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Merge pull request #1746 from sparklemotion/flavorjones-revert-libxml…
…-unescaped-attrs revert libxml unescaped attrs
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patches/libxml2/0001-Revert-Do-not-URI-escape-in-server-side-includes.patch
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,78 @@ | ||
| From c5538465c08a8ea248a370bf55bc39cd3385e4af Mon Sep 17 00:00:00 2001 | ||
| From: Mike Dalessio <mike.dalessio@gmail.com> | ||
| Date: Thu, 29 Mar 2018 14:09:00 -0400 | ||
| Subject: [PATCH] Revert "Do not URI escape in server side includes" | ||
|
|
||
| This reverts commit 960f0e275616cadc29671a218d7fb9b69eb35588. | ||
| --- | ||
| HTMLtree.c | 49 +++++++++++-------------------------------------- | ||
| 1 file changed, 11 insertions(+), 38 deletions(-) | ||
|
|
||
| diff --git a/HTMLtree.c b/HTMLtree.c | ||
| index 2fd0c9c..67160c5 100644 | ||
| --- a/HTMLtree.c | ||
| +++ b/HTMLtree.c | ||
| @@ -717,49 +717,22 @@ htmlAttrDumpOutput(xmlOutputBufferPtr buf, xmlDocPtr doc, xmlAttrPtr cur, | ||
| (!xmlStrcasecmp(cur->name, BAD_CAST "src")) || | ||
| ((!xmlStrcasecmp(cur->name, BAD_CAST "name")) && | ||
| (!xmlStrcasecmp(cur->parent->name, BAD_CAST "a"))))) { | ||
| + xmlChar *escaped; | ||
| xmlChar *tmp = value; | ||
| - /* xmlURIEscapeStr() escapes '"' so it can be safely used. */ | ||
| - xmlBufCCat(buf->buffer, "\""); | ||
|
|
||
| while (IS_BLANK_CH(*tmp)) tmp++; | ||
|
|
||
| - /* URI Escape everything, except server side includes. */ | ||
| - for ( ; ; ) { | ||
| - xmlChar *escaped; | ||
| - xmlChar endChar; | ||
| - xmlChar *end = NULL; | ||
| - xmlChar *start = (xmlChar *)xmlStrstr(tmp, BAD_CAST "<!--"); | ||
| - if (start != NULL) { | ||
| - end = (xmlChar *)xmlStrstr(tmp, BAD_CAST "-->"); | ||
| - if (end != NULL) { | ||
| - *start = '\0'; | ||
| - } | ||
| - } | ||
| - | ||
| - /* Escape the whole string, or until start (set to '\0'). */ | ||
| - escaped = xmlURIEscapeStr(tmp, BAD_CAST"@/:=?;#%&,+"); | ||
| - if (escaped != NULL) { | ||
| - xmlBufCat(buf->buffer, escaped); | ||
| - xmlFree(escaped); | ||
| - } else { | ||
| - xmlBufCat(buf->buffer, tmp); | ||
| - } | ||
| - | ||
| - if (end == NULL) { /* Everything has been written. */ | ||
| - break; | ||
| - } | ||
| - | ||
| - /* Do not escape anything within server side includes. */ | ||
| - *start = '<'; /* Restore the first character of "<!--". */ | ||
| - end += 3; /* strlen("-->") */ | ||
| - endChar = *end; | ||
| - *end = '\0'; | ||
| - xmlBufCat(buf->buffer, start); | ||
| - *end = endChar; | ||
| - tmp = end; | ||
| + /* | ||
| + * the < and > have already been escaped at the entity level | ||
| + * And doing so here breaks server side includes | ||
| + */ | ||
| + escaped = xmlURIEscapeStr(tmp, BAD_CAST"@/:=?;#%&,+<>"); | ||
| + if (escaped != NULL) { | ||
| + xmlBufWriteQuotedString(buf->buffer, escaped); | ||
| + xmlFree(escaped); | ||
| + } else { | ||
| + xmlBufWriteQuotedString(buf->buffer, value); | ||
| } | ||
| - | ||
| - xmlBufCCat(buf->buffer, "\""); | ||
| } else { | ||
| xmlBufWriteQuotedString(buf->buffer, value); | ||
| } | ||
| -- | ||
| 2.9.5 | ||
|
|
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,85 @@ | ||
| require "helper" | ||
|
|
||
| module Nokogiri | ||
| module HTML | ||
| class TestAttr < Nokogiri::TestCase | ||
