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2022-11-17libbpf: Check the validity of size in user_ring_buffer__reserve()Hou Tao1-0/+4
The top two bits of size are used as busy and discard flags, so reject the reservation that has any of these special bits in the size. With the addition of validity check, these is also no need to check whether or not total_size is overflowed. Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221116072351.1168938-5-houtao@huaweicloud.com
2022-11-17libbpf: Handle size overflow for user ringbuf mmapHou Tao1-2/+8
Similar with the overflow problem on ringbuf mmap, in user_ringbuf_map() 2 * max_entries may overflow u32 when mapping writeable region. Fixing it by casting the size of writable mmap region into a __u64 and checking whether or not there will be overflow during mmap. Fixes: b66ccae01f1d ("bpf: Add libbpf logic for user-space ring buffer") Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221116072351.1168938-4-houtao@huaweicloud.com
2022-11-17libbpf: Handle size overflow for ringbuf mmapHou Tao1-4/+8
The maximum size of ringbuf is 2GB on x86-64 host, so 2 * max_entries will overflow u32 when mapping producer page and data pages. Only casting max_entries to size_t is not enough, because for 32-bits application on 64-bits kernel the size of read-only mmap region also could overflow size_t. So fixing it by casting the size of read-only mmap region into a __u64 and checking whether or not there will be overflow during mmap. Fixes: bf99c936f947 ("libbpf: Add BPF ring buffer support") Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221116072351.1168938-3-houtao@huaweicloud.com
2022-11-17libbpf: Use page size as max_entries when probing ring buffer mapHou Tao1-1/+1
Using page size as max_entries when probing ring buffer map, else the probe may fail on host with 64KB page size (e.g., an ARM64 host). After the fix, the output of "bpftool feature" on above host will be correct. Before : eBPF map_type ringbuf is NOT available eBPF map_type user_ringbuf is NOT available After : eBPF map_type ringbuf is available eBPF map_type user_ringbuf is available Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221116072351.1168938-2-houtao@huaweicloud.com
2022-11-14libbpf: Use correct return pointer in attach_raw_tpJiri Olsa1-1/+1
We need to pass '*link' to final libbpf_get_error, because that one holds the return value, not 'link'. Fixes: 4fa5bcfe07f7 ("libbpf: Allow BPF program auto-attach handlers to bail out") Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20221114145257.882322-1-jolsa@kernel.org
2022-09-30libbpf: Fix overrun in netlink attribute iterationXin Liu1-1/+1
I accidentally found that a change in commit 1045b03e07d8 ("netlink: fix overrun in attribute iteration") was not synchronized to the function `nla_ok` in tools/lib/bpf/nlattr.c, I think it is necessary to modify, this patch will do it. Signed-off-by: Xin Liu <liuxin350@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220930090708.62394-1-liuxin350@huawei.com
2022-09-27libbpf: Don't require full struct enum64 in UAPI headersAndrii Nakryiko1-1/+24
Drop the requirement for system-wide kernel UAPI headers to provide full struct btf_enum64 definition. This is an unexpected requirement that slipped in libbpf 1.0 and put unnecessary pressure ([0]) on users to have a bleeding-edge kernel UAPI header from unreleased Linux 6.0. To achieve this, we forward declare struct btf_enum64. But that's not enough as there is btf_enum64_value() helper that expects to know the layout of struct btf_enum64. So we get a bit creative with reinterpreting memory layout as array of __u32 and accesing lo32/hi32 fields as array elements. Alternative way would be to have a local pointer variable for anonymous struct with exactly the same layout as struct btf_enum64, but that gets us into C++ compiler errors complaining about invalid type casts. So play it safe, if ugly. [0] Closes: https://github.com/libbpf/libbpf/issues/562 Fixes: d90ec262b35b ("libbpf: Add enum64 support for btf_dump") Reported-by: Toke Høiland-Jørgensen <toke@toke.dk> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> Link: https://lore.kernel.org/bpf/20220927042940.147185-1-andrii@kernel.org
2022-09-26libbpf: Fix the case of running as non-root with capabilitiesJon Doron3-5/+5
When running rootless with special capabilities like: FOWNER / DAC_OVERRIDE / DAC_READ_SEARCH The "access" API will not make the proper check if there is really access to a file or not. >From the access man page: " The check is done using the calling process's real UID and GID, rather than the effective IDs as is done when actually attempting an operation (e.g., open(2)) on the file. Similarly, for the root user, the check uses the set of permitted capabilities rather than the set of effective capabilities; ***and for non-root users, the check uses an empty set of capabilities.*** " What that means is that for non-root user the access API will not do the proper validation if the process really has permission to a file or not. To resolve this this patch replaces all the access API calls with faccessat with AT_EACCESS flag. Signed-off-by: Jon Doron <jond@wiz.io> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220925070431.1313680-1-arilou@gmail.com
2022-09-23libbpf: restore memory layout of bpf_object_open_optsAndrii Nakryiko1-1/+3
