/*
* Copyright notice from original mutt:
* Copyright (C) 1996-2000 Michael R. Elkins <me@mutt.org>
* Copyright (C) 2000-2001 Edmund Grimley Evans <edmundo@rano.org>
*
* This file is part of mutt-ng, see http://www.muttng.org/.
* It's licensed under the GNU General Public License,
* please see the file GPL in the top level source directory.
*/
#if HAVE_CONFIG_H
# include "config.h"
#endif
#include "mutt.h"
#include "ascii.h"
#include "mime.h"
#include "charset.h"
#include "rfc2047.h"
#include "thread.h"
#include "lib/mem.h"
#include "lib/str.h"
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* If you are debugging this file, comment out the following line. */
/*#define NDEBUG*/
#ifdef NDEBUG
#define assert(x)
#else
#include <assert.h>
#endif
#define ENCWORD_LEN_MAX 75
#define ENCWORD_LEN_MIN 9 /* str_len ("=?.?.?.?=") */
#define HSPACE(x) ((x) == '\0' || (x) == ' ' || (x) == '\t')
#define CONTINUATION_BYTE(c) (((c) & 0xc0) == 0x80)
extern char RFC822Specials[];
typedef size_t (*encoder_t) (char *, ICONV_CONST char *, size_t,
const char *);
static size_t convert_string (ICONV_CONST char *f, size_t flen,
const char *from, const char *to,
char **t, size_t * tlen)
{
iconv_t cd;
char *buf, *ob;
size_t obl, n;
int e;
cd = mutt_iconv_open (to, from, 0);
if (cd == (iconv_t) (-1))
return (size_t) (-1);
obl = 4 * flen + 1;
ob = buf = mem_malloc (obl);
n = iconv (cd, &f, &flen, &ob, &obl);
if (n == (size_t) (-1) || iconv (cd, 0, 0, &ob, &obl) == (size_t) (-1)) {
e = errno;
mem_free (&buf);
iconv_close (cd);
errno = e;
return (size_t) (-1);
}
*ob = '\0';
*tlen = ob - buf;
mem_realloc (&buf, ob - buf + 1);
*t = buf;
iconv_close (cd);
return n;
}
char *mutt_choose_charset (const char *fromcode, const char *charsets,
char *u, size_t ulen, char **d, size_t * dlen)
{
char canonical_buff[LONG_STRING];
char *e = 0, *tocode = 0;
size_t elen = 0, bestn = 0;
const char *p, *q;
for (p = charsets; p; p = q ? q + 1 : 0) {
char *s, *t;
size_t slen, n;
q = strchr (p, ':');
n = q ? q - p : str_len (p);
if (!n ||
/* Assume that we never need more than 12 characters of
encoded-text to encode a single character. */
n > (ENCWORD_LEN_MAX - ENCWORD_LEN_MIN + 2 - 12))
continue;
t = mem_malloc (n + 1);
memcpy (t, p, n);
t[n] = '\0';
n = convert_string (u, ulen, fromcode, t, &s, &slen);
if (n == (size_t) (-1))
continue;
if (!tocode || n < bestn) {
bestn = n;
mem_free (&tocode);
tocode = t;
if (d) {
mem_free (&e);
e = s;
}
else
mem_free (&s);
elen = slen;
if (!bestn)
break;
}
else {
mem_free (&t);
mem_free (&s);
}
}
if (tocode) {
if (d)
*d = e;
if (dlen)
*dlen = elen;
mutt_canonical_charset (canonical_buff, sizeof (canonical_buff), tocode);
str_replace (&tocode, canonical_buff);
}
return tocode;
}
static size_t b_encoder (char *s, ICONV_CONST char *d, size_t dlen,
const char *tocode)
{
char *s0 = s;
memcpy (s, "=?", 2), s += 2;
memcpy (s, tocode, str_len (tocode)), s += str_len (tocode);
memcpy (s, "?B?", 3), s += 3;
for (;;) {
if (!dlen)
break;
else if (dlen == 1) {
*s++ = B64Chars[(*d >> 2) & 0x3f];
