tree 4f531a0f67e3bd82658c238054a930b5d9f1280a
parent f82afbb9cd1515e9fa7f9e6df84904b832226304
author Remi Tricot-Le Breton <rlebreton@haproxy.com> 1641571921 +0100
committer William Lallemand <wlallemand@haproxy.org> 1641828682 +0100

BUG/MINOR: ssl: Store client SNI in SSL context in case of ClientHello error

If an error is raised during the ClientHello callback on the server side
(ssl_sock_switchctx_cbk), the servername callback won't be called and
the client's SNI will not be saved in the SSL context. But since we use
the SSL_get_servername function to return this SNI in the ssl_fc_sni
sample fetch, that means that in case of error, such as an SNI mismatch
with a frontend having the strict-sni option enabled, the sample fetch
would not work (making strict-sni related errors hard to debug).

This patch fixes that by storing the SNI as an ex_data in the SSL
context in case the ClientHello callback returns an error. This way the
sample fetch can fallback to getting the SNI this way. It will still
first call the SSL_get_servername function first since it is the proper
way of getting a client's SNI when the handshake succeeded.

In order to avoid memory allocations are runtime into this highly used
runtime function, a new memory pool was created to store those client
SNIs. Its entry size is set to 256 bytes since SNIs can't be longer than
255 characters.

This fixes GitHub #1484.

It can be backported in 2.5.