When attach_prog_fd field was removed in libbpf 1.0 and replaced with `long: 0` placeholder, it actually shifted all the subsequent fields by 8 byte. This is due to `long: 0` promising to adjust next field's offset to long-aligned offset. But in this case we were already long-aligned as pin_root_path is a pointer. So `long: 0` had no effect, and thus didn't feel the gap created by removed attach_prog_fd. Non-zero bitfield should have been used instead. I validated using pahole. Originally kconfig field was at offset 40. With `long: 0` it's at offset 32, which is wrong. With this change it's back at offset 40. While technically libbpf 1.0 is allowed to break backwards compatibility and applications should have been recompiled against libbpf 1.0 headers, but given how trivial it is to preserve memory layout, let's fix this. Reported-by: Grant Seltzer Richman <grantseltzer@gmail.com> Fixes: 146bf811f5ac ("libbpf: remove most other deprecated high-level APIs") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220923230559.666608-1-andrii@kernel.org Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2022-09-23libbpf: Add pathname_concat() helperWang Yufen1-47/+29
Move snprintf and len check to common helper pathname_concat() to make the code simpler. Signed-off-by: Wang Yufen <wangyufen@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/1663828124-10437-1-git-send-email-wangyufen@huawei.com
2022-09-21libbpf: Support raw BTF placed in the default search pathTao Chen1-18/+12
Currently, the default vmlinux files at '/boot/vmlinux-*', '/lib/modules/*/vmlinux-*' etc. are parsed with 'btf__parse_elf()' to extract BTF. It is possible that these files are actually raw BTF files similar to /sys/kernel/btf/vmlinux. So parse these files with 'btf__parse' which tries both raw format and ELF format. This might be useful in some scenarios where users put their custom BTF into known locations and don't want to specify btf_custom_path option. Signed-off-by: Tao Chen <chentao.kernel@linux.alibaba.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/3f59fb5a345d2e4f10e16fe9e35fbc4c03ecaa3e.1662999860.git.chentao.kernel@linux.alibaba.com
2022-09-21libbpf: Improve BPF_PROG2 macro code quality and descriptionYonghong Song1-63/+91
Commit 34586d29f8df ("libbpf: Add new BPF_PROG2 macro") added BPF_PROG2 macro for trampoline based programs with struct arguments. Andrii made a few suggestions to improve code quality and description. This patch implemented these suggestions including better internal macro name, consistent usage pattern for __builtin_choose_expr(), simpler macro definition for always-inline func arguments and better macro description. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/bpf/20220910025214.1536510-1-yhs@fb.com
2022-09-21bpf: Add libbpf logic for user-space ring bufferDavid Vernet6-3/+398
Now that all of the logic is in place in the kernel to support user-space produced ring buffers, we can add the user-space logic to libbpf. This patch therefore adds the following public symbols to libbpf: struct user_ring_buffer * user_ring_buffer__new(int map_fd, const struct user_ring_buffer_opts *opts); void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size); void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb, __u32 size, int timeout_ms); void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample); void user_ring_buffer__discard(struct user_ring_buffer *rb, void user_ring_buffer__free(struct user_ring_buffer *rb); A user-space producer must first create a struct user_ring_buffer * object with user_ring_buffer__new(), and can then reserve samples in the ring buffer using one of the following two symbols: void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size); void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb, __u32 size, int timeout_ms); With user_ring_buffer__reserve(), a pointer to a 'size' region of the ring buffer will be returned if sufficient space is available in the buffer. user_ring_buffer__reserve_blocking() provides similar semantics, but will block for up to 'timeout_ms' in epoll_wait if there is insufficient space in the buffer. This function has the guarantee from the kernel that it will receive at least one event-notification per invocation to bpf_ringbuf_drain(), provided that at least one sample is drained, and the BPF program did not pass the BPF_RB_NO_WAKEUP flag to bpf_ringbuf_drain(). Once a sample is reserved, it must either be committed to the ring buffer with user_ring_buffer__submit(), or discarded with user_ring_buffer__discard(). Signed-off-by: David Vernet <void@manifault.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220920000100.477320-4-void@manifault.com
2022-09-21bpf: Define new BPF_MAP_TYPE_USER_RINGBUF map typeDavid Vernet1-0/+1
We want to support a ringbuf map type where samples are published from user-space, to be consumed by BPF programs. BPF currently supports a kernel -> user-space circular ring buffer via the BPF_MAP_TYPE_RINGBUF map type. We'll need to define a new map type for user-space -> kernel, as none of the helpers exported for BPF_MAP_TYPE_RINGBUF will apply to a user-space producer ring buffer, and we'll want to add one or more helper functions that would not apply for a kernel-producer ring buffer. This patch therefore adds a new BPF_MAP_TYPE_USER_RINGBUF map type definition. The map type is useless in its current form, as there is no way to access or use it for anything until we one or more BPF helpers. A follow-on patch will therefore add a new helper function that allows BPF programs to run callbacks on samples that are published to the ring buffer. Signed-off-by: David Vernet <void@manifault.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220920000100.477320-2-void@manifault.com
