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[HttpKernel] Don't use eval() to render ESI/SSI #50013

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Merged
merged 1 commit into from
Apr 17, 2023
Merged

[HttpKernel] Don't use eval() to render ESI/SSI #50013

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4 changes: 4 additions & 0 deletions src/Symfony/Component/HttpKernel/HttpCache/AbstractSurrogate.php
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,10 @@
abstract class AbstractSurrogate implements SurrogateInterface
{
protected $contentTypes;

/**
* @deprecated since Symfony 6.3
*/
protected $phpEscapeMap = [
['<?', '<%', '<s', '<S'],
['<?php echo "<?"; ?>', '<?php echo "<%"; ?>', '<?php echo "<s"; ?>', '<?php echo "<S"; ?>'],
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16 changes: 6 additions & 10 deletions src/Symfony/Component/HttpKernel/HttpCache/Esi.php
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Expand Up @@ -74,8 +74,10 @@ public function process(Request $request, Response $response): Response
$content = preg_replace('#<esi\:remove>.*?</esi\:remove>#s', '', $content);
$content = preg_replace('#<esi\:comment[^>]+>#s', '', $content);

static $cookie;
$cookie = hash('xxh128', $cookie ??= random_bytes(16), true);
$boundary = base64_encode($cookie);
$chunks = preg_split('#<esi\:include\s+(.*?)\s*(?:/|</esi\:include)>#', $content, -1, \PREG_SPLIT_DELIM_CAPTURE);
$chunks[0] = str_replace($this->phpEscapeMap[0], $this->phpEscapeMap[1], $chunks[0]);

$i = 1;
while (isset($chunks[$i])) {
Expand All @@ -89,16 +91,10 @@ public function process(Request $request, Response $response): Response
throw new \RuntimeException('Unable to process an ESI tag without a "src" attribute.');
}

$chunks[$i] = sprintf('<?php echo $this->surrogate->handle($this, %s, %s, %s) ?>'."\n",
var_export($options['src'], true),
var_export($options['alt'] ?? '', true),
isset($options['onerror']) && 'continue' === $options['onerror'] ? 'true' : 'false'
);
++$i;
$chunks[$i] = str_replace($this->phpEscapeMap[0], $this->phpEscapeMap[1], $chunks[$i]);
++$i;
$chunks[$i] = $boundary.$options['src']."\n".($options['alt'] ?? '')."\n".('continue' === ($options['onerror'] ?? ''))."\n";
$i += 2;
}
$content = implode('', $chunks);
$content = $boundary.implode('', $chunks).$boundary;

$response->setContent($content);
$response->headers->set('X-Body-Eval', 'ESI');
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16 changes: 15 additions & 1 deletion src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
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Expand Up @@ -641,7 +641,21 @@ private function restoreResponseBody(Request $request, Response $response): void
if ($response->headers->has('X-Body-File')) {
include $response->headers->get('X-Body-File');
} else {
eval('; ?>'.$response->getContent().'<?php ;');
$content = $response->getContent();

if (substr($content, -24) === $boundary = substr($content, 0, 24)) {
$j = strpos($content, $boundary, 24);
echo substr($content, 24, $j - 24);
$i = $j + 24;

while (false !== $j = strpos($content, $boundary, $i)) {
[$uri, $alt, $ignoreErrors, $part] = explode("\n", substr($content, $i, $j - $i), 4);
$i = $j + 24;

echo $this->surrogate->handle($this, $uri, $alt, $ignoreErrors);
echo $part;
}
}
}

$response->setContent(ob_get_clean());
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14 changes: 6 additions & 8 deletions src/Symfony/Component/HttpKernel/HttpCache/Ssi.php
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Expand Up @@ -56,8 +56,10 @@ public function process(Request $request, Response $response): Response
// we don't use a proper XML parser here as we can have SSI tags in a plain text response
$content = $response->getContent();

static $cookie;
$cookie = hash('xxh128', $cookie ??= random_bytes(16), true);
$boundary = base64_encode($cookie);
$chunks = preg_split('#<!--\#include\s+(.*?)\s*-->#', $content, -1, \PREG_SPLIT_DELIM_CAPTURE);
$chunks[0] = str_replace($this->phpEscapeMap[0], $this->phpEscapeMap[1], $chunks[0]);

$i = 1;
while (isset($chunks[$i])) {
Expand All @@ -71,14 +73,10 @@ public function process(Request $request, Response $response): Response
throw new \RuntimeException('Unable to process an SSI tag without a "virtual" attribute.');
}

$chunks[$i] = sprintf('<?php echo $this->surrogate->handle($this, %s, \'\', false) ?>'."\n",
var_export($options['virtual'], true)
);
++$i;
$chunks[$i] = str_replace($this->phpEscapeMap[0], $this->phpEscapeMap[1], $chunks[$i]);
++$i;
$chunks[$i] = $boundary.$options['virtual']."\n\n\n";
$i += 2;
}
$content = implode('', $chunks);
$content = $boundary.implode('', $chunks).$boundary;

