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path: root/tools/lib/bpf/libbpf.c
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2024-12-09libbpf: never interpret subprogs in .text as entry programsAndrii Nakryiko
[ Upstream commit db089c9158c1d535a36dfc010e5db37fccea2561 ] Libbpf pre-1.0 had a legacy logic of allowing singular non-annotated (i.e., not having explicit SEC() annotation) function to be treated as sole entry BPF program (unless there were other explicit entry programs). This behavior was dropped during libbpf 1.0 transition period (unless LIBBPF_STRICT_SEC_NAME flag was unset in libbpf_mode). When 1.0 was released and all the legacy behavior was removed, the bug slipped through leaving this legacy behavior around. Fix this for good, as it actually causes very confusing behavior if BPF object file only has subprograms, but no entry programs. Fixes: bd054102a8c7 ("libbpf: enforce strict libbpf 1.0 behaviors") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20241010211731.4121837-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-09libbpf: fix sym_is_subprog() logic for weak global subprogsAndrii Nakryiko
[ Upstream commit 4073213488be542f563eb4b2457ab4cbcfc2b738 ] sym_is_subprog() is incorrectly rejecting relocations against *weak* global subprogs. Fix that by realizing that STB_WEAK is also a global function. While it seems like verifier doesn't support taking an address of non-static subprog right now, it's still best to fix support for it on libbpf side, otherwise users will get a very confusing error during BPF skeleton generation or static linking due to misinterpreted relocation: libbpf: prog 'handle_tp': bad map relo against 'foo' in section '.text' Error: failed to open BPF object file: Relocation failed It's clearly not a map relocation, but is treated and reported as such without this fix. Fixes: 53eddb5e04ac ("libbpf: Support subprog address relocation") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20241009011554.880168-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-09libbpf: Fix expected_attach_type set handling in program load callbackTao Chen
[ Upstream commit a400d08b3014a4f4e939366bb6fd769b9caff4c9 ] Referenced commit broke the logic of resetting expected_attach_type to zero for allowed program types if kernel doesn't yet support such field. We do need to overwrite and preserve expected_attach_type for multi-uprobe though, but that can be done explicitly in libbpf_prepare_prog_load(). Fixes: 5902da6d8a52 ("libbpf: Add uprobe multi link support to bpf_program__attach_usdt") Suggested-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Tao Chen <chen.dylane@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240925153012.212866-1-chen.dylane@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-12libbpf: Add NULL checks to bpf_object__{prev_map,next_map}Andreas Ziegler
[ Upstream commit cedc12c5b57f7efa6dbebfb2b140e8675f5a2616 ] In the current state, an erroneous call to bpf_object__find_map_by_name(NULL, ...) leads to a segmentation fault through the following call chain: bpf_object__find_map_by_name(obj = NULL, ...) -> bpf_object__for_each_map(pos, obj = NULL) -> bpf_object__next_map((obj = NULL), NULL) -> return (obj = NULL)->maps While calling bpf_object__find_map_by_name with obj = NULL is obviously incorrect, this should not lead to a segmentation fault but rather be handled gracefully. As __bpf_map__iter already handles this situation correctly, we can delegate the check for the regular case there and only add a check in case the prev or next parameter is NULL. Signed-off-by: Andreas Ziegler <ziegler.andreas@siemens.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20240703083436.505124-1-ziegler.andreas@siemens.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-12libbpf: Fix error message in attach_kprobe_multiJiri Olsa
[ Upstream commit 7c13ef16e87ac2e44d16c0468b1191bceb06f95c ] We just failed to retrieve pattern, so we need to print spec instead. Fixes: ddc6b04989eb ("libbpf: Add bpf_program__attach_kprobe_multi_opts function") Reported-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240502075541.1425761-2-jolsa@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26libbpf: Apply map_set_def_max_entries() for inner_maps on creationAndrey Grafin