2022-09-20libbpf: Fix NULL pointer exception in API btf_dump__dump_type_dataXin Liu1-1/+1
We found that function btf_dump__dump_type_data can be called by the user as an API, but in this function, the `opts` parameter may be used as a null pointer.This causes `opts->indent_str` to trigger a NULL pointer exception. Fixes: 2ce8450ef5a3 ("libbpf: add bpf_object__open_{file, mem} w/ extensible opts") Signed-off-by: Xin Liu <liuxin350@huawei.com> Signed-off-by: Weibin Kong <kongweibin2@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220917084809.30770-1-liuxin350@huawei.com
2022-09-16libbpf: Clean up legacy bpf maps declaration in bpf_helpersXin Liu1-12/+0
Legacy BPF map declarations are no longer supported in libbpf v1.0 [0]. Only BTF-defined maps are supported starting from v1.0, so it is time to remove the definition of bpf_map_def in bpf_helpers.h. [0] https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0 Signed-off-by: Xin Liu <liuxin350@huawei.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/bpf/20220913073643.19960-1-liuxin350@huawei.com
2022-09-16libbpf: Fix crash if SEC("freplace") programs don't have attach_prog_fd setAndrii Nakryiko1-4/+9
Fix SIGSEGV caused by libbpf trying to find attach type in vmlinux BTF for freplace programs. It's wrong to search in vmlinux BTF and libbpf doesn't even mark vmlinux BTF as required for freplace programs. So trying to search anything in obj->vmlinux_btf might cause NULL dereference if nothing else in BPF object requires vmlinux BTF. Instead, error out if freplace (EXT) program doesn't specify attach_prog_fd during at the load time. Fixes: 91abb4a6d79d ("libbpf: Support attachment of BPF tracing programs to kernel modules") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220909193053.577111-3-andrii@kernel.org
2022-09-09libbpf: Remove gcc support for bpf_tail_call_static for nowDaniel Borkmann1-13/+6
This reverts commit 14e5ce79943a ("libbpf: Add GCC support for bpf_tail_call_static"). Reason is that gcc invented their own BPF asm which is not conform with LLVM one, and going forward this would be more painful to maintain here and in other areas of the library. Thus remove it; ask to gcc folks is to align with LLVM one to use exact same syntax. Fixes: 14e5ce79943a ("libbpf: Add GCC support for bpf_tail_call_static") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: James Hilliard <james.hilliard1@gmail.com> Cc: Jose E. Marchesi <jose.marchesi@oracle.com>
2022-09-06libbpf: Add new BPF_PROG2 macroYonghong Song1-0/+79
To support struct arguments in trampoline based programs, existing BPF_PROG doesn't work any more since the type size is needed to find whether a parameter takes one or two registers. So this patch added a new BPF_PROG2 macro to support such trampoline programs. The idea is suggested by Andrii. For example, if the to-be-traced function has signature like typedef struct { void *x; int t; } sockptr; int blah(sockptr x, char y); In the new BPF_PROG2 macro, the argument can be represented as __bpf_prog_call( ({ union { struct { __u64 x, y; } ___z; sockptr x; } ___tmp = { .___z = { ctx[0], ctx[1] }}; ___tmp.x; }), ({ union { struct { __u8 x; } ___z; char y; } ___tmp = { .___z = { ctx[2] }}; ___tmp.y; })); In the above, the values stored on the stack are properly assigned to the actual argument type value by using 'union' magic. Note that the macro also works even if no arguments are with struct types. Note that new BPF_PROG2 works for both llvm16 and pre-llvm16 compilers where llvm16 supports bpf target passing value with struct up to 16 byte size and pre-llvm16 will pass by reference by storing values on the stack. With static functions with struct argument as always inline, the compiler is able to optimize and remove additional stack saving of struct values. Signed-off-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220831152707.2079473-1-yhs@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-08-31libbpf: Add GCC support for bpf_tail_call_staticJames Hilliard1-6/+13
The bpf_tail_call_static function is currently not defined unless using clang >= 8. To support bpf_tail_call_static on GCC we can check if __clang__ is not defined to enable bpf_tail_call_static. We need to use GCC assembly syntax when the compiler does not define __clang__ as LLVM inline assembly is not fully compatible with GCC. Signed-off-by: James Hilliard <james.hilliard1@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220829210546.755377-1-james.hilliard1@gmail.com
2022-08-25libbpf: add map_get_fd_by_id and map_delete_elem in light skeletonBenjamin Tissoires1-0/+23
This allows to have a better control over maps from the kernel when preloading eBPF programs. Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Link: https://lore.kernel.org/r/20220824134055.1328882-8-benjamin.tissoires@redhat.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-08-17Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski13-130/+205