$response->setContent($content);
$response->headers->set('X-Body-Eval', 'SSI');
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19 changes: 12 additions & 7 deletions src/Symfony/Component/HttpKernel/Tests/HttpCache/EsiTest.php
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Expand Up @@ -102,7 +102,7 @@ public function testMultilineEsiRemoveTagsAreRemoved()
$response = new Response('<esi:remove> <a href="http://www.example.com">www.example.com</a> </esi:remove> Keep this'."<esi:remove>\n <a>www.example.com</a> </esi:remove> And this");
$this->assertSame($response, $esi->process($request, $response));

$this->assertEquals(' Keep this And this', $response->getContent());
$this->assertEquals(' Keep this And this', substr($response->getContent(), 24, -24));
}

public function testCommentTagsAreRemoved()
Expand All @@ -113,7 +113,7 @@ public function testCommentTagsAreRemoved()
$response = new Response('<esi:comment text="some comment &gt;" /> Keep this');
$this->assertSame($response, $esi->process($request, $response));

$this->assertEquals(' Keep this', $response->getContent());
$this->assertEquals(' Keep this', substr($response->getContent(), 24, -24));
}

public function testProcess()
Expand All @@ -124,23 +124,27 @@ public function testProcess()
$response = new Response('foo <esi:comment text="some comment" /><esi:include src="..." alt="alt" onerror="continue" />');
$this->assertSame($response, $esi->process($request, $response));

$this->assertEquals('foo <?php echo $this->surrogate->handle($this, \'...\', \'alt\', true) ?>'."\n", $response->getContent());
$content = explode(substr($response->getContent(), 0, 24), $response->getContent());
$this->assertSame(['', 'foo ', "...\nalt\n1\n", ''], $content);
$this->assertEquals('ESI', $response->headers->get('x-body-eval'));

$response = new Response('foo <esi:comment text="some comment" /><esi:include src="foo\'" alt="bar\'" onerror="continue" />');
$this->assertSame($response, $esi->process($request, $response));

$this->assertEquals('foo <?php echo $this->surrogate->handle($this, \'foo\\\'\', \'bar\\\'\', true) ?>'."\n", $response->getContent());
$content = explode(substr($response->getContent(), 0, 24), $response->getContent());
$this->assertSame(['', 'foo ', "foo'\nbar'\n1\n", ''], $content);

$response = new Response('foo <esi:include src="..." />');
$this->assertSame($response, $esi->process($request, $response));

$this->assertEquals('foo <?php echo $this->surrogate->handle($this, \'...\', \'\', false) ?>'."\n", $response->getContent());
$content = explode(substr($response->getContent(), 0, 24), $response->getContent());
$this->assertSame(['', 'foo ', "...\n\n\n", ''], $content);

$response = new Response('foo <esi:include src="..."></esi:include>');
$this->assertSame($response, $esi->process($request, $response));

$this->assertEquals('foo <?php echo $this->surrogate->handle($this, \'...\', \'\', false) ?>'."\n", $response->getContent());
$content = explode(substr($response->getContent(), 0, 24), $response->getContent());
$this->assertSame(['', 'foo ', "...\n\n\n", ''], $content);
}

public function testProcessEscapesPhpTags()
Expand All @@ -151,7 +155,8 @@ public function testProcessEscapesPhpTags()
$response = new Response('<?php <? <% <script language=php>');
$this->assertSame($response, $esi->process($request, $response));

$this->assertEquals('<?php echo "<?"; ?>php <?php echo "<?"; ?> <?php echo "<%"; ?> <?php echo "<s"; ?>cript language=php>', $response->getContent());
$content = explode(substr($response->getContent(), 0, 24), $response->getContent());
$this->assertSame(['', '<?php <? <% <script language=php>', ''], $content);
}

public function testProcessWhenNoSrcInAnEsi()
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9 changes: 6 additions & 3 deletions src/Symfony/Component/HttpKernel/Tests/HttpCache/SsiTest.php
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Expand Up @@ -101,13 +101,15 @@ public function testProcess()
$response = new Response('foo <!--#include virtual="..." -->');
$ssi->process($request, $response);

$this->assertEquals('foo <?php echo $this->surrogate->handle($this, \'...\', \'\', false) ?>'."\n", $response->getContent());
$content = explode(substr($response->getContent(), 0, 24), $response->getContent());
$this->assertSame(['', 'foo ', "...\n\n\n", ''], $content);
$this->assertEquals('SSI', $response->headers->get('x-body-eval'));

$response = new Response('foo <!--#include virtual="foo\'" -->');
$ssi->process($request, $response);

$this->assertEquals("foo <?php echo \$this->surrogate->handle(\$this, 'foo\\'', '', false) ?>\n", $response->getContent());
$content = explode(substr($response->getContent(), 0, 24), $response->getContent());
$this->assertSame(['', 'foo ', "foo'\n\n\n", ''], $content);
}

public function testProcessEscapesPhpTags()
Expand All @@ -118,7 +120,8 @@ public function testProcessEscapesPhpTags()
$response = new Response('<?php <? <% <script language=php>');
$ssi->process($request, $response);

$this->assertEquals('<?php echo "<?"; ?>php <?php echo "<?"; ?> <?php echo "<%"; ?> <?php echo "<s"; ?>cript language=php>', $response->getContent());
$content = explode(substr($response->getContent(), 0, 24), $response->getContent());
$this->assertSame(['', '<?php <? <% <script language=php>', ''], $content);
}

public function testProcessWhenNoSrcInAnSsi()
Expand Down