| unless Nokogiri::VersionInfo.instance.libxml2? && Nokogiri::VersionInfo.instance.libxml2_using_system? | ||
| # | ||
| # libxml2 >= 2.9.2 fails to escape comments within some attributes. It | ||
| # wants to ensure these comments can be treated as "server-side includes", | ||
| # but as a result fails to ensure that serialization is well-formed, | ||
| # resulting in an opportunity for XSS injection of code into a final | ||
| # re-parsed document (presumably in a browser). | ||
| # | ||
| # the offending commit is: | ||
| # | ||
| # https://github.com/GNOME/libxml2/commit/960f0e2 | ||
| # | ||
| # we'll test this by parsing the HTML, serializing it, then | ||
| # re-parsing it to ensure there isn't any ambiguity in the output | ||
| # that might allow code injection into a browser consuming | ||
| # "sanitized" output. | ||
| # | ||
| # complaints have been made upstream about this behavior, notably at | ||
| # | ||
| # https://bugzilla.gnome.org/show_bug.cgi?id=769760 | ||
| # | ||
| # and multiple CVEs have been declared and fixed in downstream | ||
| # libraries as a result, a list is being kept up to date here: | ||
| # | ||
| # https://github.com/flavorjones/loofah/issues/144 | ||
| # | ||
| [ | ||
| # | ||
| # these tags and attributes are determined by the code at: | ||
| # | ||
| # https://git.gnome.org/browse/libxml2/tree/HTMLtree.c?h=v2.9.2#n714 | ||
| # | ||
| {tag: "a", attr: "href"}, | ||
| {tag: "div", attr: "href"}, | ||
| {tag: "a", attr: "action"}, | ||
| {tag: "div", attr: "action"}, | ||
| {tag: "a", attr: "src"}, | ||
| {tag: "div", attr: "src"}, | ||
| {tag: "a", attr: "name"}, | ||
| # | ||
| # note that div+name is _not_ affected by the libxml2 issue. | ||
| # but we test it anyway to ensure our logic isn't modifying | ||
| # attributes that don't need modifying. | ||
| # | ||
| {tag: "div", attr: "name", unescaped: true}, | ||
| ].each do |config| | ||
|
|
||
| define_method "test_uri_escaping_of_#{config[:attr]}_attr_in_#{config[:tag]}_tag" do | ||
| html = %{<#{config[:tag]} #{config[:attr]}='examp<!--" unsafeattr=unsafevalue()>-->le.com'>test</#{config[:tag]}>} | ||
|
|
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| reparsed = HTML.fragment(HTML.fragment(html).to_html) | ||
| attributes = reparsed.at_css(config[:tag]).attribute_nodes | ||
|
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| assert_equal [config[:attr]], attributes.collect(&:name) | ||
| if Nokogiri::VersionInfo.instance.libxml2? | ||
| if config[:unescaped] | ||
| # | ||
| # this attribute was emitted wrapped in single-quotes, so a double quote is A-OK. | ||
| # assert that this attribute's serialization is unaffected. | ||
| # | ||
| assert_equal %{examp<!--" unsafeattr=unsafevalue()>-->le.com}, attributes.first.value | ||
| else | ||
| # | ||
| # let's match the behavior in libxml < 2.9.2. | ||
| # test that this attribute's serialization is well-formed and sanitized. | ||
| # | ||
| assert_equal %{examp<!--%22%20unsafeattr=unsafevalue()>-->le.com}, attributes.first.value | ||
| end | ||
| else | ||
| # | ||
| # yay for consistency in javaland. move along, nothing to see here. | ||
| # | ||
| assert_equal %{examp<!--%22 unsafeattr=unsafevalue()>-->le.com}, attributes.first.value | ||
| end | ||
| end | ||
| end | ||
| end | ||
| end | ||
| end | ||
| end |