// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2021. Huawei Technologies Co., Ltd */ #include #include #include #include extern struct bpf_struct_ops bpf_bpf_dummy_ops; /* A common type for test_N with return value in bpf_dummy_ops */ typedef int (*dummy_ops_test_ret_fn)(struct bpf_dummy_ops_state *state, ...); static int dummy_ops_test_ret_function(struct bpf_dummy_ops_state *state, ...) { return 0; } struct bpf_dummy_ops_test_args { u64 args[MAX_BPF_FUNC_ARGS]; struct bpf_dummy_ops_state state; }; static struct bpf_dummy_ops_test_args * dummy_ops_init_args(const union bpf_attr *kattr, unsigned int nr) { __u32 size_in; struct bpf_dummy_ops_test_args *args; void __user *ctx_in; void __user *u_state; size_in = kattr->test.ctx_size_in; if (size_in != sizeof(u64) * nr) return ERR_PTR(-EINVAL); args = kzalloc(sizeof(*args), GFP_KERNEL); if (!args) return ERR_PTR(-ENOMEM); ctx_in = u64_to_user_ptr(kattr->test.ctx_in); if (copy_from_user(args->args, ctx_in, size_in)) goto out; /* args[0] is 0 means state argument of test_N will be NULL */ u_state = u64_to_user_ptr(args->args[0]); if (u_state && copy_from_user(&args->state, u_state, sizeof(args->state))) goto out; return args; out: kfree(args); return ERR_PTR(-EFAULT); } static int dummy_ops_copy_args(struct bpf_dummy_ops_test_args *args) { void __user *u_state; u_state = u64_to_user_ptr(args->args[0]); if (u_state && copy_to_user(u_state, &args->state, sizeof(args->state))) return -EFAULT; return 0; } static int dummy_ops_call_op(void *image, struct bpf_dummy_ops_test_args *args) { dummy_ops_test_ret_fn test = (void *)image + cfi_get_offset(); struct bpf_dummy_ops_state *state = NULL; /* state needs to be NULL if args[0] is 0 */ if (args->args[0]) state = &args->state; return test(state, args->args[1], args->args[2], args->args[3], args->args[4]); } extern const struct bpf_link_ops bpf_struct_ops_link_lops; int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, union bpf_attr __user *uattr) { const struct bpf_struct_ops *st_ops = &bpf_bpf_dummy_ops; const struct btf_type *func_proto; struct bpf_dummy_ops_test_args *args; struct bpf_tramp_links *tlinks; struct bpf_tramp_link *link = NULL; void *image = NULL; unsigned int op_idx; int prog_ret; int err; if (prog->aux->attach_btf_id != st_ops->type_id) return -EOPNOTSUPP; func_proto = prog->aux->attach_func_proto; args = dummy_ops_init_args(kattr, btf_type_vlen(func_proto)); if (IS_ERR(args)) return PTR_ERR(args); tlinks = kcalloc(BPF_TRAMP_MAX, sizeof(*tlinks), GFP_KERNEL); if (!tlinks) { err = -ENOMEM; goto out; } image = arch_alloc_bpf_trampoline(PAGE_SIZE); if (!image) { err = -ENOMEM; goto out; } link = kzalloc(sizeof(*link), GFP_USER); if (!link) { err = -ENOMEM; goto out; } /* prog doesn't take the ownership of the reference from caller */ bpf_prog_inc(prog); bpf_link_init(&link->link, BPF_LINK_TYPE_STRUCT_OPS, &bpf_struct_ops_link_lops, prog); op_idx = prog->expected_attach_type; err = bpf_struct_ops_prepare_trampoline(tlinks, link, &st_ops->func_models[op_idx], &dummy_ops_test_ret_function, image, image + PAGE_SIZE); if (err < 0) goto out; arch_protect_bpf_trampoline(image, PAGE_SIZE); prog_ret = dummy_ops_call_op(image, args); err = dummy_ops_copy_args(args); if (err) goto out; if (put_user(prog_ret, &uattr->test.retval)) err = -EFAULT; out: kfree(args); arch_free_bpf_trampoline(image, PAGE_SIZE); if (link) bpf_link_put(&link->link); kfree(tlinks); return err; } static int bpf_dummy_init(struct btf *btf) { return 0; } static bool bpf_dummy_ops_is_valid_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { return bpf_tracing_btf_ctx_access(off, size, type, prog, info); } static int bpf_dummy_ops_check_member(const struct btf_type *t, const struct btf_member *member, const struct bpf_prog *prog) { u32 moff = __btf_member_bit_offset(t, member) / 8; switch (moff) { case offsetof(struct bpf_dummy_ops, test_sleepable): break; default: if (prog->aux->sleepable) return -EINVAL; } return 0; } static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log, const struct bpf_reg_state *reg, int off, int size) { const struct btf_type *state; const struct btf_type *t; s32 type_id; type_id = btf_find_by_name_kind(reg->btf, "bpf_dummy_ops_state", BTF_KIND_STRUCT); if (type_id < 0) return -EINVAL; t = btf_type_by_id(reg->btf, reg->btf_id); state = btf_type_by_id(reg->btf, type_id); if (t != state) { bpf_log(log, "only access to bpf_dummy_ops_state is supported\n"); return -EACCES; } if (off + size > sizeof(struct bpf_dummy_ops_state)) { bpf_log(log, "write access at off %d with size %d\n", off, size); return -EACCES; } return NOT_INIT; } static const struct bpf_verifier_ops bpf_dummy_verifier_ops = { .is_valid_access = bpf_dummy_ops_is_valid_access, .btf_struct_access = bpf_dummy_ops_btf_struct_access, }; static int bpf_dummy_init_member(const struct btf_type *t, const struct btf_member *member, void *kdata, const void *udata) { return -EOPNOTSUPP; } static int bpf_dummy_reg(void *kdata) { return -EOPNOTSUPP; } static void bpf_dummy_unreg(void *kdata) { } static int bpf_dummy_test_1(struct bpf_dummy_ops_state *cb) { return 0; } static int bpf_dummy_test_2(struct bpf_dummy_ops_state *cb, int a1, unsigned short a2, char a3, unsigned long a4) { return 0; } static int bpf_dummy_test_sleepable(struct bpf_dummy_ops_state *cb) { return 0; } static struct bpf_dummy_ops __bpf_bpf_dummy_ops = { .test_1 = bpf_dummy_test_1, .test_2 = bpf_dummy_test_2, .test_sleepable = bpf_dummy_test_sleepable, }; struct bpf_struct_ops bpf_bpf_dummy_ops = { .verifier_ops = &bpf_dummy_verifier_ops, .init = bpf_dummy_init, .check_member = bpf_dummy_ops_check_member, .init_member = bpf_dummy_init_member, .reg = bpf_dummy_reg, .unreg = bpf_dummy_unreg, .name = "bpf_dummy_ops", .cfi_stubs = &__bpf_bpf_dummy_ops, };