kernel/linux.git/tools/lib/bpf/bpf.c, branch v6.12.80

libbpf: fix feature detectors when using token_fd

2024-05-15T16:34:53+00:00

Adjust `union bpf_attr` size passed to kernel in two feature-detecting functions to take into account prog_token_fd field. Libbpf is avoiding memset()'ing entire `union bpf_attr` by only using minimal set of bpf_attr's fields. Two places have been missed when wiring BPF token support in libbpf's feature detection logic. Fix them trivially. Fixes: f3dcee938f48 ("libbpf: Wire up token_fd into feature probing logic") Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20240513180804.403775-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov

libbpf: Add support for kprobe session attach

2024-04-30T16:45:53+00:00

Adding support to attach program in kprobe session mode with bpf_program__attach_kprobe_multi_opts function. Adding session bool to bpf_kprobe_multi_opts struct that allows to load and attach the bpf program via kprobe session. the attachment to create kprobe multi session. Also adding new program loader section that allows: SEC("kprobe.session/bpf_fentry_test*") and loads/attaches kprobe program as kprobe session. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20240430112830.1184228-5-jolsa@kernel.org

libbpf: add support for BPF cookie for raw_tp/tp_btf programs

2024-03-20T06:05:34+00:00

Wire up BPF cookie passing or raw_tp and tp_btf programs, both in low-level and high-level APIs. Acked-by: Stanislav Fomichev Acked-by: Eduard Zingerman Signed-off-by: Andrii Nakryiko Message-ID: <20240319233852.1977493-5-andrii@kernel.org> Signed-off-by: Alexei Starovoitov

libbpf: Wire up token_fd into feature probing logic

2024-01-25T00:21:02+00:00

Adjust feature probing callbacks to take into account optional token_fd. In unprivileged contexts, some feature detectors would fail to detect kernel support just because BPF program, BPF map, or BTF object can't be loaded due to privileged nature of those operations. So when BPF object is loaded with BPF token, this token should be used for feature probing. This patch is setting support for this scenario, but we don't yet pass non-zero token FD. This will be added in the next patch. We also switched BPF cookie detector from using kprobe program to tracepoint one, as tracepoint is somewhat less dangerous BPF program type and has higher likelihood of being allowed through BPF token in the future. This change has no effect on detection behavior. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20240124022127.2379740-25-andrii@kernel.org

libbpf: Further decouple feature checking logic from bpf_object

2024-01-25T00:21:02+00:00

Add feat_supported() helper that accepts feature cache instead of bpf_object. This allows low-level code in bpf.c to not know or care about higher-level concept of bpf_object, yet it will be able to utilize custom feature checking in cases where BPF token might influence the outcome. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20240124022127.2379740-23-andrii@kernel.org

libbpf: Add BPF token support to bpf_prog_load() API

2024-01-25T00:21:02+00:00

Wire through token_fd into bpf_prog_load(). Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20240124022127.2379740-16-andrii@kernel.org

libbpf: Add BPF token support to bpf_btf_load() API

2024-01-25T00:21:02+00:00

Allow user to specify token_fd for bpf_btf_load() API that wraps kernel's BPF_BTF_LOAD command. This allows loading BTF from unprivileged process as long as it has BPF token allowing BPF_BTF_LOAD command, which can be created and delegated by privileged process. Wire through new btf_flags as well, so that user can provide BPF_F_TOKEN_FD flag, if necessary. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20240124022127.2379740-15-andrii@kernel.org

libbpf: Add BPF token support to bpf_map_create() API

2024-01-25T00:21:01+00:00

Add ability to provide token_fd for BPF_MAP_CREATE command through bpf_map_create() API. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20240124022127.2379740-14-andrii@kernel.org

libbpf: Add bpf_token_create() API

2024-01-25T00:21:01+00:00

Add low-level wrapper API for BPF_TOKEN_CREATE command in bpf() syscall. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20240124022127.2379740-13-andrii@kernel.org

libbpf: Ensure undefined bpf_attr field stays 0

2024-01-25T00:19:39+00:00

The commit 9e926acda0c2 ("libbpf: Find correct module BTFs for struct_ops maps and progs.") sets a newly added field (value_type_btf_obj_fd) to -1 in libbpf when the caller of the libbpf's bpf_map_create did not define this field by passing a NULL "opts" or passing in a "opts" that does not cover this new field. OPT_HAS(opts, field) is used to decide if the field is defined or not: ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field)) Once OPTS_HAS decided the field is not defined, that field should be set to 0. For this particular new field (value_type_btf_obj_fd), its corresponding map_flags "BPF_F_VTYPE_BTF_OBJ_FD" is not set. Thus, the kernel does not treat it as an fd field. Fixes: 9e926acda0c2 ("libbpf: Find correct module BTFs for struct_ops maps and progs.") Reported-by: Andrii Nakryiko Signed-off-by: Martin KaFai Lau Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20240124224418.2905133-1-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov