1
2
3
4
5#include <linux/kernel.h>
6#include <linux/bpf_verifier.h>
7#include <linux/bpf.h>
8#include <linux/btf.h>
9
10extern struct bpf_struct_ops bpf_bpf_dummy_ops;
11
12
13typedef int (*dummy_ops_test_ret_fn)(struct bpf_dummy_ops_state *state, ...);
14
15struct bpf_dummy_ops_test_args {
16 u64 args[MAX_BPF_FUNC_ARGS];
17 struct bpf_dummy_ops_state state;
18};
19
20static struct bpf_dummy_ops_test_args *
21dummy_ops_init_args(const union bpf_attr *kattr, unsigned int nr)
22{
23 __u32 size_in;
24 struct bpf_dummy_ops_test_args *args;
25 void __user *ctx_in;
26 void __user *u_state;
27
28 size_in = kattr->test.ctx_size_in;
29 if (size_in != sizeof(u64) * nr)
30 return ERR_PTR(-EINVAL);
31
32 args = kzalloc(sizeof(*args), GFP_KERNEL);
33 if (!args)
34 return ERR_PTR(-ENOMEM);
35
36 ctx_in = u64_to_user_ptr(kattr->test.ctx_in);
37 if (copy_from_user(args->args, ctx_in, size_in))
38 goto out;
39
40
41 u_state = u64_to_user_ptr(args->args[0]);
42 if (u_state && copy_from_user(&args->state, u_state,
43 sizeof(args->state)))
44 goto out;
45
46 return args;
47out:
48 kfree(args);
49 return ERR_PTR(-EFAULT);
50}
51
52static int dummy_ops_copy_args(struct bpf_dummy_ops_test_args *args)
53{
54 void __user *u_state;
55
56 u_state = u64_to_user_ptr(args->args[0]);
57 if (u_state && copy_to_user(u_state, &args->state, sizeof(args->state)))
58 return -EFAULT;
59
60 return 0;
61}
62
63static int dummy_ops_call_op(void *image, struct bpf_dummy_ops_test_args *args)
64{
65 dummy_ops_test_ret_fn test = (void *)image;
66 struct bpf_dummy_ops_state *state = NULL;
67
68
69 if (args->args[0])
70 state = &args->state;
71 return test(state, args->args[1], args->args[2],
72 args->args[3], args->args[4]);
73}
74
75int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr,
76 union bpf_attr __user *uattr)
77{
78 const struct bpf_struct_ops *st_ops = &bpf_bpf_dummy_ops;
79 const struct btf_type *func_proto;
80 struct bpf_dummy_ops_test_args *args;
81 struct bpf_tramp_progs *tprogs;
82 void *image = NULL;
83 unsigned int op_idx;
84 int prog_ret;
85 int err;
86
87 if (prog->aux->attach_btf_id != st_ops->type_id)
88 return -EOPNOTSUPP;
89
90 func_proto = prog->aux->attach_func_proto;
91 args = dummy_ops_init_args(kattr, btf_type_vlen(func_proto));
92 if (IS_ERR(args))
93 return PTR_ERR(args);
94
95 tprogs = kcalloc(BPF_TRAMP_MAX, sizeof(*tprogs), GFP_KERNEL);
96 if (!tprogs) {
97 err = -ENOMEM;
98 goto out;
99 }
100
101 image = bpf_jit_alloc_exec(PAGE_SIZE);
102 if (!image) {
103 err = -ENOMEM;
104 goto out;
105 }
106 set_vm_flush_reset_perms(image);
107
108 op_idx = prog->expected_attach_type;
109 err = bpf_struct_ops_prepare_trampoline(tprogs, prog,
110 &st_ops->func_models[op_idx],
111 image, image + PAGE_SIZE);
112 if (err < 0)
113 goto out;
114
115 set_memory_ro((long)image, 1);
116 set_memory_x((long)image, 1);
117 prog_ret = dummy_ops_call_op(image, args);
118
119 err = dummy_ops_copy_args(args);
120 if (err)
121 goto out;
122 if (put_user(prog_ret, &uattr->test.retval))
123 err = -EFAULT;
124out:
125 kfree(args);
126 bpf_jit_free_exec(image);
127 kfree(tprogs);
128 return err;
129}
130
131static int bpf_dummy_init(struct btf *btf)
132{
133 return 0;
134}
135
136static bool bpf_dummy_ops_is_valid_access(int off, int size,
137 enum bpf_access_type type,
138 const struct bpf_prog *prog,
139 struct bpf_insn_access_aux *info)
140{
141 return bpf_tracing_btf_ctx_access(off, size, type, prog, info);
142}
143
144static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log,
145 const struct btf *btf,
146 const struct btf_type *t, int off,
147 int size, enum bpf_access_type atype,
148 u32 *next_btf_id)
149{
150 const struct btf_type *state;
151 s32 type_id;
152 int err;
153
154 type_id = btf_find_by_name_kind(btf, "bpf_dummy_ops_state",
155 BTF_KIND_STRUCT);
156 if (type_id < 0)
157 return -EINVAL;
158
159 state = btf_type_by_id(btf, type_id);
160 if (t != state) {
161 bpf_log(log, "only access to bpf_dummy_ops_state is supported\n");
162 return -EACCES;
163 }
164
165 err = btf_struct_access(log, btf, t, off, size, atype, next_btf_id);
166 if (err < 0)
167 return err;
168
169 return atype == BPF_READ ? err : NOT_INIT;
170}
171
172static const struct bpf_verifier_ops bpf_dummy_verifier_ops = {
173 .is_valid_access = bpf_dummy_ops_is_valid_access,
174 .btf_struct_access = bpf_dummy_ops_btf_struct_access,
175};
176
177static int bpf_dummy_init_member(const struct btf_type *t,
178 const struct btf_member *member,
179 void *kdata, const void *udata)
180{
181 return -EOPNOTSUPP;
182}
183
184static int bpf_dummy_reg(void *kdata)
185{
186 return -EOPNOTSUPP;
187}
188
189static void bpf_dummy_unreg(void *kdata)
190{
191}
192
193struct bpf_struct_ops bpf_bpf_dummy_ops = {
194 .verifier_ops = &bpf_dummy_verifier_ops,
195 .init = bpf_dummy_init,
196 .init_member = bpf_dummy_init_member,
197 .reg = bpf_dummy_reg,
198 .unreg = bpf_dummy_unreg,
199 .name = "bpf_dummy_ops",
200};
201
