/*
* Copyright (C) 2007-2008 Sourcefire, Inc.
*
* Authors: Nigel Horne
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*
* TODO: Optimise messageExport, decodeLine, messageIsEncoding
*/
static char const rcsid[] = "$Id: message.c,v 1.195 2007/02/12 20:46:09 njh Exp $";
#if HAVE_CONFIG_H
#include "clamav-config.h"
#endif
#ifdef CL_THREAD_SAFE
#ifndef _REENTRANT
#define _REENTRANT /* for Solaris 2.8 */
#endif
#endif
#ifdef C_DARWIN
#include <sys/types.h>
#endif
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#ifdef CL_THREAD_SAFE
#include <pthread.h>
#endif
#include "others.h"
#include "str.h"
#include "filetypes.h"
#include "mbox.h"
#ifndef isblank
#define isblank(c) (((c) == ' ') || ((c) == '\t'))
#endif
#define RFC2045LENGTH 76 /* maximum number of characters on a line */
#ifdef HAVE_STDBOOL_H
#include <stdbool.h>
#else
#ifdef FALSE
typedef unsigned char bool;
#else
typedef enum { FALSE = 0, TRUE = 1 } bool;
#endif
#endif
static int messageHasArgument(const message *m, const char *variable);
static void messageIsEncoding(message *m);
static unsigned char *decode(message *m, const char *in, unsigned char *out, unsigned char (*decoder)(char), bool isFast);
static void sanitiseBase64(char *s);
#ifdef __GNUC__
static unsigned char hex(char c) __attribute__((const));
static unsigned char base64(char c) __attribute__((const));
static unsigned char uudecode(char c) __attribute__((const));
#else
static unsigned char hex(char c);
static unsigned char base64(char c);
static unsigned char uudecode(char c);
#endif
static const char *messageGetArgument(const message *m, int arg);
static void *messageExport(message *m, const char *dir, void *(*create)(void), void (*destroy)(void *), void (*setFilename)(void *, const char *, const char *), void (*addData)(void *, const unsigned char *, size_t), void *(*exportText)(text *, void *, int), void (*setCTX)(void *, cli_ctx *), int destroy_text);
static int usefulArg(const char *arg);
static void messageDedup(message *m);
static char *rfc2231(const char *in);
static int simil(const char *str1, const char *str2);
/*
* These maps are ordered in decreasing likelyhood of their appearance
* in an e-mail. Probably these should be in a table...
*/
static const struct encoding_map {
const char *string;
encoding_type type;
} encoding_map[] = { /* rfc2045 */
{ "7bit", NOENCODING },
{ "text/plain", NOENCODING },
{ "quoted-printable", QUOTEDPRINTABLE }, /* rfc2045 */
{ "base64", BASE64 }, /* rfc2045 */
{ "8bit", EIGHTBIT },
{ "binary", BINARY },
{ "x-uuencode", UUENCODE }, /* uuencode(5) */
{ "x-yencode", YENCODE },
{ "x-binhex", BINHEX },
{ "us-ascii", NOENCODING }, /* incorrect */
{ "x-uue", UUENCODE }, /* incorrect */
{ "uuencode", UUENCODE }, /* incorrect */
{ NULL, NOENCODING }
};
static const struct mime_map {
const char *string;
mime_type type;
} mime_map[] = {
{ "text", TEXT },
{ "multipart", MULTIPART },
{ "application", APPLICATION },
{ "audio", AUDIO },
{ "image", IMAGE },
{ "message", MESSAGE },
{ "video", VIDEO },
{ NULL, TEXT }
};
/*
* See RFC2045, section 6.8, table 1
*/
static const unsigned char base64Table[256] = {
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,62,255,255,255,63,
52,53,54,55,56,57,58,59,60,61,255,255,255,0,255,255,
255,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,
15,16,17,18,19,20,21,22,23,24,25,255,255,255,255,255,
255,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,
41,42,43,44,45,46,47,48,49,50,51,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255
};
message *
messageCreate(void)
{
message *m = (message *)cli_calloc(1, sizeof(message));
if(m)
m->mimeType = NOMIME;
return m;
}
void
messageDestroy(message *m)
{
assert(m != NULL);
messageReset(m);
free(m);
}
void
messageReset(message *m)
{
int i;
assert(m != NULL);
if(m->mimeSubtype)
free(m->mimeSubtype);
if(m->mimeDispositionType)
free(m->mimeDispositionType);
if(m->mimeArguments) {
for(i = 0; i < m->numberOfArguments; i++)
free(m->mimeArguments[i]);
free(m->mimeArguments);
}
if(m->body_first)
textDestroy(m->body_first);
assert(m->base64chars == 0);
if(m->encodingTypes) {
assert(m->numberOfEncTypes > 0);
free(m->encodingTypes);
}
memset(m, '\0', sizeof(message));
m->mimeType = NOMIME;
}
/*
* Handle the Content-Type header. The syntax is in RFC1341.
* Return success (1) or failure (0). Failure only happens when it's an
* unknown type and we've already received a known type, or we've received an
* empty type. If we receive an unknown type by itself we default to application
*/
int
messageSetMimeType(message *mess, const char *type)
{
#ifdef CL_THREAD_SAFE
static pthread_mutex_t mime_mutex = PTHREAD_MUTEX_INITIALIZER;
#endif
const struct mime_map *m;
int typeval;
static table_t *mime_table;
assert(mess != NULL);
if(type == NULL) {
cli_dbgmsg("Empty content-type field\n");
return 0;
}
cli_dbgmsg("messageSetMimeType: '%s'\n", type);
/* Ignore leading spaces */
while(!isalpha(*type))
if(*type++ == '\0')
return 0;
#ifdef CL_THREAD_SAFE
pthread_mutex_lock(&mime_mutex);
#endif
if(mime_table == NULL) {
mime_table = tableCreate();
if(mime_table == NULL) {
#ifdef CL_THREAD_SAFE
pthread_mutex_unlock(&mime_mutex);
#endif
return 0;
}
for(m = mime_map; m->string; m++)
if(!tableInsert(mime_table, m->string, m->type)) {
tableDestroy(mime_table);
mime_table = NULL;
#ifdef CL_THREAD_SAFE
pthread_mutex_unlock(&mime_mutex);
#endif
return 0;
}
}
#ifdef CL_THREAD_SAFE
pthread_mutex_unlock(&mime_mutex);
#endif
typeval = tableFind(mime_table, type);
if(typeval != -1) {
mess->mimeType = (mime_type)typeval;
return 1;
}
if(mess->mimeType == NOMIME) {
if(strncasecmp(type, "x-", 2) == 0)
mess->mimeType = MEXTENSION;
else {
/*
* Force scanning of strange messages
*/
if(strcasecmp(type, "plain") == 0) {
cli_dbgmsg("Incorrect MIME type: `plain', set to Text\n");
mess->mimeType = TEXT;
} else {
/*
* Don't handle broken e-mail probably sending
* Content-Type: plain/text
* instead of
* Content-Type: text/plain
* as an attachment
*/
int highestSimil = 0, t = -1;
const char *closest = NULL;
for(m = mime_map; m->string; m++) {
const int s = simil(m->string, type);
if(s > highestSimil) {
highestSimil = s;
closest = m->string;
t = m->type;
}
}
if(highestSimil >= 50) {
cli_dbgmsg("Unknown MIME type \"%s\" - guessing as %s (%d%% certainty)\n",
type, closest,
highestSimil);
mess->mimeType = (mime_type)t;
} else {
cli_dbgmsg("Unknown MIME type: `%s', set to Application - if you believe this file contains a virus, submit it to www.clamav.net\n", type);
mess->mimeType = APPLICATION;
}
}
}
return 1;
}
return 0;
}
mime_type
messageGetMimeType(const message *m)
{
assert(m != NULL);
return m->mimeType;
}
void
messageSetMimeSubtype(message *m, const char *subtype)
{
assert(m != NULL);
if(subtype == NULL) {
/*
* Handle broken content-type lines, e.g.
