Issues with ftps through CONNECT

[MarvinWinks]

Using curl executable, directory listings against several ftps sites stopped working as of version 7.77 of curl. I tried compiling and testing against each of the versions from 7.76 to 7.82.

On versions 7.77 and after, the TLS handshake completes successfully. But the directory listing does not return.

I also tried writing a simple main.cpp using libcurl. I am finding that starting with v7.77, CURLOPT_WRITEFUNCTION does not get called.

I did this

I ran the curl executable to do a directory listing of an ftps site. Command-line options used:

-vv
-x
-u username:password
--ftp-ssl
--proxytunnel
<ftp site with scheme as ftp://>

I expected the following

The directory listing as output.

curl/libcurl version

I tried several versions:
Newest version that works: 7.76.1
curl 7.76.1 (x86_64-unknown-linux-gnu) libcurl/7.76.1 OpenSSL/1.0.2zd zlib/1.2.11 libssh2/1.9.0
Release-Date: 2021-04-14
Protocols: dict file ftp ftps gopher gophers http https imap imaps mqtt pop3 pop3s rtsp scp sftp smb smbs smtp smtps telnet tftp
Features: alt-svc AsynchDNS GSS-API HTTPS-proxy IPv6 Kerberos Largefile libz NTLM NTLM_WB SPNEGO SSL TLS-SRP UnixSockets

Newest version tried (that does not work): 7.82.0
curl 7.82.0 (x86_64-unknown-linux-gnu) libcurl/7.82.0 OpenSSL/1.0.2zd zlib/1.2.11 libssh2/1.9.0
Release-Date: 2022-03-05
Protocols: dict file ftp ftps gopher gophers http https imap imaps mqtt pop3 pop3s rtsp scp sftp smb smbs smtp smtps telnet tftp
Features: alt-svc AsynchDNS GSS-API HSTS HTTPS-proxy IPv6 Kerberos Largefile libz NTLM NTLM_WB SPNEGO SSL TLS-SRP UnixSockets

operating system

Linux 3.10.0-957.35.2.el7.x86_64 #1 SMP Wed Sep 18 05:51:28 EDT 2019 x86_64 x86_64 x86_64 GNU/Linux

[jay]

Is there a public server that we can use to reproduce?

[MarvinWinks]

Hi Jay, No, they are all logins. I realize this severely limits your ability to diagnose. Are there any verbose logs that I can send you to help? Jeff Get Outlook for Android<https://aka.ms/AAb9ysg>

…

________________________________ From: Jay Satiro ***@***.***> Sent: Sunday, April 24, 2022, 12:03 AM To: curl/curl ***@***.***> Cc: Jeff ***@***.***>; Author ***@***.***> Subject: Re: [curl/curl] Issues with ftps starting with version 7.77.0 of curl (Issue #8737) Is there a public server that we can use to reproduce? — Reply to this email directly, view it on GitHub<#8737 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ABCI3SFKCUUMEDFEVHZGL2TVGTBXNANCNFSM5UCIMPJQ>. You are receiving this because you authored the thread.Message ID: ***@***.***>

[jay]

You can try bisecting.

[MarvinWinks]

Using git bisect with good=curl-7_76_1 and bad=curl-7_77_0, the offending commit was:

51c0ebc is the first bad commit
commit 51c0ebc
Author: Daniel Stenberg daniel@haxx.se
Date: Thu May 6 13:04:03 2021 +0200

http: deal with partial CONNECT sends

Also added 'CURL_SMALLSENDS' to make Curl_write() send short packets,
which helped verifying this even more.

Add test 363 to verify.

Reported-by: ustcqidi on github
Fixes #6950
Closes #7024

:040000 040000 848f646d0ebde49b473ed2d88daa90ffe33b1455 c00d1ac405a2518a5d278946e66f708a958ff28c M lib
:040000 040000 66349509dfc8e8765c2650dafa865f810da693b7 e741180725e5e0473e53c705e599df00e0325b52 M tests