Re: [PATCH bpf-next] libbpf: Error out when binary_path is NULL for uprobe and USDT

[Jiri Olsa <olsajiri@gmail.com>]

On Tue, Jul 12, 2022 at 10:57:45AM +0800, Hengqi Chen wrote:
> binary_path is a required non-null parameter for bpf_program__attach_usdt
> and bpf_program__attach_uprobe_opts. Check it against NULL to prevent
> coredump on strchr.

binary_path seems to be mandatory so LGTM, cc-ing Alan to be sure ;-)

thanks,
jirka

> 
> Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
> ---
>  tools/lib/bpf/libbpf.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index cb49408eb298..72548798126b 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -10545,7 +10545,10 @@ bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid,
>  	ref_ctr_off = OPTS_GET(opts, ref_ctr_offset, 0);
>  	pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0);
> 
> -	if (binary_path && !strchr(binary_path, '/')) {
> +	if (!binary_path)
> +		return libbpf_err_ptr(-EINVAL);
> +
> +	if (!strchr(binary_path, '/')) {
>  		err = resolve_full_path(binary_path, full_binary_path,
>  					sizeof(full_binary_path));
>  		if (err) {
> @@ -10559,11 +10562,6 @@ bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid,
>  	if (func_name) {
>  		long sym_off;
> 
> -		if (!binary_path) {
> -			pr_warn("prog '%s': name-based attach requires binary_path\n",
> -				prog->name);
> -			return libbpf_err_ptr(-EINVAL);
> -		}
>  		sym_off = elf_find_func_offset(binary_path, func_name);
>  		if (sym_off < 0)
>  			return libbpf_err_ptr(sym_off);
> @@ -10711,6 +10709,9 @@ struct bpf_link *bpf_program__attach_usdt(const struct bpf_program *prog,
>  		return libbpf_err_ptr(-EINVAL);
>  	}
> 
> +	if (!binary_path)
> +		return libbpf_err_ptr(-EINVAL);
> +
>  	if (!strchr(binary_path, '/')) {
>  		err = resolve_full_path(binary_path, resolved_path, sizeof(resolved_path));
>  		if (err) {
> --
> 2.30.2