mirror of
https://github.com/ezyang/htmlpurifier.git
synced 2024-12-22 08:21:52 +00:00
Protect against font family innerHTML/cssText attacks.
Signed-off-by: Edward Z. Yang <ezyang@mit.edu>
This commit is contained in:
Edward Z. Yang
parent
0dd9e4faf4
commit
afb007d22f
3
NEWS
3
NEWS
@ -19,6 +19,9 @@ NEWS ( CHANGELOG and HISTORY ) HTMLPurifier
|
||||
spaces. This constitutes a slight semantic change, which can be
|
||||
reverted using %Output.FixInnerHTML. Reported by Neike Taika-Tessaro
|
||||
and Mario Heiderich.
|
||||
# Protect against cssText/innerHTML by restricting allowed characters
|
||||
used in fonts further than mandated by the specification. Reported
|
||||
by Neike Taika-Tessaro and Mario Heiderich.
|
||||
! Added %HTML.Nofollow to add rel="nofollow" to external links.
|
||||
! More types of SPL autoloaders allowed on later versions of PHP.
|
||||
! Implementations for position, top, left, right, bottom, z-index
|
||||
|
||||
@ -96,27 +96,32 @@
|
||||
</directive>
|
||||
<directive id="Output.CommentScriptContents">
|
||||
<file name="HTMLPurifier/Generator.php">
|
||||
<line>56</line>
|
||||
<line>61</line>
|
||||
</file>
|
||||
</directive>
|
||||
<directive id="Output.FixInnerHTML">
|
||||
<file name="HTMLPurifier/Generator.php">
|
||||
<line>62</line>
|
||||
</file>
|
||||
</directive>
|
||||
<directive id="Output.SortAttr">
|
||||
<file name="HTMLPurifier/Generator.php">
|
||||
<line>57</line>
|
||||
<line>63</line>
|
||||
</file>
|
||||
</directive>
|
||||
<directive id="Output.FlashCompat">
|
||||
<file name="HTMLPurifier/Generator.php">
|
||||
<line>58</line>
|
||||
<line>64</line>
|
||||
</file>
|
||||
</directive>
|
||||
<directive id="Output.TidyFormat">
|
||||
<file name="HTMLPurifier/Generator.php">
|
||||
<line>87</line>
|
||||
<line>93</line>
|
||||
</file>
|
||||
</directive>
|
||||
<directive id="Core.NormalizeNewlines">
|
||||
<file name="HTMLPurifier/Generator.php">
|
||||
<line>101</line>
|
||||
<line>107</line>
|
||||
</file>
|
||||
<file name="HTMLPurifier/Lexer.php">
|
||||
<line>266</line>
|
||||
@ -124,7 +129,7 @@
|
||||
</directive>
|
||||
<directive id="Output.Newline">
|
||||
<file name="HTMLPurifier/Generator.php">
|
||||
<line>102</line>
|
||||
<line>108</line>
|
||||
</file>
|
||||
</directive>
|
||||
<directive id="HTML.BlockWrapper">
|
||||
@ -254,6 +259,9 @@
|
||||
<file name="HTMLPurifier/URIDefinition.php">
|
||||
<line>64</line>
|
||||
</file>
|
||||
<file name="HTMLPurifier/URIScheme.php">
|
||||
<line>75</line>
|
||||
</file>
|
||||
</directive>
|
||||
<directive id="URI.Base">
|
||||
<file name="HTMLPurifier/URIDefinition.php">
|
||||
@ -288,6 +296,11 @@
|
||||
<line>12</line>
|
||||
</file>
|
||||
</directive>
|
||||
<directive id="CSS.AllowedFonts">
|
||||
<file name="HTMLPurifier/AttrDef/CSS/FontFamily.php">
|
||||
<line>50</line>
|
||||
</file>
|
||||
</directive>
|
||||
<directive id="Attr.AllowedClasses">
|
||||
<file name="HTMLPurifier/AttrDef/HTML/Class.php">
|
||||
<line>18</line>
|
||||
@ -454,7 +467,7 @@
|
||||
</directive>
|
||||
<directive id="Core.EscapeInvalidTags">
|
||||
<file name="HTMLPurifier/Strategy/MakeWellFormed.php">
|
||||
<line>45</line>
|
||||
<line>53</line>
|
||||
</file>
|
||||
<file name="HTMLPurifier/Strategy/RemoveForeignElements.php">
|
||||
<line>19</line>
|
||||
|
||||
@ -6,6 +6,39 @@
|
||||
class HTMLPurifier_AttrDef_CSS_FontFamily extends HTMLPurifier_AttrDef
|
||||
{
|
||||
|
||||
protected $mask = null;
|
||||
|
||||
public function __construct() {
|
||||
$this->mask = '- ';
|
||||
for ($c = 'a'; $c <= 'z'; $c++) $this->mask .= $c;
|
||||
for ($c = 'A'; $c <= 'Z'; $c++) $this->mask .= $c;
|
||||
for ($c = '0'; $c <= '9'; $c++) $this->mask .= $c; // cast-y, but should be fine
|
||||
// special bytes used by UTF-8
|
||||
for ($i = 0x80; $i <= 0xFF; $i++) {
|
||||
// We don't bother excluding invalid bytes in this range,
|
||||
// because the our restriction of well-formed UTF-8 will
|
||||
// prevent these from ever occurring.
