Tony Ambardar wrote:
> Code in btf__parse_raw() fails to detect raw BTF of non-native endianness
> and assumes it must be ELF data, which then fails to parse as ELF and
> yields a misleading error message:
>
> root:/# bpftool btf dump file /sys/kernel/btf/vmlinux
> libbpf: failed to get EHDR from /sys/kernel/btf/vmlinux
>
> For example, this could occur after cross-compiling a BTF-enabled kernel
> for a target with non-native endianness, which is currently unsupported.
>
> Check for correct endianness and emit a clearer error message:
>
> root:/# bpftool btf dump file /sys/kernel/btf/vmlinux
> libbpf: non-native BTF endianness is not supported
>
> Fixes: 94a1fedd63ed ("libbpf: Add btf__parse_raw() and generic btf__parse() APIs")
>
> Signed-off-by: Tony Ambardar <Tony.Ambardar@xxxxxxxxx>
> ---
> tools/lib/bpf/btf.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> index 7dfca7016aaa..6bdbc389b493 100644
> --- a/tools/lib/bpf/btf.c
> +++ b/tools/lib/bpf/btf.c
> @@ -659,6 +659,12 @@ struct btf *btf__parse_raw(const char *path)
> err = -EIO;
> goto err_out;
> }
> + if (magic == __bswap_16(BTF_MAGIC)) {
> + /* non-native endian raw BTF */
> + pr_warn("non-native BTF endianness is not supported\n");
> + err = -LIBBPF_ERRNO__ENDIAN;
> + goto err_out;
> + }
> if (magic != BTF_MAGIC) {
> /* definitely not a raw BTF */
> err = -EPROTO;
> --
> 2.25.1
>
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