[ Upstream commit f04deb90e516e8e48bf8693397529bc942a9e80b ] This patch allows to auto create BPF_MAP_TYPE_ARRAY_OF_MAPS and BPF_MAP_TYPE_HASH_OF_MAPS with values of BPF_MAP_TYPE_PERF_EVENT_ARRAY by bpf_object__load(). Previous behaviour created a zero filled btf_map_def for inner maps and tried to use it for a map creation but the linux kernel forbids to create a BPF_MAP_TYPE_PERF_EVENT_ARRAY map with max_entries=0. Fixes: 646f02ffdd49 ("libbpf: Add BTF-defined map-in-map support") Signed-off-by: Andrey Grafin <conquistador@yandex-team.ru> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yonghong.song@linux.dev> Acked-by: Hou Tao <houtao1@huawei.com> Link: https://lore.kernel.org/bpf/20240117130619.9403-1-conquistador@yandex-team.ru Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-02-05libbpf: Fix NULL pointer dereference in bpf_object__collect_prog_relosMingyi Zhang
[ Upstream commit fc3a5534e2a8855427403113cbeb54af5837bbe0 ] An issue occurred while reading an ELF file in libbpf.c during fuzzing: Program received signal SIGSEGV, Segmentation fault. 0x0000000000958e97 in bpf_object.collect_prog_relos () at libbpf.c:4206 4206 in libbpf.c (gdb) bt #0 0x0000000000958e97 in bpf_object.collect_prog_relos () at libbpf.c:4206 #1 0x000000000094f9d6 in bpf_object.collect_relos () at libbpf.c:6706 #2 0x000000000092bef3 in bpf_object_open () at libbpf.c:7437 #3 0x000000000092c046 in bpf_object.open_mem () at libbpf.c:7497 #4 0x0000000000924afa in LLVMFuzzerTestOneInput () at fuzz/bpf-object-fuzzer.c:16 #5 0x000000000060be11 in testblitz_engine::fuzzer::Fuzzer::run_one () #6 0x000000000087ad92 in tracing::span::Span::in_scope () #7 0x00000000006078aa in testblitz_engine::fuzzer::util::walkdir () #8 0x00000000005f3217 in testblitz_engine::entrypoint::main::{{closure}} () #9 0x00000000005f2601 in main () (gdb) scn_data was null at this code(tools/lib/bpf/src/libbpf.c): if (rel->r_offset % BPF_INSN_SZ || rel->r_offset >= scn_data->d_size) { The scn_data is derived from the code above: scn = elf_sec_by_idx(obj, sec_idx); scn_data = elf_sec_data(obj, scn); relo_sec_name = elf_sec_str(obj, shdr->sh_name); sec_name = elf_sec_name(obj, scn); if (!relo_sec_name || !sec_name)// don't check whether scn_data is NULL return -EINVAL; In certain special scenarios, such as reading a malformed ELF file, it is possible that scn_data may be a null pointer Signed-off-by: Mingyi Zhang <zhangmingyi5@huawei.com> Signed-off-by: Xin Liu <liuxin350@huawei.com> Signed-off-by: Changye Wu <wuchangye@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20231221033947.154564-1-liuxin350@huawei.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-23libbpf: Add bpf_object__unpin()Daniel Xu
For bpf_object__pin_programs() there is bpf_object__unpin_programs(). Likewise bpf_object__unpin_maps() for bpf_object__pin_maps(). But no bpf_object__unpin() for bpf_object__pin(). Adding the former adds symmetry to the API. It's also convenient for cleanup in application code. It's an API I would've used if it was available for a repro I was writing earlier. Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/bpf/b2f9d41da4a350281a0b53a804d11b68327e14e5.1692832478.git.dxu@dxuuu.xyz
2023-08-22libbpf: Free btf_vmlinux when closing bpf_objectHao Luo
I hit a memory leak when testing bpf_program__set_attach_target(). Basically, set_attach_target() may allocate btf_vmlinux, for example, when setting attach target for bpf_iter programs. But btf_vmlinux is freed only in bpf_object_load(), which means if we only open bpf object but not load it, setting attach target may leak btf_vmlinux. So let's free btf_vmlinux in bpf_object__close() anyway. Signed-off-by: Hao Luo <haoluo@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230822193840.1509809-1-haoluo@google.com
2023-08-21libbpf: Add uprobe multi link support to bpf_program__attach_usdtJiri Olsa
Adding support for usdt_manager_attach_usdt to use uprobe_multi link to attach to usdt probes. The uprobe_multi support is detected before the usdt program is loaded and its expected_attach_type is set accordingly. If uprobe_multi support is detected the usdt_manager_attach_usdt gathers uprobes info and calls bpf_program__attach_uprobe to create all needed uprobes. If uprobe_multi support is not detected the old behaviour stays. Also adding usdt.s program section for sleepable usdt probes. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230809083440.3209381-18-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-08-21libbpf: Add uprobe multi link detectionJiri Olsa
Adding uprobe-multi link detection. It will be used later in bpf_program__attach_usdt function to check and use uprobe_multi link over standard uprobe links. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230809083440.3209381-17-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-08-21libbpf: Add support for u[ret]probe.multi[.s] program sectionsJiri Olsa
