On Thu, 2017-08-31 at 13:56 -0700, Chenbo Feng wrote:
> From: Chenbo Feng <fe...@google.com>
>
> Introduce a pointer into struct bpf_map to hold the security information
> about the map. The actual security struct varies based on the security
> models implemented. Place the LSM hooks before each of the unrestricted
> eBPF operations, the map_update_elem and map_delete_elem operations are
> checked by security_map_modify. The map_lookup_elem and map_get_next_key
> operations are checked by securtiy_map_read.
>
> Signed-off-by: Chenbo Feng <fe...@google.com>
> ---
> include/linux/bpf.h | 3 +++
> kernel/bpf/syscall.c | 28 ++++++++++++++++++++++++++++
> 2 files changed, 31 insertions(+)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index b69e7a5869ff..ca3e6ff7091d 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -53,6 +53,9 @@ struct bpf_map {
> struct work_struct work;
> atomic_t usercnt;
> struct bpf_map *inner_map_meta;
> +#ifdef CONFIG_SECURITY
> + void *security;
> +#endif
> };
>
> /* function argument constraints */
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index 045646da97cc..b15580bcf3b1 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -279,6 +279,10 @@ static int map_create(union bpf_attr *attr)
> if (err)
> return -EINVAL;
>
> + err = security_map_create();
> + if (err)
> + return -EACCES;
Any reason not to just return err?
Mimi
> +
> /* find map type and init map: hashtable vs rbtree vs bloom vs ... */
> map = find_and_alloc_map(attr);
> if (IS_ERR(map))
> @@ -291,6 +295,10 @@ static int map_create(union bpf_attr *attr)
> if (err)
> goto free_map_nouncharge;
>
> + err = security_post_create(map);
> + if (err < 0)
> + goto free_map;
> +
> err = bpf_map_alloc_id(map);
> if (err)
> goto free_map;
> @@ -410,6 +418,10 @@ static int map_lookup_elem(union bpf_attr *attr)
> if (IS_ERR(map))
> return PTR_ERR(map);
>
> + err = security_map_read(map);
> + if (err)
> + return -EACCES;
> +
> key = memdup_user(ukey, map->key_size);
> if (IS_ERR(key)) {
> err = PTR_ERR(key);
> @@ -490,6 +502,10 @@ static int map_update_elem(union bpf_attr *attr)
> if (IS_ERR(map))
> return PTR_ERR(map);
>
> + err = security_map_modify(map);
> + if (err)
> + return -EACCES;
> +
> key = memdup_user(ukey, map->key_size);
> if (IS_ERR(key)) {
> err = PTR_ERR(key);
> @@ -573,6 +589,10 @@ static int map_delete_elem(union bpf_attr *attr)
> if (IS_ERR(map))
> return PTR_ERR(map);
>
> + err = security_map_modify(map);
> + if (err)
> + return -EACCES;
> +
> key = memdup_user(ukey, map->key_size);
> if (IS_ERR(key)) {
> err = PTR_ERR(key);
> @@ -616,6 +636,10 @@ static int map_get_next_key(union bpf_attr *attr)
> if (IS_ERR(map))
> return PTR_ERR(map);
>
> + err = security_map_read(map);
> + if (err)
> + return -EACCES;
> +
> if (ukey) {
> key = memdup_user(ukey, map->key_size);
> if (IS_ERR(key)) {
> @@ -935,6 +959,10 @@ static int bpf_prog_load(union bpf_attr *attr)
> if (CHECK_ATTR(BPF_PROG_LOAD))
> return -EINVAL;
>
> + err = security_prog_load();
> + if (err)
> + return -EACCES;
> +
> if (attr->prog_flags & ~BPF_F_STRICT_ALIGNMENT)
> return -EINVAL;
>
