tree 4c642db0def97ddbaa14f63856a6dd387873bde3
parent f673923629ce7b65c14a19c68c7265f82dd4f21b
author William Lallemand <wlallemand@haproxy.org> 1637114361 +0100
committer William Lallemand <wlallemand@haproxy.org> 1637290710 +0100

BUG/MEDIUM: ssl: backend TLS resumption with sni and TLSv1.3

When establishing an outboud connection, haproxy checks if the cached
TLS session has the same SNI as the connection we are trying to
resume.

This test was done by calling SSL_get_servername() which in TLSv1.2
returned the SNI. With TLSv1.3 this is not the case anymore and this
function returns NULL, which invalidates any outboud connection we are
trying to resume if it uses the sni keyword on its server line.

This patch fixes the problem by storing the SNI in the "reused_sess"
structure beside the session itself.

The ssl_sock_set_servername() now has a RWLOCK because this session
cache entry could be accessed by the CLI when trying to update a
certificate on the backend.

This fix must be backported in every maintained version, however the
RWLOCK only exists since version 2.4.