*s++ = B64Chars[(*d & 0x03) << 4];
*s++ = '=';
*s++ = '=';
break;
}
else if (dlen == 2) {
*s++ = B64Chars[(*d >> 2) & 0x3f];
*s++ = B64Chars[((*d & 0x03) << 4) | ((d[1] >> 4) & 0x0f)];
*s++ = B64Chars[(d[1] & 0x0f) << 2];
*s++ = '=';
break;
}
else {
*s++ = B64Chars[(*d >> 2) & 0x3f];
*s++ = B64Chars[((*d & 0x03) << 4) | ((d[1] >> 4) & 0x0f)];
*s++ = B64Chars[((d[1] & 0x0f) << 2) | ((d[2] >> 6) & 0x03)];
*s++ = B64Chars[d[2] & 0x3f];
d += 3, dlen -= 3;
}
}
memcpy (s, "?=", 2), s += 2;
return s - s0;
}
static size_t q_encoder (char *s, ICONV_CONST char *d, size_t dlen,
const char *tocode)
{
char hex[] = "0123456789ABCDEF";
char *s0 = s;
memcpy (s, "=?", 2), s += 2;
memcpy (s, tocode, str_len (tocode)), s += str_len (tocode);
memcpy (s, "?Q?", 3), s += 3;
while (dlen--) {
unsigned char c = *d++;
if (c == ' ')
*s++ = '_';
else if (c >= 0x7f || c < 0x20 || c == '_' || strchr (MimeSpecials, c)) {
*s++ = '=';
*s++ = hex[(c & 0xf0) >> 4];
*s++ = hex[c & 0x0f];
}
else
*s++ = c;
}
memcpy (s, "?=", 2), s += 2;
return s - s0;
}
/*
* Return 0 if and set *encoder and *wlen if the data (d, dlen) could
* be converted to an encoded word of length *wlen using *encoder.
* Otherwise return an upper bound on the maximum length of the data
* which could be converted.
* The data is converted from fromcode (which must be stateless) to
* tocode, unless fromcode is 0, in which case the data is assumed to
* be already in tocode, which should be 8-bit and stateless.
*/
static size_t try_block (ICONV_CONST char *d, size_t dlen,
const char *fromcode, const char *tocode,
encoder_t * encoder, size_t * wlen)
{
char buf1[ENCWORD_LEN_MAX - ENCWORD_LEN_MIN + 1];
iconv_t cd;
ICONV_CONST char *ib;
char *ob, *p;
size_t ibl, obl;
int count, len, len_b, len_q;
if (fromcode) {
cd = mutt_iconv_open (tocode, fromcode, 0);
assert (cd != (iconv_t) (-1));
ib = d, ibl = dlen, ob = buf1, obl = sizeof (buf1) - str_len (tocode);
if (iconv (cd, &ib, &ibl, &ob, &obl) == (size_t) (-1) ||
iconv (cd, 0, 0, &ob, &obl) == (size_t) (-1)) {
assert (errno == E2BIG);
iconv_close (cd);
assert (ib > d);
return (ib - d == dlen) ? dlen : ib - d + 1;
}
iconv_close (cd);
}
else {
if (dlen > sizeof (buf1) - str_len (tocode))
return sizeof (buf1) - str_len (tocode) + 1;
memcpy (buf1, d, dlen);
ob = buf1 + dlen;
}
count = 0;
for (p = buf1; p < ob; p++) {
unsigned char c = *p;
assert (strchr (MimeSpecials, '?'));
if (c >= 0x7f || c < 0x20 || *p == '_' ||
(c != ' ' && strchr (MimeSpecials, *p)))
++count;
}
len = ENCWORD_LEN_MIN - 2 + str_len (tocode);
len_b = len + (((ob - buf1) + 2) / 3) * 4;
len_q = len + (ob - buf1) + 2 * count;
/* Apparently RFC 1468 says to use B encoding for iso-2022-jp. */
if (!ascii_strcasecmp (tocode, "ISO-2022-JP"))
len_q = ENCWORD_LEN_MAX + 1;
if (len_b < len_q && len_b <= ENCWORD_LEN_MAX) {
*encoder = b_encoder;
*wlen = len_b;
return 0;
}
else if (len_q <= ENCWORD_LEN_MAX) {
*encoder = q_encoder;
*wlen = len_q;
return 0;
}
else
return dlen;
}
/*
* Encode the data (d, dlen) into s using the encoder.
