- 11 Oct, 2019 2 commits
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Jakub Sitnicki authored
It is currently not possible to detach the flow dissector program and attach a new one in an atomic fashion, that is with a single syscall. Attempts to do so will be met with EEXIST error. This makes updates to flow dissector program hard. Traffic steering that relies on BPF-powered flow dissection gets disrupted while old program has been already detached but the new one has not been attached yet. There is also a window of opportunity to attach a flow dissector to a non-root namespace while updating the root flow dissector, thus blocking the update. Lastly, the behavior is inconsistent with cgroup BPF programs, which can be replaced with a single bpf(BPF_PROG_ATTACH, ...) syscall without any restrictions. Allow attaching a new flow dissector program when another one is already present with a restriction that it can't be the same program. Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Stanislav Fomichev <sdf@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20191011082946.22695-2-jakub@cloudflare.com
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Eric Dumazet authored
Do not risk spanning these small structures on two cache lines. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20191011181140.2898-1-edumazet@google.com
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- 10 Oct, 2019 4 commits
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Daniel Borkmann authored
Andrii Nakryiko says: ==================== With BPF maps supporting direct map access (currently, array_map w/ single element, used for global data) that are read-only both from system call and BPF side, it's possible for BPF verifier to track its contents as known constants. Now it's possible for user-space control app to pre-initialize read-only map (e.g., for .rodata section) with user-provided flags and parameters and rely on BPF verifier to detect and eliminate dead code resulting from specific combination of input parameters. v1->v2: - BPF_F_RDONLY means nothing, stick to just map->frozen (Daniel); - stick to passing just offset into map_direct_value_addr (Martin). ==================== Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Andrii Nakryiko authored
Add tests checking that verifier does proper constant propagation for read-only maps. If constant propagation didn't work, skipp_loop and part_loop BPF programs would be rejected due to BPF verifier otherwise not being able to prove they ever complete. With constant propagation, though, they are succesfully validated as properly terminating loops. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20191009201458.2679171-3-andriin@fb.com
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Andrii Nakryiko authored
Maps that are read-only both from BPF program side and user space side have their contents constant, so verifier can track referenced values precisely and use that knowledge for dead code elimination, branch pruning, etc. This patch teaches BPF verifier how to do this. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20191009201458.2679171-2-andriin@fb.com
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Andrii Nakryiko authored
Fix typo in struct xpd_md, generated from bpf_helpers_doc.py, which is causing compilation warnings for programs using bpf_helpers.h Fixes: 7a387bed ("scripts/bpf: teach bpf_helpers_doc.py to dump BPF helper definitions") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191010042534.290562-1-andriin@fb.com
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- 09 Oct, 2019 5 commits
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Ilya Maximets authored
'struct xdp_umem_reg' has 4 bytes of padding at the end that makes valgrind complain about passing uninitialized stack memory to the syscall: Syscall param socketcall.setsockopt() points to uninitialised byte(s) at 0x4E7AB7E: setsockopt (in /usr/lib64/libc-2.29.so) by 0x4BDE035: xsk_umem__create@@LIBBPF_0.0.4 (xsk.c:172) Uninitialised value was created by a stack allocation at 0x4BDDEBA: xsk_umem__create@@LIBBPF_0.0.4 (xsk.c:140) Padding bytes appeared after introducing of a new 'flags' field. memset() is required to clear them. Fixes: 10d30e30 ("libbpf: add flags to umem config") Signed-off-by: Ilya Maximets <i.maximets@ovn.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191009164929.17242-1-i.maximets@ovn.org
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Alexei Starovoitov authored
Andrii Nakryiko says: ==================== Fix BTF-to-C logic of handling padding at the end of a struct. Fix existing test that should have captured this. Also move test_btf_dump into a test_progs test to leverage common infrastructure. ==================== Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko authored
Existing padding test case for btf_dump has a good test that was supposed to test padding generation at the end of a struct, but its expected output was specified incorrectly. Fix this. Fixes: 2d2a3ad8 ("selftests/bpf: add btf_dump BTF-to-C conversion tests") Reported-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191008231009.2991130-4-andriin@fb.com
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Andrii Nakryiko authored
