1 #include <sys/socket.h>
2 
3 #include <err.h>
4 #include <errno.h>
5 #include <netdb.h>
6 #include <stdlib.h>
7 #include <stdio.h>
8 #include <string.h>
9 #include <unistd.h>
10 
11 #include "smtp_proc.h"
12 
13 static char **blacklists = NULL;
14 static size_t nblacklists = 0;
15 int retries = 0;
16 int reject_onfailure = 0;
17 
18 void usage(void);
19 enum filter_decision dnsbl_connect(char *, int, time_t, char *, char *,
20     uint64_t, uint64_t, struct smtp_filter_connect *);
21 
22 int
23 main(int argc, char *argv[])
24 {
25 	int ch;
26 	size_t i;
27 	char *line = NULL;
28 	size_t linesize = 0;
29 	ssize_t linelen;
30 	char *msgid, *token, *ip;
31 	const char *errstr;
32 	int lookup;
33 
34 	if (pledge("stdio dns", NULL) == -1)
35 		err(1, "pledge");
36 
37 	while ((ch = getopt(argc, argv, "b:f:r:")) != -1) {
38 		switch (ch) {
39 		case 'b':
40 			blacklists = reallocarray(blacklists, nblacklists + 1,
41 			    sizeof(*blacklists));
42 			if (blacklists == NULL)
43 				err(1, NULL);
44 			if ((blacklists[nblacklists] = strdup(optarg)) == NULL)
45 				err(1, NULL);
46 			nblacklists++;
47 			break;
48 		case 'f':
49 			reject_onfailure = 1;
50 		case 'r':
51 			if ((retries = strtonum(optarg, 0, 10, &errstr)) == 0 &&
52 			    errstr != NULL)
53 				errx(1, "retries %s", errstr);
54 			break;
55 		default:
56 			usage();
57 		}
58 	}
59 
60 	if (nblacklists == 0)
61 		errx(1, "No blacklist specified");
62 
63 	smtp_register_filter_connect(dnsbl_connect);
64 	smtp_run();
65 
66 	return 0;
67 }
68 
69 enum filter_decision
70 dnsbl_connect(char *type, int version, time_t tm, char *direction, char *phase,
71     uint64_t reqid, uint64_t token, struct smtp_filter_connect *params)
72 {
73 	char query[255];
74 	char reply[1500];
75 	struct hostent *hent;
76 	u_char *addr;
77 	int i, try;
78 
79 	addr = (u_char *)&(params->addr);
80 	for (i = 0; i < nblacklists; i++) {
81 		if (params->af == AF_INET) {
82 			if (snprintf(query, sizeof(query), "%u.%u.%u.%u.%s",
83 			    addr[3], addr[2], addr[1], addr[0],
84 			    blacklists[i]) >= sizeof(query))
85 				errx(1, "Can't create query, domain too long");
86 		} else if (params->af == AF_INET6) {
87 			if (snprintf(query, sizeof(query), "%hhx.%hhx.%hhx.%hhx"
88 			    ".%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx"
89 			    ".%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx"
90 			    ".%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%hhx.%s",
91 			    (u_char) (addr[15] & 0xf), (u_char) (addr[15] >> 4),
92 			    (u_char) (addr[14] & 0xf), (u_char) (addr[14] >> 4),
93 			    (u_char) (addr[13] & 0xf), (u_char) (addr[13] >> 4),
94 			    (u_char) (addr[12] & 0xf), (u_char) (addr[12] >> 4),
95 			    (u_char) (addr[11] & 0xf), (u_char) (addr[11] >> 4),
96 			    (u_char) (addr[10] & 0xf), (u_char) (addr[10] >> 4),
97 			    (u_char) (addr[9] & 0xf), (u_char) (addr[9] >> 4),
98 			    (u_char) (addr[8] & 0xf), (u_char) (addr[8] >> 4),
99 			    (u_char) (addr[7] & 0xf), (u_char) (addr[8] >> 4),
100 			    (u_char) (addr[6] & 0xf), (u_char) (addr[7] >> 4),
101 			    (u_char) (addr[5] & 0xf), (u_char) (addr[5] >> 4),
102 			    (u_char) (addr[4] & 0xf), (u_char) (addr[4] >> 4),
103 			    (u_char) (addr[3] & 0xf), (u_char) (addr[3] >> 4),
104 			    (u_char) (addr[2] & 0xf), (u_char) (addr[2] >> 4),
105 			    (u_char) (addr[1] & 0xf), (u_char) (addr[1] >> 4),
106 			    (u_char) (addr[0] & 0xf), (u_char) (addr[0] >> 4),
107 			    blacklists[i]) >= sizeof(query))
108 				errx(1, "Can't create query, domain too long");
109 		} else
110 			errx(1, "Invalid address family received");
111 
112 		for (try = -1; try < retries; try++) {
113 			if ((hent = gethostbyname(query)) == NULL) {
114 				if (h_errno == HOST_NOT_FOUND)
115 					break;
116 				if (h_errno != TRY_AGAIN) {
117 					if (!reject_onfailure)
118 						break;
119 					else
120 						smtp_filter_disconnect(reqid,
121 						    token,
122 						    "Blacklist check failed");
123 						return FILTER_DISCONNECT;
124 				}
125 			} else {
126 				smtp_filter_disconnect(reqid, token,
127 				    "Listed at %s", blacklists[i]);
128 				return FILTER_DISCONNECT;
129 			}
130 		}
131 	}
132 	return FILTER_PROCEED;
133 }
134 
135 void
136 usage(void)
137 {
138 	fprintf(stderr, "usage: %s [-b blacklist]\n",
139 	    getprogname());
140 	exit(1);
141 }