fish: enable the legacy provider if build against OpenSSL3

OpenSSL 3.0 disables a number of "legacy" algorithms by default, and we
need to enable them manually using their provider system. Note that
explicitly loading a provider will disable the implicit default
provider, which is why we need to load it explicitly.

Closes #2629

Signed-off-by: Simon Chopin <simon.chopin@canonical.com>

V2:
  * use a local OSSL_LIB_CTX to avoid leaking the legacy algorithms
    into the main SSL context.
  * Simplify the fish_init() error paths by calling fish_deinit()

1 files changed, 4 insertions, 0 deletions

diff --git a/plugins/fishlim/plugin_hexchat.c b/plugins/fishlim/plugin_hexchat.c
index 93e28487..a8b127f2 100644
--- a/plugins/fishlim/plugin_hexchat.c
+++ b/plugins/fishlim/plugin_hexchat.c
@@ -815,6 +815,9 @@ int hexchat_plugin_init(hexchat_plugin *plugin_handle,
     hexchat_hook_server_attrs(ph, "TOPIC", HEXCHAT_PRI_NORM, handle_incoming, NULL);
     hexchat_hook_server_attrs(ph, "332", HEXCHAT_PRI_NORM, handle_incoming, NULL);
 
+    if (!fish_init())
+        return 0;
+
     if (!dh1080_init())
         return 0;
 
@@ -828,6 +831,7 @@ int hexchat_plugin_init(hexchat_plugin *plugin_handle,
 int hexchat_plugin_deinit(void) {
     g_clear_pointer(&pending_exchanges, g_hash_table_destroy);
     dh1080_deinit();
+    fish_deinit();
 
     hexchat_printf(ph, "%s plugin unloaded\n", plugin_name);
     return 1;