwards: [...] 618: (85) call bpf_perf_event_output#-47616 619: (05) goto pc-638 620: (62) *(u32 *)(r10 -64) = 0 621: (bf) r7 = r10 622: (07) r7 += -64 623: (05) goto pc-44 To illustrate the bug, situation looks as follows: ____ 0 | | <-- foo: [...] 1 |____| 2 |____| <-- pos / end_new ^ 3 | | | 4 | | | len 5 |____| | (remove region) 6 | | <-- end_old v 7 | | 8 | | <-- curr (jmp foo) 9 |____| The condition curr >= end_new && curr + off + 1 < end_new in the branch delta adjustments is never hit because curr + off + 1 < end_new is compared as unsigned and therefore curr + off + 1 > end_new in unsigned realm as curr + off + 1 becomes negative since the insns are memmove()'d before the offset adjustments. Correct BPF insns after this fix: [...] 618: (85) call bpf_perf_event_output#-47216 619: (05) goto pc-578 620: (62) *(u32 *)(r10 -64) = 0 621: (bf) r7 = r10 622: (07) r7 += -64 623: (05) goto pc-44 Note that unprivileged case is not affected from this. Fixes: 52875a04f4b2 ("bpf: verifier: remove dead code") Fixes: 2cbd95a5c4fb ("bpf: change parameters of call/branch offset adjustment") Reported-by: Frank Ch. Eigler Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Kicinski Signed-off-by: Alexei Starovoitov

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

2019-05-08T05:03:58Z

Pull networking updates from David Miller: "Highlights: 1) Support AES128-CCM ciphers in kTLS, from Vakul Garg. 2) Add fib_sync_mem to control the amount of dirty memory we allow to queue up between synchronize RCU calls, from David Ahern. 3) Make flow classifier more lockless, from Vlad Buslov. 4) Add PHY downshift support to aquantia driver, from Heiner Kallweit. 5) Add SKB cache for TCP rx and tx, from Eric Dumazet. This reduces contention on SLAB spinlocks in heavy RPC workloads. 6) Partial GSO offload support in XFRM, from Boris Pismenny. 7) Add fast link down support to ethtool, from Heiner Kallweit. 8) Use siphash for IP ID generator, from Eric Dumazet. 9) Pull nexthops even further out from ipv4/ipv6 routes and FIB entries, from David Ahern. 10) Move skb->xmit_more into a per-cpu variable, from Florian Westphal. 11) Improve eBPF verifier speed and increase maximum program size, from Alexei Starovoitov. 12) Eliminate per-bucket spinlocks in rhashtable, and instead use bit spinlocks. From Neil Brown. 13) Allow tunneling with GUE encap in ipvs, from Jacky Hu. 14) Improve link partner cap detection in generic PHY code, from Heiner Kallweit. 15) Add layer 2 encap support to bpf_skb_adjust_room(), from Alan Maguire. 16) Remove SKB list implementation assumptions in SCTP, your's truly. 17) Various cleanups, optimizations, and simplifications in r8169 driver. From Heiner Kallweit. 18) Add memory accounting on TX and RX path of SCTP, from Xin Long. 19) Switch PHY drivers over to use dynamic featue detection, from Heiner Kallweit. 20) Support flow steering without masking in dpaa2-eth, from Ioana Ciocoi. 21) Implement ndo_get_devlink_port in netdevsim driver, from Jiri Pirko. 22) Increase the strict parsing of current and future netlink attributes, also export such policies to userspace. From Johannes Berg. 23) Allow DSA tag drivers to be modular, from Andrew Lunn. 24) Remove legacy DSA probing support, also from Andrew Lunn. 25) Allow ll_temac driver to be used on non-x86 platforms, from Esben Haabendal. 26) Add a generic tracepoint for TX queue timeouts to ease debugging, from Cong Wang. 27) More indirect call optimizations, from Paolo Abeni" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1763 commits) cxgb4: Fix error path in cxgb4_init_module net: phy: improve pause mode reporting in phy_print_status dt-bindings: net: Fix a typo in the phy-mode list for ethernet bindings net: macb: Change interrupt and napi enable order in open net: ll_temac: Improve error message on error IRQ net/sched: remove block pointer from common offload structure net: ethernet: support of_get_mac_address new ERR_PTR error net: usb: smsc: fix warning reported by kbuild test robot staging: octeon-ethernet: Fix of_get_mac_address ERR_PTR check net: dsa: support of_get_mac_address new ERR_PTR error net: dsa: sja1105: Fix status initialization in sja1105_get_ethtool_stats vrf: sit mtu should not be updated when vrf netdev is the link net: dsa: Fix error cleanup path in dsa_init_module l2tp: Fix possible NULL pointer dereference taprio: add null check on sched_nest to avoid potential null pointer dereference net: mvpp2: cls: fix less than zero check on a u32 variable net_sched: sch_fq: handle non connected flows net_sched: sch_fq: do not assume EDT packets are ordered net: hns3: use devm_kcalloc when allocating desc_cb net: hns3: some cleanup for struct hns3_enet_ring ...