* Content-Type: text/
*/
cli_dbgmsg("Empty content subtype\n");
subtype = "";
}
if(m->mimeSubtype)
free(m->mimeSubtype);
m->mimeSubtype = cli_strdup(subtype);
}
const char *
messageGetMimeSubtype(const message *m)
{
return (m->mimeSubtype) ? m->mimeSubtype : "";
}
void
messageSetDispositionType(message *m, const char *disptype)
{
assert(m != NULL);
if(m->mimeDispositionType)
free(m->mimeDispositionType);
if(disptype == NULL) {
m->mimeDispositionType = NULL;
return;
}
/*
* It's broken for there to be an entry such as "Content-Disposition:"
* However some spam and viruses are rather broken, it's a sign
* that something is wrong if we get that - maybe we should force a
* scan of this part
*/
while(*disptype && isspace((int)*disptype))
disptype++;
if(*disptype) {
m->mimeDispositionType = cli_strdup(disptype);
if(m->mimeDispositionType)
strstrip(m->mimeDispositionType);
} else
m->mimeDispositionType = NULL;
}
const char *
messageGetDispositionType(const message *m)
{
return (m->mimeDispositionType) ? m->mimeDispositionType : "";
}
/*
* TODO:
* Arguments are held on a per message basis, they should be held on
* a per section basis. Otherwise what happens if two sections have two
* different values for charset? Probably doesn't matter for the use this
* code will be given, but will need fixing if this code is used elsewhere
*/
void
messageAddArgument(message *m, const char *arg)
{
int offset;
char *p;
assert(m != NULL);
if(arg == NULL)
return; /* Note: this is not an error condition */
while(isspace(*arg))
arg++;
if(*arg == '\0')
/* Empty argument? Probably a broken mail client... */
return;
cli_dbgmsg("messageAddArgument, arg='%s'\n", arg);
if(!usefulArg(arg))
return;
for(offset = 0; offset < m->numberOfArguments; offset++)
if(m->mimeArguments[offset] == NULL)
break;
else if(strcasecmp(arg, m->mimeArguments[offset]) == 0)
return; /* already in there */
if(offset == m->numberOfArguments) {
char **q;
m->numberOfArguments++;
q = (char **)cli_realloc(m->mimeArguments, m->numberOfArguments * sizeof(char *));
if(q == NULL) {
m->numberOfArguments--;
return;
}
m->mimeArguments = q;
}
p = m->mimeArguments[offset] = rfc2231(arg);
if(strchr(p, '=') == NULL) {
if(strncmp(p, "filename", 8) == 0) {
/*
* FIXME: Bounce message handling is corrupting the in
* core copies of headers
*/
cli_dbgmsg("Possible data corruption fixed\n");
p[8] = '=';
} else {
if(p && *p)
cli_dbgmsg("messageAddArgument, '%s' contains no '='\n", p);
free(m->mimeArguments[offset]);
m->mimeArguments[offset] = NULL;
return;
}
}
/*
* This is terribly broken from an RFC point of view but is useful
* for catching viruses which have a filename but no type of
* mime. By pretending defaulting to an application rather than
* to nomime we can ensure they're saved and scanned
*/
if(p && ((strncasecmp(p, "filename=", 9) == 0) || (strncasecmp(p, "name=", 5) == 0)))
if(messageGetMimeType(m) == NOMIME) {
cli_dbgmsg("Force mime encoding to application\n");
messageSetMimeType(m, "application");
}
}
/*
* Add in all the arguments.
* Cope with:
* name="foo bar.doc"
* charset=foo name=bar
*/
void
messageAddArguments(message *m, const char *s)
{
const char *string = s;
cli_dbgmsg("Add arguments '%s'\n", string);
assert(string != NULL);
while(*string) {
const char *key, *cptr;
char *data, *field;
if(isspace(*string & 0xff) || (*string == ';')) {
string++;
continue;
}
key = string;
data = strchr(string, '=');
/*
* Some spam breaks RFC2045 by using ':' instead of '='
* e.g.:
* Content-Type: text/html; charset:ISO-8859-1
* should be:
* Content-type: text/html; charset=ISO-8859-1
*
* We give up with lines that are completely broken because
* we don't have ESP and don't know what was meant to be there.
* It's unlikely to really be a problem.
*/
if(data == NULL)
data = strchr(string, ':');
if(data == NULL) {
/*
* Completely broken, give up
*/
cli_dbgmsg("Can't parse header \"%s\"\n", s);
return;
}
string = &data[1];
/*
* Handle white space to the right of the equals sign
* This breaks RFC2045 which has:
* parameter := attribute "=" value
* attribute := token ; case-insensitive
* token := 1*<any (ASCII) CHAR except SPACE, CTLs,
* or tspecials>
* But too many MUAs ignore this
*/
while(isspace(*string) && (*string != '\0'))
string++;
cptr = string++;
if(strlen(key) == 0)
continue;
if(*cptr == '"') {
char *ptr, *kcopy;
/*
* The field is in quotes, so look for the
* closing quotes
*/
kcopy = cli_strdup(key);
if(kcopy == NULL)
return;
ptr = strchr(kcopy, '=');
if(ptr == NULL)
ptr = strchr(kcopy, ':');
*ptr = '\0';
string = strchr(++cptr, '"');
if(string == NULL) {
cli_dbgmsg("Unbalanced quote character in \"%s\"\n", s);
string = "";
} else
string++;
if(!usefulArg(kcopy)) {
free(kcopy);
continue;
}
data = cli_strdup(cptr);
ptr = (data) ? strchr(data, '"') : NULL;
if(ptr == NULL) {
/*
* Weird e-mail header such as:
* Content-Type: application/octet-stream; name="
* "
* Content-Transfer-Encoding: base64
* Content-Disposition: attachment; filename="
* "
*
* TODO: the file should still be saved and
* virus checked
*/
cli_dbgmsg("Can't parse header \"%s\" - if you believe this file contains a virus, submit it to www.clamav.net\n", s);
if(data)
free(data);
free(kcopy);
return;
}
*ptr = '\0';
field = cli_realloc(kcopy, strlen(kcopy) + strlen(data) + 2);
if(field) {
strcat(field, "=");
strcat(field, data);
} else
free(kcopy);
free(data);
} else {
size_t len;
if(*cptr == '\0') {
cli_dbgmsg("Ignoring empty field in \"%s\"\n", s);
return;
}
/*
* The field is not in quotes, so look for the closing
* white space
*/
while((*string != '\0') && !isspace(*string))
string++;
len = (size_t)string - (size_t)key + 1;
field = cli_malloc(len);
if(field) {
memcpy(field, key, len - 1);
field[len - 1] = '\0';
}
}
if(field) {
messageAddArgument(m, field);
free(field);
}
}
}
static const char *
messageGetArgument(const message *m, int arg)
{
assert(m != NULL);
assert(arg >= 0);
assert(arg < m->numberOfArguments);
return (m->mimeArguments[arg]) ? m->mimeArguments[arg] : "";
}
/*
* Find a MIME variable from the header and return a COPY to the value of that
* variable. The caller must free the copy
*/
char *
messageFindArgument(const message *m, const char *variable)
{
int i;
size_t len;
assert(m != NULL);
assert(variable != NULL);
len = strlen(variable);
for(i = 0; i < m->numberOfArguments; i++) {
const char *ptr;
ptr = messageGetArgument(m, i);
if((ptr == NULL) || (*ptr == '\0'))
continue;
#ifdef CL_DEBUG
cli_dbgmsg("messageFindArgument: compare %lu bytes of %s with %s\n",
(unsigned long)len, variable, ptr);
#endif
if(strncasecmp(ptr, variable, len) == 0) {
ptr = &ptr[len];
while(isspace(*ptr))
ptr++;
if(*ptr != '=') {
cli_dbgmsg("messageFindArgument: no '=' sign found in MIME header '%s' (%s)\n", variable, messageGetArgument(m, i));
return NULL;
}
if((*++ptr == '"') && (strchr(&ptr[1], '"') != NULL)) {
/* Remove any quote characters */
char *ret = cli_strdup(++ptr);
char *p;
if(ret == NULL)
return NULL;
/*
* fix un-quoting of boundary strings from
* header, occurs if boundary was given as
* 'boundary="_Test_";'
*
* At least two quotes in string, assume
* quoted argument
* end string at next quote
*/
if((p = strchr(ret, '"')) != NULL) {
ret[strlen(ret) - 1] = '\0';
*p = '\0';
}
return ret;
}
return cli_strdup(ptr);
}
}
return NULL;
}
char *
messageGetFilename(const message *m)
{
char *filename = (char *)messageFindArgument(m, "filename");
if(filename)
return filename;
return (char *)messageFindArgument(m, "name");
}
/* Returns true or false */
static int
messageHasArgument(const message *m, const char *variable)
{
int i;
size_t len;
assert(m != NULL);
assert(variable != NULL);
len = strlen(variable);
for(i = 0; i < m->numberOfArguments; i++) {
const char *ptr;
ptr = messageGetArgument(m, i);
if((ptr == NULL) || (*ptr == '\0'))
continue;
#ifdef CL_DEBUG
cli_dbgmsg("messageHasArgument: compare %lu bytes of %s with %s\n",
(unsigned long)len, variable, ptr);
#endif
if(strncasecmp(ptr, variable, len) == 0) {
ptr = &ptr[len];
while(isspace(*ptr))
ptr++;
if(*ptr != '=') {
cli_dbgmsg("messageHasArgument: no '=' sign found in MIME header '%s' (%s)\n", variable, messageGetArgument(m, i));
return 0;
}
return 1;
}
}
return 0;
}
int
messageHasFilename(const message *m)
{
return messageHasArgument(m, "filename") || messageHasArgument(m, "file");
}
void
messageSetEncoding(message *m, const char *enctype)
{
const struct encoding_map *e;
int i;
char *type;
assert(m != NULL);
assert(enctype != NULL);
/*m->encodingType = EEXTENSION;*/
while(isblank(*enctype))
enctype++;
cli_dbgmsg("messageSetEncoding: '%s'\n", enctype);
if(strcasecmp(enctype, "8 bit") == 0) {
cli_dbgmsg("Broken content-transfer-encoding: '8 bit' changed to '8bit'\n");
enctype = "8bit";
}
/*
* Iterate through
* Content-Transfer-Encoding: base64 binary
* cli_strtok's fieldno counts from 0
*/
i = 0;
while((type = cli_strtok(enctype, i++, " \t")) != NULL) {
int highestSimil = 0;
const char *closest = NULL;
for(e = encoding_map; e->string; e++) {
int sim;
const char lowertype = tolower(type[0]);
if((lowertype != tolower(e->string[0])) && (lowertype != 'x'))
/*
* simil is expensive, I'm yet to encounter only
* one example of a missent encoding when the
* first character was wrong, so lets assume no
* match to save the call.