* Return the length of the encoded word.
*/
static size_t encode_block (char *s, char *d, size_t dlen,
const char *fromcode, const char *tocode,
encoder_t encoder)
{
char buf1[ENCWORD_LEN_MAX - ENCWORD_LEN_MIN + 1];
iconv_t cd;
ICONV_CONST char *ib;
char *ob;
size_t ibl, obl, n1, n2;
if (fromcode) {
cd = mutt_iconv_open (tocode, fromcode, 0);
assert (cd != (iconv_t) (-1));
ib = d, ibl = dlen, ob = buf1, obl = sizeof (buf1) - str_len (tocode);
n1 = iconv (cd, &ib, &ibl, &ob, &obl);
n2 = iconv (cd, 0, 0, &ob, &obl);
assert (n1 != (size_t) (-1) && n2 != (size_t) (-1));
iconv_close (cd);
return (*encoder) (s, buf1, ob - buf1, tocode);
}
else
return (*encoder) (s, d, dlen, tocode);
}
/*
* Discover how much of the data (d, dlen) can be converted into
* a single encoded word. Return how much data can be converted,
* and set the length *wlen of the encoded word and *encoder.
* We start in column col, which limits the length of the word.
*/
static size_t choose_block (char *d, size_t dlen, int col,
const char *fromcode, const char *tocode,
encoder_t * encoder, size_t * wlen)
{
size_t n, nn;
int utf8 = fromcode && !ascii_strcasecmp (fromcode, "UTF-8");
n = dlen;
for (;;) {
assert (d + n > d);
nn = try_block (d, n, fromcode, tocode, encoder, wlen);
if (!nn && (col + *wlen <= ENCWORD_LEN_MAX + 1 || n <= 1))
break;
n = (nn ? nn : n) - 1;
assert (n > 0);
if (utf8)
while (n > 1 && CONTINUATION_BYTE (d[n]))
--n;
}
return n;
}
/*
* Place the result of RFC-2047-encoding (d, dlen) into the dynamically
* allocated buffer (e, elen). The input data is in charset fromcode
* and is converted into a charset chosen from charsets.
* Return 1 if the conversion to UTF-8 failed, 2 if conversion from UTF-8
* failed, otherwise 0. If conversion failed, fromcode is assumed to be
* compatible with us-ascii and the original data is used.
* The input data is assumed to be a single line starting at column col;
* if col is non-zero, the preceding character was a space.
