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
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
|
// SPDX-License-Identifier: GPL-2.0
/* Converted from tools/testing/selftests/bpf/verifier/ctx.c */
#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
SEC("tc")
__description("context stores via BPF_ATOMIC")
__failure __msg("BPF_ATOMIC stores into R1 ctx is not allowed")
__naked void context_stores_via_bpf_atomic(void)
{
asm volatile (" \
r0 = 0; \
lock *(u32 *)(r1 + %[__sk_buff_mark]) += w0; \
exit; \
" :
: __imm_const(__sk_buff_mark, offsetof(struct __sk_buff, mark))
: __clobber_all);
}
SEC("tc")
__description("arithmetic ops make PTR_TO_CTX unusable")
__failure __msg("dereference of modified ctx ptr")
__naked void make_ptr_to_ctx_unusable(void)
{
asm volatile (" \
r1 += %[__imm_0]; \
r0 = *(u32*)(r1 + %[__sk_buff_mark]); \
exit; \
" :
: __imm_const(__imm_0,
offsetof(struct __sk_buff, data) - offsetof(struct __sk_buff, mark)),
__imm_const(__sk_buff_mark, offsetof(struct __sk_buff, mark))
: __clobber_all);
}
SEC("tc")
__description("pass unmodified ctx pointer to helper")
__success __retval(0)
__naked void unmodified_ctx_pointer_to_helper(void)
{
asm volatile (" \
r2 = 0; \
call %[bpf_csum_update]; \
r0 = 0; \
exit; \
" :
: __imm(bpf_csum_update)
: __clobber_all);
}
SEC("tc")
__description("pass modified ctx pointer to helper, 1")
__failure __msg("negative offset ctx ptr R1 off=-612 disallowed")
__naked void ctx_pointer_to_helper_1(void)
{
asm volatile (" \
r1 += -612; \
r2 = 0; \
call %[bpf_csum_update]; \
r0 = 0; \
exit; \
" :
: __imm(bpf_csum_update)
: __clobber_all);
}
SEC("socket")
__description("pass modified ctx pointer to helper, 2")
__failure __msg("negative offset ctx ptr R1 off=-612 disallowed")
__failure_unpriv __msg_unpriv("negative offset ctx ptr R1 off=-612 disallowed")
__naked void ctx_pointer_to_helper_2(void)
{
asm volatile (" \
r1 += -612; \
call %[bpf_get_socket_cookie]; \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_socket_cookie)
: __clobber_all);
}
SEC("tc")
__description("pass modified ctx pointer to helper, 3")
__failure __msg("variable ctx access var_off=(0x0; 0x4)")
__naked void ctx_pointer_to_helper_3(void)
{
asm volatile (" \
r3 = *(u32*)(r1 + 0); \
r3 &= 4; \
r1 += r3; \
r2 = 0; \
call %[bpf_csum_update]; \
r0 = 0; \
exit; \
" :
: __imm(bpf_csum_update)
: __clobber_all);
}
SEC("cgroup/sendmsg6")
__description("pass ctx or null check, 1: ctx")
__success
__naked void or_null_check_1_ctx(void)
{
asm volatile (" \
call %[bpf_get_netns_cookie]; \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_netns_cookie)
: __clobber_all);
}
SEC("cgroup/sendmsg6")
__description("pass ctx or null check, 2: null")
__success
__naked void or_null_check_2_null(void)
{
asm volatile (" \
r1 = 0; \
call %[bpf_get_netns_cookie]; \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_netns_cookie)
: __clobber_all);
}
SEC("cgroup/sendmsg6")
__description("pass ctx or null check, 3: 1")
__failure __msg("R1 type=scalar expected=ctx")
__naked void or_null_check_3_1(void)
{
asm volatile (" \
r1 = 1; \
call %[bpf_get_netns_cookie]; \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_netns_cookie)
: __clobber_all);
}
SEC("cgroup/sendmsg6")
__description("pass ctx or null check, 4: ctx - const")
__failure __msg("negative offset ctx ptr R1 off=-612 disallowed")
__naked void null_check_4_ctx_const(void)
{
asm volatile (" \
r1 += -612; \
call %[bpf_get_netns_cookie]; \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_netns_cookie)
: __clobber_all);
}
SEC("cgroup/connect4")
__description("pass ctx or null check, 5: null (connect)")
__success
__naked void null_check_5_null_connect(void)
{
asm volatile (" \
r1 = 0; \
call %[bpf_get_netns_cookie]; \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_netns_cookie)
: __clobber_all);
}
SEC("cgroup/post_bind4")
__description("pass ctx or null check, 6: null (bind)")
__success
__naked void null_check_6_null_bind(void)
{
asm volatile (" \
r1 = 0; \
call %[bpf_get_netns_cookie]; \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_netns_cookie)
: __clobber_all);
}
SEC("cgroup/post_bind4")
__description("pass ctx or null check, 7: ctx (bind)")
__success
__naked void null_check_7_ctx_bind(void)
{
asm volatile (" \
call %[bpf_get_socket_cookie]; \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_socket_cookie)
: __clobber_all);
}
SEC("cgroup/post_bind4")
__description("pass ctx or null check, 8: null (bind)")
__failure __msg("R1 type=scalar expected=ctx")
__naked void null_check_8_null_bind(void)
{
asm volatile (" \
r1 = 0; \
call %[bpf_get_socket_cookie]; \
r0 = 0; \
exit; \
" :
: __imm(bpf_get_socket_cookie)
: __clobber_all);
}
#define narrow_load(type, ctx, field) \
SEC(type) \
__description("narrow load on field " #field " of " #ctx) \
__failure __msg("invalid bpf_context access") \
__naked void invalid_narrow_load##ctx##field(void) \
{ \
asm volatile (" \
r1 = *(u32 *)(r1 + %[off]); \
r0 = 0; \
exit;" \
: \
: __imm_const(off, offsetof(struct ctx, field) + 4) \
: __clobber_all); \
}
narrow_load("cgroup/getsockopt", bpf_sockopt, sk);
narrow_load("cgroup/getsockopt", bpf_sockopt, optval);
narrow_load("cgroup/getsockopt", bpf_sockopt, optval_end);
narrow_load("tc", __sk_buff, sk);
narrow_load("cgroup/bind4", bpf_sock_addr, sk);
narrow_load("sockops", bpf_sock_ops, sk);
narrow_load("sockops", bpf_sock_ops, skb_data);
narrow_load("sockops", bpf_sock_ops, skb_data_end);
narrow_load("sockops", bpf_sock_ops, skb_hwtstamp);
#define unaligned_access(type, ctx, field) \
SEC(type) \
__description("unaligned access on field " #field " of " #ctx) \
__failure __msg("invalid bpf_context access") \
__naked void unaligned_ctx_access_##ctx##field(void) \
{ \
asm volatile (" \
r1 = *(u%[size] *)(r1 + %[off]); \
r0 = 0; \
exit;" \
: \
: __imm_const(size, sizeof_field(struct ctx, field) * 8), \
__imm_const(off, offsetof(struct ctx, field) + 1) \
: __clobber_all); \
}
unaligned_access("flow_dissector", __sk_buff, data);
unaligned_access("netfilter", bpf_nf_ctx, skb);
char _license[] SEC("license") = "GPL";
|