*
* That example was quoted-printable sent as
* X-quoted-printable.
*/
continue;
if(strcmp(e->string, "uuencode") == 0)
/*
* No need to test here - fast track visa will have
* handled uuencoded files
*/
continue;
sim = simil(type, e->string);
if(sim == 100) {
int j;
encoding_type *et;
for(j = 0; j < m->numberOfEncTypes; j++)
if(m->encodingTypes[j] == e->type)
break;
if(j < m->numberOfEncTypes) {
cli_dbgmsg("Ignoring duplicate encoding mechanism '%s'\n",
type);
break;
}
et = (encoding_type *)cli_realloc(m->encodingTypes, (m->numberOfEncTypes + 1) * sizeof(encoding_type));
if(et == NULL)
break;
m->encodingTypes = et;
m->encodingTypes[m->numberOfEncTypes++] = e->type;
cli_dbgmsg("Encoding type %d is \"%s\"\n", m->numberOfEncTypes, type);
break;
} else if(sim > highestSimil) {
closest = e->string;
highestSimil = sim;
}
}
if(e->string == NULL) {
/*
* The stated encoding type is illegal, so we
* use a best guess of what it should be.
*
* 50% is arbitary. For example 7bi will match as
* 66% certain to be 7bit
*/
if(highestSimil >= 50) {
cli_dbgmsg("Unknown encoding type \"%s\" - guessing as %s (%u%% certainty)\n",
type, closest, highestSimil);
messageSetEncoding(m, closest);
} else {
cli_dbgmsg("Unknown encoding type \"%s\" - if you believe this file contains a virus, submit it to www.clamav.net\n", type);
/*
* Err on the side of safety, enable all
* decoding modules
*/
messageSetEncoding(m, "base64");
messageSetEncoding(m, "quoted-printable");
}
}
free(type);
}
}
encoding_type
messageGetEncoding(const message *m)
{
assert(m != NULL);
if(m->numberOfEncTypes == 0)
return NOENCODING;
return m->encodingTypes[0];
}
int
messageAddLine(message *m, line_t *line)
{
assert(m != NULL);
if(m->body_first == NULL)
m->body_last = m->body_first = (text *)cli_malloc(sizeof(text));
else {
m->body_last->t_next = (text *)cli_malloc(sizeof(text));
m->body_last = m->body_last->t_next;
}
if(m->body_last == NULL)
return -1;
m->body_last->t_next = NULL;
if(line && lineGetData(line)) {
m->body_last->t_line = lineLink(line);
messageIsEncoding(m);
} else
m->body_last->t_line = NULL;
return 1;
}
/*
* Add the given line to the end of the given message
* If needed a copy of the given line is taken which the caller must free
* Line must not be terminated by a \n
*/
int
messageAddStr(message *m, const char *data)
{
line_t *repeat = NULL;
assert(m != NULL);
if(data) {
if(*data == '\0')
data = NULL;
else {
/*
* If it's only white space, just store one space to
* save memory. You must store something since it may
* be a header line
*/
int iswhite = 1;
const char *p;
for(p = data; *p; p++)
if(((*p) & 0x80) || !isspace(*p)) {
iswhite = 0;
break;
}
if(iswhite) {
/*cli_dbgmsg("messageAddStr: empty line: '%s'\n", data);*/
data = " ";
}
}
}
if(m->body_first == NULL)
m->body_last = m->body_first = (text *)cli_malloc(sizeof(text));
else {
assert(m->body_last != NULL);
if((data == NULL) && (m->body_last->t_line == NULL))
/*
* Although this would save time and RAM, some
* phish signatures have been built which need the
* blank lines
*/
if(messageGetMimeType(m) != TEXT)
/* don't save two blank lines in sucession */
return 1;
m->body_last->t_next = (text *)cli_malloc(sizeof(text));
if(m->body_last->t_next == NULL) {
messageDedup(m);
m->body_last->t_next = (text *)cli_malloc(sizeof(text));
if(m->body_last->t_next == NULL) {
cli_errmsg("messageAddStr: out of memory\n");
return -1;
}
}
if(data && m->body_last->t_line && (strcmp(data, lineGetData(m->body_last->t_line)) == 0))
repeat = m->body_last->t_line;
m->body_last = m->body_last->t_next;
}
if(m->body_last == NULL) {
cli_errmsg("messageAddStr: out of memory\n");
return -1;
}
m->body_last->t_next = NULL;
if(data && *data) {
if(repeat)
m->body_last->t_line = lineLink(repeat);
else {
m->body_last->t_line = lineCreate(data);
if(m->body_last->t_line == NULL) {
messageDedup(m);
m->body_last->t_line = lineCreate(data);
if(m->body_last->t_line == NULL) {
cli_errmsg("messageAddStr: out of memory\n");
return -1;
}
}
/* cli_chomp(m->body_last->t_text); */
messageIsEncoding(m);
}
} else
m->body_last->t_line = NULL;
return 1;
}
/*
* Add the given line to the start of the given message
* A copy of the given line is taken which the caller must free
* Line must not be terminated by a \n
*/
int
messageAddStrAtTop(message *m, const char *data)
{
text *oldfirst;
assert(m != NULL);
if(m->body_first == NULL)
return messageAddLine(m, lineCreate(data));
oldfirst = m->body_first;
m->body_first = (text *)cli_malloc(sizeof(text));
if(m->body_first == NULL) {
m->body_first = oldfirst;
return -1;
}
m->body_first->t_next = oldfirst;
m->body_first->t_line = lineCreate((data) ? data : "");
if(m->body_first->t_line == NULL) {
cli_errmsg("messageAddStrAtTop: out of memory\n");
return -1;
}
return 1;
}
/*
* Put the contents of the given text at the end of the current object.
* Can be used either to move a text object into a message, or to move a
* message's text into another message only moving from a given offset.
* The given text emptied; it can be used again if needed, though be warned that
* it will have an empty line at the start.
* Returns 0 for failure, 1 for success
*/
int
messageMoveText(message *m, text *t, message *old_message)
{
int rc;
if(m->body_first == NULL) {
if(old_message) {
text *u;
/*
* t is within old_message which is about to be
* destroyed
*/
assert(old_message->body_first != NULL);
m->body_first = t;
for(u = old_message->body_first; u != t;) {
text *next;
if(u->t_line)
lineUnlink(u->t_line);
next = u->t_next;
free(u);
u = next;
if(u == NULL) {
cli_dbgmsg("messageMoveText sanity check: t not within old_message\n");
return -1;
}
}
assert(old_message->body_last->t_next == NULL);
m->body_last = old_message->body_last;
old_message->body_first = old_message->body_last = NULL;
/* Do any pointers need to be reset? */
if((old_message->bounce == NULL) &&
(old_message->encoding == NULL) &&
(old_message->binhex == NULL) &&
(old_message->yenc == NULL))
return 0;
m->body_last = m->body_first;
rc = 0;
} else {
m->body_last = m->body_first = textMove(NULL, t);
if(m->body_first == NULL)
rc = -1;
else
rc = 0;
}
} else {
m->body_last = textMove(m->body_last, t);
if(m->body_last == NULL) {
rc = -1;
m->body_last = m->body_first;
} else
rc = 0;
}
while(m->body_last->t_next) {
m->body_last = m->body_last->t_next;
if(m->body_last->t_line)
messageIsEncoding(m);
}
return rc;
}
/*
* See if the last line marks the start of a non MIME inclusion that
* will need to be scanned
*/
static void
messageIsEncoding(message *m)
{
static const char encoding[] = "Content-Transfer-Encoding";
static const char binhex[] = "(This file must be converted with BinHex 4.0)";
const char *line = lineGetData(m->body_last->t_line);
/*if(m->ctx == NULL)
cli_dbgmsg("messageIsEncoding, ctx == NULL\n");*/
if((m->encoding == NULL) &&
(strncasecmp(line, encoding, sizeof(encoding) - 1) == 0) &&
(strstr(line, "7bit") == NULL))
m->encoding = m->body_last;
else if((m->bounce == NULL) && m->ctx &&
(strncasecmp(line, "Received: ", 10) == 0) &&
(cli_filetype((const unsigned char *)line, strlen(line), m->ctx->engine) == CL_TYPE_MAIL))
m->bounce = m->body_last;
/* Not needed with fast track visa technology */
/*else if((m->uuencode == NULL) && isuuencodebegin(line))
m->uuencode = m->body_last;*/
else if((m->binhex == NULL) &&
strstr(line, "BinHex") &&
(simil(line, binhex) > 90))
/*
* Look for close matches for BinHex, but
* simil() is expensive so only do it if it's
* likely to be found
*/
m->binhex = m->body_last;
else if((m->yenc == NULL) && (strncmp(line, "=ybegin line=", 13) == 0))
m->yenc = m->body_last;
}
/*
* Returns a pointer to the body of the message. Note that it does NOT return
* a copy of the data
*/
text *
messageGetBody(message *m)
{
assert(m != NULL);
return m->body_first;
}
/*
* Export a message using the given export routines
*
* TODO: It really should export into an array, one
* for each encoding algorithm. However, what it does is it returns the
* last item that was exported. That's sufficient for now.