|
||||
$this->mask .= chr($i);
|
||||
}
|
||||
|
||||
/*
|
||||
PHP's internal strcspn implementation is
|
||||
O(length of string * length of mask), making it inefficient
|
||||
for large masks. However, it's still faster than
|
||||
preg_match 8)
|
||||
for (p = s1;;) {
|
||||
spanp = s2;
|
||||
do {
|
||||
if (*spanp == c || p == s1_end) {
|
||||
return p - s1;
|
||||
}
|
||||
} while (spanp++ < (s2_end - 1));
|
||||
c = *++p;
|
||||
}
|
||||
*/
|
||||
// possible optimization: invert the mask.
|
||||
}
|
||||
|
||||
public function validate($string, $config, $context) {
|
||||
static $generic_names = array(
|
||||
'serif' => true,
|
||||
@ -56,17 +89,103 @@ class HTMLPurifier_AttrDef_CSS_FontFamily extends HTMLPurifier_AttrDef
|
||||
// shouldn't show up regardless
|
||||
$font = str_replace(array("\n", "\t", "\r", "\x0C"), ' ', $font);
|
||||
|
||||
// These ugly transforms don't pose a security
|
||||
// risk (as \\ and \" might). We could try to be clever and
|
||||
// use single-quote wrapping when there is a double quote
|
||||
// present, but I have choosen not to implement that.
|
||||
// (warning: this code relies on the selection of quotation
|
||||
// mark below)
|
||||
$font = str_replace('\\', '\\5C ', $font);
|
||||
$font = str_replace('"', '\\22 ', $font);
|
||||
// Here, there are various classes of characters which need
|
||||
// to be treated differently:
|
||||
// - Alphanumeric characters are essentially safe. We
|
||||
// handled these above.
|
||||
// - Spaces require quoting, though most parsers will do
|
||||
// the right thing if there aren't any characters that
|
||||
// can be misinterpreted
|
||||
// - Dashes rarely occur, but they fairly unproblematic
|
||||
// for parsing/rendering purposes.
|
||||
// The above characters cover the majority of Western font
|
||||
// names.
|
||||
// - Arbitrary Unicode characters not in ASCII. Because
|
||||
// most parsers give little thought to Unicode, treatment
|
||||
// of these codepoints is basically uniform, even for
|
||||
// punctuation-like codepoints. These characters can
|
||||
// show up in non-Western pages and are supported by most
|
||||
// major browsers, for example: "ＭＳ 明朝" is a
|
||||
// legitimate font-name
|
||||
// <http://ja.wikipedia.org/wiki/MS_明朝>. See
|
||||
// the CSS3 spec for more examples:
|
||||
// <http://www.w3.org/TR/2011/WD-css3-fonts-20110324/localizedfamilynames.png>
|
||||
// You can see live samples of these on the Internet:
|
||||
// <http://www.google.co.jp/search?q=font-family+ＭＳ+明朝|ゴシック>
|
||||
// However, most of these fonts have ASCII equivalents:
|
||||
// for example, 'MS Mincho', and it's considered
|
||||
// professional to use ASCII font names instead of
|
||||
// Unicode font names. Thanks Takeshi Terada for
|
||||
// providing this information.
|
||||
// The following characters, to my knowledge, have not been
|
||||
// used to name font names.