Convert test_btf_dump into a part of test_progs, instead of a stand-alone test binary. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191008231009.2991130-3-andriin@fb.com
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Andrii Nakryiko authored
Fix a case where explicit padding at the end of a struct is necessary due to non-standart alignment requirements of fields (which BTF doesn't capture explicitly). Fixes: 351131b5 ("libbpf: add btf_dump API for BTF-to-C conversion") Reported-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20191008231009.2991130-2-andriin@fb.com
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- 08 Oct, 2019 14 commits
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Daniel Borkmann authored
Andrii Nakryiko says: ==================== This patch set makes bpf_helpers.h and bpf_endian.h a part of libbpf itself for consumption by user BPF programs, not just selftests. It also splits off tracing helpers into bpf_tracing.h, which also becomes part of libbpf. Some of the legacy stuff (BPF_ANNOTATE_KV_PAIR, load_{byte,half,word}, bpf_map_def with unsupported fields, etc, is extracted into selftests-only bpf_legacy.h. All the selftests and samples are switched to use libbpf's headers and selftests' ones are removed. As part of this patch set we also add BPF_CORE_READ variadic macros, that are simplifying BPF CO-RE reads, especially the ones that have to follow few pointers. E.g., what in non-BPF world (and when using BCC) would be: int x = s->a->b.c->d; /* s, a, and b.c are pointers */ Today would have to be written using explicit bpf_probe_read() calls as: void *t; int x; bpf_probe_read(&t, sizeof(t), s->a); bpf_probe_read(&t, sizeof(t), ((struct b *)t)->b.c); bpf_probe_read(&x, sizeof(x), ((struct c *)t)->d); This is super inconvenient and distracts from program logic a lot. Now, with added BPF_CORE_READ() macros, you can write the above as: int x = BPF_CORE_READ(s, a, b.c, d); Up to 9 levels of pointer chasing are supported, which should be enough for any practical purpose, hopefully, without adding too much boilerplate macro definitions (though there is admittedly some, given how variadic and recursive C macro have to be implemented). There is also BPF_CORE_READ_INTO() variant, which relies on caller to allocate space for result: int x; BPF_CORE_READ_INTO(&x, s, a, b.c, d); Result of last bpf_probe_read() call in the chain of calls is the result of BPF_CORE_READ_INTO(). If any intermediate bpf_probe_read() aall fails, then all the subsequent ones will fail too, so this is sufficient to know whether overall "operation" succeeded or not. No short-circuiting of bpf_probe_read()s is done, though. BPF_CORE_READ_STR_INTO() is added as well, which differs from BPF_CORE_READ_INTO() only in that last bpf_probe_read() call (to read final field after chasing pointers) is replaced with bpf_probe_read_str(). Result of bpf_probe_read_str() is returned as a result of BPF_CORE_READ_STR_INTO() macro itself, so that applications can track return code and/or length of read string. Patch set outline: - patch #1 undoes previously added GCC-specific bpf-helpers.h include; - patch #2 splits off legacy stuff we don't want to carry over; - patch #3 adjusts CO-RE reloc tests to avoid subsequent naming conflict with BPF_CORE_READ; - patch #4 splits off bpf_tracing.h; - patch #5 moves bpf_{helpers,endian,tracing}.h and bpf_helper_defs.h generation into libbpf and adjusts Makefiles to include libbpf for header search; - patch #6 adds variadic BPF_CORE_READ() macro family, as described above; - patch #7 adds tests to verify all possible levels of pointer nestedness for BPF_CORE_READ(), as well as correctness test for BPF_CORE_READ_STR_INTO(). v4->v5: - move BPF_CORE_READ() stuff into bpf_core_read.h header (Alexei); v3->v4: - rebase on latest bpf-next master; - bpf_helper_defs.h generation is moved into libbpf's Makefile; v2->v3: - small formatting fixes and macro () fixes (Song); v1->v2: - fix CO-RE reloc tests before bpf_helpers.h move (Song); - split off legacy stuff we don't want to carry over (Daniel, Toke); - split off bpf_tracing.h (Daniel); - fix samples/bpf build (assuming other fixes are applied); - switch remaining maps either to bpf_map_def_legacy or BTF-defined maps; ==================== Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Andrii Nakryiko authored
Validate BPF_CORE_READ correctness and handling of up to 9 levels of nestedness using cyclic task->(group_leader->)*->tgid chains. Also add a test of maximum-dpeth BPF_CORE_READ_STR_INTO() macro. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20191008175942.1769476-8-andriin@fb.com
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Andrii Nakryiko authored
Add few macros simplifying BCC-like multi-level probe reads, while also emitting CO-RE relocations for each read. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20191008175942.1769476-7-andriin@fb.com
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Andrii Nakryiko authored
Move bpf_helpers.h, bpf_tracing.h, and bpf_endian.h into libbpf. Move bpf_helper_defs.h generation into libbpf's Makefile. Ensure all those headers are installed along the other libbpf headers. Also, adjust selftests and samples include path to include libbpf now. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20191008175942.1769476-6-andriin@fb.com
