bpf: Inline map creation logic in map_create() function

Currently find_and_alloc_map() performs two separate functions: some argument sanity checking and partial map creation workflow hanling. Neither of those functions are self-sufficient and are augmented by further checks and initialization logic in the caller (map_create() function). So unify all the sanity checks, permission checks, and creation and initialization logic in one linear piece of code in map_create() instead. This also make it easier to further enhance permission checks and keep them located in one place.

Andrii Nakryiko committed 3 years ago

Commit 22db4121 parent 1d286351 file · +24 −33Browse files

Unified · Split

kernel/bpf/syscall.c+24−33

@@ -109,37 +109,6 @@ const struct bpf_map_ops bpf_map_offload_ops = { · 108 unmodified lines
109	109	.map_mem_usage = bpf_map_offload_map_mem_usage,
110	110	};
111	111
112		−static struct bpf_map find_and_alloc_map(union bpf_attr attr)
113		−{
114		− const struct bpf_map_ops *ops;
115		− u32 type = attr->map_type;
116		− struct bpf_map *map;
117		− int err;
118		−
119		− if (type >= ARRAY_SIZE(bpf_map_types))
120		− return ERR_PTR(-EINVAL);
121		− type = array_index_nospec(type, ARRAY_SIZE(bpf_map_types));
122		− ops = bpf_map_types[type];
123		− if (!ops)
124		− return ERR_PTR(-EINVAL);
125		−
126		− if (ops->map_alloc_check) {
127		− err = ops->map_alloc_check(attr);
128		− if (err)
129		− return ERR_PTR(err);
130		− }
131		− if (attr->map_ifindex)
132		− ops = &bpf_map_offload_ops;
133		− if (!ops->map_mem_usage)
134		− return ERR_PTR(-EINVAL);
135		− map = ops->map_alloc(attr);
136		− if (IS_ERR(map))
137		− return map;
138		− map->ops = ops;
139		− map->map_type = type;
140		− return map;
141		−}
142		−
143	112	static void bpf_map_write_active_inc(struct bpf_map *map)
144	113	{
145	114	atomic64_inc(&map->writecnt);
@@ -1127,7 +1096,9 @@ free_map_tab: · 981 unmodified lines
1127	1096	/* called via syscall */
1128	1097	static int map_create(union bpf_attr *attr)
1129	1098	{
	1099	+ const struct bpf_map_ops *ops;
1130	1100	int numa_node = bpf_map_attr_numa_node(attr);
	1101	+ u32 map_type = attr->map_type;
1131	1102	struct bpf_map *map;
1132	1103	int f_flags;
1133	1104	int err;
@@ -1157,6 +1128,25 @@ static int map_create(union bpf_attr *attr) · 23 unmodified lines
1157	1128	!node_online(numa_node)))
1158	1129	return -EINVAL;
1159	1130
	1131	+ /* find map type and init map: hashtable vs rbtree vs bloom vs ... */
	1132	+ map_type = attr->map_type;
	1133	+ if (map_type >= ARRAY_SIZE(bpf_map_types))
	1134	+ return -EINVAL;
	1135	+ map_type = array_index_nospec(map_type, ARRAY_SIZE(bpf_map_types));
	1136	+ ops = bpf_map_types[map_type];
	1137	+ if (!ops)
	1138	+ return -EINVAL;
	1139	+
	1140	+ if (ops->map_alloc_check) {
	1141	+ err = ops->map_alloc_check(attr);
	1142	+ if (err)
	1143	+ return err;
	1144	+ }
	1145	+ if (attr->map_ifindex)
	1146	+ ops = &bpf_map_offload_ops;
	1147	+ if (!ops->map_mem_usage)
	1148	+ return -EINVAL;
	1149	+
1160	1150	/* Intent here is for unprivileged_bpf_disabled to block BPF map
1161	1151	* creation for unprivileged users; other actions depend
1162	1152	* on fd availability and access to bpffs, so are dependent on
@@ -1166,10 +1156,11 @@ static int map_create(union bpf_attr *attr) · 3 unmodified lines
1166	1156	if (sysctl_unprivileged_bpf_disabled && !bpf_capable())
1167	1157	return -EPERM;
1168	1158
1169		− /* find map type and init map: hashtable vs rbtree vs bloom vs ... */
1170		− map = find_and_alloc_map(attr);
	1159	+ map = ops->map_alloc(attr);
1171	1160	if (IS_ERR(map))
1172	1161	return PTR_ERR(map);
	1162	+ map->ops = ops;
	1163	+ map->map_type = map_type;
1173	1164
1174	1165	err = bpf_obj_name_cpy(map->name, attr->map_name,
1175	1166	sizeof(attr->map_name));