1 /*
2 * Check decoding of socket filters.
3 *
4 * Copyright (c) 2017 Dmitry V. Levin <ldv@altlinux.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 #include "tests.h"
31
32 #include <stdio.h>
33 #include <unistd.h>
34 #include <netinet/in.h>
35 #include <sys/socket.h>
36 #include <linux/filter.h>
37
38 #define PRINT_STMT_SYM(pfx, code, k) PRINT_STMT_SYM_(pfx, #code, #k)
39 #define PRINT_STMT_SYM_(pfx, code, k) \
40 printf("%sBPF_STMT(%s, %s)", pfx, code, k)
41 #define PRINT_STMT_VAL(pfx, code, k) PRINT_STMT_VAL_(pfx, #code, k)
42 #define PRINT_STMT_VAL_(pfx, code, k) \
43 printf("%sBPF_STMT(%s, %#x)", pfx, code, k)
44
45 #define PRINT_JUMP(pfx, code, k, jt, jf) PRINT_JUMP_(pfx, #code, k, jt, jf)
46 #define PRINT_JUMP_(pfx, code, k, jt, jf) \
47 printf("%sBPF_JUMP(%s, %#x, %#x, %#x)", pfx, code, k, jt, jf)
48
49 static const struct sock_filter bpf_filter[] = {
50 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, SKF_LL_OFF+4),
51 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, SKF_NET_OFF+8),
52 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, SKF_AD_OFF+SKF_AD_PROTOCOL),
53 BPF_JUMP(BPF_JMP|BPF_K|BPF_JEQ, IPPROTO_UDP, 0, 5),
54 BPF_STMT(BPF_LD|BPF_W|BPF_LEN, 0),
55 BPF_JUMP(BPF_JMP|BPF_K|BPF_JGE, 100, 0, 3),
56 BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 42),
57 BPF_JUMP(BPF_JMP|BPF_K|BPF_JEQ, 'a', 0, 1),
58 BPF_STMT(BPF_RET|BPF_K, -1U),
59 BPF_STMT(BPF_RET|BPF_K, 0)
60 };
61
62 static void
print_filter(void)63 print_filter(void)
64 {
65 PRINT_STMT_SYM("[", BPF_LD|BPF_B|BPF_ABS, SKF_LL_OFF+4);
66 PRINT_STMT_SYM(", ", BPF_LD|BPF_B|BPF_ABS, SKF_NET_OFF+8);
67 PRINT_STMT_SYM(", ", BPF_LD|BPF_B|BPF_ABS, SKF_AD_OFF+SKF_AD_PROTOCOL);
68 PRINT_JUMP(", ", BPF_JMP|BPF_K|BPF_JEQ, IPPROTO_UDP, 0, 5);
69 PRINT_STMT_VAL(", ", BPF_LD|BPF_W|BPF_LEN, 0);
70 PRINT_JUMP(", ", BPF_JMP|BPF_K|BPF_JGE, 100, 0, 3);
71 PRINT_STMT_VAL(", ", BPF_LD|BPF_B|BPF_ABS, 42);
72 PRINT_JUMP(", ", BPF_JMP|BPF_K|BPF_JEQ, 'a', 0, 1);
73 PRINT_STMT_VAL(", ", BPF_RET|BPF_K, -1U);
74 PRINT_STMT_VAL(", ", BPF_RET|BPF_K, 0);
75 putchar(']');
76 }
77
78 static const char *errstr;
79
80 static int
get_filter(int fd,void * val,socklen_t * len)81 get_filter(int fd, void *val, socklen_t *len)
82 {
83 int rc = getsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, val, len);
84 errstr = sprintrc(rc);
85 return rc;
86 }
87
88 static int
set_filter(int fd,void * val,socklen_t len)89 set_filter(int fd, void *val, socklen_t len)
90 {
91 int rc = setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, val, len);
92 errstr = sprintrc(rc);
93 return rc;
94 }
95
96 int
main(void)97 main(void)
98 {
99 int rc;
100 struct sock_filter *const filter =
101 tail_memdup(bpf_filter, sizeof(bpf_filter));
102 void *const efault = filter + ARRAY_SIZE(bpf_filter);
103 TAIL_ALLOC_OBJECT_CONST_PTR(struct sock_fprog, prog);