*/
static void *
messageExport(message *m, const char *dir, void *(*create)(void), void (*destroy)(void *), void (*setFilename)(void *, const char *, const char *), void (*addData)(void *, const unsigned char *, size_t), void *(*exportText)(text *, void *, int), void(*setCTX)(void *, cli_ctx *), int destroy_text)
{
void *ret;
text *t_line;
char *filename;
int i;
assert(m != NULL);
if(messageGetBody(m) == NULL)
return NULL;
ret = (*create)();
if(ret == NULL)
return NULL;
cli_dbgmsg("messageExport: numberOfEncTypes == %d\n", m->numberOfEncTypes);
if((t_line = binhexBegin(m)) != NULL) {
unsigned char byte;
unsigned long newlen = 0L, len, dataforklen, resourceforklen, l;
unsigned char *data;
char *ptr;
int bytenumber;
blob *tmp;
/*
* HQX conversion table - illegal chars are 0xff
*/
const unsigned char hqxtbl[] = {
/* 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f */
/* 00-0f */ 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
/* 10-1f */ 0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,
/* 20-2f */ 0xff,0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0xff,0xff,
/* 30-3f */ 0x0d,0x0e,0x0f,0x10,0x11,0x12,0x13,0xff,0x14,0x15,0xff,0xff,0xff,0xff,0xff,0xff,
/* 40-4f */ 0x16,0x17,0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f,0x20,0x21,0x22,0x23,0x24,0xff,
/* 50-5f */ 0x25,0x26,0x27,0x28,0x29,0x2a,0x2b,0xff,0x2c,0x2d,0x2e,0x2f,0xff,0xff,0xff,0xff,
/* 60-6f */ 0x30,0x31,0x32,0x33,0x34,0x35,0x36,0xff,0x37,0x38,0x39,0x3a,0x3b,0x3c,0xff,0xff,
/* 70-7f */ 0x3d,0x3e,0x3f,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff
};
cli_dbgmsg("messageExport: decode binhex\n");
/*
* Decode BinHex4. First create a temporary blob which contains
* the encoded message. Then decode that blob to the target
* blob, free the temporary blob and return the target one
*
* FIXME: EICAR isn't detected: should create 3 files in fork
* format: .info, .data and .rsrc. This is needed for
* position dependant detection such as EICAR
*
* See RFC1741
*/
while(((t_line = t_line->t_next) != NULL) &&
(t_line->t_line == NULL))
;
tmp = textToBlob(t_line, NULL,
((m->numberOfEncTypes == 1) && (m->encodingTypes[0] == BINHEX)) ? destroy_text : 0);
if(tmp == NULL) {
/*
* FIXME: We've probably run out of memory during the
* text to blob.
*/
cli_warnmsg("Couldn't start binhex parser\n");
(*destroy)(ret);
return NULL;
}
data = blobGetData(tmp);
if(data == NULL) {
cli_warnmsg("Couldn't locate the binhex message that was claimed to be there\n");
blobDestroy(tmp);
(*destroy)(ret);
return NULL;
}
len = blobGetDataSize(tmp);
if(data[0] == ':') {
unsigned char *uptr;
/* 7 bit (ala RFC1741) */
/*
* FIXME: this is dirty code, modification of the
* contents of a member of the blob object should be
* done through blob.c
*
* Convert 7 bit data into 8 bit
*/
cli_dbgmsg("decode HQX7 message (%lu bytes)\n", len);
uptr = cli_malloc(len);
if(uptr == NULL) {
blobDestroy(tmp);
(*destroy)(ret);
return NULL;
}
memcpy(uptr, data, len);
bytenumber = 0;
/*
* uptr now contains the encoded (7bit) data - len bytes long
* data will contain the unencoded (8bit) data
*/
for(l = 1; l < len; l++) {
unsigned char c = uptr[l];
if(c == ':')
break;
if((c == '\n') || (c == '\r'))
continue;
if((c < 0x20) || (c > 0x7f) || (hqxtbl[c] == 0xff)) {
cli_dbgmsg("Invalid HQX7 character '%c' (0x%02x)\n", c, c);
break;
}
c = hqxtbl[c];
assert(c <= 63);
/*
* These masks probably aren't needed, but
* they're here to verify the code is correct
*/
switch(bytenumber) {
case 0:
data[newlen] = (c << 2) & 0xFC;
bytenumber = 1;
break;
case 1:
data[newlen++] |= (c >> 4) & 0x3;
data[newlen] = (c << 4) & 0xF0;
bytenumber = 2;
break;
case 2:
data[newlen++] |= (c >> 2) & 0xF;
data[newlen] = (c << 6) & 0xC0;
bytenumber = 3;
break;
case 3:
data[newlen++] |= c & 0x3F;
bytenumber = 0;
break;
}
}
cli_dbgmsg("decoded HQX7 message (now %lu bytes)\n", newlen);
/*
* Throw away the old encoded (7bit) data
* data now points to the encoded (8bit) data - newlen bytes
*
* The data array may contain repetitive characters
*/
free(uptr);
} else {
cli_warnmsg("HQX8 messages not yet supported, extraction may fail - if you believe this file contains a virus, submit it to www.clamav.net\n");
newlen = len;
}
/*
* Uncompress repetitive characters
*/
if(memchr(data, 0x90, newlen)) {
blob *u = blobCreate(); /* uncompressed data */
if(u == NULL) {
(*destroy)(ret);
blobDestroy(tmp);
return NULL;
}
/*
* Includes compression
*/
for(l = 0L; l < newlen; l++) {
unsigned char c = data[l];
/*
* TODO: handle the case where the first byte
* is 0x90
*/
blobAddData(u, &c, 1);
if((l < (newlen - 1L)) && (data[l + 1] == 0x90)) {
int count;
l += 2;
count = data[l];
if(count == 0) {
c = 0x90;
blobAddData(u, &c, 1);
} else {
#ifdef CL_DEBUG
cli_dbgmsg("uncompress HQX7 at 0x%06lu: %d repetitive bytes\n", l, count);
#endif
blobGrow(u, count);
while(--count > 0)
blobAddData(u, &c, 1);
}
}
}
blobDestroy(tmp);
tmp = u;
data = blobGetData(tmp);
len = blobGetDataSize(tmp);
cli_dbgmsg("Uncompressed %lu bytes to %lu\n", newlen, len);
} else {
len = newlen;
cli_dbgmsg("HQX7 message (%lu bytes) is not compressed\n",
len);
}
if(len == 0) {
cli_dbgmsg("Discarding empty binHex attachment\n");
(*destroy)(ret);
blobDestroy(tmp);
return NULL;
}
/*
* The blob tmp now contains the uncompressed data
* of len bytes, i.e. the repetitive bytes have been removed
*/
/*
* Parse the header
*
* TODO: set filename argument in message as well
*/
byte = data[0];
if(byte >= len) {
(*destroy)(ret);
blobDestroy(tmp);
return NULL;
}
filename = cli_malloc(byte + 1);
if(filename == NULL) {
(*destroy)(ret);
blobDestroy(tmp);
return NULL;
}
memcpy(filename, &data[1], byte);
filename[byte] = '\0';
(*setFilename)(ret, dir, filename);
/*ptr = cli_malloc(strlen(filename) + 6);*/
ptr = cli_malloc(byte + 6);
if(ptr) {
sprintf(ptr, "name=%s", filename);
messageAddArgument(m, ptr);
free(ptr);
}
/*
* skip over length, filename, version, type, creator and flags
*/
byte = 1 + byte + 1 + 4 + 4 + 2;
/*
* Set len to be the data fork length
*/
dataforklen = ((data[byte] << 24) & 0xFF000000) |
((data[byte + 1] << 16) & 0xFF0000) |
((data[byte + 2] << 8) & 0xFF00) |
(data[byte + 3] & 0xFF);
resourceforklen = ((data[byte + 4] << 24) & 0xFF000000) |
((data[byte + 5] << 16) & 0xFF0000) |
((data[byte + 6] << 8) & 0xFF00) |
(data[byte + 7] & 0xFF);
cli_dbgmsg("Filename = '%s', data fork length = %lu, resource fork length = %lu bytes\n",
filename, dataforklen, resourceforklen);
free((char *)filename);
/*
* Skip over data fork length, resource fork length and CRC
*/
byte += 10;
l = blobGetDataSize(tmp) - byte;