Adding support for several uprobe_multi program sections to allow auto attach of multi_uprobe programs. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230809083440.3209381-16-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-08-21libbpf: Add bpf_program__attach_uprobe_multi functionJiri Olsa
Adding bpf_program__attach_uprobe_multi function that allows to attach multiple uprobes with uprobe_multi link. The user can specify uprobes with direct arguments: binary_path/func_pattern/pid or with struct bpf_uprobe_multi_opts opts argument fields: const char **syms; const unsigned long *offsets; const unsigned long *ref_ctr_offsets; const __u64 *cookies; User can specify 2 mutually exclusive set of inputs: 1) use only path/func_pattern/pid arguments 2) use path/pid with allowed combinations of: syms/offsets/ref_ctr_offsets/cookies/cnt - syms and offsets are mutually exclusive - ref_ctr_offsets and cookies are optional Any other usage results in error. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230809083440.3209381-15-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-08-21libbpf: Add elf_resolve_pattern_offsets functionJiri Olsa
Adding elf_resolve_pattern_offsets function that looks up offsets for symbols specified by pattern argument. The 'pattern' argument allows wildcards (*?' supported). Offsets are returned in allocated array together with its size and needs to be released by the caller. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230809083440.3209381-13-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-08-21libbpf: Move elf_find_func_offset* functions to elf objectJiri Olsa
Adding new elf object that will contain elf related functions. There's no functional change. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230809083440.3209381-9-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-08-21libbpf: Add uprobe_multi attach type and link namesJiri Olsa
Adding new uprobe_multi attach type and link names, so the functions can resolve the new values. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20230809083440.3209381-8-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-08-18libbpf: Support triple-underscore flavors for kfunc relocationDave Marchevsky
The function signature of kfuncs can change at any time due to their intentional lack of stability guarantees. As kfuncs become more widely used, BPF program writers will need facilities to support calling different versions of a kfunc from a single BPF object. Consider this simplified example based on a real scenario we ran into at Meta: /* initial kfunc signature */ int some_kfunc(void *ptr) /* Oops, we need to add some flag to modify behavior. No problem, change the kfunc. flags = 0 retains original behavior */ int some_kfunc(void *ptr, long flags) If the initial version of the kfunc is deployed on some portion of the fleet and the new version on the rest, a fleetwide service that uses some_kfunc will currently need to load different BPF programs depending on which some_kfunc is available. Luckily CO-RE provides a facility to solve a very similar problem, struct definition changes, by allowing program writers to declare my_struct___old and my_struct___new, with ___suffix being considered a 'flavor' of the non-suffixed name and being ignored by bpf_core_type_exists and similar calls. This patch extends the 'flavor' facility to the kfunc extern relocation process. BPF program writers can now declare extern int some_kfunc___old(void *ptr) extern int some_kfunc___new(void *ptr, int flags) then test which version of the kfunc exists with bpf_ksym_exists. Relocation and verifier's dead code elimination will work in concert as expected, allowing this pattern: if (bpf_ksym_exists(some_kfunc___old)) some_kfunc___old(ptr); else some_kfunc___new(ptr, 0); Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: David Vernet <void@manifault.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/20230817225353.2570845-1-davemarchevsky@fb.com
2023-08-14libbpf: Set close-on-exec flag on gzopenMarco Vedovati
Enable the close-on-exec flag when using gzopen. This is especially important for multithreaded programs making use of libbpf, where a fork + exec could race with libbpf library calls, potentially resulting in a file descriptor leaked to the new process. This got missed in 59842c5451fe ("libbpf: Ensure libbpf always opens files with O_CLOEXEC"). Fixes: 59842c5451fe ("libbpf: Ensure libbpf always opens files with O_CLOEXEC") Signed-off-by: Marco Vedovati <marco.vedovati@crowdstrike.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230810214350.106301-1-martin.kelly@crowdstrike.com
2023-07-19libbpf: Add link-based API for tcxDaniel Borkmann