Andrii Nakryiko says: ==================== bpf-next 2022-08-17 We've added 45 non-merge commits during the last 14 day(s) which contain a total of 61 files changed, 986 insertions(+), 372 deletions(-). The main changes are: 1) New bpf_ktime_get_tai_ns() BPF helper to access CLOCK_TAI, from Kurt Kanzenbach and Jesper Dangaard Brouer. 2) Few clean ups and improvements for libbpf 1.0, from Andrii Nakryiko. 3) Expose crash_kexec() as kfunc for BPF programs, from Artem Savkov. 4) Add ability to define sleepable-only kfuncs, from Benjamin Tissoires. 5) Teach libbpf's bpf_prog_load() and bpf_map_create() to gracefully handle unsupported names on old kernels, from Hangbin Liu. 6) Allow opting out from auto-attaching BPF programs by libbpf's BPF skeleton, from Hao Luo. 7) Relax libbpf's requirement for shared libs to be marked executable, from Henqgi Chen. 8) Improve bpf_iter internals handling of error returns, from Hao Luo. 9) Few accommodations in libbpf to support GCC-BPF quirks, from James Hilliard. 10) Fix BPF verifier logic around tracking dynptr ref_obj_id, from Joanne Koong. 11) bpftool improvements to handle full BPF program names better, from Manu Bretelle. 12) bpftool fixes around libcap use, from Quentin Monnet. 13) BPF map internals clean ups and improvements around memory allocations, from Yafang Shao. 14) Allow to use cgroup_get_from_file() on cgroupv1, allowing BPF cgroup iterator to work on cgroupv1, from Yosry Ahmed. 15) BPF verifier internal clean ups, from Dave Marchevsky and Joanne Koong. 16) Various fixes and clean ups for selftests/bpf and vmtest.sh, from Daniel Xu, Artem Savkov, Joanne Koong, Andrii Nakryiko, Shibin Koikkara Reeny. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (45 commits) selftests/bpf: Few fixes for selftests/bpf built in release mode libbpf: Clean up deprecated and legacy aliases libbpf: Streamline bpf_attr and perf_event_attr initialization libbpf: Fix potential NULL dereference when parsing ELF selftests/bpf: Tests libbpf autoattach APIs libbpf: Allows disabling auto attach selftests/bpf: Fix attach point for non-x86 arches in test_progs/lsm libbpf: Making bpf_prog_load() ignore name if kernel doesn't support selftests/bpf: Update CI kconfig selftests/bpf: Add connmark read test selftests/bpf: Add existing connection bpf_*_ct_lookup() test bpftool: Clear errno after libcap's checks bpf: Clear up confusion in bpf_skb_adjust_room()'s documentation bpftool: Fix a typo in a comment libbpf: Add names for auxiliary maps bpf: Use bpf_map_area_alloc consistently on bpf map creation bpf: Make __GFP_NOWARN consistent in bpf map creation bpf: Use bpf_map_area_free instread of kvfree bpf: Remove unneeded memset in queue_stack_map creation libbpf: preserve errno across pr_warn/pr_info/pr_debug ... ==================== Link: https://lore.kernel.org/r/20220817215656.1180215-1-andrii@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-17libbpf: Clean up deprecated and legacy aliasesAndrii Nakryiko5-10/+2
Remove three missed deprecated APIs that were aliased to new APIs: bpf_object__unload, bpf_prog_attach_xattr and btf__load. Also move legacy API libbpf_find_kernel_btf (aliased to btf__load_vmlinux_btf) into libbpf_legacy.h. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Hao Luo <haoluo@google.com> Link: https://lore.kernel.org/bpf/20220816001929.369487-4-andrii@kernel.org
2022-08-17libbpf: Streamline bpf_attr and perf_event_attr initializationAndrii Nakryiko4-91/+138
Make sure that entire libbpf code base is initializing bpf_attr and perf_event_attr with memset(0). Also for bpf_attr make sure we clear and pass to kernel only relevant parts of bpf_attr. bpf_attr is a huge union of independent sub-command attributes, so there is no need to clear and pass entire union bpf_attr, which over time grows quite a lot and for most commands this growth is completely irrelevant. Few cases where we were relying on compiler initialization of BPF UAPI structs (like bpf_prog_info, bpf_map_info, etc) with `= {};` were switched to memset(0) pattern for future-proofing. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Hao Luo <haoluo@google.com> Link: https://lore.kernel.org/bpf/20220816001929.369487-3-andrii@kernel.org
2022-08-17libbpf: Fix potential NULL dereference when parsing ELFAndrii Nakryiko1-1/+1
Fix if condition filtering empty ELF sections to prevent NULL dereference. Fixes: 47ea7417b074 ("libbpf: Skip empty sections in bpf_object__init_global_data_maps") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Hao Luo <haoluo@google.com> Link: https://lore.kernel.org/bpf/20220816001929.369487-2-andrii@kernel.org
2022-08-17libbpf: Allows disabling auto attachHao Luo3-1/+18
Adds libbpf APIs for disabling auto-attach for individual functions. This is motivated by the use case of cgroup iter [1]. Some iter types require their parameters to be non-zero, therefore applying auto-attach on them will fail. With these two new APIs, users who want to use auto-attach and these types of iters can disable auto-attach on the program and perform manual attach. [1] https://lore.kernel.org/bpf/CAEf4BzZ+a2uDo_t6kGBziqdz--m2gh2_EUwkGLDtMd65uwxUjA@mail.gmail.com/ Signed-off-by: Hao Luo <haoluo@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220816234012.910255-1-haoluo@google.com