if(l < dataforklen) {
cli_dbgmsg("Corrupt BinHex file, claims it is %lu bytes long in a message of %lu bytes\n",
dataforklen, l);
dataforklen = l;
}
if(setCTX && m->ctx)
(*setCTX)(ret, m->ctx);
(*addData)(ret, &data[byte], dataforklen);
blobDestroy(tmp);
if(destroy_text)
m->binhex = NULL;
if((m->numberOfEncTypes == 0) ||
((m->numberOfEncTypes == 1) && (m->encodingTypes[0] == BINHEX))) {
cli_dbgmsg("Finished exporting binhex file\n");
return ret;
}
}
if(m->numberOfEncTypes == 0) {
/*
* Fast copy
*/
cli_dbgmsg("messageExport: Entering fast copy mode\n");
#if 0
filename = messageGetFilename(m);
if(filename == NULL) {
cli_dbgmsg("Unencoded attachment sent with no filename\n");
messageAddArgument(m, "name=attachment");
} else if((strcmp(filename, "textportion") != 0) && (strcmp(filename, "mixedtextportion") != 0))
/*
* Some virus attachments don't say how they've
* been encoded. We assume base64
*/
messageSetEncoding(m, "base64");
#else
filename = (char *)messageFindArgument(m, "filename");
if(filename == NULL) {
filename = (char *)messageFindArgument(m, "name");
if(filename == NULL) {
cli_dbgmsg("Unencoded attachment sent with no filename\n");
messageAddArgument(m, "name=attachment");
} else
/*
* Some virus attachments don't say how they've
* been encoded. We assume base64
*/
messageSetEncoding(m, "base64");
}
#endif
(*setFilename)(ret, dir, (filename && *filename) ? filename : "attachment");
if(filename)
free((char *)filename);
if(m->numberOfEncTypes == 0)
return exportText(messageGetBody(m), ret, destroy_text);
}
if(setCTX && m->ctx)
(*setCTX)(ret, m->ctx);
for(i = 0; i < m->numberOfEncTypes; i++) {
encoding_type enctype = m->encodingTypes[i];
size_t size;
if(i > 0) {
void *newret;
newret = (*create)();
if(newret == NULL) {
cli_dbgmsg("Not all decoding algorithms were run\n");
return ret;
}
(*destroy)(ret);
ret = newret;
}
cli_dbgmsg("messageExport: enctype %d is %d\n", i, (int)enctype);
/*
* Find the filename to decode
*/
if(((enctype == YENCODE) || (i == 0)) && yEncBegin(m)) {
const char *f;
/*
* TODO: handle multipart yEnc encoded files
*/
t_line = yEncBegin(m);
f = lineGetData(t_line->t_line);
if((filename = strstr(f, " name=")) != NULL) {
filename = cli_strdup(&filename[6]);
if(filename) {
cli_chomp(filename);
strstrip(filename);
cli_dbgmsg("Set yEnc filename to \"%s\"\n", filename);
}
}
(*setFilename)(ret, dir, (filename && *filename) ? filename : "attachment");
if(filename) {
free((char *)filename);
filename = NULL;
}
t_line = t_line->t_next;
enctype = YENCODE;
m->yenc = NULL;
} else {
if(enctype == UUENCODE) {
/*
* The body will have been stripped out by the
* fast track visa system. Treat as plain/text,
* which means we'll still scan for funnies
* outside of the uuencoded portion.
*/
cli_dbgmsg("messageExport: treat uuencode as text/plain\n");
enctype = m->encodingTypes[i] = NOENCODING;
}
filename = messageGetFilename(m);
if(filename == NULL) {
cli_dbgmsg("Attachment sent with no filename\n");
messageAddArgument(m, "name=attachment");
} else if(enctype == NOENCODING)
/*
* Some virus attachments don't say how
* they've been encoded. We assume
* base64.
*
* FIXME: don't do this if it's a fall
* through from uuencode
*/
messageSetEncoding(m, "base64");
(*setFilename)(ret, dir, (filename && *filename) ? filename : "attachment");
t_line = messageGetBody(m);
}
if(filename)
free((char *)filename);
/*
* t_line should now point to the first (encoded) line of the
* message
*/
if(t_line == NULL) {
cli_dbgmsg("Empty attachment not saved\n");
(*destroy)(ret);
return NULL;
}
if(enctype == NOENCODING) {
/*
* Fast copy
*/
if(i == m->numberOfEncTypes - 1) {
/* last one */
(void)exportText(t_line, ret, destroy_text);
break;
}
(void)exportText(t_line, ret, 0);
continue;
}
size = 0;
do {
unsigned char smallbuf[1024];
unsigned char *uptr, *data;
const char *line = lineGetData(t_line->t_line);
unsigned char *bigbuf;
size_t datasize;
if(enctype == YENCODE) {
if(line == NULL)
continue;
if(strncmp(line, "=yend ", 6) == 0)
break;
}
/*
* Add two bytes for '\n' and '\0'
*/
datasize = (line) ? strlen(line) + 2 : 0;
if(datasize >= sizeof(smallbuf))
data = bigbuf = (unsigned char *)cli_malloc(datasize);
else {
bigbuf = NULL;
data = smallbuf;
datasize = sizeof(smallbuf);
}
uptr = decodeLine(m, enctype, line, data, datasize);
if(uptr == NULL) {
if(data == bigbuf)
free(data);
break;
}
if(uptr != data) {
assert((size_t)(uptr - data) < datasize);
(*addData)(ret, data, (size_t)(uptr - data));
size += (size_t)(uptr - data);
}
if(data == bigbuf)
free(data);
/*
* According to RFC2045, '=' is used to pad out
* the last byte and should be used as evidence
* of the end of the data. Some mail clients
* annoyingly then put plain text after the '='
* byte and viruses exploit this bug. Sigh
*/
/*if(enctype == BASE64)
if(strchr(line, '='))
break;*/
if(line && destroy_text && (i == m->numberOfEncTypes - 1)) {
lineUnlink(t_line->t_line);
t_line->t_line = NULL;
}
} while((t_line = t_line->t_next) != NULL);
cli_dbgmsg("Exported %lu bytes using enctype %d\n",
(unsigned long)size, (int)enctype);
/* Verify we have nothing left to flush out */
if(m->base64chars) {
unsigned char data[4];
unsigned char *ptr;
ptr = base64Flush(m, data);
if(ptr)
(*addData)(ret, data, (size_t)(ptr - data));
}
}
return ret;
}
unsigned char *
base64Flush(message *m, unsigned char *buf)
{
cli_dbgmsg("%d trailing bytes to export\n", m->base64chars);
if(m->base64chars) {
unsigned char *ret = decode(m, NULL, buf, base64, FALSE);
m->base64chars = 0;
return ret;
}
return NULL;
}
int messageSavePartial(message *m, const char *dir, const char *md5id, unsigned part)
{
char fullname[1024];
fileblob *fb;
unsigned long time_val;
cli_dbgmsg("messageSavePartial\n");
time_val = time(NULL);
snprintf(fullname, 1024, "%s/clamav-partial-%lu_%s-%u", dir, time_val, md5id, part);
fb = messageExport(m, fullname,
(void *(*)(void))fileblobCreate,
(void(*)(void *))fileblobDestroy,
(void(*)(void *, const char *, const char *))fileblobPartialSet,
(void(*)(void *, const unsigned char *, size_t))fileblobAddData,
(void *(*)(text *, void *, int))textToFileblob,
(void(*)(void *, cli_ctx *))fileblobSetCTX,
0);
if(!fb)
return CL_EFORMAT;
fileblobDestroy(fb);
return CL_SUCCESS;
}
/*
* Decode and transfer the contents of the message into a fileblob
* The caller must free the returned fileblob
*/
fileblob *
messageToFileblob(message *m, const char *dir, int destroy)
{
fileblob *fb;
cli_dbgmsg("messageToFileblob\n");
fb = messageExport(m, dir,
(void *(*)(void))fileblobCreate,
(void(*)(void *))fileblobDestroy,
