[RFC PATCH bpf-next v2 2/4] bpf: restrict use of peek/push/pop

[Mauricio Vasquez B]

Restrict the use of peek, push and pop helpers only to queue and stack
maps.

Signed-off-by: Mauricio Vasquez B <mauricio.vasq...@polito.it>
---
 kernel/bpf/verifier.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 5bd67feb2f07..9e177ff4a3b9 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2172,6 +2172,13 @@ static int check_map_func_compatibility(struct 
bpf_verifier_env *env,
                if (func_id != BPF_FUNC_sk_select_reuseport)
                        goto error;
                break;
+       case BPF_MAP_TYPE_QUEUE:
+       case BPF_MAP_TYPE_STACK:
+               if (func_id != BPF_FUNC_map_peek_elem &&
+                   func_id != BPF_FUNC_map_pop_elem &&
+                   func_id != BPF_FUNC_map_push_elem)
+                       goto error;
+               break;
        default:
                break;
        }
@@ -2227,6 +2234,13 @@ static int check_map_func_compatibility(struct 
bpf_verifier_env *env,
                if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY)
                        goto error;
                break;
+       case BPF_FUNC_map_peek_elem:
+       case BPF_FUNC_map_pop_elem:
+       case BPF_FUNC_map_push_elem:
+               if (map->map_type != BPF_MAP_TYPE_QUEUE &&
+                   map->map_type != BPF_MAP_TYPE_STACK)
+                       goto error;
+               break;
        default:
                break;
        }