bpf: Centralize permissions checks for all BPF map types

This allows to do more centralized decisions later on, and generally
makes it very explicit which maps are privileged and which are not
(e.g., LRU_HASH and LRU_PERCPU_HASH, which are privileged HASH variants,
as opposed to unprivileged HASH and HASH_PERCPU; now this is explicit
and easy to verify).

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230613223533.3689589-4-andrii@kernel.org

kernel/bpf/queue_stack_maps.c

@@ -7,7 +7,6 @@
 #include <linux/bpf.h>
 #include <linux/list.h>
 #include <linux/slab.h>
-#include <linux/capability.h>
 #include <linux/btf_ids.h>
 #include "percpu_freelist.h"
 
@@ -46,9 +45,6 @@ static bool queue_stack_map_is_full(struct bpf_queue_stack *qs)
 /* Called from syscall */
 static int queue_stack_map_alloc_check(union bpf_attr *attr)
 {
-	if (!bpf_capable())
-		return -EPERM;
-
 	/* check sanity of attributes */
 	if (attr->max_entries == 0 || attr->key_size != 0 ||
 	    attr->value_size == 0 ||