2022-08-15libbpf: Making bpf_prog_load() ignore name if kernel doesn't supportHangbin Liu3-6/+16
Similar with commit 10b62d6a38f7 ("libbpf: Add names for auxiliary maps"), let's make bpf_prog_load() also ignore name if kernel doesn't support program name. To achieve this, we need to call sys_bpf_prog_load() directly in probe_kern_prog_name() to avoid circular dependency. sys_bpf_prog_load() also need to be exported in the libbpf_internal.h file. Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20220813000936.6464-1-liuhangbin@gmail.com
2022-08-11libbpf: Add names for auxiliary mapsHangbin Liu2-4/+4
The bpftool self-created maps can appear in final map show output due to deferred removal in kernel. These maps don't have a name, which would make users confused about where it comes from. With a libbpf_ prefix name, users could know who created these maps. It also could make some tests (like test_offload.py, which skip base maps without names as a workaround) filter them out. Kernel adds bpf prog/map name support in the same merge commit fadad670a8ab ("Merge branch 'bpf-extend-info'"). So we can also use kernel_supports(NULL, FEAT_PROG_NAME) to check if kernel supports map name. As discussed [1], Let's make bpf_map_create accept non-null name string, and silently ignore the name if kernel doesn't support. [1] https://lore.kernel.org/bpf/CAEf4BzYL1TQwo1231s83pjTdFPk9XWWhfZC5=KzkU-VO0k=0Ug@mail.gmail.com/ Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220811034020.529685-1-liuhangbin@gmail.com
2022-08-10libbpf: preserve errno across pr_warn/pr_info/pr_debugAndrii Nakryiko1-0/+5
As suggested in [0], make sure that libbpf_print saves and restored errno and as such guaranteed that no matter what actual print callback user installs, macros like pr_warn/pr_info/pr_debug are completely transparent as far as errno goes. While libbpf code is pretty careful about not clobbering important errno values accidentally with pr_warn(), it's a trivial change to make sure that pr_warn can be used anywhere without a risk of clobbering errno. No functional changes, just future proofing. [0] https://github.com/libbpf/libbpf/pull/536 Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Daniel Müller <deso@posteo.net> Link: https://lore.kernel.org/r/20220810183425.1998735-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-08-10bpf: Disallow bpf programs call prog_run command.Alexei Starovoitov1-2/+2
The verifier cannot perform sufficient validation of bpf_attr->test.ctx_in pointer, therefore bpf programs should not be allowed to call BPF_PROG_RUN command from within the program. To fix this issue split bpf_sys_bpf() bpf helper into normal kern_sys_bpf() kernel function that can only be used by the kernel light skeleton directly. Reported-by: YiFei Zhu <zhuyifei@google.com> Fixes: b1d18a7574d0 ("bpf: Extend sys_bpf commands for bpf_syscall programs.") Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-08-08libbpf: Do not require executable permission for shared librariesHengqi Chen1-3/+5
Currently, resolve_full_path() requires executable permission for both programs and shared libraries. This causes failures on distos like Debian since the shared libraries are not installed executable and Linux is not requiring shared libraries to have executable permissions. Let's remove executable permission check for shared libraries. Reported-by: Goro Fuji <goro@fastly.com> Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220806102021.3867130-1-hengqi.chen@gmail.com
2022-08-08libbpf: Reject legacy 'maps' ELF sectionAndrii Nakryiko1-5/+3
Add explicit error message if BPF object file is still using legacy BPF map definitions in SEC("maps"). Before this change, if BPF object file is still using legacy map definition user will see a bit confusing: libbpf: elf: skipping unrecognized data section(4) maps libbpf: prog 'handler': bad map relo against 'server_map' in section 'maps' Now libbpf will be explicit about rejecting "maps" ELF section: libbpf: elf: legacy map definitions in 'maps' section are not supported by libbpf v1.0+ Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220803214202.23750-1-andrii@kernel.org
2022-08-04libbpf: Ensure functions with always_inline attribute are inlineJames Hilliard2-9/+9
GCC expects the always_inline attribute to only be set on inline functions, as such we should make all functions with this attribute use the __always_inline macro which makes the function inline and sets the attribute. Fixes errors like: /home/buildroot/bpf-next/tools/testing/selftests/bpf/tools/include/bpf/bpf_tracing.h:439:1: error: ‘always_inline’ function might not be inlinable [-Werror=attributes] 439 | ____##name(unsigned long long *ctx, ##args) | ^~~~ Signed-off-by: James Hilliard <james.hilliard1@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/20220803151403.793024-1-james.hilliard1@gmail.com
2022-08-04libbpf: Initialize err in probe_map_createFlorian Fainelli1-1/+1
GCC-11 warns about the possibly unitialized err variable in probe_map_create: libbpf_probes.c: In function 'probe_map_create': libbpf_probes.c:361:38: error: 'err' may be used uninitialized in this function [-Werror=maybe-uninitialized] 361 | return fd < 0 && err == exp_err ? 1 : 0; | ~~~~^~~~~~~~~~ Fixes: 878d8def0603 ("libbpf: Rework feature-probing APIs") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/20220801025109.1206633-1-f.fainelli@gmail.com
