linux/kernel/bpf/btf.c, branch v6.0

bpf: btf: Fix vsnprintf return value check

2022-07-29T16:57:14Z

vsnprintf returns the number of characters which would have been written if enough space had been available, excluding the terminating null byte. Thus, the return value of 'len_left' means that the last character has been dropped. Signed-off-by: Fedor Tokarev Signed-off-by: Andrii Nakryiko Acked-by: Alan Maguire Link: https://lore.kernel.org/bpf/20220711211317.GA1143610@laptop

bpf: Add support for forcing kfunc args to be trusted

2022-07-22T04:03:09Z

Teach the verifier to detect a new KF_TRUSTED_ARGS kfunc flag, which means each pointer argument must be trusted, which we define as a pointer that is referenced (has non-zero ref_obj_id) and also needs to have its offset unchanged, similar to how release functions expect their argument. This allows a kfunc to receive pointer arguments unchanged from the result of the acquire kfunc. This is required to ensure that kfunc that operate on some object only work on acquired pointers and not normal PTR_TO_BTF_ID with same type which can be obtained by pointer walking. The restrictions applied to release arguments also apply to trusted arguments. This implies that strict type matching (not deducing type by recursively following members at offset) and OBJ_RELEASE offset checks (ensuring they are zero) are used for trusted pointer arguments. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20220721134245.2450-5-memxor@gmail.com Signed-off-by: Alexei Starovoitov

bpf: Switch to new kfunc flags infrastructure

2022-07-22T03:59:42Z

Instead of populating multiple sets to indicate some attribute and then researching the same BTF ID in them, prepare a single unified BTF set which indicates whether a kfunc is allowed to be called, and also its attributes if any at the same time. Now, only one call is needed to perform the lookup for both kfunc availability and its attributes. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20220721134245.2450-4-memxor@gmail.com Signed-off-by: Alexei Starovoitov

bpf: Fix check against plain integer v 'NULL'

2022-07-15T16:55:20Z

When checking with sparse, btf_show_type_value() is causing a warning about checking integer vs NULL when the macro is passed a pointer, due to the 'value != 0' check. Stop sparse complaining about any type-casting by adding a cast to the typeof(value). This fixes the following sparse warnings: kernel/bpf/btf.c:2579:17: warning: Using plain integer as NULL pointer kernel/bpf/btf.c:2581:17: warning: Using plain integer as NULL pointer kernel/bpf/btf.c:3407:17: warning: Using plain integer as NULL pointer kernel/bpf/btf.c:3758:9: warning: Using plain integer as NULL pointer Signed-off-by: Ben Dooks Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20220714100322.260467-1-ben.dooks@sifive.com

Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2022-07-09T19:24:16Z

Daniel Borkmann says: ==================== pull-request: bpf-next 2022-07-09 We've added 94 non-merge commits during the last 19 day(s) which contain a total of 125 files changed, 5141 insertions(+), 6701 deletions(-). The main changes are: 1) Add new way for performing BTF type queries to BPF, from Daniel Müller. 2) Add inlining of calls to bpf_loop() helper when its function callback is statically known, from Eduard Zingerman. 3) Implement BPF TCP CC framework usability improvements, from Jörn-Thorben Hinz. 4) Add LSM flavor for attaching per-cgroup BPF programs to existing LSM hooks, from Stanislav Fomichev. 5) Remove all deprecated libbpf APIs in prep for 1.0 release, from Andrii Nakryiko. 6) Add benchmarks around local_storage to BPF selftests, from Dave Marchevsky. 7) AF_XDP sample removal (given move to libxdp) and various improvements around AF_XDP selftests, from Magnus Karlsson & Maciej Fijalkowski. 8) Add bpftool improvements for memcg probing and bash completion, from Quentin Monnet. 9) Add arm64 JIT support for BPF-2-BPF coupled with tail calls, from Jakub Sitnicki. 10) Sockmap optimizations around throughput of UDP transmissions which have been improved by 61%, from Cong Wang. 11) Rework perf's BPF prologue code to remove deprecated functions, from Jiri Olsa. 12) Fix sockmap teardown path to avoid sleepable sk_psock_stop, from John Fastabend. 13) Fix libbpf's cleanup around legacy kprobe/uprobe on error case, from Chuang Wang. 14) Fix libbpf's bpf_helpers.h to work with gcc for the case of its sec/pragma macro, from James Hilliard. 15) Fix libbpf's pt_regs macros for riscv to use a0 for RC register, from Yixun Lan. 16) Fix bpftool to show the name of type BPF_OBJ_LINK, from Yafang Shao. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (94 commits) selftests/bpf: Fix xdp_synproxy build failure if CONFIG_NF_CONNTRACK=m/n bpf: Correctly propagate errors up from bpf_core_composites_match libbpf: Disable SEC pragma macro on GCC bpf: Check attach_func_proto more carefully in check_return_code selftests/bpf: Add test involving restrict type qualifier bpftool: Add support for KIND_RESTRICT to gen min_core_btf command MAINTAINERS: Add entry for AF_XDP selftests files selftests, xsk: Rename AF_XDP testing app bpf, docs: Remove deprecated xsk libbpf APIs description selftests/bpf: Add benchmark for local_storage RCU Tasks Trace usage libbpf, riscv: Use a0 for RC register libbpf: Remove unnecessary usdt_rel_ip assignments selftests/bpf: Fix few more compiler warnings selftests/bpf: Fix bogus uninitialized variable warning bpftool: Remove zlib feature test from Makefile libbpf: Cleanup the legacy uprobe_event on failed add/attach_event() libbpf: Fix wrong variable used in perf_event_uprobe_open_legacy() libbpf: Cleanup the legacy kprobe_event on failed add/attach_event() selftests/bpf: Add type match test against kernel's task_struct selftests/bpf: Add nested type to type based tests ... ==================== Link: https://lore.kernel.org/r/20220708233145.32365-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski

bpf, libbpf: Add type match support

2022-07-06T04:14:25Z

This patch adds support for the proposed type match relation to relo_core where it is shared between userspace and kernel. It plumbs through both kernel-side and libbpf-side support. The matching relation is defined as follows (copy from source): - modifiers and typedefs are stripped (and, hence, effectively ignored) - generally speaking types need to be of same kind (struct vs. struct, union vs. union, etc.) - exceptions are struct/union behind a pointer which could also match a forward declaration of a struct or union, respectively, and enum vs. enum64 (see below) Then, depending on type: - integers: - match if size and signedness match - arrays & pointers: - target types are recursively matched - structs & unions: - local members need to exist in target with the same name - for each member we recursively check match unless it is already behind a pointer, in which case we only check matching names and compatible kind - enums: - local variants have to have a match in target by symbolic name (but not numeric value) - size has to match (but enum may match enum64 and vice versa) - function pointers: - number and position of arguments in local type has to match target - for each argument and the return value we recursively check match Signed-off-by: Daniel Müller Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220628160127.607834-5-deso@posteo.net

bpf: minimize number of allocated lsm slots per program

2022-06-29T20:21:52Z

Previous patch adds 1:1 mapping between all 211 LSM hooks and bpf_cgroup program array. Instead of reserving a slot per possible hook, reserve 10 slots per cgroup for lsm programs. Those slots are dynamically allocated on demand and reclaimed. struct cgroup_bpf { struct bpf_prog_array * effective[33]; /* 0 264 */ /* --- cacheline 4 boundary (256 bytes) was 8 bytes ago --- */ struct hlist_head progs[33]; /* 264 264 */ /* --- cacheline 8 boundary (512 bytes) was 16 bytes ago --- */ u8 flags[33]; /* 528 33 */ /* XXX 7 bytes hole, try to pack */ struct list_head storages; /* 568 16 */ /* --- cacheline 9 boundary (576 bytes) was 8 bytes ago --- */ struct bpf_prog_array * inactive; /* 584 8 */ struct percpu_ref refcnt; /* 592 16 */ struct work_struct release_work; /* 608 72 */ /* size: 680, cachelines: 11, members: 7 */ /* sum members: 673, holes: 1, sum holes: 7 */ /* last cacheline: 40 bytes */ }; Reviewed-by: Martin KaFai Lau Signed-off-by: Stanislav Fomichev Link: https://lore.kernel.org/r/20220628174314.1216643-5-sdf@google.com Signed-off-by: Alexei Starovoitov

bpf: per-cgroup lsm flavor

2022-06-29T20:21:51Z

Allow attaching to lsm hooks in the cgroup context. Attaching to per-cgroup LSM works exactly like attaching to other per-cgroup hooks. New BPF_LSM_CGROUP is added to trigger new mode; the actual lsm hook we attach to is signaled via existing attach_btf_id. For the hooks that have 'struct socket' or 'struct sock' as its first argument, we use the cgroup associated with that socket. For the rest, we use 'current' cgroup (this is all on default hierarchy == v2 only). Note that for some hooks that work on 'struct sock' we still take the cgroup from 'current' because some of them work on the socket that hasn't been properly initialized yet. Behind the scenes, we allocate a shim program that is attached to the trampoline and runs cgroup effective BPF programs array. This shim has some rudimentary ref counting and can be shared between several programs attaching to the same lsm hook from different cgroups. Note that this patch bloats cgroup size because we add 211 cgroup_bpf_attach_type(s) for simplicity sake. This will be addressed in the subsequent patch. Also note that we only add non-sleepable flavor for now. To enable sleepable use-cases, bpf_prog_run_array_cg has to grab trace rcu, shim programs have to be freed via trace rcu, cgroup_bpf.effective should be also trace-rcu-managed + maybe some other changes that I'm not aware of. Reviewed-by: Martin KaFai Lau Signed-off-by: Stanislav Fomichev Link: https://lore.kernel.org/r/20220628174314.1216643-4-sdf@google.com Signed-off-by: Alexei Starovoitov

bpf: Merge "types_are_compat" logic into relo_core.c

2022-06-24T21:15:37Z

BPF type compatibility checks (bpf_core_types_are_compat()) are currently duplicated between kernel and user space. That's a historical artifact more than intentional doing and can lead to subtle bugs where one implementation is adjusted but another is forgotten. That happened with the enum64 work, for example, where the libbpf side was changed (commit 23b2a3a8f63a ("libbpf: Add enum64 relocation support")) to use the btf_kind_core_compat() helper function but the kernel side was not (commit 6089fb325cf7 ("bpf: Add btf enum64 support")). This patch addresses both the duplication issue, by merging both implementations and moving them into relo_core.c, and fixes the alluded to kind check (by giving preference to libbpf's already adjusted logic). For discussion of the topic, please refer to: https://lore.kernel.org/bpf/CAADnVQKbWR7oarBdewgOBZUPzryhRYvEbkhyPJQHHuxq=0K1gw@mail.gmail.com/T/#mcc99f4a33ad9a322afaf1b9276fb1f0b7add9665 Changelog: v1 -> v2: - limited libbpf recursion limit to 32 - changed name to __bpf_core_types_are_compat - included warning previously present in libbpf version - merged kernel and user space changes into a single patch Signed-off-by: Daniel Müller Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220623182934.2582827-1-deso@posteo.net

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2022-06-23T19:33:24Z

No conflicts. Signed-off-by: Jakub Kicinski