Implement tcx BPF link support for libbpf. The bpf_program__attach_fd() API has been refactored slightly in order to pass bpf_link_create_opts pointer as input. A new bpf_program__attach_tcx() has been added on top of this which allows for passing all relevant data via extensible struct bpf_tcx_opts. The program sections tcx/ingress and tcx/egress correspond to the hook locations for tc ingress and egress, respectively. For concrete usage examples, see the extensive selftests that have been developed as part of this series. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230719140858.13224-5-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-19libbpf: Add opts-based attach/detach/query API for tcxDaniel Borkmann
Extend libbpf attach opts and add a new detach opts API so this can be used to add/remove fd-based tcx BPF programs. The old-style bpf_prog_detach() and bpf_prog_detach2() APIs are refactored to reuse the new bpf_prog_detach_opts() internally. The bpf_prog_query_opts() API got extended to be able to handle the new link_ids, link_attach_flags and revision fields. For concrete usage examples, see the extensive selftests that have been developed as part of this series. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230719140858.13224-4-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-11libbpf: Fix realloc API handling in zero-sized edge casesAndrii Nakryiko
realloc() and reallocarray() can either return NULL or a special non-NULL pointer, if their size argument is zero. This requires a bit more care to handle NULL-as-valid-result situation differently from NULL-as-error case. This has caused real issues before ([0]), and just recently bit again in production when performing bpf_program__attach_usdt(). This patch fixes 4 places that do or potentially could suffer from this mishandling of NULL, including the reported USDT-related one. There are many other places where realloc()/reallocarray() is used and NULL is always treated as an error value, but all those have guarantees that their size is always non-zero, so those spot don't need any extra handling. [0] d08ab82f59d5 ("libbpf: Fix double-free when linker processes empty sections") Fixes: 999783c8bbda ("libbpf: Wire up spec management and other arch-independent USDT logic") Fixes: b63b3c490eee ("libbpf: Add bpf_program__set_insns function") Fixes: 697f104db8a6 ("libbpf: Support custom SEC() handlers") Fixes: b12688267280 ("libbpf: Change the order of data and text relocations.") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230711024150.1566433-1-andrii@kernel.org
2023-07-08libbpf: only reset sec_def handler when necessaryAndrii Nakryiko
Don't reset recorded sec_def handler unconditionally on bpf_program__set_type(). There are two situations where this is wrong. First, if the program type didn't actually change. In that case original SEC handler should work just fine. Second, catch-all custom SEC handler is supposed to work with any BPF program type and SEC() annotation, so it also doesn't make sense to reset that. This patch fixes both issues. This was reported recently in the context of breaking perf tool, which uses custom catch-all handler for fancy BPF prologue generation logic. This patch should fix the issue. [0] https://lore.kernel.org/linux-perf-users/ab865e6d-06c5-078e-e404-7f90686db50d@amd.com/ Fixes: d6e6286a12e7 ("libbpf: disassociate section handler on explicit bpf_program__set_type() call") Reported-by: Ravi Bangoria <ravi.bangoria@amd.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20230707231156.1711948-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-07-06libbpf: Use available_filter_functions_addrs with multi-kprobesJackie Liu
Now that kernel provides a new available_filter_functions_addrs file which can help us avoid the need to cross-validate available_filter_functions and kallsyms, we can improve efficiency of multi-attach kprobes. For example, on my device, the sample program [1] of start time: $ sudo ./funccount "tcp_*" before after 1.2s 1.0s [1]: https://github.com/JackieLiu1/ketones/tree/master/src/funccount Signed-off-by: Jackie Liu <liuyun01@kylinos.cn> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230705091209.3803873-2-liu.yun@linux.dev
2023-07-06libbpf: Cross-join available_filter_functions and kallsyms for multi-kprobesJackie Liu
When using regular expression matching with "kprobe multi", it scans all the functions under "/proc/kallsyms" that can be matched. However, not all of them can be traced by kprobe.multi. If any one of the functions fails to be traced, it will result in the failure of all functions. The best approach is to filter out the functions that cannot be traced to ensure proper tracking of the functions. Closes: https://lore.kernel.org/oe-kbuild-all/202307030355.TdXOHklM-lkp@intel.com/ Reported-by: kernel test robot <lkp@intel.com> Suggested-by: Jiri Olsa <jolsa@kernel.org> Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Signed-off-by: Jackie Liu <liuyun01@kylinos.cn> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230705091209.3803873-1-liu.yun@linux.dev