(void(*)(void *, const char *, const char *))fileblobSetFilename,
(void(*)(void *, const unsigned char *, size_t))fileblobAddData,
(void *(*)(text *, void *, int))textToFileblob,
(void(*)(void *, cli_ctx *))fileblobSetCTX,
destroy);
if(destroy && m->body_first) {
textDestroy(m->body_first);
m->body_first = m->body_last = NULL;
}
return fb;
}
/*
* Decode and transfer the contents of the message into a closed blob
* The caller must free the returned blob
*/
blob *
messageToBlob(message *m, int destroy)
{
blob *b;
cli_dbgmsg("messageToBlob\n");
b = messageExport(m, NULL,
(void *(*)(void))blobCreate,
(void(*)(void *))blobDestroy,
(void(*)(void *, const char *, const char *))blobSetFilename,
(void(*)(void *, const unsigned char *, size_t))blobAddData,
(void *(*)(text *, void *, int))textToBlob,
(void(*)(void *, cli_ctx *))NULL,
destroy);
if(destroy && m->body_first) {
textDestroy(m->body_first);
m->body_first = m->body_last = NULL;
}
return b;
}
/*
* Decode and transfer the contents of the message into a text area
* The caller must free the returned text
*/
text *
messageToText(message *m)
{
int i;
text *first = NULL, *last = NULL;
const text *t_line;
assert(m != NULL);
if(m->numberOfEncTypes == 0) {
/*
* Fast copy
*/
for(t_line = messageGetBody(m); t_line; t_line = t_line->t_next) {
if(first == NULL)
first = last = cli_malloc(sizeof(text));
else {
last->t_next = cli_malloc(sizeof(text));
last = last->t_next;
}
if(last == NULL) {
if(first)
textDestroy(first);
return NULL;
}
if(t_line->t_line)
last->t_line = lineLink(t_line->t_line);
else
last->t_line = NULL; /* empty line */
}
if(last)
last->t_next = NULL;
return first;
}
/*
* Scan over the data a number of times once for each claimed encoding
* type
*/
for(i = 0; i < m->numberOfEncTypes; i++) {
const encoding_type enctype = m->encodingTypes[i];
cli_dbgmsg("messageToText: export transfer method %d = %d\n",
i, (int)enctype);
switch(enctype) {
case NOENCODING:
case BINARY:
case EIGHTBIT:
/*
* Fast copy
*/
for(t_line = messageGetBody(m); t_line; t_line = t_line->t_next) {
if(first == NULL)
first = last = cli_malloc(sizeof(text));
else if (last) {
last->t_next = cli_malloc(sizeof(text));
last = last->t_next;
}
if(last == NULL) {
if(first) {
textDestroy(first);
}
return NULL;
}
if(t_line->t_line)
last->t_line = lineLink(t_line->t_line);
else
last->t_line = NULL; /* empty line */
}
continue;
case UUENCODE:
cli_warnmsg("messageToText: Unexpected attempt to handle uuencoded file\n");
if(first) {
if(last)
last->t_next = NULL;
textDestroy(first);
}
return NULL;
case YENCODE:
t_line = yEncBegin(m);
if(t_line == NULL) {
/*cli_warnmsg("YENCODED attachment is missing begin statement\n");*/
if(first) {
if(last)
last->t_next = NULL;
textDestroy(first);
}
return NULL;
}
t_line = t_line->t_next;
default:
if((i == 0) && binhexBegin(m))
cli_warnmsg("Binhex messages not supported yet.\n");
t_line = messageGetBody(m);
}
for(; t_line; t_line = t_line->t_next) {
unsigned char data[1024];
unsigned char *uptr;
const char *line = lineGetData(t_line->t_line);
if(enctype == BASE64)
/*
* ignore blanks - breaks RFC which is
* probably the point!
*/
if(line == NULL)
continue;
assert((line == NULL) || (strlen(line) <= sizeof(data)));
uptr = decodeLine(m, enctype, line, data, sizeof(data));
if(uptr == NULL)
break;
assert(uptr <= &data[sizeof(data)]);
if(first == NULL)
first = last = cli_malloc(sizeof(text));
else if (last) {
last->t_next = cli_malloc(sizeof(text));
last = last->t_next;
}
if(last == NULL)
break;
/*
* If the decoded line is the same as the encoded
* there's no need to take a copy, just link it.
* Note that the comparison is done without the
* trailing newline that the decoding routine may have
* added - that's why there's a strncmp rather than a
* strcmp - that'd be bad for MIME decoders, but is OK
* for AV software
*/
if((data[0] == '\n') || (data[0] == '\0'))
last->t_line = NULL;
else if(line && (strncmp((const char *)data, line, strlen(line)) == 0)) {
#ifdef CL_DEBUG
cli_dbgmsg("messageToText: decoded line is the same(%s)\n", data);
#endif
last->t_line = lineLink(t_line->t_line);
} else
last->t_line = lineCreate((char *)data);
if(line && enctype == BASE64)
if(strchr(line, '='))
break;
}
if(m->base64chars) {
unsigned char data[4];
memset(data, '\0', sizeof(data));
if(decode(m, NULL, data, base64, FALSE) && data[0]) {
if(first == NULL)
first = last = cli_malloc(sizeof(text));
else if (last) {
last->t_next = cli_malloc(sizeof(text));
last = last->t_next;
}
if(last != NULL)
last->t_line = lineCreate((char *)data);
}
m->base64chars = 0;
}
}
if(last)
last->t_next = NULL;
return first;
}
text *
yEncBegin(message *m)
{
return m->yenc;
}
/*
* Scan to find the BINHEX message (if any)
*/
#if 0
const text *
binhexBegin(message *m)
{
const text *t_line;
for(t_line = messageGetBody(m); t_line; t_line = t_line->t_next)
if(strcasecmp(t_line->t_text, "(This file must be converted with BinHex 4.0)") == 0)
return t_line;
return NULL;
}
#else
text *
binhexBegin(message *m)
{
return m->binhex;
}
#endif
/*
* Scan to find a bounce message. There is no standard for these, not
* even a convention, so don't expect this to be foolproof
*/
#if 0
text *
bounceBegin(message *m)
{
const text *t_line;
for(t_line = messageGetBody(m); t_line; t_line = t_line->t_next)
if(cli_filetype(t_line->t_text, strlen(t_line->t_text)) == CL_TYPE_MAIL)
return t_line;
return NULL;
}
#else
text *
bounceBegin(message *m)
{
return m->bounce;
}
#endif
/*
* If a message doesn't not contain another message which could be harmful
* it is deemed to be safe.
*
* TODO: ensure nothing can get through this
*
* TODO: check to see if we need to
* find anything else, perhaps anything
* from the RFC821 table?
*/
#if 0
int
messageIsAllText(const message *m)
{
const text *t;
for(t = messageGetBody(m); t; t = t->t_next)
if(strncasecmp(t->t_text,
"Content-Transfer-Encoding",
strlen("Content-Transfer-Encoding")) == 0)
return 0;
return 1;
}
#else
text *
encodingLine(message *m)
{
return m->encoding;
}
#endif
/*
* Decode a line and add it to a buffer, return the end of the buffer
* to help appending callers. There is no new line at the end of "line"
*
* len is sizeof(ptr)
*/
unsigned char *
decodeLine(message *m, encoding_type et, const char *line, unsigned char *buf, size_t buflen)
{
size_t len, reallen;
bool softbreak;
char *p2, *copy;
char base64buf[RFC2045LENGTH + 1];
/*cli_dbgmsg("decodeLine(et = %d buflen = %u)\n", (int)et, buflen);*/
assert(m != NULL);
assert(buf != NULL);
switch(et) {
case BINARY:
/*
* TODO: find out what this is, encoded as binary??
