php / php/php-src

UndefinedBehaviorSanitizer crash in SQLite3 BLOB fseek(PHP_INT_MIN, SEEK_END)

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Bug Category: Streams Extension: sqlite3 Status: Needs Triage
Dominant language
C
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Description

Description

The following code:

<?php

$db = new SQLite3(':memory:');

$db->exec('CREATE TABLE test (id TEXT, data BLOB)');

$stmt = $db->prepare('INSERT INTO test (id, data) VALUES (:id, :data)');
$stmt->bindValue(':id', 'a', SQLITE3_TEXT);
$stmt->bindValue(':data', 'TEST TEST', SQLITE3_BLOB);
$stmt->execute();

$row = $db->querySingle("SELECT data FROM test WHERE id='a'", true);

$stream = $db->openBlob('test', 'data', 1); 
var_dump(fseek($stream, PHP_INT_MIN, SEEK_END));

Resulted in this output:

php-src/ext/sqlite3/sqlite3.c:1193:47: runtime error: negation of -9223372036854775808 cannot be represented in type 'zend_off_t' (aka 'long long'); cast to an unsigned type to negate this value to itself
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /Users/arshid/Downloads/php-src/ext/sqlite3/sqlite3.c:1193:47 
[2]    88129 abort      sapi/cli/php z.php

But I expected this output instead:

int(-1)
PHP Version
PHP 8.4.11 (cli) (built: Jul 29 2025 15:30:21) (NTS)
Copyright (c) The PHP Group
Built by Homebrew
Zend Engine v4.4.11, Copyright (c) Zend Technologies
    with Xdebug v3.5.0, Copyright (c) 2002-2025, by Derick Rethans
    with Zend OPcache v8.4.11, Copyright (c), by Zend Technologies
Operating System

No response

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start in ext/sqlite3/sqlite3.c at line 1193, using the supplied PHP script to reproduce the UndefinedBehaviorSanitizer failure. Check the fseek handling for PHP_INT_MIN with SEEK_END and add or update the relevant SQLite3 stream test so the call completes without undefined behavior and returns -1.

Written by the indexing model from the issue text.

Assessment

Tech stack
c, php, sqlite
Domain
database
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Quiet
Clarity
Clearly specified
Newbie friendliness
72/100

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