2023-06-30libbpf: Add netfilter link attach helperFlorian Westphal
Add new api function: bpf_program__attach_netfilter. It takes a bpf program (netfilter type), and a pointer to a option struct that contains the desired attachment (protocol family, priority, hook location, ...). It returns a pointer to a 'bpf_link' structure or NULL on error. Next patch adds new netfilter_basic test that uses this function to attach a program to a few pf/hook/priority combinations. v2: change name and use bpf_link_create. Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com> Acked-by: Daniel Xu <dxu@dxuuu.xyz> Link: https://lore.kernel.org/bpf/CAEf4BzZrmUv27AJp0dDxBDMY_B8e55-wLs8DUKK69vCWsCG_pQ@mail.gmail.com/ Link: https://lore.kernel.org/bpf/CAEf4BzZ69YgrQW7DHCJUT_X+GqMq_ZQQPBwopaJJVGFD5=d5Vg@mail.gmail.com/ Link: https://lore.kernel.org/bpf/20230628152738.22765-2-fw@strlen.de
2023-06-30libbpf: Skip modules BTF loading when CAP_SYS_ADMIN is missingAndrea Terzolo
If during CO-RE relocations libbpf is not able to find the target type in the running kernel BTF, it searches for it in modules' BTF. The downside of this approach is that loading modules' BTF requires CAP_SYS_ADMIN and this prevents BPF applications from running with more granular capabilities (e.g. CAP_BPF) when they don't need to search types into modules' BTF. This patch skips by default modules' BTF loading phase when CAP_SYS_ADMIN is missing. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Co-developed-by: Federico Di Pierro <nierro92@gmail.com> Signed-off-by: Federico Di Pierro <nierro92@gmail.com> Signed-off-by: Andrea Terzolo <andreaterzolo3@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/CAGQdkDvYU_e=_NX+6DRkL_-TeH3p+QtsdZwHkmH0w3Fuzw0C4w@mail.gmail.com Link: https://lore.kernel.org/bpf/20230626093614.21270-1-andreaterzolo3@gmail.com
2023-06-08Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR. Conflicts: net/sched/sch_taprio.c d636fc5dd692 ("net: sched: add rcu annotations around qdisc->qdisc_sleeping") dced11ef84fb ("net/sched: taprio: don't overwrite "sch" variable in taprio_dump_class_stats()") net/ipv4/sysctl_net_ipv4.c e209fee4118f ("net/ipv4: ping_group_range: allow GID from 2147483648 to 4294967294") ccce324dabfe ("tcp: make the first N SYN RTO backoffs linear") https://lore.kernel.org/all/20230605100816.08d41a7b@canb.auug.org.au/ No adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-06-05bpf: netfilter: Add BPF_NETFILTER bpf_attach_typeFlorian Westphal
Andrii Nakryiko writes: And we currently don't have an attach type for NETLINK BPF link. Thankfully it's not too late to add it. I see that link_create() in kernel/bpf/syscall.c just bypasses attach_type check. We shouldn't have done that. Instead we need to add BPF_NETLINK attach type to enum bpf_attach_type. And wire all that properly throughout the kernel and libbpf itself. This adds BPF_NETFILTER and uses it. This breaks uabi but this wasn't in any non-rc release yet, so it should be fine. v2: check link_attack prog type in link_create too Fixes: 84601d6ee68a ("bpf: add bpf_link support for BPF_NETFILTER programs") Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/CAEf4BzZ69YgrQW7DHCJUT_X+GqMq_ZQQPBwopaJJVGFD5=d5Vg@mail.gmail.com/ Link: https://lore.kernel.org/bpf/20230605131445.32016-1-fw@strlen.de
2023-05-26libbpf: Ensure FD >= 3 during bpf_map__reuse_fd()Andrii Nakryiko
Improve bpf_map__reuse_fd() logic and ensure that dup'ed map FD is "good" (>= 3) and has O_CLOEXEC flags. Use fcntl(F_DUPFD_CLOEXEC) for that, similarly to ensure_good_fd() helper we already use in low-level APIs that work with bpf() syscall. Suggested-by: Lennart Poettering <lennart@poettering.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230525221311.2136408-2-andrii@kernel.org
2023-05-26libbpf: Ensure libbpf always opens files with O_CLOEXECAndrii Nakryiko
Make sure that libbpf code always gets FD with O_CLOEXEC flag set, regardless if file is open through open() or fopen(). For the latter this means to add "e" to mode string, which is supported since pretty ancient glibc v2.7. Also drop the outdated TODO comment in usdt.c, which was already completed. Suggested-by: Lennart Poettering <lennart@poettering.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230525221311.2136408-1-andrii@kernel.org
2023-05-25libbpf: Change var type in datasec resize funcJP Kobryn
