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
|
#include "byte.h"
#include "str.h"
#include "scan.h"
#include "fmt.h"
#include "env.h"
#include "exit.h"
#include "sig.h"
#include "buffer.h"
#include "readwrite.h"
#include "sgetopt.h"
#include "strerr.h"
#include "stralloc.h"
#include "commands.h"
#include "pathexec.h"
#include "dns.h"
#define FATAL "rblsmtpd: fatal: "
void nomem(void)
{
strerr_die2x(111,FATAL,"out of memory");
}
void usage(void)
{
strerr_die1x(100,"rblsmtpd: usage: rblsmtpd [ -b ] [ -R ] [ -t timeout ] [ -r base ] [ -a base ] smtpd [ arg ... ]");
}
char *ip_env;
static stralloc ip_reverse;
void ip_init(void)
{
unsigned int i;
unsigned int j;
ip_env = env_get("TCPREMOTEIP");
if (!ip_env) ip_env = "";
if (!stralloc_copys(&ip_reverse,"")) nomem();
i = str_len(ip_env);
while (i) {
for (j = i;j > 0;--j) if (ip_env[j - 1] == '.') break;
if (!stralloc_catb(&ip_reverse,ip_env + j,i - j)) nomem();
if (!stralloc_cats(&ip_reverse,".")) nomem();
if (!j) break;
i = j - 1;
}
}
unsigned long timeout = 60;
int flagrblbounce = 0;
int flagfailclosed = 0;
int flagmustnotbounce = 0;
int decision = 0; /* 0 undecided, 1 accept, 2 reject, 3 bounce */
static stralloc text; /* defined if decision is 2 or 3 */
static stralloc tmp;
void rbl(char *base)
{
if (decision) return;
if (!stralloc_copy(&tmp,&ip_reverse)) nomem();
if (!stralloc_cats(&tmp,base)) nomem();
if (dns_txt(&text,&tmp) == -1) {
flagmustnotbounce = 1;
if (flagfailclosed) {
if (!stralloc_copys(&text,"temporary RBL lookup error")) nomem();
decision = 2;
}
return;
}
if (text.len)
if (flagrblbounce)
decision = 3;
else
decision = 2;
}
void antirbl(char *base)
{
if (decision) return;
if (!stralloc_copy(&tmp,&ip_reverse)) nomem();
if (!stralloc_cats(&tmp,base)) nomem();
if (dns_ip4(&text,&tmp) == -1) {
flagmustnotbounce = 1;
if (!flagfailclosed)
decision = 1;
return;
}
if (text.len)
decision = 1;
}
char strnum[FMT_ULONG];
static stralloc message;
char inspace[64]; buffer in = BUFFER_INIT(read,0,inspace,sizeof inspace);
char outspace[1]; buffer out = BUFFER_INIT(write,1,outspace,sizeof outspace);
void reject() { buffer_putflush(&out,message.s,message.len); }
void accept() { buffer_putsflush(&out,"250 rblsmtpd.local\r\n"); }
void greet() { buffer_putsflush(&out,"220 rblsmtpd.local\r\n"); }
void quit() { buffer_putsflush(&out,"221 rblsmtpd.local\r\n"); _exit(0); }
void drop() { _exit(0); }
struct commands smtpcommands[] = {
{ "quit", quit, 0 }
, { "helo", accept, 0 }
, { "ehlo", accept, 0 }
, { "mail", accept, 0 }
, { "rset", accept, 0 }
, { "noop", accept, 0 }
, { 0, reject, 0 }
} ;
void rblsmtpd(void)
{
int i;
if (flagmustnotbounce || (decision == 2)) {
if (!stralloc_copys(&message,"451 ")) nomem();
}
else
if (!stralloc_copys(&message,"553 ")) nomem();
if (text.len > 200) text.len = 200;
if (!stralloc_cat(&message,&text)) nomem();
for (i = 0;i < message.len;++i)
if ((message.s[i] < 32) || (message.s[i] > 126))
message.s[i] = '?';
buffer_puts(buffer_2,"rblsmtpd: ");
buffer_puts(buffer_2,ip_env);
buffer_puts(buffer_2," pid ");
buffer_put(buffer_2,strnum,fmt_ulong(strnum,getpid()));
buffer_puts(buffer_2,": ");
buffer_put(buffer_2,message.s,message.len);
buffer_puts(buffer_2,"\n");
buffer_flush(buffer_2);
if (!stralloc_cats(&message,"\r\n")) nomem();
if (!timeout)
reject();
else {
sig_catch(sig_alarm,drop);
alarm(timeout);
greet();
commands(&in,smtpcommands);
}
_exit(0);
}
main(int argc,char **argv,char **envp)
{
int flagwantdefaultrbl = 1;
char *x;
int opt;
ip_init();
x = env_get("RBLSMTPD");
if (x) {
if (!*x)
decision = 1;
else if (*x == '-') {
if (!stralloc_copys(&text,x + 1)) nomem();
decision = 3;
}
else {
if (!stralloc_copys(&text,x)) nomem();
decision = 2;
}
}
while ((opt = getopt(argc,argv,"bBcCt:r:a:")) != opteof)
switch(opt) {
case 'b': flagrblbounce = 1; break;
case 'B': flagrblbounce = 0; break;
case 'c': flagfailclosed = 1; break;
case 'C': flagfailclosed = 0; break;
case 't': scan_ulong(optarg,&timeout); break;
case 'r': rbl(optarg); flagwantdefaultrbl = 0; break;
case 'a': antirbl(optarg); break;
default: usage();
}
argv += optind;
if (!*argv) usage();
if (flagwantdefaultrbl) rbl("rbl.maps.vix.com");
if (decision >= 2) rblsmtpd();
pathexec_run(*argv,argv,envp);
strerr_die4sys(111,FATAL,"unable to run ",*argv,": ");
}
|
