SSL_read() and SSL_write() are limited to int. The new SSL_write_ex() and SSL_read_ex() APIs support size_t just like read(2) and recv(2). Also see bpo-42853.

int SSL_write_ex(SSL *s, const void *buf, size_t num, size_t *written);
int SSL_read_ex(SSL *ssl, void *buf, size_t num, size_t *readbytes);

Both functions return 1 for success or 0 for failure.

As of version 3.3.1, LibreSSL does not have SSL_write_ex() and SSL_read_ex(). The read and write functions are limited to int.

3.10 branch now requires OpenSSL 1.1.1. This should be easy to implement.

SSL_write_ex() and SSL_read_ex() solve two issues:

* bpo-42853: SSLSocket no longer raises overflow error when sending or receiving more than 2 GB of data
* bpo-31711: empty send(b"") no longer fails with protocol violation exception

New changeset 89d1550d14ba689af12eeb726e4ff8ce73cee7e1 by Christian Heimes in branch 'master':
bpo-42854: Use SSL_read/write_ex() (GH-25468)
https://github.com/python/cpython/commit/89d1550d14ba689af12eeb726e4ff8ce73cee7e1

Ethan, what's your platform and OpenSSL version?

False alarm, sorry.  Still getting used to merging, rebasing, etc.

Current tests run fine.

I am still seeing failures to read responses over 2 GB in Python 3.10b1. I'm working on a reproducer, but I'm getting the same "OverflowError: signed integer is greater than maximum" that I get in 3.9.

Christian mentioned on Twitter that this is probably due to a missing argument clinic change from "int" to "Py_ssize_t". I can confirm that fixing that and rerunning argument clinic makes things start to work.

I don't have the ability to reopen this bug (I think), can someone reopen it please?

https://twitter.com/geofft/status/1417167982665551877

I will push a fix today

New changeset 83d1430ee5b8008631e7f2a75447e740eed065c1 by Pablo Galindo Salgado in branch 'main':
bpo-42854: Correctly use size_t for _ssl._SSLSocket.read and _ssl._SSLSocket.write (GH-27271)
https://github.com/python/cpython/commit/83d1430ee5b8008631e7f2a75447e740eed065c1

New changeset 5ec275758dbc307e9838e7038bfc3b5390950ea7 by Miss Islington (bot) in branch '3.10':
bpo-42854: Correctly use size_t for _ssl._SSLSocket.read and _ssl._SSLSocket.write (GH-27271) (GH-27308)
https://github.com/python/cpython/commit/5ec275758dbc307e9838e7038bfc3b5390950ea7