This changes a local variable type that stores a new array id to match the return type of btf__add_array(). Signed-off-by: JP Kobryn <inwardvessel@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20230525001323.8554-1-inwardvessel@gmail.com
2023-05-24libbpf: Add capability for resizing datasec mapsJP Kobryn
This patch updates bpf_map__set_value_size() so that if the given map is memory mapped, it will attempt to resize the mapped region. Initial contents of the mapped region are preserved. BTF is not required, but after the mapping is resized an attempt is made to adjust the associated BTF information if the following criteria is met: - BTF info is present - the map is a datasec - the final variable in the datasec is an array ... the resulting BTF info will be updated so that the final array variable is associated with a new BTF array type sized to cover the requested size. Note that the initial resizing of the memory mapped region can succeed while the subsequent BTF adjustment can fail. In this case, BTF info is dropped from the map by clearing the key and value type. Signed-off-by: JP Kobryn <inwardvessel@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/bpf/20230524004537.18614-2-inwardvessel@gmail.com
2023-04-27Merge tag 'mm-nonmm-stable-2023-04-27-16-01' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: "Mainly singleton patches all over the place. Series of note are: - updates to scripts/gdb from Glenn Washburn - kexec cleanups from Bjorn Helgaas" * tag 'mm-nonmm-stable-2023-04-27-16-01' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (50 commits) mailmap: add entries for Paul Mackerras libgcc: add forward declarations for generic library routines mailmap: add entry for Oleksandr ocfs2: reduce ioctl stack usage fs/proc: add Kthread flag to /proc/$pid/status ia64: fix an addr to taddr in huge_pte_offset() checkpatch: introduce proper bindings license check epoll: rename global epmutex scripts/gdb: add GDB convenience functions $lx_dentry_name() and $lx_i_dentry() scripts/gdb: create linux/vfs.py for VFS related GDB helpers uapi/linux/const.h: prefer ISO-friendly __typeof__ delayacct: track delays from IRQ/SOFTIRQ scripts/gdb: timerlist: convert int chunks to str scripts/gdb: print interrupts scripts/gdb: raise error with reduced debugging information scripts/gdb: add a Radix Tree Parser lib/rbtree: use '+' instead of '|' for setting color. proc/stat: remove arch_idle_time() checkpatch: check for misuse of the link tags checkpatch: allow Closes tags with links ...
2023-04-21tools: bpftool: print netfilter link infoFlorian Westphal
Dump protocol family, hook and priority value: $ bpftool link 2: netfilter prog 14 ip input prio -128 pids install(3264) 5: netfilter prog 14 ip6 forward prio 21 pids a.out(3387) 9: netfilter prog 14 ip prerouting prio 123 pids a.out(5700) 10: netfilter prog 14 ip input prio 21 pids test2(5701) v2: Quentin Monnet suggested to also add 'bpftool net' support: $ bpftool net xdp: tc: flow_dissector: netfilter: ip prerouting prio 21 prog_id 14 ip input prio -128 prog_id 14 ip input prio 21 prog_id 14 ip forward prio 21 prog_id 14 ip output prio 21 prog_id 14 ip postrouting prio 21 prog_id 14 'bpftool net' only dumps netfilter link type, links are sorted by protocol family, hook and priority. v5: fix bpf ci failure: libbpf needs small update to prog_type_name[] and probe_prog_load helper. v4: don't fail with -EOPNOTSUPP in libbpf probe_prog_load, update prog_type_name[] with "netfilter" entry (bpf ci) v3: fix bpf.h copy, 'reserved' member was removed (Alexei) use p_err, not fprintf (Quentin) Suggested-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/eeeaac99-9053-90c2-aa33-cc1ecb1ae9ca@isovalent.com/ Reviewed-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Florian Westphal <fw@strlen.de> Link: https://lore.kernel.org/r/20230421170300.24115-6-fw@strlen.de Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-04-18libbpf: improve handling of unresolved kfuncsAndrii Nakryiko