2022-08-04libbpf: Skip empty sections in bpf_object__init_global_data_mapsJames Hilliard1-0/+4
The GNU assembler generates an empty .bss section. This is a well established behavior in GAS that happens in all supported targets. The LLVM assembler doesn't generate an empty .bss section. bpftool chokes on the empty .bss section. Additionally in bpf_object__elf_collect the sec_desc->data is not initialized when a section is not recognized. In this case, this happens with .comment. So we must check that sec_desc->data is initialized before checking if the size is 0. Signed-off-by: James Hilliard <james.hilliard1@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/20220731232649.4668-1-james.hilliard1@gmail.com
2022-07-29libbpf: Add bpf_obj_get_opts()Joe Burton3-0/+21
Add an extensible variant of bpf_obj_get() capable of setting the `file_flags` parameter. This parameter is needed to enable unprivileged access to BPF maps. Without a method like this, users must manually make the syscall. Signed-off-by: Joe Burton <jevburton@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220729202727.3311806-1-jevburton.kernel@gmail.com
2022-07-28libbpf: Support PPC in arch_specific_syscall_pfxDaniel Müller1-1/+10
Commit 708ac5bea0ce ("libbpf: add ksyscall/kretsyscall sections support for syscall kprobes") added the arch_specific_syscall_pfx() function, which returns a string representing the architecture in use. As it turns out this function is currently not aware of Power PC, where NULL is returned. That's being flagged by the libbpf CI system, which builds for ppc64le and the compiler sees a NULL pointer being passed in to a %s format string. With this change we add representations for two more architectures, for Power PC and Power PC 64, and also adjust the string format logic to handle NULL pointers gracefully, in an attempt to prevent similar issues with other architectures in the future. Fixes: 708ac5bea0ce ("libbpf: add ksyscall/kretsyscall sections support for syscall kprobes") Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220728222345.3125975-1-deso@posteo.net
2022-07-26libbpf: Extend BPF_KSYSCALL documentationIlya Leoshkevich1-4/+11
Explicitly list known quirks. Mention that socket-related syscalls can be invoked via socketcall(). Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/20220726134008.256968-2-iii@linux.ibm.com
2022-07-21libbpf: Fix str_has_sfx()'s return valueDan Carpenter1-3/+3
The return from strcmp() is inverted so it wrongly returns true instead of false and vice versa. Fixes: a1c9d61b19cb ("libbpf: Improve library identification for uprobe binary path resolution") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Cc: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/YtZ+/dAA195d99ak@kili
2022-07-21libbpf: Fix sign expansion bug in btf_dump_get_enum_value()Dan Carpenter1-1/+1
The code here is supposed to take a signed int and store it in a signed long long. Unfortunately, the way that the type promotion works with this conditional statement is that it takes a signed int, type promotes it to a __u32, and then stores that as a signed long long. The result is never negative. This is from static analysis, but I made a little test program just to test it before I sent the patch: #include <stdio.h> int main(void) { unsigned long long src = -1ULL; signed long long dst1, dst2; int is_signed = 1; dst1 = is_signed ? *(int *)&src : *(unsigned int *)0; dst2 = is_signed ? (signed long long)*(int *)&src : *(unsigned int *)0; printf("%lld\n", dst1); printf("%lld\n", dst2); return 0; } Fixes: d90ec262b35b ("libbpf: Add enum64 support for btf_dump") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/YtZ+LpgPADm7BeEd@kili
2022-07-19libbpf: fix an snprintf() overflow checkDan Carpenter1-1/+1
The snprintf() function returns the number of bytes it *would* have copied if there were enough space. So it can return > the sizeof(gen->attach_target). Fixes: 67234743736a ("libbpf: Generate loader program out of BPF ELF file.") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/r/YtZ+oAySqIhFl6/J@kili Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-19libbpf: make RINGBUF map size adjustments more eagerlyAndrii Nakryiko1-35/+42
Make libbpf adjust RINGBUF map size (rounding it up to closest power-of-2 of page_size) more eagerly: during open phase when initializing the map and on explicit calls to bpf_map__set_max_entries(). Such approach allows user to check actual size of BPF ringbuf even before it's created in the kernel, but also it prevents various edge case scenarios where BPF ringbuf size can get out of sync with what it would be in kernel. One of them (reported in [0]) is during an attempt to pin/reuse BPF ringbuf. Move adjust_ringbuf_sz() helper closer to its first actual use. The implementation of the helper is unchanged. Also make detection of whether bpf_object is already loaded more robust by checking obj->loaded explicitly, given that map->fd can be < 0 even if bpf_object is already loaded due to ability to disable map creation with bpf_map__set_autocreate(map, false). [0] Closes: https://github.com/libbpf/libbpf/pull/530 Fixes: 0087a681fa8c ("libbpf: Automatically fix up BPF_MAP_TYPE_RINGBUF size, if necessary") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220715230952.2219271-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-19libbpf: fallback to tracefs mount point if debugfs is not mountedAndrii Nakryiko1-21/+40