*/
/* fall through */
case NOENCODING:
case EIGHTBIT:
default: /* unknown encoding type - try our best */
if(line) /* empty line? */
buf = (unsigned char *)cli_strrcpy((char *)buf, line);
/* Put the new line back in */
return (unsigned char *)cli_strrcpy((char *)buf, "\n");
case QUOTEDPRINTABLE:
if(line == NULL) { /* empty line */
*buf++ = '\n';
break;
}
softbreak = FALSE;
while(buflen && *line) {
if(*line == '=') {
unsigned char byte;
if((*++line == '\0') || (*line == '\n')) {
softbreak = TRUE;
/* soft line break */
break;
}
byte = hex(*line);
if((*++line == '\0') || (*line == '\n')) {
/*
* broken e-mail, not
* adhering to RFC2045
*/
*buf++ = byte;
break;
}
/*
* Handle messages that use a broken
* quoted-printable encoding of
* href=\"http://, instead of =3D
*/
if(byte != '=')
byte = (byte << 4) | hex(*line);
else
line -= 2;
*buf++ = byte;
} else
*buf++ = *line;
++line;
--buflen;
}
if(!softbreak)
/* Put the new line back in */
*buf++ = '\n';
break;
case BASE64:
if(line == NULL)
break;
/*
* RFC2045 sets the maximum length to 76 bytes
* but many e-mail clients ignore that
*/
if(strlen(line) < sizeof(base64buf)) {
strcpy(base64buf, line);
copy = base64buf;
} else {
copy = cli_strdup(line);
if(copy == NULL)
break;
}
p2 = strchr(copy, '=');
if(p2)
*p2 = '\0';
sanitiseBase64(copy);
/*
* Klez doesn't always put "=" on the last line
*/
buf = decode(m, copy, buf, base64, (p2 == NULL) && ((strlen(copy) & 3) == 0));
if(copy != base64buf)
free(copy);
break;
case UUENCODE:
assert(m->base64chars == 0);
if((line == NULL) || (*line == '\0')) /* empty line */
break;
if(strcasecmp(line, "end") == 0)
break;
if(isuuencodebegin(line))
break;
if((line[0] & 0x3F) == ' ')
break;
/*
* reallen contains the number of bytes that were
* encoded
*/
reallen = (size_t)uudecode(*line++);
if(reallen <= 0)
break;
if(reallen > 62)
break;
len = strlen(line);
if((len > buflen) || (reallen > len))
/*
* In practice this should never occur since
* the maximum length of a uuencoded line is
* 62 characters
*/
cli_dbgmsg("uudecode: buffer overflow stopped, attempting to ignore but decoding may fail\n");
else {
(void)decode(m, line, buf, uudecode, (len & 3) == 0);
buf = &buf[reallen];
}
m->base64chars = 0; /* this happens with broken uuencoded files */
break;
case YENCODE:
if((line == NULL) || (*line == '\0')) /* empty line */
break;
if(strncmp(line, "=yend ", 6) == 0)
break;
while(*line)
if(*line == '=') {
if(*++line == '\0')
break;
*buf++ = ((*line++ - 64) & 255);
} else
*buf++ = ((*line++ - 42) & 255);
break;
}
*buf = '\0';
return buf;
}
/*
* Remove the non base64 characters such as spaces from a string. Spaces
* shouldn't appear mid string in base64 files, but some broken mail clients
* ignore such errors rather than discarding the mail, and virus writers
* exploit this bug
*/
static void
sanitiseBase64(char *s)
{
cli_dbgmsg("sanitiseBase64 '%s'\n", s);
while(*s)
if(base64Table[(unsigned int)(*s & 0xFF)] == 255) {
char *p1;
for(p1 = s; p1[0] != '\0'; p1++)
p1[0] = p1[1];
} else
s++;
}
/*
* Returns one byte after the end of the decoded data in "out"
*
* Update m->base64chars with the last few bytes of data that we haven't
* decoded. After the last line is found, decode will be called with in = NULL
* to flush these out
*/
static unsigned char *
decode(message *m, const char *in, unsigned char *out, unsigned char (*decoder)(char), bool isFast)
{
unsigned char b1, b2, b3, b4;
unsigned char cb1, cb2, cb3; /* carried over from last line */
/*cli_dbgmsg("decode %s (len %d isFast %d base64chars %d)\n", in,
in ? strlen(in) : 0,
isFast, m->base64chars);*/
cb1 = cb2 = cb3 = '\0';
switch(m->base64chars) {
case 3:
cb3 = m->base64_3;
/* FALLTHROUGH */
case 2:
cb2 = m->base64_2;
/* FALLTHROUGH */
case 1:
cb1 = m->base64_1;
isFast = FALSE;
break;
default:
assert(m->base64chars <= 3);
}
if(isFast)
/* Fast decoding if not last line */
while(*in) {
b1 = (*decoder)(*in++);
b2 = (*decoder)(*in++);
b3 = (*decoder)(*in++);
/*
* Put this line here to help on some compilers which
* can make use of some architecure's ability to
* multiprocess when different variables can be
* updated at the same time - here b3 is used in
* one line, b1/b2 in the next and b4 in the next after
* that, b3 and b4 rely on in but b1/b2 don't
*/
*out++ = (b1 << 2) | ((b2 >> 4) & 0x3);
b4 = (*decoder)(*in++);
*out++ = (b2 << 4) | ((b3 >> 2) & 0xF);
*out++ = (b3 << 6) | (b4 & 0x3F);
}
else if(in == NULL) { /* flush */
int nbytes;
if(m->base64chars == 0)
return out;
cli_dbgmsg("base64chars = %d (%c %c %c)\n", m->base64chars,
isalnum(cb1) ? cb1 : '@',
isalnum(cb2) ? cb2 : '@',
isalnum(cb3) ? cb3 : '@');
m->base64chars--;
b1 = cb1;
nbytes = 1;
if(m->base64chars) {
m->base64chars--;
b2 = cb2;
if(m->base64chars) {
nbytes = 2;
m->base64chars--;
b3 = cb3;
nbytes = 3;
} else if(b2)
nbytes = 2;
}
switch(nbytes) {
case 3:
b4 = '\0';
/* fall through */
case 4:
*out++ = (b1 << 2) | ((b2 >> 4) & 0x3);
*out++ = (b2 << 4) | ((b3 >> 2) & 0xF);
if((nbytes == 4) || (b3&0x3))
*out++ = (b3 << 6) | (b4 & 0x3F);
break;
case 2:
*out++ = (b1 << 2) | ((b2 >> 4) & 0x3);
if((b2 << 4) & 0xFF)
*out++ = b2 << 4;
break;
case 1:
*out++ = b1 << 2;
break;
default:
assert(0);
}
} else while(*in) {
int nbytes;
if(m->base64chars) {
m->base64chars--;
b1 = cb1;
} else
b1 = (*decoder)(*in++);
if(*in == '\0') {
b2 = '\0';
nbytes = 1;
} else {
if(m->base64chars) {
m->base64chars--;
b2 = cb2;
} else
b2 = (*decoder)(*in++);
if(*in == '\0') {
b3 = '\0';
nbytes = 2;
} else {
if(m->base64chars) {
m->base64chars--;
b3 = cb3;
} else
b3 = (*decoder)(*in++);
if(*in == '\0') {
b4 = '\0';
nbytes = 3;
} else {
b4 = (*decoder)(*in++);
nbytes = 4;
}
}
}
switch(nbytes) {
case 4:
*out++ = (b1 << 2) | ((b2 >> 4) & 0x3);
*out++ = (b2 << 4) | ((b3 >> 2) & 0xF);
*out++ = (b3 << 6) | (b4 & 0x3F);
continue;
case 3:
m->base64_3 = b3;
case 2:
m->base64_2 = b2;
case 1:
m->base64_1 = b1;
m->base64chars = nbytes;
break;
default:
assert(0);
}
break; /* nbytes != 4 => EOL */
}
return out;
}
static unsigned char
hex(char c)
{
if(isdigit(c))
return c - '0';
if((c >= 'A') && (c <= 'F'))
return c - 'A' + 10;
if((c >= 'a') && (c <= 'f'))
return c - 'a' + 10;
cli_dbgmsg("Illegal hex character '%c'\n", c);
/*
* Some mails (notably some spam) break RFC2045 by failing to encode
* the '=' character
*/
return '=';
}
static unsigned char
base64(char c)
{
const unsigned char ret = base64Table[(unsigned int)(c & 0xFF)];
if(ret == 255) {
/*cli_dbgmsg("Illegal character <%c> in base64 encoding\n", c);*/
return 63;
}
return ret;
}
static unsigned char
uudecode(char c)
{
return c - ' ';
}
/*
* These are the only arguments we're interested in.
* Do 'fgrep messageFindArgument *.c' if you don't believe me!
* It's probably not good doing this since each time a new
* messageFindArgument is added I need to remember to look here,
* but it can save a lot of memory...
*/
static int
usefulArg(const char *arg)
{
if((strncasecmp(arg, "name", 4) != 0) &&
(strncasecmp(arg, "filename", 8) != 0) &&
(strncasecmp(arg, "boundary", 8) != 0) &&
(strncasecmp(arg, "protocol", 8) != 0) &&
(strncasecmp(arg, "id", 2) != 0) &&
(strncasecmp(arg, "number", 6) != 0) &&
(strncasecmp(arg, "total", 5) != 0) &&
(strncasecmp(arg, "type", 4) != 0)) {
cli_dbgmsg("Discarding unwanted argument '%s'\n", arg);
return 0;
}
return 1;
}
void
messageSetCTX(message *m, cli_ctx *ctx)
{
m->ctx = ctx;
}
int
messageContainsVirus(const message *m)
{
return m->isInfected ? TRUE : FALSE;
}
/*
* We've run out of memory. Try to recover some by
* deduping the message
*
* FIXME: this can take a long time. The real solution is for system admins
* to refrain from setting ulimits too low, then this routine won't be
* called
*/
static void
messageDedup(message *m)
{
const text *t1;
size_t saved = 0;
cli_dbgmsg("messageDedup\n");
t1 = m->dedupedThisFar ? m->dedupedThisFar : m->body_first;
for(t1 = m->body_first; t1; t1 = t1->t_next) {
const char *d1;
text *t2;
line_t *l1;
unsigned int r1;
if(saved >= 100*1000)
break; /* that's enough */
l1 = t1->t_line;
if(l1 == NULL)
continue;
d1 = lineGetData(l1);
if(strlen(d1) < 8)
continue; /* wouldn't recover many bytes */
r1 = (unsigned int)lineGetRefCount(l1);
if(r1 == 255)
continue;
/*
* We don't want to foul up any pointers
*/
if(t1 == m->encoding)
continue;
if(t1 == m->bounce)
continue;
if(t1 == m->binhex)
continue;
if(t1 == m->yenc)
continue;
for(t2 = t1->t_next; t2; t2 = t2->t_next) {
const char *d2;
line_t *l2 = t2->t_line;
if(l2 == NULL)
continue;
d2 = lineGetData(l2);
if(d1 == d2)
/* already linked */
continue;
if(strcmp(d1, d2) == 0) {
if(lineUnlink(l2) == NULL)
saved += strlen(d1) + 1;
t2->t_line = lineLink(l1);
if(t2->t_line == NULL) {
cli_errmsg("messageDedup: out of memory\n");
return;
}
if(++r1 == 255)
break;
}
}
}
cli_dbgmsg("messageDedup reclaimed %lu bytes\n", (unsigned long)saved);
m->dedupedThisFar = t1;
}
/*
* Handle RFC2231 encoding. Returns a malloc'd buffer that the caller must
* free, or NULL on error.