Currently, libbpf leaves `call #0` instruction for __weak unresolved kfuncs, which might lead to a confusing verifier log situations, where invalid `call #0` will be treated as successfully validated. We can do better. Libbpf already has an established mechanism of poisoning instructions that failed some form of resolution (e.g., CO-RE relocation and BPF map set to not be auto-created). Libbpf doesn't fail them outright to allow users to guard them through other means, and as long as BPF verifier can prove that such poisoned instructions cannot be ever reached, this doesn't consistute an invalid BPF program. If user didn't guard such code, libbpf will extract few pieces of information to tie such poisoned instructions back to additional information about what entitity wasn't resolved (e.g., BPF map name, or CO-RE relocation information). __weak unresolved kfuncs fit this model well, so this patch extends libbpf with poisioning and log fixup logic for kfunc calls. Note, this poisoning is done only for kfunc *calls*, not kfunc address resolution (ldimm64 instructions). The former cannot be ever valid, if reached, so it's safe to poison them. The latter is a valid mechanism to check if __weak kfunc ksym was resolved, and do necessary guarding and work arounds based on this result, supported in most recent kernels. As such, libbpf keeps such ldimm64 instructions as loading zero, never poisoning them. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230418002148.3255690-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-04-18libbpf: report vmlinux vs module name when dealing with ksymsAndrii Nakryiko
Currently libbpf always reports "kernel" as a source of ksym BTF type, which is ambiguous given ksym's BTF can come from either vmlinux or kernel module BTFs. Make this explicit and log module name, if used BTF is from kernel module. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230418002148.3255690-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-04-18libbpf: misc internal libbpf clean ups around log fixupAndrii Nakryiko
Normalize internal constants, field names, and comments related to log fixup. Also add explicit `ext_idx` alias for relocation where relocation is pointing to extern description for additional information. No functional changes, just a clean up before subsequent additions. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230418002148.3255690-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-04-08ELF: fix all "Elf" typosAlexey Dobriyan
ELF is acronym and therefore should be spelled in all caps. I left one exception at Documentation/arm/nwfpe/nwfpe.rst which looks like being written in the first person. Link: https://lkml.kernel.org/r/Y/3wGWQviIOkyLJW@p183 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-29libbpf: disassociate section handler on explicit bpf_program__set_type() callAndrii Nakryiko
If user explicitly overrides programs's type with bpf_program__set_type() API call, we need to disassociate whatever SEC_DEF handler libbpf determined initially based on program's SEC() definition, as it's not goind to be valid anymore and could lead to crashes and/or confusing failures. Also, fix up bpf_prog_test_load() helper in selftests/bpf, which is force-setting program type (even if that's completely unnecessary; this is quite a legacy piece of code), and thus should expect auto-attach to not work, yet one of the tests explicitly relies on auto-attach for testing. Instead, force-set program type only if it differs from the desired one. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230327185202.1929145-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-27libbpf: Ensure print callback usage is thread-safeJP Kobryn
This patch prevents races on the print function pointer, allowing the libbpf_set_print() function to become thread-safe. Signed-off-by: JP Kobryn <inwardvessel@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230325010845.46000-1-inwardvessel@gmail.com
2023-03-22libbpf: Use .struct_ops.link section to indicate a struct_ops with a link.Kui-Feng Lee
Flags a struct_ops is to back a bpf_link by putting it to the ".struct_ops.link" section. Once it is flagged, the created struct_ops can be used to create a bpf_link or update a bpf_link that has been backed by another struct_ops. Signed-off-by: Kui-Feng Lee <kuifeng@meta.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230323032405.3735486-8-kuifeng@meta.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-03-22libbpf: Update a bpf_link with another struct_ops.Kui-Feng Lee
Introduce bpf_link__update_map(), which allows to atomically update underlying struct_ops implementation for given struct_ops BPF link. Also add old_map_fd to struct bpf_link_update_opts to handle BPF_F_REPLACE feature. Signed-off-by: Kui-Feng Lee <kuifeng@meta.com> Link: https://lore.kernel.org/r/20230323032405.3735486-7-kuifeng@meta.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-03-22libbpf: Create a bpf_link in bpf_map__attach_struct_ops().Kui-Feng Lee
bpf_map__attach_struct_ops() was creating a dummy bpf_link as a placeholder, but now it is constructing an authentic one by calling bpf_link_create() if the map has the BPF_F_LINK flag. You can flag a struct_ops map with BPF_F_LINK by calling bpf_map__set_map_flags(). Signed-off-by: Kui-Feng Lee <kuifeng@meta.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20230323032405.3735486-5-kuifeng@meta.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-03-22libbpf: Support kfunc detection in light skeleton.Alexei Starovoitov