104 TAIL_ALLOC_OBJECT_CONST_PTR(socklen_t, len);
105
106 prog->len = ARRAY_SIZE(bpf_filter);
107 prog->filter = filter;
108
109 int fd = socket(AF_INET, SOCK_DGRAM, 0);
110 if (fd < 0)
111 perror_msg_and_skip("socket AF_INET SOCK_DGRAM");
112
113 /* query sock_filter program length -> 0 */
114 *len = BPF_MAXINSNS;
115 rc = get_filter(fd, NULL, len);
116 if (rc)
117 perror_msg_and_skip("getsockopt SOL_SOCKET SO_ATTACH_FILTER");
118 printf("getsockopt(%d, SOL_SOCKET, SO_ATTACH_FILTER"
119 ", NULL, [%u->0]) = 0\n", fd, BPF_MAXINSNS);
120
121 /* getsockopt NULL optlen - EFAULT */
122 rc = get_filter(fd, NULL, NULL);
123 printf("getsockopt(%d, SOL_SOCKET, SO_ATTACH_FILTER, NULL, NULL)"
124 " = %s\n", fd, errstr);
125
126 /* attach a filter */
127 rc = set_filter(fd, prog, sizeof(*prog));
128 if (rc)
129 perror_msg_and_skip("setsockopt SOL_SOCKET SO_ATTACH_FILTER");
130 printf("setsockopt(%d, SOL_SOCKET, SO_ATTACH_FILTER, {len=%u, filter=",
131 fd, prog->len);
132 print_filter();
133 printf("}, %u) = 0\n", (unsigned int) sizeof(*prog));
134
135 /* setsockopt optlen is too small - EINVAL */
136 rc = set_filter(fd, prog, sizeof(*prog) - 4);
137 printf("setsockopt(%d, SOL_SOCKET, SO_ATTACH_FILTER, %p, %u) = %s\n",
138 fd, prog, (unsigned int) sizeof(*prog) - 4, errstr);
139
140 #ifdef SO_ATTACH_REUSEPORT_CBPF
141 rc = setsockopt(fd, SOL_SOCKET, SO_ATTACH_REUSEPORT_CBPF,
142 prog, sizeof(*prog));
143 errstr = sprintrc(rc);
144 printf("setsockopt(%d, SOL_SOCKET, SO_ATTACH_REUSEPORT_CBPF"
145 ", {len=%u, filter=", fd, prog->len);
146 print_filter();
147 printf("}, %u) = %s\n", (unsigned int) sizeof(*prog), errstr);
148 #endif
149
150 /* query sock_filter program length -> ARRAY_SIZE(bpf_filter) */
151 *len = 0;
152 rc = get_filter(fd, efault, len);
153 printf("getsockopt(%d, SOL_SOCKET, SO_ATTACH_FILTER, %p"
154 ", [0->%u]) = %s\n",
155 fd, efault, (unsigned int) ARRAY_SIZE(bpf_filter), errstr);
156
157 /* getsockopt optlen is too small - EINVAL */
158 *len = ARRAY_SIZE(bpf_filter) - 1;
159 rc = get_filter(fd, efault, len);
160 printf("getsockopt(%d, SOL_SOCKET, SO_ATTACH_FILTER, %p"
161 ", [%u]) = %s\n",
162 fd, efault, (unsigned int) ARRAY_SIZE(bpf_filter) - 1, errstr);
163
164 /* getsockopt optval EFAULT */
165 *len = ARRAY_SIZE(bpf_filter);
166 rc = get_filter(fd, filter + 1, len);
167 printf("getsockopt(%d, SOL_SOCKET, SO_ATTACH_FILTER, %p"
168 ", [%u]) = %s\n", fd, filter + 1,
169 (unsigned int) ARRAY_SIZE(bpf_filter), errstr);
170
171 /* getsockopt optlen is too large - truncated */
172 *len = ARRAY_SIZE(bpf_filter) + 1;
173 rc = get_filter(fd, filter, len);
174 printf("getsockopt(%d, SOL_SOCKET, SO_ATTACH_FILTER, ", fd);
175 print_filter();
176 printf(", [%u->%d]) = %s\n",
177 (unsigned int) ARRAY_SIZE(bpf_filter) + 1, *len, errstr);
178
179 puts("+++ exited with 0 +++");
180 return 0;
181 }
182