Commit 4ddb7416 authored by Dmitrii Banshchikov's avatar Dmitrii Banshchikov Committed by Alexei Starovoitov
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bpf: Extract nullable reg type conversion into a helper function 



Extract conversion from a register's nullable type to a type with a
value. The helper will be used in mark_ptr_not_null_reg().

Signed-off-by: default avatarDmitrii Banshchikov <me@ubique.spb.ru>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210212205642.620788-3-me@ubique.spb.ru
parent feb4adfa

kernel/bpf/verifier.c

+52 −31
Original line number Diff line number Diff line
@@ -1079,6 +1079,51 @@ static void mark_reg_known_zero(struct bpf_verifier_env *env, 
	__mark_reg_known_zero(regs + regno);

}



static void mark_ptr_not_null_reg(struct bpf_reg_state *reg)

{

	switch (reg->type) {

	case PTR_TO_MAP_VALUE_OR_NULL: {

		const struct bpf_map *map = reg->map_ptr;



		if (map->inner_map_meta) {

			reg->type = CONST_PTR_TO_MAP;

			reg->map_ptr = map->inner_map_meta;

		} else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {

			reg->type = PTR_TO_XDP_SOCK;

		} else if (map->map_type == BPF_MAP_TYPE_SOCKMAP ||

			   map->map_type == BPF_MAP_TYPE_SOCKHASH) {

			reg->type = PTR_TO_SOCKET;

		} else {

			reg->type = PTR_TO_MAP_VALUE;

		}

		break;

	}

	case PTR_TO_SOCKET_OR_NULL:

		reg->type = PTR_TO_SOCKET;

		break;

	case PTR_TO_SOCK_COMMON_OR_NULL:

		reg->type = PTR_TO_SOCK_COMMON;

		break;

	case PTR_TO_TCP_SOCK_OR_NULL:

		reg->type = PTR_TO_TCP_SOCK;

		break;

	case PTR_TO_BTF_ID_OR_NULL:

		reg->type = PTR_TO_BTF_ID;

		break;

	case PTR_TO_MEM_OR_NULL:

		reg->type = PTR_TO_MEM;

		break;

	case PTR_TO_RDONLY_BUF_OR_NULL:

		reg->type = PTR_TO_RDONLY_BUF;

		break;

	case PTR_TO_RDWR_BUF_OR_NULL:

		reg->type = PTR_TO_RDWR_BUF;

		break;

	default:

		WARN_ON("unknown nullable register type");

	}

}



static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg)

{

	return type_is_pkt_pointer(reg->type);
@@ -7737,43 +7782,19 @@ static void mark_ptr_or_null_reg(struct bpf_func_state *state, 
		}

		if (is_null) {

			reg->type = SCALAR_VALUE;

		} else if (reg->type == PTR_TO_MAP_VALUE_OR_NULL) {

			const struct bpf_map *map = reg->map_ptr;



			if (map->inner_map_meta) {

				reg->type = CONST_PTR_TO_MAP;

				reg->map_ptr = map->inner_map_meta;

			} else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {

				reg->type = PTR_TO_XDP_SOCK;

			} else if (map->map_type == BPF_MAP_TYPE_SOCKMAP ||

				   map->map_type == BPF_MAP_TYPE_SOCKHASH) {

				reg->type = PTR_TO_SOCKET;

			} else {

				reg->type = PTR_TO_MAP_VALUE;

			}

		} else if (reg->type == PTR_TO_SOCKET_OR_NULL) {

			reg->type = PTR_TO_SOCKET;

		} else if (reg->type == PTR_TO_SOCK_COMMON_OR_NULL) {

			reg->type = PTR_TO_SOCK_COMMON;

		} else if (reg->type == PTR_TO_TCP_SOCK_OR_NULL) {

			reg->type = PTR_TO_TCP_SOCK;

		} else if (reg->type == PTR_TO_BTF_ID_OR_NULL) {

			reg->type = PTR_TO_BTF_ID;

		} else if (reg->type == PTR_TO_MEM_OR_NULL) {

			reg->type = PTR_TO_MEM;

		} else if (reg->type == PTR_TO_RDONLY_BUF_OR_NULL) {

			reg->type = PTR_TO_RDONLY_BUF;

		} else if (reg->type == PTR_TO_RDWR_BUF_OR_NULL) {

			reg->type = PTR_TO_RDWR_BUF;

		}

		if (is_null) {

			/* We don't need id and ref_obj_id from this point

			 * onwards anymore, thus we should better reset it,

			 * so that state pruning has chances to take effect.

			 */

			reg->id = 0;

			reg->ref_obj_id = 0;

		} else if (!reg_may_point_to_spin_lock(reg)) {



			return;

		}



		mark_ptr_not_null_reg(reg);



		if (!reg_may_point_to_spin_lock(reg)) {

			/* For not-NULL ptr, reg->ref_obj_id will be reset

			 * in release_reg_references().

			 *