[php-src] Issue #9369: HTTPS cURL request fails at 340th request when used in a recursive function

Issue: https://github.com/php/php-src/issues/9369 Author: tschoonen ### Description Recently a consumer of an API I had made ran into some strange issues, upon inspection of his code I discovered that the problem was because he used cURL in a recursive function, once put in a regular loop the problems disappeared. Further inspection revealed this only seemed to occur with HTTPS requests, not plain HTTP. The server that the requests are made to does not make a difference as I've tested several differen hosts. The included code uses the default snakeoil Apache configuration, the extra cert opts do not affect the outcome if left out on a properly configured server with TLS. The following code: ```php <?php /** * This will end at request #340 */ function recursiveFunctionTest($request_no = 1) { echo "Request no #$request_no...\n"; $ch = curl_init(); curl_setopt($ch, CURLOPT_URL, 'https://localhost/'); curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET'); curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true); curl_setopt($ch, CURLOPT_CAINFO, '/etc/ssl/certs/ssl-cert-snakeoil.pem'); $response = curl_exec($ch); curl_close($ch); if ($response === false) { echo 'Request returned false', PHP_EOL; exit(1); } if ($request_no < 400) { recursiveFunctionTest(++$request_no); } echo "Done!\n"; } recursiveFunctionTest(); ``` Resulted in this output: ``` Request no #1... Request no #2... Request no #3... [...] Request no #338... Request no #339... Request no #340... Request returned false ``` But I expected this output instead: ``` Request no #1... Request no #2... Request no #3... [...] Request no #398... Request no #399... Request no #400... Done! ``` This code will run just fine: ```php <?php /** * This will comfortably come to request #400 */ function whileLoopTest() { $request_no = 0; do { $request_no++; echo "Request no #$request_no...\n"; $ch = curl_init(); curl_setopt($ch, CURLOPT_URL, 'https://localhost/'); curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET'); curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false); curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true); curl_setopt($ch, CURLOPT_CAINFO, '/etc/ssl/certs/ssl-cert-snakeoil.pem'); $response = curl_exec($ch); curl_close($ch); if ($response === false) { echo 'Request returned false', PHP_EOL; exit(1); } } while($request_no < 400); echo "Done!\n"; } whileLoopTest(); ``` ### PHP Version 8.1.8 ### Operating System Ubuntu 22.04 LTS