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Andrii Nakryiko authored
Split-off PT_REGS-related helpers into bpf_tracing.h header. Adjust selftests and samples to include it where necessary. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20191008175942.1769476-5-andriin@fb.com
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Andrii Nakryiko authored
To allow adding a variadic BPF_CORE_READ macro with slightly different syntax and semantics, define CORE_READ in CO-RE reloc tests, which is a thin wrapper around low-level bpf_core_read() macro, which in turn is just a wrapper around bpf_probe_read(). Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20191008175942.1769476-4-andriin@fb.com
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Andrii Nakryiko authored
Split off few legacy things from bpf_helpers.h into separate bpf_legacy.h file: - load_{byte|half|word}; - remove extra inner_idx and numa_node fields from bpf_map_def and introduce bpf_map_def_legacy for use in samples; - move BPF_ANNOTATE_KV_PAIR into bpf_legacy.h. Adjust samples and selftests accordingly by either including bpf_legacy.h and using bpf_map_def_legacy, or switching to BTF-defined maps altogether. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20191008175942.1769476-3-andriin@fb.com
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Andrii Nakryiko authored
Having GCC provide its own bpf-helper.h is not the right approach and is going to be changed. Undo bpf_helpers.h change before moving bpf_helpers.h into libbpf. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: Ilya Leoshkevich <iii@linux.ibm.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20191008175942.1769476-2-andriin@fb.com
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Daniel T. Lee authored
Currently, at xdp_adjust_tail_kern.c, MAX_PCKT_SIZE is limited to 600. To make this size flexible, static global variable 'max_pcktsz' is added. By updating new packet size from the user space, xdp_adjust_tail_kern.o will use this value as a new max packet size. This static global variable can be accesible from .data section with bpf_object__find_map* from user space, since it is considered as internal map (accessible with .bss/.data/.rodata suffix). If no '-P <MAX_PCKT_SIZE>' option is used, the size of maximum packet will be 600 as a default. For clarity, change the helper to fetch map from 'bpf_map__next' to 'bpf_object__find_map_fd_by_name'. Also, changed the way to test prog_fd, map_fd from '!= 0' to '< 0', since fd could be 0 when stdin is closed. Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191007172117.3916-1-danieltimlee@gmail.com
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Alexei Starovoitov authored
Stanislav Fomichev says: ==================== While having a per-net-ns flow dissector programs is convenient for testing, security-wise it's better to have only one vetted global flow dissector implementation. Let's have a convention that when BPF flow dissector is installed in the root namespace, child namespaces can't override it. The intended use-case is to attach global BPF flow dissector early from the init scripts/systemd. Attaching global dissector is prohibited if some non-root namespace already has flow dissector attached. Also, attaching to non-root namespace is prohibited when there is flow dissector attached to the root namespace. v3: * drop extra check and empty line (Andrii Nakryiko) v2: * EPERM -> EEXIST (Song Liu) * Make sure we don't have dissector attached to non-root namespaces when attaching the global one (Andrii Nakryiko) ==================== Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Stanislav Fomichev authored
Make sure non-root namespaces get an error if root flow dissector is attached. Cc: Petar Penkov <ppenkov@google.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Stanislav Fomichev authored
Always use init_net flow dissector BPF program if it's attached and fall back to the per-net namespace one. Also, deny installing new programs if there is already one attached to the root namespace. Users can still detach their BPF programs, but can't attach any new ones (-EEXIST). Cc: Petar Penkov <ppenkov@google.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Anton Ivanov authored
Fix spelling mistake. Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20191007082636.14686-1-anton.ivanov@cambridgegreys.com
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Andrii Nakryiko authored
As part of libbpf in 5e61f270 ("libbpf: stop enforcing kern_version, populate it for users") non-LIBBPF_API __bpf_object__open_xattr() API was removed from libbpf.h header. This broke bpftool, which relied on that function. This patch fixes the build by switching to newly added bpf_object__open_file() which provides the same capabilities, but is official and future-proof API. v1->v2: - fix prog_type shadowing (Stanislav). Fixes: 5e61f270 ("libbpf: stop enforcing kern_version, populate it for users") Reported-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/bpf/20191007225604.2006146-1-andriin@fb.com
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- 07 Oct, 2019 5 commits