bpf: Use vmalloc special flag

2019-04-30T10:37:59Z

Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special permissioned memory in vmalloc and remove places where memory was set RW before freeing which is no longer needed. Don't track if the memory is RO anymore because it is now tracked in vmalloc. Signed-off-by: Rick Edgecombe Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Cc: Cc: Cc: Cc: Cc: Cc: Alexei Starovoitov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Daniel Borkmann Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Nadav Amit Cc: Rik van Riel Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20190426001143.4983-19-namit@vmware.com Signed-off-by: Ingo Molnar

bpf: implement lookup-free direct value access for maps

2019-04-10T00:05:46Z

This generic extension to BPF maps allows for directly loading an address residing inside a BPF map value as a single BPF ldimm64 instruction! The idea is similar to what BPF_PSEUDO_MAP_FD does today, which is a special src_reg flag for ldimm64 instruction that indicates that inside the first part of the double insns's imm field is a file descriptor which the verifier then replaces as a full 64bit address of the map into both imm parts. For the newly added BPF_PSEUDO_MAP_VALUE src_reg flag, the idea is the following: the first part of the double insns's imm field is again a file descriptor corresponding to the map, and the second part of the imm field is an offset into the value. The verifier will then replace both imm parts with an address that points into the BPF map value at the given value offset for maps that support this operation. Currently supported is array map with single entry. It is possible to support more than just single map element by reusing both 16bit off fields of the insns as a map index, so full array map lookup could be expressed that way. It hasn't been implemented here due to lack of concrete use case, but could easily be done so in future in a compatible way, since both off fields right now have to be 0 and would correctly denote a map index 0. The BPF_PSEUDO_MAP_VALUE is a distinct flag as otherwise with BPF_PSEUDO_MAP_FD we could not differ offset 0 between load of map pointer versus load of map's value at offset 0, and changing BPF_PSEUDO_MAP_FD's encoding into off by one to differ between regular map pointer and map value pointer would add unnecessary complexity and increases barrier for debugability thus less suitable. Using the second part of the imm field as an offset into the value does /not/ come with limitations since maximum possible value size is in u32 universe anyway. This optimization allows for efficiently retrieving an address to a map value memory area without having to issue a helper call which needs to prepare registers according to calling convention, etc, without needing the extra NULL test, and without having to add the offset in an additional instruction to the value base pointer. The verifier then treats the destination register as PTR_TO_MAP_VALUE with constant reg->off from the user passed offset from the second imm field, and guarantees that this is within bounds of the map value. Any subsequent operations are normally treated as typical map value handling without anything extra needed from verification side. The two map operations for direct value access have been added to array map for now. In future other types could be supported as well depending on the use case. The main use case for this commit is to allow for BPF loader support for global variables that reside in .data/.rodata/.bss sections such that we can directly load the address of them with minimal additional infrastructure required. Loader support has been added in subsequent commits for libbpf library. Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov

bpf: verbose jump offset overflow check

2019-04-03T23:27:38Z

Larger programs may trigger 16-bit jump offset overflow check during instruction patching. Make this error verbose otherwise users cannot decipher error code without printks in the verifier. Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann

Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-03-06T15:59:36Z

Pull perf updates from Ingo Molnar: "Lots of tooling updates - too many to list, here's a few highlights: - Various subcommand updates to 'perf trace', 'perf report', 'perf record', 'perf annotate', 'perf script', 'perf test', etc. - CPU and NUMA topology and affinity handling improvements, - HW tracing and HW support updates: - Intel PT updates - ARM CoreSight updates - vendor HW event updates - BPF updates - Tons of infrastructure updates, both on the build system and the library support side - Documentation updates. - ... and lots of other changes, see the changelog for details. Kernel side updates: - Tighten up kprobes blacklist handling, reduce the number of places where developers can install a kprobe and hang/crash the system. - Fix/enhance vma address filter handling. - Various PMU driver updates, small fixes and additions. - refcount_t conversions - BPF updates - error code propagation enhancements - misc other changes" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (238 commits) perf script python: Add Python3 support to syscall-counts-by-pid.py perf script python: Add Python3 support to syscall-counts.py perf script python: Add Python3 support to stat-cpi.py perf script python: Add Python3 support to stackcollapse.py perf script python: Add Python3 support to sctop.py perf script python: Add Python3 support to powerpc-hcalls.py perf script python: Add Python3 support to net_dropmonitor.py perf script python: Add Python3 support to mem-phys-addr.py perf script python: Add Python3 support to failed-syscalls-by-pid.py perf script python: Add Python3 support to netdev-times.py perf tools: Add perf_exe() helper to find perf binary perf script: Handle missing fields with -F +.. perf data: Add perf_data__open_dir_data function perf data: Add perf_data__(create_dir|close_dir) functions perf data: Fail check_backup in case of error perf data: Make check_backup work over directories perf tools: Add rm_rf_perf_data function perf tools: Add pattern name checking to rm_rf perf tools: Add depth checking to rm_rf perf data: Add global path holder ...