Teach libbpf to fallback to tracefs mount point (/sys/kernel/tracing) if debugfs (/sys/kernel/debug/tracing) isn't mounted. Acked-by: Yonghong Song <yhs@fb.com> Suggested-by: Connor O'Brien <connoro@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220715185736.898848-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-19libbpf: add ksyscall/kretsyscall sections support for syscall kprobesAndrii Nakryiko4-9/+157
Add SEC("ksyscall")/SEC("ksyscall/<syscall_name>") and corresponding kretsyscall variants (for return kprobes) to allow users to kprobe syscall functions in kernel. These special sections allow to ignore complexities and differences between kernel versions and host architectures when it comes to syscall wrapper and corresponding __<arch>_sys_<syscall> vs __se_sys_<syscall> differences, depending on whether host kernel has CONFIG_ARCH_HAS_SYSCALL_WRAPPER (though libbpf itself doesn't rely on /proc/config.gz for detecting this, see BPF_KSYSCALL patch for how it's done internally). Combined with the use of BPF_KSYSCALL() macro, this allows to just specify intended syscall name and expected input arguments and leave dealing with all the variations to libbpf. In addition to SEC("ksyscall+") and SEC("kretsyscall+") add bpf_program__attach_ksyscall() API which allows to specify syscall name at runtime and provide associated BPF cookie value. At the moment SEC("ksyscall") and bpf_program__attach_ksyscall() do not handle all the calling convention quirks for mmap(), clone() and compat syscalls. It also only attaches to "native" syscall interfaces. If host system supports compat syscalls or defines 32-bit syscalls in 64-bit kernel, such syscall interfaces won't be attached to by libbpf. These limitations may or may not change in the future. Therefore it is recommended to use SEC("kprobe") for these syscalls or if working with compat and 32-bit interfaces is required. Tested-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220714070755.3235561-5-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-19libbpf: improve BPF_KPROBE_SYSCALL macro and rename it to BPF_KSYSCALLAndrii Nakryiko2-13/+40
Improve BPF_KPROBE_SYSCALL (and rename it to shorter BPF_KSYSCALL to match libbpf's SEC("ksyscall") section name, added in next patch) to use __kconfig variable to determine how to properly fetch syscall arguments. Instead of relying on hard-coded knowledge of whether kernel's architecture uses syscall wrapper or not (which only reflects the latest kernel versions, but is not necessarily true for older kernels and won't necessarily hold for later kernel versions on some particular host architecture), determine this at runtime by attempting to create perf_event (with fallback to kprobe event creation through tracefs on legacy kernels, just like kprobe attachment code is doing) for kernel function that would correspond to bpf() syscall on a system that has CONFIG_ARCH_HAS_SYSCALL_WRAPPER set (e.g., for x86-64 it would try '__x64_sys_bpf'). If host kernel uses syscall wrapper, syscall kernel function's first argument is a pointer to struct pt_regs that then contains syscall arguments. In such case we need to use bpf_probe_read_kernel() to fetch actual arguments (which we do through BPF_CORE_READ() macro) from inner pt_regs. But if the kernel doesn't use syscall wrapper approach, input arguments can be read from struct pt_regs directly with no probe reading. All this feature detection is done without requiring /proc/config.gz existence and parsing, and BPF-side helper code uses newly added LINUX_HAS_SYSCALL_WRAPPER virtual __kconfig extern to keep in sync with user-side feature detection of libbpf. BPF_KSYSCALL() macro can be used both with SEC("kprobe") programs that define syscall function explicitly (e.g., SEC("kprobe/__x64_sys_bpf")) and SEC("ksyscall") program added in the next patch (which are the same kprobe program with added benefit of libbpf determining correct kernel function name automatically). Kretprobe and kretsyscall (added in next patch) programs don't need BPF_KSYSCALL as they don't provide access to input arguments. Normal BPF_KRETPROBE is completely sufficient and is recommended. Tested-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220714070755.3235561-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-19libbpf: generalize virtual __kconfig externs and use it for USDTAndrii Nakryiko2-45/+66
Libbpf supports single virtual __kconfig extern currently: LINUX_KERNEL_VERSION. LINUX_KERNEL_VERSION isn't coming from /proc/kconfig.gz and is intead customly filled out by libbpf. This patch generalizes this approach to support more such virtual __kconfig externs. One such extern added in this patch is LINUX_HAS_BPF_COOKIE which is used for BPF-side USDT supporting code in usdt.bpf.h instead of using CO-RE-based enum detection approach for detecting bpf_get_attach_cookie() BPF helper. This allows to remove otherwise not needed CO-RE dependency and keeps user-space and BPF-side parts of libbpf's USDT support strictly in sync in terms of their feature detection. We'll use similar approach for syscall wrapper detection for BPF_KSYSCALL() BPF-side macro in follow up patch. Generally, currently libbpf reserves CONFIG_ prefix for Kconfig values and