don't load the built-in list when using `types'

allow add_mime to fail add_mime nows allocate dinamically copies of the passed strings, so that we can actually free what we parse from the config file. This matters a lot especially with lengthy `types' block: strings that reach the internal mapping are never free'd, so every manual addition is leaked.

fix an out-of-bound access in start_cgi Long time ago, client->req was a static buffer so the memcpy was safe. However, it's been since moved to a dynamically allocated string, so it's very often smaller than sizeof(req.buf) (1024), hence the out of bound access which results in a SIGSEGV very often on OpenBSD thanks to Otto' malloc. The situation with the iri parser, client->req and how the request is forwarded to the other process needs to be improved: this is just a fix to address the issue quickly, a better one would be to restructure the iri parser APIs and rethink how the info is forwarded to the ex process.

swap try_client_by_id with client_by_id i.e. allow client_by_id to fail and return NULL. Initially I thought it was a good idea to shut down a server process if we receive an invalid client id as reply from one of our requests to the executor process. This turned out not to be correct since a client can (read: will) disconnect in the delay beteewn we acknowledge their request and the cgi script execution. The fastcgi and proxy handler already handled this situation, so they're unaffected. This allows an attacker to make gmid unresponsible by just making enough requests until they hit the right timing.

allow using a custom hostname for SNI during proxying add a `sni' option for the `proxy' block: the given name is used instead of the one extracted by the `relay-to' rule.

improve proxy error path properly release everything when during client_close if the request was managed by a proxy.

add `require client ca' for proxy blocks refactor the code that calls validate_against_ca into an helper function to reuse it in both apply_require_ca and (optionally) in apply_reverse_proxy.

proxy: allow multiple proxy blocks, matching options and validations as a side effect the order of the content of a server block is relaxed: options, location or proxy blocks can be put in any order.

allow to disable TLS when proxying requests

add `protocols' option to `proxy' rule

add `verifyname' option for `proxy' rule

simplify the proxying code it doesn't make any sense to keep the proxying info per-location: proxying only one per-vhost. It can't work differently, it doesn't make sense anyway.

update copyright years

support optional client certificate for proxy rule

add ability to proxy requests Add to gmid the ability to forwad a request to another gemini server and thus acting like a reverse proxy. The current syntax for the config file is server "example.com" { ... proxy relay-to host:port } Further options (like the use of custom certificates) are planned. cf. github issue #7