bpf: fix u64_stats_init() usage in bpf_prog_alloc()

2019-03-01T23:31:36Z

We need to iterate through all possible cpus. Fixes: 492ecee892c2 ("bpf: enable program stats") Signed-off-by: Eric Dumazet Reported-by: Guenter Roeck Tested-by: Guenter Roeck Acked-by: Song Liu Signed-off-by: Daniel Borkmann

bpf: enable program stats

2019-02-27T16:22:50Z

JITed BPF programs are indistinguishable from kernel functions, but unlike kernel code BPF code can be changed often. Typical approach of "perf record" + "perf report" profiling and tuning of kernel code works just as well for BPF programs, but kernel code doesn't need to be monitored whereas BPF programs do. Users load and run large amount of BPF programs. These BPF stats allow tools monitor the usage of BPF on the server. The monitoring tools will turn sysctl kernel.bpf_stats_enabled on and off for few seconds to sample average cost of the programs. Aggregated data over hours and days will provide an insight into cost of BPF and alarms can trigger in case given program suddenly gets more expensive. The cost of two sched_clock() per program invocation adds ~20 nsec. Fast BPF progs (like selftests/bpf/progs/test_pkt_access.c) will slow down from ~10 nsec to ~30 nsec. static_key minimizes the cost of the stats collection. There is no measurable difference before/after this patch with kernel.bpf_stats_enabled=0 Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann

bpf: introduce bpf_spin_lock

2019-02-01T19:55:38Z

Introduce 'struct bpf_spin_lock' and bpf_spin_lock/unlock() helpers to let bpf program serialize access to other variables. Example: struct hash_elem { int cnt; struct bpf_spin_lock lock; }; struct hash_elem * val = bpf_map_lookup_elem(&hash_map, &key); if (val) { bpf_spin_lock(&val->lock); val->cnt++; bpf_spin_unlock(&val->lock); } Restrictions and safety checks: - bpf_spin_lock is only allowed inside HASH and ARRAY maps. - BTF description of the map is mandatory for safety analysis. - bpf program can take one bpf_spin_lock at a time, since two or more can cause dead locks. - only one 'struct bpf_spin_lock' is allowed per map element. It drastically simplifies implementation yet allows bpf program to use any number of bpf_spin_locks. - when bpf_spin_lock is taken the calls (either bpf2bpf or helpers) are not allowed. - bpf program must bpf_spin_unlock() before return. - bpf program can access 'struct bpf_spin_lock' only via bpf_spin_lock()/bpf_spin_unlock() helpers. - load/store into 'struct bpf_spin_lock lock;' field is not allowed. - to use bpf_spin_lock() helper the BTF description of map value must be a struct and have 'struct bpf_spin_lock anyname;' field at the top level. Nested lock inside another struct is not allowed. - syscall map_lookup doesn't copy bpf_spin_lock field to user space. - syscall map_update and program map_update do not update bpf_spin_lock field. - bpf_spin_lock cannot be on the stack or inside networking packet. bpf_spin_lock can only be inside HASH or ARRAY map value. - bpf_spin_lock is available to root only and to all program types. - bpf_spin_lock is not allowed in inner maps of map-in-map. - ld_abs is not allowed inside spin_lock-ed region. - tracing progs and socket filter progs cannot use bpf_spin_lock due to insufficient preemption checks Implementation details: - cgroup-bpf class of programs can nest with xdp/tc programs. Hence bpf_spin_lock is equivalent to spin_lock_irqsave. Other solutions to avoid nested bpf_spin_lock are possible. Like making sure that all networking progs run with softirq disabled. spin_lock_irqsave is the simplest and doesn't add overhead to the programs that don't use it. - arch_spinlock_t is used when its implemented as queued_spin_lock - archs can force their own arch_spinlock_t - on architectures where queued_spin_lock is not available and sizeof(arch_spinlock_t) != sizeof(__u32) trivial lock is used. - presence of bpf_spin_lock inside map value could have been indicated via extra flag during map_create, but specifying it via BTF is cleaner. It provides introspection for map key/value and reduces user mistakes. Next steps: - allow bpf_spin_lock in other map types (like cgroup local storage) - introduce BPF_F_LOCK flag for bpf_map_update() syscall and helper to request kernel to grab bpf_spin_lock before rewriting the value. That will serialize access to map elements. Acked-by: Peter Zijlstra (Intel) Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann