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ext/session: fix missing zval_ptr_dtor for retval in PS_GC_FUNC(user) #21747

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ext/session: fix missing zval_ptr_dtor for retval in PS_GC_FUNC(user) #21747

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1 change: 1 addition & 0 deletions ext/session/mod_user.c
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Original file line number Diff line number Diff line change
Expand Up @@ -218,6 +218,7 @@ PS_GC_FUNC(user)
/* Anything else is some kind of error */
*nrdels = -1; // Error
}
zval_ptr_dtor(&retval);
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@ndossche ndossche Apr 16, 2026

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Why not only do this in the error case?
Besides there's a subtle additional problem in the callback code: it doesn't handle reference returns (this may be solved in ps_call_handler).

return *nrdels;
}

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33 changes: 33 additions & 0 deletions ext/session/tests/user_session_module/gh_gc_retval_leak.phpt
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@@ -0,0 +1,33 @@
--TEST--
session_gc(): user handler returning non-bool/non-int does not leak memory
--INI--
session.gc_probability=0
session.save_handler=files
--EXTENSIONS--
session
--FILE--
<?php
ob_start();

// Procedural API has no return type enforcement, so gc can return a string
// (reference-counted), which PS_GC_FUNC(user) previously did not free.
session_set_save_handler(
function(string $path, string $name) { return true; },
function() { return true; },
function(string $id): string|false { return ""; },
function(string $id, string $data) { return true; },
function(string $id) { return true; },
function(int $max) { return str_repeat("x", 100); }
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@ndossche ndossche Apr 16, 2026

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Just FYI: this won't leak when the test runs with opcache, which nowadays is almost always. This is because of SCCP computing the string at compile time which causes the string to get interned.
To solve this, replace 100 by random_int(100, 100)

);

session_start();
$result = session_gc();
var_dump($result);
session_write_close();

ob_end_flush();
?>
--EXPECTF--

Deprecated: session_set_save_handler(): Providing individual callbacks instead of an object implementing SessionHandlerInterface is deprecated in %s on line %d
bool(false)
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