Unfortunately, these are also some of the worst APIs in the SSL stack.
I've tried to capture all the things they expose to the caller. 0 vs -1
is intentionally left unexpanded on for now. Upstream's documentation
says 0 means transport EOF, which is a nice idea but isn't true. (A lot
of random functions return 0 on error and pass it up to the caller.)
https://crbug.com/466303 tracks fixing that.
SSL_set_bio is intentionally documented to NOT be usable when they're
already configured. The function tries to behave in this case and even
with additional cases when |rbio| and/or |wbio| are unchanged, but this
is buggy. For instance, this will explode:
SSL_set_bio(ssl, bio1, bio1);
SSL_set_bio(ssl, bio2, SSL_get_wbio(ssl));
As will this, though it's less clear this is part of the API contract
due to SSL taking ownership.
SSL_set_bio(ssl, bio1, bio2);
SSL_set_bio(ssl, bio2, bio1);
It also tries to handle ssl->bbio already existing, but I doubt it quite
works. Hopefully we can drop ssl->bbio eventually. (Why is this so
complicated...)
Change-Id: I5f9f3043915bffc67e2ebd282813e04afbe076e6
Reviewed-on: https://boringssl-review.googlesource.com/5872
Reviewed-by: Adam Langley <agl@google.com>
3c1ccc017c