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ext/odbc: fix cond for SQL_NO_TOTAL that led to single byte buffer #23462

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ext/odbc: fix cond for SQL_NO_TOTAL that led to single byte buffer #23462

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10 changes: 7 additions & 3 deletions ext/pdo_odbc/odbc_stmt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -763,10 +763,14 @@ static int odbc_stmt_get_col(pdo_stmt_t *stmt, int colno, zval *result, enum pdo
* changed from 256 byte to LONG_COLUMN_BUFFER_SIZE.
*/
ssize_t to_fetch_len;
if (orig_fetched_len == SQL_NO_TOTAL) {
to_fetch_len = C->datalen > (LONG_COLUMN_BUFFER_SIZE - 1) ? (LONG_COLUMN_BUFFER_SIZE - 1) : C->datalen;
} else {
if (orig_fetched_len == SQL_NO_TOTAL && C->datalen > (LONG_COLUMN_BUFFER_SIZE - 1)) {
to_fetch_len = C->datalen;
} else if (orig_fetched_len > 0) {
/* implicitly not SQL_NO_TOTAL, should be OK */
to_fetch_len = orig_fetched_len;
} else {
/* size must be > 0 to actually get data */
to_fetch_len = (LONG_COLUMN_BUFFER_SIZE - 1);
}
ssize_t to_fetch_byte = to_fetch_len + 1;
char *buf2 = emalloc(to_fetch_byte);
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24 changes: 24 additions & 0 deletions ext/pdo_odbc/tests/gh23443.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,24 @@
--TEST--
GH-23443 (infinite loop / 100% CPU when fetching a large nvarchar(max))
--EXTENSIONS--
pdo_odbc
--SKIPIF--
<?php
require 'ext/pdo/tests/pdo_test.inc';
PDOTest::skip();
?>
--FILE--
<?php
require 'ext/pdo/tests/pdo_test.inc';
$db = PDOTest::test_factory('ext/pdo_odbc/tests/common.phpt');

/*
* Likely depends on ZendMM page size + string overhead that affects long
* column buffer size
*/
$n = 4499;
$row = $db->query("SELECT REPLICATE(CAST(N'A' AS nvarchar(max)), $n) AS v")->fetch(PDO::FETCH_ASSOC);
echo "ok\n";
?>
--EXPECT--
ok
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