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Andrii Nakryiko authored
Current Makefile dependency chain is not strict enough and allows test_attach_probe.o to be built before test_progs's prog_test/attach_probe.o is built, which leads to assembler complaining about missing included binary. This patch is a minimal fix to fix this issue by enforcing that test_attach_probe.o (BPF object file) is built before prog_tests/attach_probe.c is attempted to be compiled. Fixes: 928ca75e ("selftests/bpf: switch tests to new bpf_object__open_{file, mem}() APIs") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191007204149.1575990-1-andriin@fb.com
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Alexei Starovoitov authored
Andrii Nakryiko says: ==================== This patch set adds ability to auto-generate list of BPF helper definitions. It relies on existing scripts/bpf_helpers_doc.py and include/uapi/linux/bpf.h having a well-defined set of comments. bpf_helper_defs.h contains all BPF helper signatures which stay in sync with latest bpf.h UAPI. This auto-generated header is included from bpf_helpers.h, while all previously hand-written BPF helper definitions are simultaneously removed in patch #3. The end result is less manually maintained and redundant boilerplate code, while also more consistent and well-documented set of BPF helpers. Generated helper definitions are completely independent from a specific bpf.h on a target system, because it doesn't use BPF_FUNC_xxx enums. v3->v4: - instead of libbpf's Makefile, integrate with selftest/bpf's Makefile (Alexei); v2->v3: - delete bpf_helper_defs.h properly (Alexei); v1->v2: - add bpf_helper_defs.h to .gitignore and `make clean` (Alexei). ==================== Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko authored
Get rid of list of BPF helpers in bpf_helpers.h (irony...) and auto-generate it into bpf_helpers_defs.h, which is now included from bpf_helpers.h. Suggested-by: Alexei Starovoitov <ast@fb.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko authored
Enhance scripts/bpf_helpers_doc.py to emit C header with BPF helper definitions (to be included from libbpf's bpf_helpers.h). Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko authored
Various small fixes to BPF helper documentation comments, enabling automatic header generation with a list of BPF helpers. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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- 06 Oct, 2019 7 commits
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Toke Høiland-Jørgensen authored
Using cscope and/or TAGS files for navigating the source code is useful. Add simple targets to the Makefile to generate the index files for both tools. Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20191004153444.1711278-1-toke@redhat.com
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Alexei Starovoitov authored
Andrii Nakryiko says: ==================== Add bpf_object__open_file() and bpf_object__open_mem() APIs that use a new approach to providing future-proof non-ABI-breaking API changes. It relies on APIs accepting optional self-describing "opts" struct, containing its own size, filled out and provided by potentially outdated (as well as newer-than-libbpf) user application. A set of internal helper macros (OPTS_VALID, OPTS_HAS, and OPTS_GET) streamline and simplify a graceful handling forward and backward compatibility for user applications dynamically linked against different versions of libbpf shared library. Users of libbpf are provided with convenience macro LIBBPF_OPTS that takes care of populating correct structure size and zero-initializes options struct, which helps avoid obscure issues of unitialized padding. Uninitialized padding in a struct might turn into garbage-populated new fields understood by future versions of libbpf. Patch #1 removes enforcement of kern_version in libbpf and always populates correct one on behalf of users. Patch #2 defines necessary infrastructure for options and two new open APIs relying on it. Patch #3 fixes bug in bpf_object__name(). Patch #4 switches two of test_progs' tests to use new APIs as a validation that they work as expected. v2->v3: - fix LIBBPF_OPTS() to ensure zero-initialization of padded bytes; - pass through name override and relaxed maps flag for open_file() (Toke); - fix bpf_object__name() to actually return object name; - don't bother parsing and verifying version section (John); v1->v2: - use better approach for tracking last field in opts struct; - convert few tests to new APIs for validation; - fix bug with using offsetof(last_field) instead of offsetofend(last_field). ==================== Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko authored
Verify new bpf_object__open_mem() and bpf_object__open_file() APIs work as expected by switching test_attach_probe test to use embedded BPF object and bpf_object__open_mem() and test_reference_tracking to bpf_object__open_file(). Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko authored
bpf_object__name() was returning file path, not name. Fix this. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko authored
