On Fri, Jan 22, 2016 at 12:46:28AM +0100, Daniel Borkmann wrote:
> Add a test that symbol from relocation entry is actually related
> to map section and bail out with an error message if it's not the
> case; in relation to [1].
>
> [1] https://llvm.org/bugs/show_bug.cgi?id=26243
>
> Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
Acked-by: Alexei Starovoitov <a...@kernel.org>
Thanks. Useful check.
Wang, we probably want something like this in libbpf as well.
> ---
> tc/tc_bpf.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/tc/tc_bpf.c b/tc/tc_bpf.c
> index 219ffa5..3c97cdb 100644
> --- a/tc/tc_bpf.c
> +++ b/tc/tc_bpf.c
> @@ -1336,6 +1336,12 @@ static int bpf_apply_relo_data(struct bpf_elf_ctx *ctx,
>
> if (gelf_getsym(ctx->sym_tab, GELF_R_SYM(relo.r_info), &sym) !=
> &sym)
> return -EIO;
> + if (sym.st_shndx != ctx->sec_maps) {
> + fprintf(stderr, "ELF contains non-map related relo data
> in "
> + "entry %u pointing to section %u! Compiler
> bug?!\n",
> + relo_ent, sym.st_shndx);
> + return -EIO;
> + }
>
> rmap = sym.st_value / sizeof(struct bpf_elf_map);
> if (rmap >= ARRAY_SIZE(ctx->map_fds))
> --
> 1.9.3
>