*
* TODO: Currently only handles paragraph 4 of RFC2231 e.g.
* protocol*=ansi-x3.4-1968''application%2Fpgp-signature;
*/
static char *
rfc2231(const char *in)
{
const char *ptr;
char *ret, *out;
enum { LANGUAGE, CHARSET, CONTENTS } field;
if(strstr(in, "*0*=") != NULL) {
char *p;
/* Don't handle continuations, decode what we can */
p = ret = cli_malloc(strlen(in) + 16);
if(ret == NULL)
return NULL;
do {
switch(*in) {
default:
*p++ = *in++;
continue;
case '*':
do
in++;
while((*in != '*') && *in);
if(*in) {
in++;
continue;
}
*p = '\0';
break;
case '=':
/*strcpy(p, in);*/
strcpy(p, "=rfc2231failure");
break;
}
break;
} while(*in);
cli_dbgmsg("RFC2231 parameter continuations are not yet handled, returning \"%s\"\n",
ret);
return ret;
}
ptr = strstr(in, "*0=");
if(ptr != NULL)
/*
* Parameter continuation, with no continuation
* Thunderbird 1.5 (and possibly other versions) does this
*/
field = CONTENTS;
else {
ptr = strstr(in, "*=");
field = LANGUAGE;
}
if(ptr == NULL) { /* quick return */
out = ret = cli_strdup(in);
while(*out)
*out++ &= 0x7F;
return ret;
}
cli_dbgmsg("rfc2231 '%s'\n", in);
ret = cli_malloc(strlen(in) + 1);
if(ret == NULL)
return NULL;
/*
* memcpy(out, in, (ptr - in));
* out = &out[ptr - in];
* in = ptr;
*/
out = ret;
while(in != ptr)
*out++ = *in++;
*out++ = '=';
while(*ptr++ != '=')
;
/*
* We don't do anything with the language and character set, just skip
* over them!
*/
while(*ptr) {
switch(field) {
case LANGUAGE:
if(*ptr == '\'')
field = CHARSET;
break;
case CHARSET:
if(*ptr == '\'')
field = CONTENTS;
break;
case CONTENTS:
if(*ptr == '%') {
unsigned char byte;
if((*++ptr == '\0') || (*ptr == '\n'))
break;
byte = hex(*ptr);
if((*++ptr == '\0') || (*ptr == '\n')) {
*out++ = byte;
break;
}
byte <<= 4;
byte += hex(*ptr);
*out++ = byte;
} else
*out++ = *ptr;
}
if(*ptr++ == '\0')
/*
* Incorrect message that has just one character after
* a '%'.
* FIXME: stash something in out that would, for example
* treat %2 as %02, assuming field == CONTENTS
*/
break;
}
if(field != CONTENTS) {
free(ret);
cli_dbgmsg("Invalid RFC2231 header: '%s'\n", in);
return cli_strdup("");
}
*out = '\0';
cli_dbgmsg("rfc2231 returns '%s'\n", ret);
return ret;
}
/*
* common/simil:
* From Computing Magazine 20/8/92
* Returns %ge number from 0 to 100 - how similar are 2 strings?
* 100 for exact match, < for error
*/
struct pstr_list { /* internal stack */
char *d1;
struct pstr_list *next;
};
#define OUT_OF_MEMORY (-2)
#define FAILURE (-3)
#define SUCCESS (-4)
#define ARRAY_OVERFLOW (-5)
typedef struct pstr_list ELEMENT1;
typedef ELEMENT1 *LINK1;
static int push(LINK1 *top, const char *string);
static int pop(LINK1 *top, char *buffer);
static unsigned int compare(char *ls1, char **rs1, char *ls2, char **rs2);
#define MAX_PATTERN_SIZ 50 /* maximum string lengths */
static int
simil(const char *str1, const char *str2)
{
LINK1 top = NULL;
unsigned int score = 0;
size_t common, total;
size_t len1, len2;
char *rs1 = NULL, *rs2 = NULL;
char *s1, *s2;
char ls1[MAX_PATTERN_SIZ], ls2[MAX_PATTERN_SIZ];
if(strcasecmp(str1, str2) == 0)
return 100;
if((s1 = cli_strdup(str1)) == NULL)
return OUT_OF_MEMORY;
if((s2 = cli_strdup(str2)) == NULL) {
free(s1);
return OUT_OF_MEMORY;
}
if(((total = strstrip(s1)) > MAX_PATTERN_SIZ - 1) || ((len2 = strstrip(s2)) > MAX_PATTERN_SIZ - 1)) {
free(s1);
free(s2);
return ARRAY_OVERFLOW;
}
total += len2;
if((push(&top, s1) == OUT_OF_MEMORY) ||
(push(&top, s2) == OUT_OF_MEMORY)) {
free(s1);
free(s2);
return OUT_OF_MEMORY;
}
while(pop(&top, ls2) == SUCCESS) {
pop(&top, ls1);
common = compare(ls1, &rs1, ls2, &rs2);
if(common > 0) {
score += (unsigned int)common;
len1 = strlen(ls1);
len2 = strlen(ls2);
if((len1 > 1 && len2 >= 1) || (len2 > 1 && len1 >= 1))
if((push(&top, ls1) == OUT_OF_MEMORY) || (push(&top, ls2) == OUT_OF_MEMORY)) {
free(s1);
free(s2);
return OUT_OF_MEMORY;
}
len1 = strlen(rs1);
len2 = strlen(rs2);
if((len1 > 1 && len2 >= 1) || (len2 > 1 && len1 >= 1))
if((push(&top, rs1) == OUT_OF_MEMORY) || (push(&top, rs2) == OUT_OF_MEMORY)) {
free(s1);
free(s2);
return OUT_OF_MEMORY;
}
}
}
free(s1);
free(s2);
return (total > 0) ? ((score * 200) / total) : 0;
}
static unsigned int
compare(char *ls1, char **rs1, char *ls2, char **rs2)
{
unsigned int common, maxchars = 0;
bool some_similarity = FALSE;
char *s1, *s2;
char *maxs1 = NULL, *maxs2 = NULL, *maxe1 = NULL, *maxe2 = NULL;
char *cs1, *cs2, *start1, *end1, *end2;
end1 = ls1 + strlen(ls1);
end2 = ls2 + strlen(ls2);
start1 = ls1;
for(;;) {
s1 = start1;
s2 = ls2;
if(s1 < end1) {
while(s1 < end1 && s2 < end2) {
if(tolower(*s1) == tolower(*s2)) {
some_similarity = TRUE;
cs1 = s1;
cs2 = s2;
common = 0;
do
if(s1 == end1 || s2 == end2)
break;
else {
s1++;
s2++;
common++;
}
while(tolower(*s1) == tolower(*s2));
if(common > maxchars) {
unsigned int diff = common - maxchars;
maxchars = common;
maxs1 = cs1;
maxs2 = cs2;
maxe1 = s1;
maxe2 = s2;
end1 -= diff;
end2 -= diff;
} else
s1 -= common;
} else
s2++;
}
start1++;
} else
break;
}
if(some_similarity) {
*maxs1 = '\0';
*maxs2 = '\0';
*rs1 = maxe1;
*rs2 = maxe2;
}
return maxchars;
}
static int
push(LINK1 *top, const char *string)
{
LINK1 element;
if((element = (LINK1)cli_malloc(sizeof(ELEMENT1))) == NULL)
return OUT_OF_MEMORY;
if((element->d1 = cli_strdup(string)) == NULL)
return OUT_OF_MEMORY;
element->next = *top;
*top = element;
return SUCCESS;
}
static int
pop(LINK1 *top, char *buffer)
{
LINK1 t1;
if((t1 = *top) != NULL) {
(void)strcpy(buffer, t1->d1);
*top = t1->next;
free(t1->d1);
free((char *)t1);
return SUCCESS;
}
return FAILURE;
}
/*
* Have we found a line that is a start of a uuencoded file (see uuencode(5))?
*/
int
isuuencodebegin(const char *line)
{
if(line[0] != 'b') /* quick check */
return 0;
if(strlen(line) < 10)
return 0;
return (strncasecmp(line, "begin ", 6) == 0) &&
isdigit(line[6]) && isdigit(line[7]) &&
isdigit(line[8]) && (line[9] == ' ');
}