Add new set of bpf_object__open APIs using new approach to optional parameters extensibility allowing simpler ABI compatibility approach. This patch demonstrates an approach to implementing libbpf APIs that makes it easy to extend existing APIs with extra optional parameters in such a way, that ABI compatibility is preserved without having to do symbol versioning and generating lots of boilerplate code to handle it. To facilitate succinct code for working with options, add OPTS_VALID, OPTS_HAS, and OPTS_GET macros that hide all the NULL, size, and zero checks. Additionally, newly added libbpf APIs are encouraged to follow similar pattern of having all mandatory parameters as formal function parameters and always have optional (NULL-able) xxx_opts struct, which should always have real struct size as a first field and the rest would be optional parameters added over time, which tune the behavior of existing API, if specified by user. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko authored
Kernel version enforcement for kprobes/kretprobes was removed from 5.0 kernel in 6c4fc209 ("bpf: remove useless version check for prog load"). Since then, BPF programs were specifying SEC("version") just to please libbpf. We should stop enforcing this in libbpf, if even kernel doesn't care. Furthermore, libbpf now will pre-populate current kernel version of the host system, in case we are still running on old kernel. This patch also removes __bpf_object__open_xattr from libbpf.h, as nothing in libbpf is relying on having it in that header. That function was never exported as LIBBPF_API and even name suggests its internal version. So this should be safe to remove, as it doesn't break ABI. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Andrii Nakryiko authored
Due to a quirky C syntax of declaring pointers to array or function prototype, existing __type() macro doesn't work with map key/value types that are array or function prototype. One has to create a typedef first and use it to specify key/value type for a BPF map. By using typeof(), pointer to type is now handled uniformly for all kinds of types. Convert one of self-tests as a demonstration. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191004040211.2434033-1-andriin@fb.com
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- 04 Oct, 2019 2 commits
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Daniel Borkmann authored
Add a loop test with 32 bit register against 0 immediate: # ./test_verifier 631 #631/p taken loop with back jump to 1st insn, 2 OK Disassembly: [...] 1b: test %edi,%edi 1d: jne 0x0000000000000014 [...] Pretty much similar to prior "taken loop with back jump to 1st insn" test case just as jmp32 variant. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com>
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Daniel Borkmann authored
Replace 'cmp reg, 0' with 'test reg, reg' for comparisons against zero. Saves 1 byte of instruction encoding per occurrence. The flag results of test 'reg, reg' are identical to 'cmp reg, 0' in all cases except for AF which we don't use/care about. In terms of macro-fusibility in combination with a subsequent conditional jump instruction, both have the same properties for the jumps used in the JIT translation. For example, same JITed Cilium program can shrink a bit from e.g. 12,455 to 12,317 bytes as tests with 0 are used quite frequently. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: John Fastabend <john.fastabend@gmail.com>
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- 03 Oct, 2019 1 commit
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Ivan Khoronzhuk authored
The "path" buf is supposed to contain path + printf msg up to 24 bytes. It will be cut anyway, but compiler generates truncation warns like: " samples/bpf/../../tools/testing/selftests/bpf/cgroup_helpers.c: In function ‘setup_cgroup_environment’: samples/bpf/../../tools/testing/selftests/bpf/cgroup_helpers.c:52:34: warning: ‘/cgroup.controllers’ directive output may be truncated writing 19 bytes into a region of size between 1 and 4097 [-Wformat-truncation=] snprintf(path, sizeof(path), "%s/cgroup.controllers", cgroup_path); ^~~~~~~~~~~~~~~~~~~ samples/bpf/../../tools/testing/selftests/bpf/cgroup_helpers.c:52:2: note: ‘snprintf’ output between 20 and 4116 bytes into a destination of size 4097 snprintf(path, sizeof(path), "%s/cgroup.controllers", cgroup_path); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ samples/bpf/../../tools/testing/selftests/bpf/cgroup_helpers.c:72:34: warning: ‘/cgroup.subtree_control’ directive output may be truncated writing 23 bytes into a region of size between 1 and 4097 [-Wformat-truncation=] snprintf(path, sizeof(path), "%s/cgroup.subtree_control", ^~~~~~~~~~~~~~~~~~~~~~~ cgroup_path); samples/bpf/../../tools/testing/selftests/bpf/cgroup_helpers.c:72:2: note: ‘snprintf’ output between 24 and 4120 bytes into a destination of size 4097 snprintf(path, sizeof(path), "%s/cgroup.subtree_control", cgroup_path); " In order to avoid warns, lets decrease buf size for cgroup workdir on 24 bytes with assumption to include also "/cgroup.subtree_control" to the address. The cut will never happen anyway. Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20191002120404.26962-3-ivan.khoronzhuk@linaro.org
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