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ext/pdo_firebird: Fixed GH-18276 - persistent connection - "zend_mm_heap corrupted" with setAttribute() #18280

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ext/pdo_firebird: Fixed GH-18276 - persistent connection - "zend_mm_heap corrupted" with setAttribute() #18280

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1c25919
Added a test
SakiTakamachi Apr 8, 2025
3bf28c7
When freeing memory, set the pointer to NULL.
SakiTakamachi Apr 8, 2025
8d15cdb
Allocate and free memory properly
SakiTakamachi Apr 9, 2025
af6528e
address comments
SakiTakamachi Apr 10, 2025
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24 changes: 15 additions & 9 deletions ext/pdo_firebird/firebird_driver.c
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Original file line number Diff line number Diff line change
Expand Up @@ -492,13 +492,16 @@ static void firebird_handle_closer(pdo_dbh_t *dbh) /* {{{ */
}

if (H->date_format) {
efree(H->date_format);
pefree(H->date_format, dbh->is_persistent);
H->date_format = NULL;
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Since you're freeing the entire structure anyway below, you don't need to set the pointers for these 3 fields to NULL.

}
if (H->time_format) {
efree(H->time_format);
pefree(H->time_format, dbh->is_persistent);
H->time_format = NULL;
}
if (H->timestamp_format) {
efree(H->timestamp_format);
pefree(H->timestamp_format, dbh->is_persistent);
H->timestamp_format = NULL;
}

pefree(H, dbh->is_persistent);
Expand Down Expand Up @@ -881,9 +884,10 @@ static bool firebird_handle_set_attribute(pdo_dbh_t *dbh, zend_long attr, zval *
return false;
}
if (H->date_format) {
efree(H->date_format);
pefree(H->date_format, dbh->is_persistent);
H->date_format = NULL;
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I'm okay with these being set to NULL because technically we could bail out if the pestrdup below fails.

}
spprintf(&H->date_format, 0, "%s", ZSTR_VAL(str));
H->date_format = pestrdup(ZSTR_VAL(str), dbh->is_persistent);
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Since we know the length, you should use pestrndup instead and pass in ZSTR_LEN(str) as well (same below).

zend_string_release_ex(str, 0);
}
return true;
Expand All @@ -895,9 +899,10 @@ static bool firebird_handle_set_attribute(pdo_dbh_t *dbh, zend_long attr, zval *
return false;
}
if (H->time_format) {
efree(H->time_format);
pefree(H->time_format, dbh->is_persistent);
H->time_format = NULL;
}
spprintf(&H->time_format, 0, "%s", ZSTR_VAL(str));
H->time_format = pestrdup(ZSTR_VAL(str), dbh->is_persistent);
zend_string_release_ex(str, 0);
}
return true;
Expand All @@ -909,9 +914,10 @@ static bool firebird_handle_set_attribute(pdo_dbh_t *dbh, zend_long attr, zval *
return false;
}
if (H->timestamp_format) {
efree(H->timestamp_format);
pefree(H->timestamp_format, dbh->is_persistent);
H->timestamp_format = NULL;
}
spprintf(&H->timestamp_format, 0, "%s", ZSTR_VAL(str));
H->timestamp_format = pestrdup(ZSTR_VAL(str), dbh->is_persistent);
zend_string_release_ex(str, 0);
}
return true;
Expand Down
35 changes: 35 additions & 0 deletions ext/pdo_firebird/tests/gh18276.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,35 @@
--TEST--
GH-18276 (persistent connection - setAttribute(Pdo\Firebird::ATTR_DATE_FORMAT, ..) results in "zend_mm_heap corrupted")
--EXTENSIONS--
pdo_firebird
--SKIPIF--
<?php require('skipif.inc'); ?>
--XLEAK--
A bug in firebird causes a memory leak when calling `isc_attach_database()`.
See https://github.com/FirebirdSQL/firebird/issues/7849
--FILE--
<?php

require("testdb.inc");
unset($dbh);

for ($i = 0; $i < 2; $i++) {
$dbh = new PDO(
PDO_FIREBIRD_TEST_DSN,
PDO_FIREBIRD_TEST_USER,
PDO_FIREBIRD_TEST_PASS,
[
PDO::ATTR_PERSISTENT => true,
],
);
// Avoid interned
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str_repeat is special cased in the SCCP optimization pass if you have a constant number as a second argument, and so you'll still get an interned string here.
You need to do this: str_repeat('my string', random_int(1, 1));

$dbh->setAttribute(PDO::FB_ATTR_DATE_FORMAT, str_repeat('Y----m----d', 1));
$dbh->setAttribute(PDO::FB_ATTR_TIME_FORMAT, str_repeat('H::::i::::s', 1));
$dbh->setAttribute(PDO::FB_ATTR_TIMESTAMP_FORMAT, str_repeat('Y----m----d....H::::i::::s', 1));
unset($dbh);
}

echo 'done!';
?>
--EXPECT--
done!
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