1 // SPDX-License-Identifier: GPL-2.0
2 /* Converted from tools/testing/selftests/bpf/verifier/map_ptr.c */
3
4 #include <linux/bpf.h>
5 #include <bpf/bpf_helpers.h>
6 #include "bpf_misc.h"
7
8 #define MAX_ENTRIES 11
9
10 struct test_val {
11 unsigned int index;
12 int foo[MAX_ENTRIES];
13 };
14
15 struct {
16 __uint(type, BPF_MAP_TYPE_ARRAY);
17 __uint(max_entries, 1);
18 __type(key, int);
19 __type(value, struct test_val);
20 } map_array_48b SEC(".maps");
21
22 struct other_val {
23 long long foo;
24 long long bar;
25 };
26
27 struct {
28 __uint(type, BPF_MAP_TYPE_HASH);
29 __uint(max_entries, 1);
30 __type(key, long long);
31 __type(value, struct other_val);
32 } map_hash_16b SEC(".maps");
33
34 SEC("socket")
35 __description("bpf_map_ptr: read with negative offset rejected")
36 __failure __msg("R1 is bpf_array invalid negative access: off=-8")
37 __failure_unpriv
38 __msg_unpriv("access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN")
read_with_negative_offset_rejected(void)39 __naked void read_with_negative_offset_rejected(void)
40 {
41 asm volatile (" \
42 r1 = r10; \
43 r1 = %[map_array_48b] ll; \
44 r6 = *(u64*)(r1 - 8); \
45 r0 = 1; \
46 exit; \
47 " :
48 : __imm_addr(map_array_48b)
49 : __clobber_all);
50 }
51
52 SEC("socket")
53 __description("bpf_map_ptr: write rejected")
54 __failure __msg("only read from bpf_array is supported")
55 __failure_unpriv
56 __msg_unpriv("access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN")
bpf_map_ptr_write_rejected(void)57 __naked void bpf_map_ptr_write_rejected(void)
58 {
59 asm volatile (" \
60 r0 = 0; \
61 *(u64*)(r10 - 8) = r0; \
62 r2 = r10; \
63 r2 += -8; \
64 r1 = %[map_array_48b] ll; \
65 *(u64*)(r1 + 0) = r2; \
66 r0 = 1; \
67 exit; \
68 " :
69 : __imm_addr(map_array_48b)
70 : __clobber_all);
71 }
72
73 /*
74 * struct bpf_map starts with the SHA256 hash sha[32] at offset 0 (a readable
75 * byte array), followed by the ops pointer at offset 32 and the inner_map_meta
76 * pointer at offset 40. Reading a u32 at offset 41 reaches into the middle of
77 * the inner_map_meta pointer, i.e. a partial pointer access, which is
78 * rejected.
79 */
80 SEC("socket")
81 __description("bpf_map_ptr: read non-existent field rejected")
82 __failure
83 __msg("cannot access ptr member inner_map_meta with moff 40 in struct bpf_map with off 41 size 4")
84 __failure_unpriv
85 __msg_unpriv("access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN")
__flag(BPF_F_ANY_ALIGNMENT)86 __flag(BPF_F_ANY_ALIGNMENT)
87 __naked void read_non_existent_field_rejected(void)
88 {
89 asm volatile (" \
90 r6 = 0; \
91 r1 = %[map_array_48b] ll; \
92 r6 = *(u32*)(r1 + 41); \
93 r0 = 1; \
94 exit; \
95 " :
96 : __imm_addr(map_array_48b)
97 : __clobber_all);
98 }
99
100 /*
101 * The sha byte array spans offsets 0..31 (mend 32). Reading a u32 at offset
102 * 30 starts inside sha but extends past its end, which the verifier rejects
103 * as an out-of-bounds scalar access.
104 */
105 SEC("socket")
106 __description("bpf_map_ptr: read beyond sha field rejected")
107 __failure
108 __msg("access beyond the end of member sha (mend:32) in struct bpf_map with off 30 size 4")
109 __failure_unpriv
110 __msg_unpriv("access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN")
__flag(BPF_F_ANY_ALIGNMENT)111 __flag(BPF_F_ANY_ALIGNMENT)
112 __naked void read_beyond_sha_field_rejected(void)
113 {
114 asm volatile (" \
115 r6 = 0; \
116 r1 = %[map_array_48b] ll; \
117 r6 = *(u32*)(r1 + 30); \
118 r0 = 1; \
119 exit; \
120 " :
121 : __imm_addr(map_array_48b)
122 : __clobber_all);
123 }
124
125 SEC("socket")
126 __description("bpf_map_ptr: read ops field accepted")
127 __success __failure_unpriv
128 __msg_unpriv("access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN")
129 __retval(1)
ptr_read_ops_field_accepted(void)130 __naked void ptr_read_ops_field_accepted(void)
131 {
132 asm volatile (" \
133 r6 = 0; \
134 r1 = %[map_array_48b] ll; \
135 r6 = *(u64*)(r1 + 32); \
136 r0 = 1; \
137 exit; \
138 " :
139 : __imm_addr(map_array_48b)
140 : __clobber_all);
141 }
142
143 SEC("socket")
144 __description("bpf_map_ptr: r = 0, map_ptr = map_ptr + r")
145 __success __failure_unpriv
146 __msg_unpriv("R1 has pointer with unsupported alu operation")
147 __retval(0)
map_ptr_map_ptr_r(void)148 __naked void map_ptr_map_ptr_r(void)
149 {
150 asm volatile (" \
151 r0 = 0; \
152 *(u64*)(r10 - 8) = r0; \
153 r2 = r10; \
154 r2 += -8; \
155 r0 = 0; \
156 r1 = %[map_hash_16b] ll; \
157 r1 += r0; \
158 call %[bpf_map_lookup_elem]; \
159 r0 = 0; \
160 exit; \
161 " :
162 : __imm(bpf_map_lookup_elem),
163 __imm_addr(map_hash_16b)
164 : __clobber_all);
165 }
166
167 SEC("socket")
168 __description("bpf_map_ptr: r = 0, r = r + map_ptr")
169 __success __failure_unpriv
170 __msg_unpriv("R0 has pointer with unsupported alu operation")
171 __retval(0)
_0_r_r_map_ptr(void)172 __naked void _0_r_r_map_ptr(void)
173 {
174 asm volatile (" \
175 r0 = 0; \
176 *(u64*)(r10 - 8) = r0; \
177 r2 = r10; \
178 r2 += -8; \
179 r1 = 0; \
180 r0 = %[map_hash_16b] ll; \
181 r1 += r0; \
182 call %[bpf_map_lookup_elem]; \
183 r0 = 0; \
184 exit; \
185 " :
186 : __imm(bpf_map_lookup_elem),
187 __imm_addr(map_hash_16b)
188 : __clobber_all);
189 }
190
191 char _license[] SEC("license") = "GPL";
192