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