*/
static int rfc2047_encode (ICONV_CONST char *d, size_t dlen, int col,
const char *fromcode, const char *charsets,
char **e, size_t * elen, char *specials)
{
int ret = 0;
char *buf;
size_t bufpos, buflen;
char *u, *t0, *t1, *t;
char *s0, *s1;
size_t ulen, r, n, wlen;
encoder_t encoder;
char *tocode1 = 0;
const char *tocode;
char *icode = "UTF-8";
/* Try to convert to UTF-8. */
if (convert_string (d, dlen, fromcode, icode, &u, &ulen)) {
ret = 1;
icode = 0;
u = mem_malloc ((ulen = dlen) + 1);
memcpy (u, d, dlen);
u[ulen] = 0;
}
/* Find earliest and latest things we must encode. */
s0 = s1 = t0 = t1 = 0;
for (t = u; t < u + ulen; t++) {
if ((*t & 0x80) ||
(*t == '=' && t[1] == '?' && (t == u || HSPACE (*(t - 1))))) {
if (!t0)
t0 = t;
t1 = t;
}
else if (specials && strchr (specials, *t)) {
if (!s0)
s0 = t;
s1 = t;
}
}
/* If we have something to encode, include RFC822 specials */
if (t0 && s0 && s0 < t0)
t0 = s0;
if (t1 && s1 && s1 > t1)
t1 = s1;
if (!t0) {
/* No encoding is required. */
*e = u;
*elen = ulen;
return ret;
}
/* Choose target charset. */
tocode = fromcode;
if (icode) {
if ((tocode1 = mutt_choose_charset (icode, charsets, u, ulen, 0, 0)))
tocode = tocode1;
else
ret = 2, icode = 0;
}
/* Hack to avoid labelling 8-bit data as us-ascii. */
if (!icode && mutt_is_us_ascii (tocode))
tocode = "unknown-8bit";
/* Adjust t0 for maximum length of line. */
t = u + (ENCWORD_LEN_MAX + 1) - col - ENCWORD_LEN_MIN;
if (t < u)
t = u;
if (t < t0)
t0 = t;
/* Adjust t0 until we can encode a character after a space. */
for (; t0 > u; t0--) {
if (!HSPACE (*(t0 - 1)))
continue;
t = t0 + 1;
if (icode)
while (t < u + ulen && CONTINUATION_BYTE (*t))
++t;
if (!try_block (t0, t - t0, icode, tocode, &encoder, &wlen) &&
col + (t0 - u) + wlen <= ENCWORD_LEN_MAX + 1)
break;
}
/* Adjust t1 until we can encode a character before a space. */
for (; t1 < u + ulen; t1++) {
if (!HSPACE (*t1))
continue;
t = t1 - 1;
if (icode)
while (CONTINUATION_BYTE (*t))
--t;
if (!try_block (t, t1 - t, icode, tocode, &encoder, &wlen) &&
1 + wlen + (u + ulen - t1) <= ENCWORD_LEN_MAX + 1)
break;
}
/* We shall encode the region [t0,t1). */
/* Initialise the output buffer with the us-ascii prefix. */
buflen = 2 * ulen;
buf = mem_malloc (buflen);
bufpos = t0 - u;
memcpy (buf, u, t0 - u);
col += t0 - u;
t = t0;
for (;;) {
/* Find how much we can encode. */
n = choose_block (t, t1 - t, col, icode, tocode, &encoder, &wlen);
if (n == t1 - t) {
/* See if we can fit the us-ascii suffix, too. */
if (col + wlen + (u + ulen - t1) <= ENCWORD_LEN_MAX + 1)
break;
n = t1 - t - 1;
if (icode)
while (CONTINUATION_BYTE (t[n]))
--n;
assert (t + n >= t);
if (!n) {
/* This should only happen in the really stupid case where the
only word that needs encoding is one character long, but
there is too much us-ascii stuff after it to use a single
encoded word. We add the next word to the encoded region
and try again. */
assert (t1 < u + ulen);
for (t1++; t1 < u + ulen && !HSPACE (*t1); t1++);
continue;
}
n = choose_block (t, n, col, icode, tocode, &encoder, &wlen);
}
/* Add to output buffer. */
#define LINEBREAK "\n\t"
if (bufpos + wlen + str_len (LINEBREAK) > buflen) {
buflen = bufpos + wlen + str_len (LINEBREAK);
