[PATCH] lsm,selinux: Add LSM blob support for BPF objects

[Song Liu]

On Tue, Jul 15, 2025 at 3:27 PM Blaise Boscaccy
<bboscaccy at linux.microsoft.com> wrote:
[...]
> +/**
> + * lsm_bpf_map_alloc - allocate a composite bpf_map blob
> + * @map: the bpf_map that needs a blob
> + *
> + * Allocate the bpf_map blob for all the modules
> + *
> + * Returns 0, or -ENOMEM if memory can't be allocated.
> + */
> +static int lsm_bpf_map_alloc(struct bpf_map *map)
> +{
> +       if (blob_sizes.lbs_bpf_map == 0) {
> +               map->security = NULL;
> +               return 0;
> +       }
> +
> +       map->security = kzalloc(blob_sizes.lbs_bpf_map, GFP_KERNEL);
> +       if (!map->security)
> +               return -ENOMEM;
> +
> +       return 0;
> +}
> +
> +/**
> + * lsm_bpf_prog_alloc - allocate a composite bpf_prog blob
> + * @prog: the bpf_prog that needs a blob
> + *
> + * Allocate the bpf_prog blob for all the modules
> + *
> + * Returns 0, or -ENOMEM if memory can't be allocated.
> + */
> +static int lsm_bpf_prog_alloc(struct bpf_prog *prog)
> +{
> +       if (blob_sizes.lbs_bpf_prog == 0) {
> +               prog->aux->security = NULL;
> +               return 0;
> +       }
> +
> +       prog->aux->security = kzalloc(blob_sizes.lbs_bpf_prog, GFP_KERNEL);
> +       if (!prog->aux->security)
> +               return -ENOMEM;
> +
> +       return 0;
> +}
> +
> +/**
> + * lsm_bpf_token_alloc - allocate a composite bpf_token blob
> + * @token: the bpf_token that needs a blob
> + *
> + * Allocate the bpf_token blob for all the modules
> + *
> + * Returns 0, or -ENOMEM if memory can't be allocated.
> + */
> +static int lsm_bpf_token_alloc(struct bpf_token *token)
> +{
> +       if (blob_sizes.lbs_bpf_token == 0) {
> +               token->security = NULL;
> +               return 0;
> +       }
> +
> +       token->security = kzalloc(blob_sizes.lbs_bpf_token, GFP_KERNEL);
> +       if (!token->security)
> +               return -ENOMEM;
> +
> +       return 0;
> +}

We need the above 3 functions inside #ifdef CONFIG_BPF_SYSCALL.

Also, can we use lsm_blob_alloc() in these functions?

Thanks,
Song

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