Bug #74247 [Opn]: Mysql Blob field data gets corrupted after 16MB

Edit report at https://bugs.php.net/bug.php?id=74247&edit=1 ID: 74247 User updated by: support at dsolutions dot lv Reported by: support at dsolutions dot lv -Summary: Blob +Summary: Mysql Blob field data gets corrupted after 16MB Status: Open Type: Bug Package: MySQLi related Operating System: Linux PHP Version: 7.1.3RC1 Block user comment: N Private report: N New Comment: Correction: Since PHP version *7.0.15* Previous Comments: ------------------------------------------------------------------------ [2017-03-14 21:57:20] support at dsolutions dot lv Description: ------------ Since PHP version 7.1.15 when reading a longblob field from MySQL, mysqlnd driver inserts a 0x00 byte at position 16777204 ( or 2^24-12). Therefore all data following said zero is shifted 1 byte to the right. However the total length of the data is unchanged, as the last byte of the blob is not returned. Test script is for mysqli, however I was able to reproduce the same behaviour with pdo. I have some suspicion that the problem resides within the file "ext/mysqlnd/mysqlnd_wireprotocol.c" as it was modified for version 7.0.15. Test script: --------------- echo "\nPHP version:".phpversion(); $mysqli = new mysqli('localhost', 'root', '', 'test'); $mysqli->query("DROP TABLE IF EXISTS blob_tb;"); $mysqli->query("CREATE TABLE blob_tb (bdata longblob);"); $sql = "INSERT INTO blob_tb (bdata) VALUES(?)"; $insertStm = $mysqli->prepare($sql); $blob = NULL; $insertStm->bind_param('b', $blob); $crypto_strong=false; $blob = (binary) openssl_random_pseudo_bytes (20*1024*1024,$crypto_strong); $insertStm->send_long_data(0, $blob); $insertStm->execute(); $insertStm->close(); echo "\nInserted data md5: ".md5($blob).", len ".strlen($blob); $selectStm = $mysqli->prepare("SELECT bdata FROM blob_tb LIMIT 1"); $selectStm->execute(); $selectStm->bind_result($savedBlob); $selectStm->fetch(); $selectStm->close(); echo "\nAre the blobs equal?: " . ((int) ($blob == $savedBlob)); echo "\nSelected data: md5: ".md5($savedBlob); echo "\nSQL md5(): ".$mysqli->query("select md5(bdata) as database_md5 from blob_tb;")->fetch_assoc()['database_md5']; $mysqli->close(); Expected result: ---------------- PHP version:7.0.14 Inserted data md5: 7792a7fd3351033132f991e7a8e939f3, len 20971520 Are the blobs equal?: 1 Selected data: md5: 7792a7fd3351033132f991e7a8e939f3 SQL md5(): 7792a7fd3351033132f991e7a8e939f3 PHP version:7.0.13-1+deb.sury.org~trusty+1 Inserted data md5: b6130b103663d6facbcba10301dd23e1, len 20971520 Are the blobs equal?: 1 Selected data: md5: b6130b103663d6facbcba10301dd23e1 SQL md5(): b6130b103663d6facbcba10301dd23e1 Actual result: -------------- On Centos 7: PHP version:7.0.16 Inserted data md5: 7354bdcb5ee180e069fb686bd289242c, len 20971520 Are the blobs equal?: 0 Selected data: md5: 887f9bbf56e7ad378e8672277d07c267 SQL md5(): 7354bdcb5ee180e069fb686bd289242c PHP version:7.0.15 Inserted data md5: e13724a895dc46e073c4c7ddb005d09d, len 20971520 Are the blobs equal?: 0 Selected data: md5: aa68f482f6a75ae77027728a09485da0 SQL md5(): e13724a895dc46e073c4c7ddb005d09d On Ubuntu: PHP version:7.0.16-4+deb.sury.org~trusty+1 Inserted data md5: 5ab7bb3d517fbfbbd21ec02c48da2d88, len 20971520 Are the blobs equal?: 0 Selected data: md5: 9eb90f968797d617b7385fd166f34067 SQL md5(): 5ab7bb3d517fbfbbd21ec02c48da2d88 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=74247&edit=1