|
||||
// - Single quote. While theoretically you might find a
|
||||
// font name that has a single quote in its name (serving
|
||||
// as an apostrophe, e.g. Dave's Scribble), I haven't
|
||||
// been able to find any actual examples of this.
|
||||
// Internet Explorer's cssText translation (which I
|
||||
// believe is invoked by innerHTML) normalizes any
|
||||
// quoting to single quotes, and fails to escape single
|
||||
// quotes. (Note that this is not IE's behavior for all
|
||||
// CSS properties, just some sort of special casing for
|
||||
// font-family). So a single quote *cannot* be used
|
||||
// safely in the font-family context if there will be an
|
||||
// innerHTML/cssText translation. Note that Firefox 3.x
|
||||
// does this too.
|
||||
// - Double quote. In IE, these get normalized to
|
||||
// single-quotes, no matter what the encoding. (Fun
|
||||
// fact, in IE8, the 'content' CSS property gained
|
||||
// support, where they special cased to preserve encoded
|
||||
// double quotes, but still translate unadorned double
|
||||
// quotes into single quotes.) So, because their
|
||||
// fixpoint behavior is identical to single quotes, they
|
||||
// cannot be allowed either. Firefox 3.x displays
|
||||
// single-quote style behavior.
|
||||
// - Backslashes are reduced by one (so \\ -> \) every
|
||||
// iteration, so they cannot be used safely. This shows
|
||||
// up in IE7, IE8 and FF3
|
||||
// - Semicolons, commas and backticks are handled properly.
|
||||
// - The rest of the ASCII punctuation is handled properly.
|
||||
// We haven't checked what browsers do to unadorned
|
||||
// versions, but this is not important as long as the
|
||||
// browser doesn't /remove/ surrounding quotes (as IE does
|
||||
// for HTML).
|
||||
//
|
||||
// With these results in hand, we conclude that there are
|
||||
// various levels of safety:
|
||||
// - Paranoid: alphanumeric, spaces and dashes(?)
|
||||
// - International: Paranoid + non-ASCII Unicode
|
||||
// - Edgy: Everything except quotes, backslashes
|
||||
// - NoJS: Standards compliance, e.g. sod IE. Note that
|
||||
// with some judicious character escaping (since certain
|
||||
// types of escaping doesn't work) this is theoretically
|
||||
// OK as long as innerHTML/cssText is not called.
|
||||
// We believe that international is a reasonable default
|
||||
// (that we will implement now), and once we do more
|
||||
// extensive research, we may feel comfortable with dropping
|
||||
// it down to edgy.
|
||||
|
||||
// complicated font, requires quoting
|
||||
$final .= "\"$font\", "; // note that this will later get turned into "
|
||||
// Edgy: alphanumeric, spaces, dashes and Unicode. Use of
|
||||
// str(c)spn assumes that the string was already well formed
|
||||
// Unicode (which of course it is).
|
||||
if (strspn($font, $this->mask) !== strlen($font)) {
|
||||
continue;
|
||||
}
|
||||
|
||||
// Historical:
|
||||
// In the absence of innerHTML/cssText, these ugly
|
||||
// transforms don't pose a security risk (as \\ and \"
|
||||
// might--these escapes are not supported by most browsers).
|
||||
// We could try to be clever and use single-quote wrapping
|
||||
// when there is a double quote present, but I have choosen
|
||||
// not to implement that. (NOTE: you can reduce the amount
|
||||
// of escapes by one depending on what quoting style you use)
|
||||
// $font = str_replace('\\', '\\5C ', $font);
|
||||
// $font = str_replace('"', '\\22 ', $font);
|
||||
// $font = str_replace("'", '\\27 ', $font);
|
||||
|
||||
// font possibly with spaces, requires quoting
|
||||
$final .= "'$font', ";
|
||||
}
|
||||
$final = rtrim($final, ', ');
|
||||
if ($final === '') return false;
|
||||
|
||||
@ -185,7 +185,7 @@ class HTMLPurifier_URI
|
||||
|
||||
// Reconstruct the result
|
||||
// One might wonder about parsing quirks from browsers after
|
||||
// this reconstruction. Unfortunately, parsing behaviro depends
|
||||
// this reconstruction. Unfortunately, parsing behavior depends
|
||||
// on what *scheme* was employed (file:///foo is handled *very*
|
||||
// differently than http:///foo), so unfortunately we have to
|
||||
// defer to the schemes to do the right thing.
