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Fix bug #79945: Stream wrappers in imagecreatefrompng causes segfault #12696

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Fix bug #79945: Stream wrappers in imagecreatefrompng causes segfault #12696

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22 changes: 22 additions & 0 deletions ext/gd/tests/bug79945.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,22 @@
--TEST--
Bug #79945 (using php wrappers in imagecreatefrompng causes segmentation fault)
--EXTENSIONS--
gd
--SKIPIF--
<?php
set_error_handler(function($errno, $errstr) {
if (str_contains($errstr, 'Cannot cast a filtered stream on this system')) {
die('skip: fopencookie not support on this system');
}
});
imagecreatefrompng('php://filter/read=convert.base64-encode/resource=' . __DIR__ . '/test.png');
restore_error_handler();
?>
--FILE--
<?php
imagecreatefrompng('php://filter/read=convert.base64-encode/resource=' . __DIR__ . '/test.png');
?>
--CLEAN--
--EXPECTF--

Warning: imagecreatefrompng(): "php://filter/read=convert.base64-encode/resource=%s" is not a valid PNG file in %s on line %d
3 changes: 3 additions & 0 deletions main/php_streams.h
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Expand Up @@ -211,6 +211,9 @@ struct _php_stream {
* PHP_STREAM_FCLOSE_XXX as appropriate */
uint8_t fclose_stdiocast:2;

/* whether stdio cast flushing is in progress */
int8_t fclose_stdiocast_flush_in_progress:1;

char mode[16]; /* "rwb" etc. ala stdio */

uint32_t flags; /* PHP_STREAM_FLAG_XXX */
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9 changes: 7 additions & 2 deletions main/streams/streams.c
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Expand Up @@ -1294,8 +1294,13 @@ PHPAPI zend_off_t _php_stream_tell(php_stream *stream)
PHPAPI int _php_stream_seek(php_stream *stream, zend_off_t offset, int whence)
{
if (stream->fclose_stdiocast == PHP_STREAM_FCLOSE_FOPENCOOKIE) {
/* flush to commit data written to the fopencookie FILE* */
fflush(stream->stdiocast);
/* flush can call seek internally so we need to prevent an infinite loop */
if (!stream->fclose_stdiocast_flush_in_progress) {
stream->fclose_stdiocast_flush_in_progress = 1;
/* flush to commit data written to the fopencookie FILE* */
fflush(stream->stdiocast);
stream->fclose_stdiocast_flush_in_progress = 0;
}
}

/* handle the case where we are in the buffer */
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