Bug #53891 [Ver->Ana]: iconv_mime_encode() fails converting UTF-8 string to quoted-printable
Edit report at https://bugs.php.net/bug.php?id=53891&edit=1
ID: 53891
Updated by: cmb@php.net
Reported by: can at strg dot at
Summary: iconv_mime_encode() fails converting UTF-8 string to
quoted-printable
-Status: Verified
+Status: Analyzed
Type: Bug
Package: ICONV related
Operating System: GNU/linux (gentoo/kernel 2.6.35)
PHP Version: 5.3.5
-Assigned To:
+Assigned To: cmb
Block user comment: N
Private report: N
New Comment:
The culprit is the check whether there is sufficient place in the
line to add another encoded word[1]. out_charset_len + 12 is not
sufficient for quoted-printable encoding of UTF-8. In the worst
case it is out_charset_len + BOILERPLATE + CHARS_PER_BYTE *
MAX_BYTES (where BOILERPLATE == 7, CHARS_PER_BYTE == 3 and
MAX_BYTES == 6), i.e. out_charset_len + 25.
AFAIK, this would be sufficient for all other character encodings
and for Base64 encoding as well. Of course, changing this
threshold might change the result of iconv_mime_encode with regard
to folding, but that supposedly would only break some tests, if
they're relying on the exact output. It would more severly affect
any code that uses small line-length values, but presumably such
code doesn't exist â actually, I can't see a reason to set
line-length < 76.
[1] <https://github.com/php/php-src/blob/php-7.0.0RC2/ext/iconv/iconv.c#L1238>
Previous Comments:
------------------------------------------------------------------------
[2015-09-09 18:09:21] cmb@php.net
Confirmed: <https://3v4l.org/JLman>
Error 7 is likely E2BIG, what occurs if there's not enough room at
*outbuf when calling iconv().
------------------------------------------------------------------------
[2011-01-31 14:25:20] can at strg dot at
Description:
------------
iconv_mime_encode() fails on certain UTF-8 strings containing at least one multibyte character. The
error is reproducable for these strings.
I have further noticed that it is more likely that this error occurs if a multibyte character is
found at the following character positions within the string:
24±1, 52±3, 82±4, 112±5, 143±5
The code that led me to the previous conclusion can be found here: http://pastebin.com/GXQZ129M
Test script:
---------------
$preferences = array(
'scheme' => 'Q',
'input-charset' => 'utf-8',
'output-charset' => 'utf-8',
'line-length' => 74,
'line-break-chars' => "\r\n",
);
// Note the ellipsis character at the end of the following string:
iconv_mime_encode('subject', "d obeybiubrsfqllpdtpgeâ¦", $preferences);
Actual result:
--------------
PHP Notice: iconv_mime_encode(): Unknown error (7) in /home/soulmerge/test.php on line 11
Notice: iconv_mime_encode(): Unknown error (7) in /home/soulmerge/test.php on line 11
------------------------------------------------------------------------
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