## Gopher over TLS and spreading the revolution
Seamless encryption in the gopherspace!
.-, [+] _l=l_
((")) (("))i (("))
__/ \/ __/_\/ __/.\/
/___\ /___\ |:|
_| \_ _| \_ _| \_
Ivan J. <
[email protected]>
## Gopher over TLS - Why
* We're in 2021
* Privacy & security ️️(tm)
* Fight police terror and surveillance
* Tor isn't always convenient
* Opens a path to secure services on Gopher
## Gopher over TLS - What
* Community-adopted protocol
* No changes to the existing gopher protocol
* Instead simply encapsulated with TLS
* Optional(!) differentiation with URI (gopher|gophers)
* No need to change specification, protocol, nor port!
## Gopher over TLS - Server abstract
record handshake client
header header version
recv: [16 03 01 00 a5, 01 00 00 a1, 03 03, .......]
#pause
|
V
(bytes[0] == 0x16)
## Gopher over TLS - Server abstract
record handshake client
header header version
recv: [16 03 01 00 a5, 01 00 00 a1, 03 03, .......]
|
V (true) initialize tls context and serve
(bytes[0] == 0x16) ----<
#pause
(false) serve over plain text (or refuse)
## Gopher over TLS - How
* Example:
$ printf "/brcon\r\n" | nc parazyd.org 70
$ printf "/brcon\r\n" | gnutls-cli parazyd.org:70
## Gopher over TLS
* We have a plan. Let's implement it!
## Five steps to domination
1. Gain understanding of core infrastructure
#pause
2. Write patch for core infrastructure
#pause
3. Get it upstream
#pause
4. Advocate this to other software using "core infrastructure"
#pause
5. Get it everywhere
## Example 1. - curl
* Arguably the most used software for data transfer with
various protocols
* Influential
* Written in C
## Example 1. - curl
Git commit: a1f06f32b8603427535fc21183a84ce92a9b96f7
configure.ac | 3 +++
lib/gopher.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
lib/gopher.h | 3 +++
lib/url.c | 3 +++
lib/version.c | 3 +++
5 files changed, 62 insertions(+)
## Example 1. - curl
* Reuse the existing Gopher protocol implementation
* Add a "gophers://" handler which is existing gopher code, plus TLS
* Explain the protocol is useful and adopted
#pause
* Merged in November 2020
* First mainstream software to include Gopher over TLS support
## Example 2. - ffmpeg
* The most widely used media tools and library
* Influential
* Written in C
## Example 2. - ffmpeg
Git commit: 51367267c8a9f1a840f5e810f8c788e6e03712a5
Changelog | 1 +
configure | 1 +
doc/general_contents.texi | 1 +
doc/protocols.texi | 6 ++++++
libavformat/Makefile | 1 +
libavformat/gopher.c | 30 ++++++++++++++++++++++++++----
libavformat/protocols.c | 1 +
libavformat/version.h | 2 +-
8 files changed, 38 insertions(+), 5 deletions(-)
## Example 2. - ~~curl~~ ffmpeg
* Reuse the existing Gopher protocol implementation
* Add a "gophers://" handler which is existing gopher code, plus TLS
* Explain the protocol is useful and adopted (and merged by curl)
#pause
* Merged in February 2021
## Post-domination, pt.1
* Now at state where a core tool has support for Gopher over TLS
#pause
Let's see what happens with a project that uses curl:
## feh
* Solid, minimal image viewer
* Uses libcurl to fetch pictures from the Internet
* No gopher support at all!
* Written in C
## feh - the patch
Git commit: 7cb8ce10e542f27b176b6ecfb1a1ff114d9fef2d
diff --git a/src/utils.c b/src/utils.c
index 087e7f62..eb128a23 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -146,6 +146,8 @@ char *estrjoin(const char *separator, ...)
char path_is_url(char *path) {
if ((!strncmp(path, "http://", 7))
|| (!strncmp(path, "https://", 8))
+ || (!strncmp(path, "gopher://", 9))
+ || (!strncmp(path, "gophers://", 10))
|| (!strncmp(path, "ftp://", 6))
|| (!strncmp(path, "file://", 7)))
return 1;
## Post-domination, pt.2
* Now at state where multiple core tools have support for
Gopher over TLS
#pause
* And a downstream project using a core tool supports
Gopher over TLS
#pause
Let's see what happens with a project that uses ffmpeg:
## mpv
* Widely-used media player
* Works on commandline, and in GUIs
* Probably using it to listen to brcon audio stream
* Supports Gopher, but not Gopher over TLS
* Written in C
## mpv - the patch
Git commit: 6a903a9a087e9639eb3323a7e5adeb49871011af
diff --git a/stream/stream_lavf.c b/stream/stream_lavf.c
index 1c7fd35ae2a..27a948d5e5c 100644
--- a/stream/stream_lavf.c
+++ b/stream/stream_lavf.c
@@ -413,7 +413,7 @@ const stream_info_t stream_info_ffmpeg = {
.protocols = (const char *const[]){
"rtmp", "rtsp", "rtsps", "http", "https", "mms", "mmst", "mmsh", "mmshttp",
"rtp", "httpproxy", "rtmpe", "rtmps", "rtmpt", "rtmpte", "rtmpts", "srt",
- "srtp", "gopher", "data",
+ "srtp", "gopher", "gophers", "data",
NULL },
.can_write = true,
.stream_origin = STREAM_ORIGIN_NET,
## Post-domination, pt.3
* Now at a state where multiple core tools, widely-used software,
and enthusiast projects have support for Gopher over TLS!
## Taking the role of dominatrix
* Find mainstream software and libraries that could benefit from
Gopher over TLS
#pause
* Difficulty level 4/10
* Satisfaction level 10/10
#pause
* Find downstream projects using core tools that already have
Gopher over TLS support and add this support to project-of-choice
#pause
* Difficulty level 1/10
* Satisfaction level 10/10
## Outro
#job
Thanks for listening!
