libbpf: Reject static entry-point BPF programs

Detect use of static entry-point BPF programs (those with SEC() markings) and
emit error message. This is similar to
c1cccec9c636 ("libbpf: Reject static maps") but for BPF programs.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20210514195534.1440970-1-andrii@kernel.org

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 182bd3d..e58f51b 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -677,6 +677,11 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data,
                        return -LIBBPF_ERRNO__FORMAT;
                }
 
+               if (sec_idx != obj->efile.text_shndx && GELF_ST_BIND(sym.st_info) == STB_LOCAL) {
+                       pr_warn("sec '%s': program '%s' is static and not supported\n", sec_name, name);
+                       return -ENOTSUP;
+               }
+
                pr_debug("sec '%s': found program '%s' at insn offset %zu (%zu bytes), code size %zu insns (%zu bytes)\n",
                         sec_name, name, sec_off / BPF_INSN_SZ, sec_off, prog_sz / BPF_INSN_SZ, prog_sz);