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Fix #75776: Flushing streams with compression filter is broken
First, the `bzip2.compress` filter has the same issue as `zlib.deflate` so we port the respective fix[1] to ext/bz2. Second, there is still an issue, if a stream with an attached compression filter is flushed before it is closed, without any writes in between. In that case, the compression is never finalized. We fix this by enforcing a `_php_stream_flush()` with the `closing` flag set in `_php_stream_free()`, whenever a write filter is attached. This call is superfluous for most write filters, but does not hurt, even when it is unnecessary. [1] <http://git.php.net/?p=php-src.git;a=commit;h=20e75329f2adb11dd231852c061926d0e4080929> Closes GH-6703.
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‎NEWS‎

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Original file line numberDiff line numberDiff line change
@@ -5,6 +5,7 @@ PHP NEWS
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- Core:
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. Fixed bug #80781 (Error handler that throws ErrorException infinite loop).
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(Nikita)
8+
. Fixed bug #75776 (Flushing streams with compression filter is broken). (cmb)
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- Intl:
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. Fixed bug #80763 (msgfmt_format() does not accept DateTime references).

‎ext/bz2/bz2_filter.c‎

Lines changed: 10 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -41,6 +41,7 @@ typedef struct _php_bz2_filter_data {
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enum strm_status status; /* Decompress option */
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unsigned int small_footprint : 1; /* Decompress option */
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unsigned int expect_concatenated : 1; /* Decompress option */
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unsigned int is_flushed : 1; /* only for compression */
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int persistent;
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} php_bz2_filter_data;
@@ -228,14 +229,18 @@ static php_stream_filter_status_t php_bz2_compress_filter(
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bucket = php_stream_bucket_make_writeable(buckets_in->head);
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230231
while (bin < bucket->buflen) {
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int flush_mode;
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desired = bucket->buflen - bin;
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if (desired > data->inbuf_len) {
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desired = data->inbuf_len;
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}
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memcpy(data->strm.next_in, bucket->buf + bin, desired);
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data->strm.avail_in = desired;
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238-
status = BZ2_bzCompress(&(data->strm), flags & PSFS_FLAG_FLUSH_CLOSE ? BZ_FINISH : (flags & PSFS_FLAG_FLUSH_INC ? BZ_FLUSH : BZ_RUN));
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flush_mode = flags & PSFS_FLAG_FLUSH_CLOSE ? BZ_FINISH : (flags & PSFS_FLAG_FLUSH_INC ? BZ_FLUSH : BZ_RUN);
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data->is_flushed = flush_mode != BZ_RUN;
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status = BZ2_bzCompress(&(data->strm), flush_mode);
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if (status != BZ_RUN_OK && status != BZ_FLUSH_OK && status != BZ_FINISH_OK) {
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/* Something bad happened */
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php_stream_bucket_delref(bucket);
@@ -261,11 +266,12 @@ static php_stream_filter_status_t php_bz2_compress_filter(
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php_stream_bucket_delref(bucket);
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}
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264-
if (flags & PSFS_FLAG_FLUSH_CLOSE) {
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if (flags & PSFS_FLAG_FLUSH_CLOSE || ((flags & PSFS_FLAG_FLUSH_INC) && !data->is_flushed)) {
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/* Spit it out! */
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status = BZ_FINISH_OK;
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while (status == BZ_FINISH_OK) {
268-
status = BZ2_bzCompress(&(data->strm), BZ_FINISH);
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status = BZ2_bzCompress(&(data->strm), (flags & PSFS_FLAG_FLUSH_CLOSE ? BZ_FINISH : BZ_FLUSH));
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data->is_flushed = 1;
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if (data->strm.avail_out < data->outbuf_len) {
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size_t bucketlen = data->outbuf_len - data->strm.avail_out;
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@@ -381,6 +387,7 @@ static php_stream_filter *php_bz2_filter_create(const char *filtername, zval *fi
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}
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status = BZ2_bzCompressInit(&(data->strm), blockSize100k, 0, workFactor);
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data->is_flushed = 1;
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fops = &php_bz2_compress_ops;
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} else {
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status = BZ_DATA_ERROR;

‎ext/bz2/tests/bug75776.phpt‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,24 @@
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--TEST--
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Bug #75776 (Flushing streams with compression filter is broken)
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--SKIPIF--
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<?php
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if (!extension_loaded('bz2')) die('skip bz2 extension not available');
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?>
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--FILE--
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<?php
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$text = str_repeat('0123456789abcdef', 1000);
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$temp = fopen('php://temp', 'r+');
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stream_filter_append($temp, 'bzip2.compress', STREAM_FILTER_WRITE);
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fwrite($temp, $text);
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rewind($temp);
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var_dump(bin2hex(stream_get_contents($temp)));
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var_dump(ftell($temp));
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fclose($temp);
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?>
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--EXPECT--
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string(144) "425a68343141592653599fe7bbbf0001f389007fe03f002000902980026826aa80003ea9061520c6a41954833a9069520d6a41b54837a9071520e6a41d5483ba9079520f6a41f548"
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int(72)

‎ext/standard/tests/streams/bug75776.phpt‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,32 @@
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--TEST--
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Bug #75776 (Flushing streams with compression filter is broken)
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--SKIPIF--
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<?php
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if (!extension_loaded('zlib')) die('skip zlib extension not available');
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if (!extension_loaded('bz2')) die('skip bz2 extension not available');
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?>
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--FILE--
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<?php
10+
$compression = [
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'gz' => ['zlib.deflate', 'gzinflate'],
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'bz2' => ['bzip2.compress', 'bzdecompress']
13+
];
14+
foreach ($compression as $ext => [$filter, $function]) {
15+
$stream = fopen(__DIR__ . "/75776.$ext", 'w');
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stream_filter_append($stream, $filter);
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fwrite($stream,"sdfgdfg");
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fflush($stream);
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fclose($stream);
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21+
$compressed = file_get_contents(__DIR__ . "/75776.$ext");
22+
var_dump($function($compressed));
23+
}
24+
?>
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--EXPECT--
26+
string(7) "sdfgdfg"
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string(7) "sdfgdfg"
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--CLEAN--
29+
<?php
30+
@unlink(__DIR__ . "/75776.gz");
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@unlink(__DIR__ . "/75776.bz2");
32+
?>

‎main/streams/streams.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -445,7 +445,7 @@ fprintf(stderr, "stream_free: %s:%p[%s] preserve_handle=%d release_cast=%d remov
445445
(close_options & PHP_STREAM_FREE_RSRC_DTOR) == 0);
446446
#endif
447447

448-
if (stream->flags & PHP_STREAM_FLAG_WAS_WRITTEN) {
448+
if (stream->flags & PHP_STREAM_FLAG_WAS_WRITTEN || stream->writefilters.head) {
449449
/* make sure everything is saved */
450450
_php_stream_flush(stream, 1);
451451
}

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