LINUX_ for virtual libbpf-backed externs. In the future we might extend the set of prefixes that are supported. This can be done without any breaking changes, as currently any __kconfig extern with unrecognized name is rejected. For LINUX_xxx externs we support the normal "weak rule": if libbpf doesn't recognize given LINUX_xxx extern but such extern is marked as __weak, it is not rejected and defaults to zero. This follows CONFIG_xxx handling logic and will allow BPF applications to opportunistically use newer libbpf virtual externs without breaking on older libbpf versions unnecessarily. Tested-by: Alan Maguire <alan.maguire@oracle.com> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20220714070755.3235561-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-07-15libbpf: perfbuf: Add API to get the ring bufferJon Doron3-0/+33
Add support for writing a custom event reader, by exposing the ring buffer. With the new API perf_buffer__buffer() you will get access to the raw mmaped()'ed per-cpu underlying memory of the ring buffer. This region contains both the perf buffer data and header (struct perf_event_mmap_page), which manages the ring buffer state (head/tail positions, when accessing the head/tail position it's important to take into consideration SMP). With this type of low level access one can implement different types of consumers here are few simple examples where this API helps with: 1. perf_event_read_simple is allocating using malloc, perhaps you want to handle the wrap-around in some other way. 2. Since perf buf is per-cpu then the order of the events is not guarnteed, for example: Given 3 events where each event has a timestamp t0 < t1 < t2, and the events are spread on more than 1 CPU, then we can end up with the following state in the ring buf: CPU[0] => [t0, t2] CPU[1] => [t1] When you consume the events from CPU[0], you could know there is a t1 missing, (assuming there are no drops, and your event data contains a sequential index). So now one can simply do the following, for CPU[0], you can store the address of t0 and t2 in an array (without moving the tail, so there data is not perished) then move on the CPU[1] and set the address of t1 in the same array. So you end up with something like: void **arr[] = [&t0, &t1, &t2], now you can consume it orderely and move the tails as you process in order. 3. Assuming there are multiple CPUs and we want to start draining the messages from them, then we can "pick" with which one to start with according to the remaining free space in the ring buffer. Signed-off-by: Jon Doron <jond@wiz.io> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220715181122.149224-1-arilou@gmail.com
2022-07-13libbpf: Fix the name of a reused mapAnquan Wu1-2/+7
BPF map name is limited to BPF_OBJ_NAME_LEN. A map name is defined as being longer than BPF_OBJ_NAME_LEN, it will be truncated to BPF_OBJ_NAME_LEN when a userspace program calls libbpf to create the map. A pinned map also generates a path in the /sys. If the previous program wanted to reuse the map， it can not get bpf_map by name, because the name of the map is only partially the same as the name which get from pinned path. The syscall information below show that map name "process_pinned_map" is truncated to "process_pinned_". bpf(BPF_OBJ_GET, {pathname="/sys/fs/bpf/process_pinned_map", bpf_fd=0, file_flags=0}, 144) = -1 ENOENT (No such file or directory) bpf(BPF_MAP_CREATE, {map_type=BPF_MAP_TYPE_HASH, key_size=4, value_size=4,max_entries=1024, map_flags=0, inner_map_fd=0, map_name="process_pinned_",map_ifindex=0, btf_fd=3, btf_key_type_id=6, btf_value_type_id=10,btf_vmlinux_value_type_id=0}, 72) = 4 This patch check that if the name of pinned map are the same as the actual name for the first (BPF_OBJ_NAME_LEN - 1), bpf map still uses the name which is included in bpf object. Fixes: 26736eb9a483 ("tools: libbpf: allow map reuse") Signed-off-by: Anquan Wu <leiqi96@hotmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/OSZP286MB1725CEA1C95C5CB8E7CCC53FB8869@OSZP286MB1725.JPNP286.PROD.OUTLOOK.COM
2022-07-13libbpf: Error out when binary_path is NULL for uprobe and USDTHengqi Chen1-6/+7
binary_path is a required non-null parameter for bpf_program__attach_usdt and bpf_program__attach_uprobe_opts. Check it against NULL to prevent coredump on strchr. Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220712025745.2703995-1-hengqi.chen@gmail.com
2022-07-08bpf: Correctly propagate errors up from bpf_core_composites_matchDaniel Müller1-1/+8
This change addresses a comment made earlier [0] about a missing return of an error when __bpf_core_types_match is invoked from bpf_core_composites_match, which could have let to us erroneously ignoring errors. Regarding the typedef name check pointed out in the same context, it is not actually an issue, because callers of the function perform a name check for the root type anyway. To make that more obvious, let's add comments to the function (similar to what we have for bpf_core_types_are_compat, which is called in pretty much the same context). [0]: https://lore.kernel.org/bpf/165708121449.4919.13204634393477172905.git-patchwork-notify@kernel.org/T/#m55141e8f8cfd2e8d97e65328fa04852870d01af6 Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220707211931.3415440-1-deso@posteo.net
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