mem_realloc (&buf, buflen);
}
r = encode_block (buf + bufpos, t, n, icode, tocode, encoder);
assert (r == wlen);
bufpos += wlen;
memcpy (buf + bufpos, LINEBREAK, str_len (LINEBREAK));
bufpos += str_len (LINEBREAK);
#undef LINEBREAK
col = 1;
t += n;
}
/* Add last encoded word and us-ascii suffix to buffer. */
buflen = bufpos + wlen + (u + ulen - t1);
mem_realloc (&buf, buflen + 1);
r = encode_block (buf + bufpos, t, t1 - t, icode, tocode, encoder);
assert (r == wlen);
bufpos += wlen;
memcpy (buf + bufpos, t1, u + ulen - t1);
mem_free (&tocode1);
mem_free (&u);
buf[buflen] = '\0';
*e = buf;
*elen = buflen + 1;
return ret;
}
void _rfc2047_encode_string (char **pd, int encode_specials, int col)
{
char *e;
size_t elen;
char *charsets;
if (!Charset || !*pd)
return;
charsets = SendCharset;
if (!charsets || !*charsets)
charsets = "UTF-8";
rfc2047_encode (*pd, str_len (*pd), col,
Charset, charsets, &e, &elen,
encode_specials ? RFC822Specials : NULL);
mem_free (pd);
*pd = e;
}
void rfc2047_encode_adrlist (ADDRESS * addr, const char *tag)
{
ADDRESS *ptr = addr;
int col = tag ? str_len (tag) + 2 : 32;
while (ptr) {
if (ptr->personal)
_rfc2047_encode_string (&ptr->personal, 1, col);
ptr = ptr->next;
}
}
static int rfc2047_decode_word (char *d, const char *s, size_t len)
{
const char *pp, *pp1;
char *pd, *d0;
const char *t, *t1;
int enc = 0, count = 0;
char *charset = NULL;
pd = d0 = mem_malloc (str_len (s));
for (pp = s; (pp1 = strchr (pp, '?')); pp = pp1 + 1) {
count++;
switch (count) {
case 2:
/* ignore language specification a la RFC 2231 */
t = pp1;
if ((t1 = memchr (pp, '*', t - pp)))
t = t1;
charset = mem_malloc (t - pp + 1);
memcpy (charset, pp, t - pp);
charset[t - pp] = '\0';
break;
case 3:
if (toupper ((unsigned char) *pp) == 'Q')
enc = ENCQUOTEDPRINTABLE;
else if (toupper ((unsigned char) *pp) == 'B')
enc = ENCBASE64;
else {
mem_free (&charset);
mem_free (&d0);
return (-1);
}
break;
case 4:
if (enc == ENCQUOTEDPRINTABLE) {
for (; pp < pp1; pp++) {
if (*pp == '_')
*pd++ = ' ';
else if (*pp == '=' &&
(!(pp[1] & ~127) && hexval (pp[1]) != -1) &&
(!(pp[2] & ~127) && hexval (pp[2]) != -1)) {
*pd++ = (hexval (pp[1]) << 4) | hexval (pp[2]);
pp += 2;
}
else
*pd++ = *pp;
}
*pd = 0;
}
else if (enc == ENCBASE64) {
int c, b = 0, k = 0;
for (; pp < pp1; pp++) {
if (*pp == '=')
break;
if ((*pp & ~127) || (c = base64val (*pp)) == -1)
continue;
if (k + 6 >= 8) {
k -= 2;
*pd++ = b | (c >> k);
b = c << (8 - k);
}
else {
b |= c << (k + 2);
k += 6;
}
}
*pd = 0;
}
break;
}
}
if (charset)
mutt_convert_string (&d0, charset, Charset, M_ICONV_HOOK_FROM);
strfcpy (d, d0, len);
mem_free (&charset);
mem_free (&d0);
return (0);
}
/*
* Find the start and end of the first encoded word in the string.
* We use the grammar in section 2 of RFC 2047, but the "encoding"
* must be B or Q. Also, we don't require the encoded word to be
* separated by linear-white-space (section 5(1)).
*/
static const char *find_encoded_word (const char *s, const char **x)
{
const char *p, *q;
q = s;
while ((p = strstr (q, "=?"))) {
for (q = p + 2;
0x20 < *q && *q < 0x7f && !strchr ("()<>@,;:\"/[]?.=", *q); q++);
if (q[0] != '?' || !strchr ("BbQq", q[1]) || q[2] != '?')
