bpf: also check elf for official e_machine value

Use the official BPF ELF e_machine value that was assigned recently [1]
and will be propagated to glibc, libelf et al. LLVM will switch to it
in 3.9 release, therefore we need to prepare tc to check for EM_ELF as
well, older version still have the EM_NONE.

  [1] https://github.com/llvm-mirror/llvm/commit/36b9c09330bfb5e771914cfe307588f30d5510d2

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tc/tc_bpf.c b/tc/tc_bpf.c
index 86c6069b68ec45f8675f9b42cac6f79631095e14..7eb1cd74acca0ca54e509c54a2a628f4b97bdd8a 100644 (file)
--- a/tc/tc_bpf.c
+++ b/tc/tc_bpf.c
@@ -54,6 +54,10 @@
 #define AF_ALG 38
 #endif
 
+#ifndef EM_BPF
+#define EM_BPF 247
+#endif
+
 #ifdef HAVE_ELF
 static int bpf_obj_open(const char *path, enum bpf_prog_type type,
                        const char *sec, bool verbose);
@@ -1690,7 +1694,8 @@ static void bpf_hash_destroy(struct bpf_elf_ctx *ctx)
 static int bpf_elf_check_ehdr(const struct bpf_elf_ctx *ctx)
 {
        if (ctx->elf_hdr.e_type != ET_REL ||
-           ctx->elf_hdr.e_machine != 0 ||
+           (ctx->elf_hdr.e_machine != EM_NONE &&
+            ctx->elf_hdr.e_machine != EM_BPF) ||
            ctx->elf_hdr.e_version != EV_CURRENT) {
                fprintf(stderr, "ELF format error, ELF file not for eBPF?\n");
                return -EINVAL;