|
||||
|
||||
@ -8,30 +8,32 @@ class HTMLPurifier_AttrDef_CSS_FontFamilyTest extends HTMLPurifier_AttrDefHarnes
|
||||
$this->def = new HTMLPurifier_AttrDef_CSS_FontFamily();
|
||||
|
||||
$this->assertDef('Gill, Helvetica, sans-serif');
|
||||
$this->assertDef('"Times New Roman", serif');
|
||||
$this->assertDef('\'Times New Roman\'', '"Times New Roman"');
|
||||
$this->assertDef("'Times New Roman', serif");
|
||||
$this->assertDef("\"Times New Roman\"", "'Times New Roman'");
|
||||
$this->assertDef('01234');
|
||||
$this->assertDef(',', false);
|
||||
$this->assertDef('Times New Roman, serif', '"Times New Roman", serif');
|
||||
$this->assertDef($d = '"John\'s Font"');
|
||||
$this->assertDef("John's Font", $d);
|
||||
$this->assertDef($d = "\"\xE5\xAE\x8B\xE4\xBD\x93\"");
|
||||
$this->assertDef('Times New Roman, serif', "'Times New Roman', serif");
|
||||
$this->assertDef($d = "'\xE5\xAE\x8B\xE4\xBD\x93'");
|
||||
$this->assertDef("\xE5\xAE\x8B\xE4\xBD\x93", $d);
|
||||
$this->assertDef("'\\','f'", "\"\\5C \", f");
|
||||
$this->assertDef("'\\01'", "\"\"");
|
||||
$this->assertDef("'\\20'", "\" \"");
|
||||
$this->assertDef("\\0020", "\" \"");
|
||||
$this->assertDef("'\\01'", "''");
|
||||
$this->assertDef("'\\20'", "' '");
|
||||
$this->assertDef("\\0020", "' '");
|
||||
$this->assertDef("'\\000045'", "E");
|
||||
$this->assertDef("','", false);
|
||||
$this->assertDef("',' foobar','", "\" foobar\"");
|
||||
$this->assertDef("'\\27'", "\"'\"");
|
||||
$this->assertDef('"\\22"', "\"\\22 \"");
|
||||
$this->assertDef('"\\""', "\"\\22 \"");
|
||||
$this->assertDef('"\'"', "\"'\"");
|
||||
$this->assertDef("',' foobar','", "' foobar'");
|
||||
$this->assertDef("'\\000045a'", "Ea");
|
||||
$this->assertDef("'\\00045 a'", "Ea");
|
||||
$this->assertDef("'\\00045 a'", "\"E a\"");
|
||||
$this->assertDef("'\\00045 a'", "'E a'");
|
||||
$this->assertDef("'\\\nf'", "f");
|
||||
// No longer supported, except maybe in NoJS mode (see source
|
||||
// file for more explanation)
|
||||
//$this->assertDef($d = '"John\'s Font"');
|
||||
//$this->assertDef("John's Font", $d);
|
||||
//$this->assertDef("'\\','f'", "\"\\5C \", f");
|
||||
//$this->assertDef("'\\27'", "\"'\"");
|
||||
//$this->assertDef('"\\22"', "\"\\22 \"");
|
||||
//$this->assertDef('"\\""', "\"\\22 \"");
|
||||
//$this->assertDef('"\'"', "\"'\"");
|
||||
}
|
||||
|
||||
function testAllowed() {
|
||||
@ -40,8 +42,8 @@ class HTMLPurifier_AttrDef_CSS_FontFamilyTest extends HTMLPurifier_AttrDefHarnes
|
||||
$this->assertDef('serif');
|
||||
$this->assertDef('sans-serif', false);
|
||||
$this->assertDef('serif, sans-serif', 'serif');
|
||||
$this->assertDef('Times New Roman', '"Times New Roman"');
|
||||
$this->assertDef('"Times New Roman"');
|
||||
$this->assertDef('Times New Roman', "'Times New Roman'");
|
||||
$this->assertDef("'Times New Roman'");
|
||||
$this->assertDef('foo', false);
|
||||
}
|
||||
|
||||
|
||||
@ -11,10 +11,10 @@ class HTMLPurifier_AttrDef_CSS_FontTest extends HTMLPurifier_AttrDefHarness
|
||||
// hodgepodge of usage cases from W3C spec, but " -> '
|
||||
$this->assertDef('12px/14px sans-serif');
|
||||
$this->assertDef('80% sans-serif');
