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tcp_smtp.c
286 lines (261 loc) · 6.34 KB
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tcp_smtp.c
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/* David Leonard, 2002. Public domain. */
/* $Id: tcp_http.c 1193 2007-08-30 10:33:24Z d $ */
#if HAVE_CONFIG_H
# include "config.h"
#endif
#if STDC_HEADERS
# include <stdio.h>
# include <string.h>
# include <stdlib.h>
# include <ctype.h>
#endif
#if HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#if TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# if HAVE_SYS_TIME_H
# include <sys/time.h>
# else
# include <time.h>
# endif
#endif
#include "type.h"
#include "flow.h"
#include "tcp.h"
#include "compat.h"
#define CR '\r'
#define LF '\n'
struct smtp_state {
int in_data; /* true while client sends DATA */
int in_header; /* true in DATA's headers */
char line[2048]; /* buffer for data sent to server */
int line_len; /* length of line read so far */
enum { sLINE, sEXPECT_LF, sENCRYPTED } state;
char to_addr[512]; /* RCPT TO: */
char from_addr[512]; /* MAIL FROM: */
};
/* Returns pointer to string after prefix, or NULL if no match */
const char *
strip_prefix(s, prefix)
const char *s;
const char *prefix;
{
while (*prefix)
if (*s++ != *prefix++)
return 0;
return s;
}
/* Normalize a line by uppercasing the command word(s), and stripping
* and collapsing whitespace */
static void
normalize_line(line)
char *line;
{
char *s, *p;
int has_colon;
s = p = line;
/* Skip leading whitespace */
while (*s == ' ' || *s == '\t')
s++;
/* Collapse whitespace */
while (*s && *s != ':') {
if (*s == ' ' || *s == '\t') {
while (*s == ' ' || *s == '\t')
s++;
*p++ = ' ';
} else {
*p++ = *s++;
}
}
/* Remove whitespace before a colon */
if (*s == ':' && p > line && p[-1] == ' ')
p--;
if (*s == ':') {
*p++ = *s++;
has_colon = 1;
} else
has_colon = 0;
/* Remove whitespace after colon */
while (*s == ' ' || *s == '\t')
s++;
/* Copy the rest of the line, collapsing whitespace */
while (*s) {
if (*s == ' ' || *s == '\t') {
while (*s == ' ' || *s == '\t')
s++;
*p++ = ' ';
} else
*p++ = *s++;
}
/* Strip trailing whitespace */
if (p > line && p[-1] == ' ')
p--;
*p = 0;
/* Uppercase the first word, unless there is a colon in which case
* we uppercase to the colon */
for (s = line; *s && *s != (has_colon ? ':' : ' '); s++)
if (*s != ' ')
*s = toupper(*s);
}
/* Normalize an email address
* u@h -> u@h
* N<u@h> -> u@h
*/
static void
normalize_addr(line)
char *line;
{
char *s, *t, *u;
/* Search for the opening angle bracket */
for (s = line; *s; s++)
if (*s == '<')
break;
if (!*s)
return; /* no '<' */
s++; /* skip '<' */
/* Check that there is a closing bracket */
for (u = s; *u; u++)
if (*u == '>')
break;
if (*u != '>')
return; /* no '>' */
for (t = line; s < u; t++,s++)
*t = *s;
*t = 0;
}
static void
smtp_line(f, line)
struct flow *f;
const char *line;
{
struct smtp_state *state;
const char *s;
int addr_changed = 0;
FILE*log;
state = (struct smtp_state *)f->udata;
if ((log = fopen("/tmp/smtp.log", "a")))
fprintf(log, "smpt_line [%s]\n", line);
if (state->in_data) {
if (strcmp(line, ".") == 0) {
state->in_data = 0;
state->from_addr[0] = 0;
state->to_addr[0] = 0;
} else if (state->in_header) {
if (!*line)
state->in_header = 0;
#if 0
/* Tag the Subject: line inside DATA */
else if ((line[0] == 'S' || line[0] == 's') &&
(line[1] == 'U' || line[1] == 'u') &&
(line[2] == 'B' || line[2] == 'b') &&
(line[3] == 'J' || line[3] == 'j') &&
(line[4] == 'E' || line[4] == 'e') &&
(line[5] == 'C' || line[5] == 'c') &&
(line[6] == 'T' || line[6] == 't') &&
line[7] == ':')
snprintf(f->desc, sizeof f->desc, "%s", line);
#endif
}
} else {
/* Normalize the command line */
normalize_line(line);
if (log)fprintf(log, "normalized to [%s]\n", line);
if ((s = strip_prefix(line, "MAIL FROM:"))) {
snprintf(state->from_addr, sizeof state->from_addr, "%s", s);
normalize_addr(state->from_addr);
addr_changed = 1;
if (log)fprintf(log, "from_addr = [%s]\n", state->from_addr);
}
else if ((s = strip_prefix(line, "RCPT TO:"))) {
snprintf(state->to_addr, sizeof state->to_addr, "%s", s);
normalize_addr(state->to_addr);
addr_changed = 1;
if (log)fprintf(log, "to_addr = [%s]\n", state->to_addr);
}
else if (strcmp(line, "DATA") == 0) {
state->in_data = 1;
state->in_header = 1;
}
else if (strcmp(line, "STARTTLS") == 0) {
state->state = sENCRYPTED;
snprintf(f->desc, sizeof f->desc, "STARTTLS");
}
if ((addr_changed ||
strcmp(line, "QUIT") == 0 ||
strcmp(line, "DATA") == 0) &&
(*state->from_addr && *state->to_addr))
{
snprintf(f->desc, sizeof f->desc, "%s -> %s",
state->from_addr, state->to_addr);
} else {
if (strcmp(line, "QUIT") != 0)
snprintf(f->desc, sizeof f->desc, "%s", line);
}
if (log)fprintf(log, "set desc to: [%s]\n", f->desc);
}
if (log)fclose(log);
}
/*
* Look for simple SMTP (RFC 2822) commands.
*/
void
tcp_smtp(f, data, end, toserver)
struct flow *f;
const char *data;
const char *end;
int toserver;
{
const char *d;
struct smtp_state *state;
if (!toserver)
return;
if (!f->udata) {
/* Initialize state */
state = (struct smtp_state *)malloc(sizeof *state);
if (!state)
errx(1, "malloc");
memset(state, 0, sizeof *state);
f->udata = state;
f->freeudata = free;
state->line_len = 0;
state->state = sLINE;
state->to_addr[0] = 0;
state->from_addr[0] = 0;
} else
state = (struct smtp_state *)f->udata;
/* Extract data, line by line */
for (d = data; d < end; d++)
switch (state->state) {
case sENCRYPTED:
/* Don't bother */
d = end - 1;
break;
case sLINE:
if (*d == CR) {
state->state = sEXPECT_LF;
} else {
if (state->line_len < sizeof state->line - 1)
state->line[state->line_len++] = *d;
/*state->state = sLINE;*/
}
break;
case sEXPECT_LF:
if (*d == LF) {
state->line[state->line_len] = 0;
smtp_line(f, state->line);
state->line_len = 0;
state->state = sLINE;
} else if (*d == CR) {
state->line_len = 0;
/*state->state = sEXPECT_LF;*/
} else {
state->line[0] = *d;
state->line_len = 1;
state->state = sLINE;
}
break;
}
}