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 <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-25-andrii@kernel.org

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 <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-23-andrii@kernel.org

Wire through token_fd into bpf_prog_load().

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-16-andrii@kernel.org

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 <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-15-andrii@kernel.org

Add ability to provide token_fd for BPF_MAP_CREATE command through
bpf_map_create() API.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-14-andrii@kernel.org

Add low-level wrapper API for BPF_TOKEN_CREATE command in bpf() syscall.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-13-andrii@kernel.org

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 <andrii@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240124224418.2905133-1-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Locate the module BTFs for struct_ops maps and progs and pass them to the
kernel. This ensures that the kernel correctly resolves type IDs from the
appropriate module BTFs.

For the map of a struct_ops object, the FD of the module BTF is set to
bpf_map to keep a reference to the module BTF. The FD is passed to the
kernel as value_type_btf_obj_fd when the struct_ops object is loaded.

For a bpf_struct_ops prog, attach_btf_obj_fd of bpf_prog is the FD of a
module BTF in the kernel.

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240119225005.668602-13-thinker.li@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

This adds bpf_program__attach_netkit() API to libbpf. Overall it is very
similar to tcx. The API looks as following:

  LIBBPF_API struct bpf_link *
  bpf_program__attach_netkit(const struct bpf_program *prog, int ifindex,
                             const struct bpf_netkit_opts *opts);

The struct bpf_netkit_opts is done in similar way as struct bpf_tcx_opts
for supporting bpf_mprog control parameters. The attach location for the
primary and peer device is derived from the program section "netkit/primary"
and "netkit/peer", respectively.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20231024214904.29825-4-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

Adding new uprobe_multi struct to bpf_link_create_opts object
to pass multiple uprobe data to link_create attr uapi.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230809083440.3209381-14-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>