4 files changed, 41 insertions, 0 deletions

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index ddfa6cc13e57..0a4fe5a7dc91 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -684,6 +684,8 @@ cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
                 return &bpf_map_delete_elem_proto;
         case BPF_FUNC_get_current_uid_gid:
                 return &bpf_get_current_uid_gid_proto;
+        case BPF_FUNC_get_local_storage:
+                return &bpf_get_local_storage_proto;
         case BPF_FUNC_trace_printk:
                 if (capable(CAP_SYS_ADMIN))
                         return bpf_get_trace_printk_proto();
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 9abcf25ebf9f..4d09e610777f 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1795,6 +1795,7 @@ const struct bpf_func_proto bpf_get_current_comm_proto __weak;
 const struct bpf_func_proto bpf_sock_map_update_proto __weak;
 const struct bpf_func_proto bpf_sock_hash_update_proto __weak;
 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak;
+const struct bpf_func_proto bpf_get_local_storage_proto __weak;
 
 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
 {
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 73065e2d23c2..1991466b8327 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -193,4 +193,24 @@ const struct bpf_func_proto bpf_get_current_cgroup_id_proto = {
         .gpl_only       = false,
         .ret_type       = RET_INTEGER,
 };
+
+DECLARE_PER_CPU(void*, bpf_cgroup_storage);
+
+BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags)
+{
+        /* map and flags arguments are not used now,
+         * but provide an ability to extend the API
+         * for other types of local storages.
+         * verifier checks that their values are correct.
+         */
+        return (unsigned long) this_cpu_read(bpf_cgroup_storage);
+}
+
+const struct bpf_func_proto bpf_get_local_storage_proto = {
+        .func           = bpf_get_local_storage,
+        .gpl_only       = false,
+        .ret_type       = RET_PTR_TO_MAP_VALUE,
+        .arg1_type      = ARG_CONST_MAP_PTR,
+        .arg2_type      = ARG_ANYTHING,
+};
 #endif
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 1ede16c8bb40..587468a9c37d 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2127,6 +2127,10 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
                     func_id != BPF_FUNC_current_task_under_cgroup)
                         goto error;
                 break;
+        case BPF_MAP_TYPE_CGROUP_STORAGE:
+                if (func_id != BPF_FUNC_get_local_storage)
+                        goto error;
+                break;
         /* devmap returns a pointer to a live net_device ifindex that we cannot
          * allow to be modified from bpf side. So do not allow lookup elements
          * for now.
@@ -2209,6 +2213,10 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
                 if (map->map_type != BPF_MAP_TYPE_SOCKHASH)
                         goto error;
                 break;
+        case BPF_FUNC_get_local_storage:
+                if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE)
+                        goto error;
+                break;
         default:
                 break;
         }
@@ -2533,6 +2541,16 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
         }
 
         regs = cur_regs(env);
+
+        /* check that flags argument in get_local_storage(map, flags) is 0,
+         * this is required because get_local_storage() can't return an error.
+         */
+        if (func_id == BPF_FUNC_get_local_storage &&
+            !register_is_null(&regs[BPF_REG_2])) {
+                verbose(env, "get_local_storage() doesn't support non-zero flags\n");
+                return -EINVAL;
+        }
+
         /* reset caller saved regs */
         for (i = 0; i < CALLER_SAVED_REGS; i++) {
                 mark_reg_not_init(env, regs, caller_saved[i]);