1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2021. Huawei Technologies Co., Ltd
*/
#include <linux/kernel.h>
#include <linux/bpf_verifier.h>
#include <linux/bpf.h>
#include <linux/btf.h>
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, ...);
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;
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 = bpf_jit_alloc_exec(PAGE_SIZE);
if (!image) {
err = -ENOMEM;
goto out;
}
set_vm_flush_reset_perms(image);
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],
image, image + PAGE_SIZE);
if (err < 0)
goto out;
set_memory_ro((long)image, 1);
set_memory_x((long)image, 1);
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);
bpf_jit_free_exec(image);
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_btf_struct_access(struct bpf_verifier_log *log,
const struct btf *btf,
const struct btf_type *t, int off,
int size, enum bpf_access_type atype,
u32 *next_btf_id,
enum bpf_type_flag *flag)
{
const struct btf_type *state;
s32 type_id;
int err;
type_id = btf_find_by_name_kind(btf, "bpf_dummy_ops_state",
BTF_KIND_STRUCT);
if (type_id < 0)
return -EINVAL;
state = btf_type_by_id(btf, type_id);
if (t != state) {
bpf_log(log, "only access to bpf_dummy_ops_state is supported\n");
return -EACCES;
}
err = btf_struct_access(log, btf, t, off, size, atype, next_btf_id,
flag);
if (err < 0)
return err;
return atype == BPF_READ ? err : 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)
{
}
struct bpf_struct_ops bpf_bpf_dummy_ops = {
.verifier_ops = &bpf_dummy_verifier_ops,
.init = bpf_dummy_init,
.init_member = bpf_dummy_init_member,
.reg = bpf_dummy_reg,
.unreg = bpf_dummy_unreg,
.name = "bpf_dummy_ops",
};
|