Teach gen_loader to find {btf_id, btf_obj_fd} of kernel variables and kfuncs and populate corresponding ld_imm64 and bpf_call insns. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230321203854.3035-4-alexei.starovoitov@gmail.com
2023-03-22libbpf: Rename RELO_EXTERN_VAR/FUNC.Alexei Starovoitov
RELO_EXTERN_VAR/FUNC names are not correct anymore. RELO_EXTERN_VAR represent ksym symbol in ld_imm64 insn. It can point to kernel variable or kfunc. Rename RELO_EXTERN_VAR->RELO_EXTERN_LD64 and RELO_EXTERN_FUNC->RELO_EXTERN_CALL to match what they actually represent. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/bpf/20230321203854.3035-2-alexei.starovoitov@gmail.com
2023-03-20libbpf: Explicitly call write to append content to fileLiu Pan
Write data to fd by calling "vdprintf", in most implementations of the standard library, the data is finally written by the writev syscall. But "uprobe_events/kprobe_events" does not allow segmented writes, so switch the "append_to_file" function to explicit write() call. Signed-off-by: Liu Pan <patteliu@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230320030720.650-1-patteliu@gmail.com
2023-03-17libbpf: Fix relocation of kfunc ksym in ld_imm64 insn.Alexei Starovoitov
void *p = kfunc; -> generates ld_imm64 insn. kfunc() -> generates bpf_call insn. libbpf patches bpf_call insn correctly while only btf_id part of ld_imm64 is set in the former case. Which means that pointers to kfuncs in modules are not patched correctly and the verifier rejects load of such programs due to btf_id being out of range. Fix libbpf to patch ld_imm64 for kfunc. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230317201920.62030-3-alexei.starovoitov@gmail.com
2023-03-06libbpf: Add support to set kprobe/uprobe attach modeMenglong Dong
By default, libbpf will attach the kprobe/uprobe BPF program in the latest mode that supported by kernel. In this patch, we add the support to let users manually attach kprobe/uprobe in legacy or perf mode. There are 3 mode that supported by the kernel to attach kprobe/uprobe: LEGACY: create perf event in legacy way and don't use bpf_link PERF: create perf event with perf_event_open() and don't use bpf_link Signed-off-by: Menglong Dong <imagedong@tencent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Biao Jiang <benbjiang@tencent.com> Link: create perf event with perf_event_open() and use bpf_link Link: https://lore.kernel.org/bpf/20230113093427.1666466-1-imagedong@tencent.com/ Link: https://lore.kernel.org/bpf/20230306064833.7932-2-imagedong@tencent.com Users now can manually choose the mode with bpf_program__attach_uprobe_opts()/bpf_program__attach_kprobe_opts().
2023-03-01libbpf: Add support for attaching uprobes to shared objects in APKsDaniel Müller
This change adds support for attaching uprobes to shared objects located in APKs, which is relevant for Android systems where various libraries may reside in APKs. To make that happen, we extend the syntax for the "binary path" argument to attach to with that supported by various Android tools: <archive>!/<binary-in-archive> For example: /system/app/test-app/test-app.apk!/lib/arm64-v8a/libc++_shared.so APKs need to be specified via full path, i.e., we do not attempt to resolve mere file names by searching system directories. We cannot currently test this functionality end-to-end in an automated fashion, because it relies on an Android system being present, but there is no support for that in CI. I have tested the functionality manually, by creating a libbpf program containing a uretprobe, attaching it to a function inside a shared object inside an APK, and verifying the sanity of the returned values. Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230301212308.1839139-4-deso@posteo.net
2023-03-01libbpf: Introduce elf_find_func_offset_from_file() functionDaniel Müller
This change splits the elf_find_func_offset() function in two: elf_find_func_offset(), which now accepts an already opened Elf object instead of a path to a file that is to be opened, as well as elf_find_func_offset_from_file(), which opens a binary based on a path and then invokes elf_find_func_offset() on the Elf object. Having this split in responsibilities will allow us to call elf_find_func_offset() from other code paths on Elf objects that did not necessarily come from a file on disk. Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230301212308.1839139-3-deso@posteo.net
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