continue;
for (q = q + 3; 0x20 <= *q && *q < 0x7f && *q != '?'; q++);
if (q[0] != '?' || q[1] != '=') {
--q;
continue;
}
*x = q + 2;
return p;
}
return 0;
}
/* return length of linear white space */
static size_t lwslen (const char *s, size_t n)
{
const char *p = s;
size_t len = n;
if (n <= 0)
return 0;
for (; p < s + n; p++)
if (!strchr (" \t\r\n", *p)) {
len = (size_t) (p - s);
break;
}
if (strchr ("\r\n", *(p - 1))) /* LWS doesn't end with CRLF */
len = (size_t) 0;
return len;
}
/* return length of linear white space : reverse */
static size_t lwsrlen (const char *s, size_t n)
{
const char *p = s + n - 1;
size_t len = n;
if (n <= 0)
return 0;
if (strchr ("\r\n", *p)) /* LWS doesn't end with CRLF */
return (size_t) 0;
for (; p >= s; p--)
if (!strchr (" \t\r\n", *p)) {
len = (size_t) (s + n - 1 - p);
break;
}
return len;
}
/* try to decode anything that looks like a valid RFC2047 encoded
* header field, ignoring RFC822 parsing rules
*/
void rfc2047_decode (char **pd)
{
const char *p, *q;
size_t m, n;
int found_encoded = 0;
char *d0, *d;
const char *s = *pd;
size_t dlen;
if (!s || !*s)
return;
dlen = 4 * str_len (s); /* should be enough */
d = d0 = mem_malloc (dlen + 1);
while (*s && dlen > 0) {
if (!(p = find_encoded_word (s, &q))) {
/* no encoded words */
if (!option (OPTSTRICTMIME)) {
n = str_len (s);
if (found_encoded && (m = lwslen (s, n)) != 0) {
if (m != n)
*d = ' ', d++, dlen--;
n -= m, s += m;
}
if (ascii_strcasecmp (AssumedCharset, "us-ascii")) {
char *t;
size_t tlen;
t = mem_malloc (n + 1);
strfcpy (t, s, n + 1);
if (mutt_convert_nonmime_string (&t) == 0) {
tlen = str_len (t);
strncpy (d, t, tlen);
d += tlen;
}
else {
strncpy (d, s, n);
d += n;
}
mem_free (&t);
break;
}
}
strncpy (d, s, dlen);
d += dlen;
break;
}
if (p != s) {
n = (size_t) (p - s);
/* ignore spaces between encoded words
* and linear white spaces between encoded word and *text */
if (!option (OPTSTRICTMIME)) {
if (found_encoded && (m = lwslen (s, n)) != 0) {
if (m != n)
*d = ' ', d++, dlen--;
n -= m, s += m;
}
if ((m = n - lwsrlen (s, n)) != 0) {
if (m > dlen)
m = dlen;
memcpy (d, s, m);
d += m;
dlen -= m;
if (m != n)
*d = ' ', d++, dlen--;
}
}
else if (!found_encoded || strspn (s, " \t\r\n") != n) {
if (n > dlen)
n = dlen;
memcpy (d, s, n);
d += n;
dlen -= n;
}
}
rfc2047_decode_word (d, p, dlen);
found_encoded = 1;
s = q;
n = str_len (d);
dlen -= n;
d += n;
}
*d = 0;
mem_free (pd);
*pd = d0;
str_adjust (pd);
}
void rfc2047_decode_adrlist (ADDRESS * a)
{
while (a) {
if (a->personal)
rfc2047_decode (&a->personal);
a = a->next;
}
}
void rfc2047_decode_envelope (ENVELOPE* e) {
if (!e)
return;
/* do RFC2047 decoding */
rfc2047_decode_adrlist (e->from);
rfc2047_decode_adrlist (e->to);
rfc2047_decode_adrlist (e->cc);
rfc2047_decode_adrlist (e->bcc);
rfc2047_decode_adrlist (e->reply_to);
rfc2047_decode_adrlist (e->mail_followup_to);
rfc2047_decode_adrlist (e->return_path);
rfc2047_decode_adrlist (e->sender);
if (e->subject) {
rfc2047_decode (&e->subject);
mutt_adjust_subject (e);
}
}
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