|
||||
$this->assertDef('x-large/110% "New Century Schoolbook", serif');
|
||||
$this->assertDef("x-large/110% 'New Century Schoolbook', serif");
|
||||
$this->assertDef('bold italic large Palatino, serif');
|
||||
$this->assertDef('normal small-caps 120%/120% fantasy');
|
||||
$this->assertDef('300 italic 1.3em/1.7em "FB Armada", sans-serif');
|
||||
$this->assertDef("300 italic 1.3em/1.7em 'FB Armada', sans-serif");
|
||||
$this->assertDef('600 9px Charcoal');
|
||||
$this->assertDef('600 9px/ 12px Charcoal', '600 9px/12px Charcoal');
|
||||
|
||||
|
||||
@ -62,7 +62,7 @@ class HTMLPurifier_AttrDef_CSSTest extends HTMLPurifier_AttrDefHarness
|
||||
$this->assertDef('width:-50px;', false);
|
||||
$this->assertDef('text-decoration:underline;');
|
||||
$this->assertDef('font-family:sans-serif;');
|
||||
$this->assertDef('font-family:Gill, "Times New Roman", sans-serif;');
|
||||
$this->assertDef("font-family:Gill, 'Times New Roman', sans-serif;");
|
||||
$this->assertDef('font:12px serif;');
|
||||
$this->assertDef('border:1px solid #000;');
|
||||
$this->assertDef('border-bottom:2em double #FF00FA;');
|
||||
|
||||
@ -79,10 +79,13 @@ class HTMLPurifier_Filter_ExtractStyleBlocksTest extends HTMLPurifier_Harness
|
||||
}
|
||||
|
||||
function test_cleanCSS_angledBrackets() {
|
||||
$this->assertCleanCSS(
|
||||
".class {\nfont-family:'</style>';\n}",
|
||||
".class {\nfont-family:\"\\3C /style\\3E \";\n}"
|
||||
);
|
||||
// [Content] No longer can smuggle in angled brackets using
|
||||
// font-family; when we add support for 'content', reinstate
|
||||
// this test.
|
||||
//$this->assertCleanCSS(
|
||||
// ".class {\nfont-family:'</style>';\n}",
|
||||
// ".class {\nfont-family:\"\\3C /style\\3E \";\n}"
|
||||
//);
|
||||
}
|
||||
|
||||
function test_cleanCSS_angledBrackets2() {
|
||||
@ -97,6 +100,7 @@ class HTMLPurifier_Filter_ExtractStyleBlocksTest extends HTMLPurifier_Harness
|
||||
$this->assertCleanCSS("div {bogus:tree;}", "div {\n}");
|
||||
}
|
||||
|
||||
/* [CONTENT]
|
||||
function test_cleanCSS_escapeCodes() {
|
||||
$this->assertCleanCSS(
|
||||
".class {\nfont-family:\"\\3C /style\\3E \";\n}"
|
||||
@ -109,6 +113,7 @@ class HTMLPurifier_Filter_ExtractStyleBlocksTest extends HTMLPurifier_Harness
|
||||
".class {\nfont-family:\"</style>\";\n}"
|
||||
);
|
||||
}
|
||||
*/
|
||||
|
||||
function test_cleanCSS_scope() {
|
||||
$this->config->set('Filter.ExtractStyleBlocks.Scope', '#foo');
|
||||
|
||||
@ -4,5 +4,5 @@ if (!function_exists('iconv')) return true;
|
||||
Core.Encoding = "Shift_JIS"
|
||||
Core.EscapeNonASCIICharacters = true
|
||||
--HTML--
|
||||
<b style="font-family:"¥";">111</b>
|
||||
<b style="font-family:'¥';">111</b>
|
||||
--# vim: et sw=4 sts=4
|
||||
|
||||
@ -3,7 +3,7 @@ if (!function_exists('iconv')) return true;
|
||||
--INI--
|
||||
Core.Encoding = Shift_JIS
|
||||
--HTML--
|
||||
<b style="font-family:"¥";">111</b>
|
||||
<b style="font-family:'¥';">111</b>
|
||||
--EXPECT--
|
||||
<b style="font-family:"";">111</b>
|
||||
<b style="font-family:'';">111</b>
|
||||
--# vim: et sw=4 sts=4
|
||||
|
||||
Loading…
Reference in New Issue
Block a user