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ext/sysvshm: don't orphan the segment shm_attach() just created #22959

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ext/sysvshm: don't orphan the segment shm_attach() just created #22959

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5 changes: 5 additions & 0 deletions ext/sysvshm/sysvshm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -132,6 +132,7 @@ PHP_FUNCTION(shm_attach)
sysvshm_chunk_head *chunk_ptr;
zend_long shm_key, shm_id, shm_size, shm_flag = 0666;
bool shm_size_is_null = 1;
bool created = false;

if (SUCCESS != zend_parse_parameters(ZEND_NUM_ARGS(), "l|l!l", &shm_key, &shm_size, &shm_size_is_null, &shm_flag)) {
RETURN_THROWS();
Expand All @@ -156,10 +157,14 @@ PHP_FUNCTION(shm_attach)
php_error_docref(NULL, E_WARNING, "Failed for key 0x" ZEND_XLONG_FMT ": %s", shm_key, strerror(errno));
RETURN_FALSE;
}
created = true;
}

if ((shm_ptr = shmat(shm_id, NULL, 0)) == (void *) -1) {
php_error_docref(NULL, E_WARNING, "Failed for key 0x" ZEND_XLONG_FMT ": %s", shm_key, strerror(errno));
if (created) {
shmctl(shm_id, IPC_RMID, NULL);
}
RETURN_FALSE;
}

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34 changes: 34 additions & 0 deletions ext/sysvshm/tests/shm_attach_failed_attach.phpt
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@@ -0,0 +1,34 @@
--TEST--
shm_attach() removes the segment it created when shmat() fails
--EXTENSIONS--
sysvshm
posix
--SKIPIF--
<?php
if (posix_geteuid() === 0) die('skip cannot run as root');
?>
--FILE--
<?php
$key = ftok(__FILE__, 't');

var_dump(shm_attach($key, 1024, 0));

$segment = shm_attach($key, 1024, 0600);

if (!$segment instanceof SysvSharedMemory) {
die("the key is still held by the segment of the failed attach\n");
}

try {
var_dump(shm_put_var($segment, 1, 'value'));
var_dump(shm_get_var($segment, 1));
} finally {
var_dump(shm_remove($segment));
}
?>
--EXPECTF--
Warning: shm_attach(): Failed for key 0x%x: %s in %s on line %d
bool(false)
bool(true)
string(5) "value"
bool(true)
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