Commit 02f7c958 authored by Lorenz Bauer's avatar Lorenz Bauer Committed by Alexei Starovoitov
Browse files

bpf: Make reference tracking generic 



Instead of dealing with reg->ref_obj_id individually for every arg type that
needs it, rely on the fact that ref_obj_id is zero if the register is not
reference tracked.

Signed-off-by: default avatarLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-7-lmb@cloudflare.com
parent d7b9454a

kernel/bpf/verifier.c

+10 −16
Original line number Diff line number Diff line
@@ -4030,15 +4030,6 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, 
		/* Any sk pointer can be ARG_PTR_TO_SOCK_COMMON */

		if (!type_is_sk_pointer(type))

			goto err_type;

		if (reg->ref_obj_id) {

			if (meta->ref_obj_id) {

				verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",

					regno, reg->ref_obj_id,

					meta->ref_obj_id);

				return -EFAULT;

			}

			meta->ref_obj_id = reg->ref_obj_id;

		}

	} else if (arg_type == ARG_PTR_TO_SOCKET ||

		   arg_type == ARG_PTR_TO_SOCKET_OR_NULL) {

		expected_type = PTR_TO_SOCKET;
@@ -4087,13 +4078,6 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, 
			/* final test in check_stack_boundary() */;

		else if (type != expected_type)

			goto err_type;

		if (meta->ref_obj_id) {

			verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",

				regno, reg->ref_obj_id,

				meta->ref_obj_id);

			return -EFAULT;

		}

		meta->ref_obj_id = reg->ref_obj_id;

	} else if (arg_type_is_int_ptr(arg_type)) {

		expected_type = PTR_TO_STACK;

		if (!type_is_pkt_pointer(type) &&
@@ -4125,6 +4109,16 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, 
		}

	}



	if (reg->ref_obj_id) {

		if (meta->ref_obj_id) {

			verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",

				regno, reg->ref_obj_id,

				meta->ref_obj_id);

			return -EFAULT;

		}

		meta->ref_obj_id = reg->ref_obj_id;

	}



	if (arg_type == ARG_CONST_MAP_PTR) {

		/* bpf_map_xxx(map_ptr) call: remember that map_ptr */

		meta->map_ptr = reg->map_ptr;