Re: [PATCH] libbpf: Add length checks for path parameters before memory allocation

["Alexei Starovoitov" <alexei.starovoitov@gmail.com>]

On Mon Jun 29, 2026 at 5:25 AM PDT, Masoud Aghasi wrote:
> Several libbpf API functions such as bpf_object__open_file() and
> bpf_program__pin() allocate memory based on user-provided paths without
> first validating input length.
>
> This can result in out-of-memory errors or different error codes
> (ENAMETOOLONG, ENOMEM) being returned.
>
> This patch adds missing path length checks to ensure all affected APIs
> return a consistent error code (ENAMETOOLONG) for invalid path lengths,
> preventing potential memory allocation failures.
>
> Additionally, adds some missing NULL pointer checks to prevent
> potential segmentation faults.
>
> Best regards,
>
> Signed-off-by: Masoud Aghasi <maghasi@disroot.org>
> ---
>  tools/lib/bpf/libbpf.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 7162146280a8..bb3f1dd0663e 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -8536,6 +8536,9 @@ bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts)
>  	if (!path)
>  		return libbpf_err_ptr(-EINVAL);
>  
> +	if (strlen(path) >= PATH_MAX)
> +		return libbpf_err_ptr(-ENAMETOOLONG);
> +

The code is fine as-is. We don't add defensive checks.

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