libbpf: add BPF token support to bpf_btf_load() API

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.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231130185229.2688956-15-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 1653b64b701581b8ed029f6e0ef064a2283bf3f1..544ae2376b6bd8b0dd4bcd0ebb8616bc7c5d0289 100644 (file)
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -1184,7 +1184,7 @@ int bpf_raw_tracepoint_open(const char *name, int prog_fd)
 
 int bpf_btf_load(const void *btf_data, size_t btf_size, struct bpf_btf_load_opts *opts)
 {
-       const size_t attr_sz = offsetofend(union bpf_attr, btf_log_true_size);
+       const size_t attr_sz = offsetofend(union bpf_attr, btf_token_fd);
        union bpf_attr attr;
        char *log_buf;
        size_t log_size;
@@ -1209,6 +1209,8 @@ int bpf_btf_load(const void *btf_data, size_t btf_size, struct bpf_btf_load_opts
 
        attr.btf = ptr_to_u64(btf_data);
        attr.btf_size = btf_size;
+       attr.btf_token_fd = OPTS_GET(opts, token_fd, 0);
+
        /* log_level == 0 and log_buf != NULL means "try loading without
         * log_buf, but retry with log_buf and log_level=1 on error", which is
         * consistent across low-level and high-level BTF and program loading

diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index ae2136f596b4af1d5dc601f86972ab36a08b2609..4b0f25e97b0d8a52149e279919b327f2dabdc4df 100644 (file)
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -133,9 +133,10 @@ struct bpf_btf_load_opts {
         * If kernel doesn't support this feature, log_size is left unchanged.
         */
        __u32 log_true_size;
+       __u32 token_fd;
        size_t :0;
 };
-#define bpf_btf_load_opts__last_field log_true_size
+#define bpf_btf_load_opts__last_field token_fd
 
 LIBBPF_API int bpf_btf_load(const void *btf_data, size_t btf_size,
                            struct bpf_btf_load_opts *opts);