Re: [PATCH bpf-next v13 7/8] libbpf: Add syscall common attributes support for map_create

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Missing OPTS_VALID() validation for the nested log_opts structure breaks forward compatibility.
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commit 25b6e95560edf0a2b76e5b2fc840a6200407a730
Author: Leon Hwang <leon.hwang@linux.dev>

libbpf: Add syscall common attributes support for map_create

This commit introduces bpf_log_opts and extends bpf_map_create_opts to
allow users to capture detailed log messages during map creation failures.
It passes these common attributes via the extended sys_bpf_ext_fd() call.

> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
[ ... ]
> @@ -242,7 +245,18 @@ int bpf_map_create(enum bpf_map_type map_type,
>  	attr.excl_prog_hash = ptr_to_u64(OPTS_GET(opts, excl_prog_hash, NULL));
>  	attr.excl_prog_hash_size = OPTS_GET(opts, excl_prog_hash_size, 0);
>  
> -	fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, attr_sz);
> +	log_opts = OPTS_GET(opts, log_opts, NULL);
> +	if (log_opts && feat_supported(NULL, FEAT_BPF_SYSCALL_COMMON_ATTRS)) {

Should there be an OPTS_VALID() check for the nested log_opts structure
before we start extracting its fields?

While the parent opts structure is correctly validated with OPTS_VALID()
at the start of bpf_map_create(), log_opts is a newly introduced option
structure with its own sz field for forward and backward compatibility.

If an application compiled against a future libbpf header passes a
bpf_log_opts struct with new, non-zero fields, wouldn't this silently
ignore those fields instead of returning -EINVAL?

> +		memset(&attr_common, 0, attr_common_sz);
> +		attr_common.log_buf = ptr_to_u64(OPTS_GET(log_opts, buf, NULL));
> +		attr_common.log_size = OPTS_GET(log_opts, size, 0);
> +		attr_common.log_level = OPTS_GET(log_opts, level, 0);

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Sashiko AI review · https://sashiko.dev/#/patchset/20260511152817.89191-1-leon.hwang@linux.dev?part=7