[PATCH bpf-next v2 2/4] bpf: Implement bpf_local_storage for inodes

[Martin KaFai Lau]

On Wed, Jun 17, 2020 at 10:29:39PM +0200, KP Singh wrote:
[ ... ]

> diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h
> index af74712af585..8efd7562e3de 100644
> --- a/include/linux/bpf_lsm.h
> +++ b/include/linux/bpf_lsm.h
> @@ -17,9 +17,24 @@
>  #include <linux/lsm_hook_defs.h>
>  #undef LSM_HOOK
>  
> +struct bpf_storage_blob {
> +	struct bpf_local_storage __rcu *storage;
> +};
> +
> +extern struct lsm_blob_sizes bpf_lsm_blob_sizes;
> +
>  int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
>  			const struct bpf_prog *prog);
>  
> +static inline struct bpf_storage_blob *bpf_inode(
> +	const struct inode *inode)
> +{
> +	if (unlikely(!inode->i_security))
> +		return NULL;
> +
> +	return inode->i_security + bpf_lsm_blob_sizes.lbs_inode;
> +}
> +
>  #else /* !CONFIG_BPF_LSM */
>  
>  static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
> @@ -28,6 +43,12 @@ static inline int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
>  	return -EOPNOTSUPP;
>  }
>  
> +static inline struct bpf_storage_blob *bpf_inode_storage(
This does not seem to match the newly added "bpf_inode()"
above for the "CONFIG_BPF_LSM" case.

A typo?  May be a good idea to test compiling with !CONFIG_BPF_LSM.

> +	const struct inode *inode)
> +{
> +	return NULL;
> +}
> +
>  #endif /* CONFIG_BPF_LSM */
>  
>  #endif /* _LINUX_BPF_LSM_H */
> diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
> index a18ae82a298a..881e7954c956 100644
> --- a/include/linux/bpf_types.h
> +++ b/include/linux/bpf_types.h
> @@ -101,6 +101,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_HASH_OF_MAPS, htab_of_maps_map_ops)
>  BPF_MAP_TYPE(BPF_MAP_TYPE_DEVMAP, dev_map_ops)
>  BPF_MAP_TYPE(BPF_MAP_TYPE_DEVMAP_HASH, dev_map_hash_ops)
>  BPF_MAP_TYPE(BPF_MAP_TYPE_SK_STORAGE, sk_storage_map_ops)
> +BPF_MAP_TYPE(BPF_MAP_TYPE_INODE_STORAGE, inode_storage_map_ops)
sk_storage is under CONFIG_NET.

inode_storage should be CONFIG_BPF_LSM?

>  #if defined(CONFIG_BPF_STREAM_PARSER)
>  BPF_MAP_TYPE(BPF_MAP_TYPE_SOCKMAP, sock_map_ops)
>  BPF_MAP_TYPE(BPF_MAP_TYPE_SOCKHASH, sock_hash_ops)