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Fix use-after-free of CURLOPT_STDERR stream on cloned curl handle #24427

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Fix use-after-free of CURLOPT_STDERR stream on cloned curl handle #24427

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4 changes: 4 additions & 0 deletions ext/curl/interface.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1289,6 +1289,10 @@ void _php_setup_easy_copy_handlers(php_curl *ch, php_curl *source)
Z_ADDREF(source->handlers.write_header->stream);
}
ch->handlers.write_header->stream = source->handlers.write_header->stream;
if (!Z_ISUNDEF(source->handlers.std_err)) {
Z_ADDREF(source->handlers.std_err);
}
ch->handlers.std_err = source->handlers.std_err;

ch->handlers.write->fp = source->handlers.write->fp;
ch->handlers.write_header->fp = source->handlers.write_header->fp;
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38 changes: 38 additions & 0 deletions ext/curl/tests/curl_copy_handle_stderr_uaf.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,38 @@
--TEST--
Cloning a curl handle keeps CURLOPT_STDERR tracked so a closed stream is detected on the clone too
--EXTENSIONS--
curl
--FILE--
<?php
$srcfile = __DIR__ . '/curl_copy_handle_stderr_uaf_src.txt';
file_put_contents($srcfile, "Test.");

$stderrfile = __DIR__ . '/curl_copy_handle_stderr_uaf_stderr.txt';
$stream = fopen($stderrfile, 'w+');

$ch1 = curl_init();
curl_setopt($ch1, CURLOPT_URL, "file://" . $srcfile);
curl_setopt($ch1, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch1, CURLOPT_VERBOSE, true);
curl_setopt($ch1, CURLOPT_STDERR, $stream);

$ch2 = clone $ch1;

fclose($stream);

var_dump(curl_exec($ch1));
var_dump(curl_exec($ch2));
?>
--CLEAN--
<?php
@unlink(__DIR__ . '/curl_copy_handle_stderr_uaf_src.txt');
@unlink(__DIR__ . '/curl_copy_handle_stderr_uaf_stderr.txt');
?>
--EXPECTF--
Warning: curl_exec(): CURLOPT_STDERR resource has gone away, resetting to stderr in %s on line %d
%A
string(5) "Test."

Warning: curl_exec(): CURLOPT_STDERR resource has gone away, resetting to stderr in %s on line %d
%A
string(5) "Test."
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