Adding visual captchas for register and login. (#1027)

* Adding visual captchas for register and login.

* Adding audio wav file for Captcha using espeak.

* Lots of captcha fixes.

- Removed login captchas.
- Added settings to disable captchas, and change difficulty.
- Captchas can only be checked / used once, front end gives a new one on
  failure.
- Added front end button for regenerating captcha.
- Added a disabled / pause button audio playing.

* Some more fixes.

docker/dev/Dockerfile

@@ -41,6 +41,9 @@ FROM alpine:3.12
 # Install libpq for postgres
 RUN apk add libpq
 
+# Install Espeak for captchas
+RUN apk add espeak
+
 # Copy resources
 COPY server/config/defaults.hjson /config/defaults.hjson
 COPY --from=rust /app/server/target/x86_64-unknown-linux-musl/debug/lemmy_server /app/lemmy

docker/prod/Dockerfile

@@ -50,6 +50,10 @@ FROM alpine:3.12 as lemmy
 
 # Install libpq for postgres
 RUN apk add libpq
+
+# Install Espeak for captchas
+RUN apk add espeak
+
 RUN addgroup -g 1000 lemmy
 RUN adduser -D -s /bin/sh -u 1000 -G lemmy lemmy
 

docs/src/contributing_websocket_http_api.md

@@ -390,7 +390,9 @@ Only the first user will be able to be the admin.
     email: Option<String>,
     password: String,
     password_verify: String,
-    admin: bool
+    admin: bool,
+    captcha_uuid: Option<String>, // Only checked if these are enabled in the server
+    captcha_answer: Option<String>,
   }
 }
 ```
@@ -408,6 +410,34 @@ Only the first user will be able to be the admin.
 
 `POST /user/register`
 
+#### Get Captcha
+
+These expire after 10 minutes.
+
+##### Request
+```rust
+{
+  op: "GetCaptcha",
+}
+```
+##### Response
+```rust
+{
+  op: "GetCaptcha",
+  data: {
+    ok?: { // Will be undefined if captchas are disabled
+      png: String, // A Base64 encoded png
+      wav: Option<String>, // A Base64 encoded wav audio file
+      uuid: String,
+    }
+  }
+}
+```
+
+##### HTTP
+
+`GET /user/get_captcha`
+
 #### Get User Details
 ##### Request
 ```rust

server/Cargo.lock

@@ -31,7 +31,7 @@ checksum = "a9028932f36d45df020c92317ccb879ab77d8f066f57ff143dd5bee93ba3de0d"
 dependencies = [
  "actix-rt",
  "actix_derive",
- "bitflags",
+ "bitflags 1.2.1",
  "bytes",
  "crossbeam-channel",
  "derive_more",
@@ -54,7 +54,7 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09e55f0a5c2ca15795035d90c46bd0e73a5123b72f68f12596d6ba5282051380"
 dependencies = [
- "bitflags",
+ "bitflags 1.2.1",
  "bytes",
  "futures-core",
  "futures-sink",
@@ -94,7 +94,7 @@ dependencies = [
  "actix-http",
  "actix-service",
  "actix-web",
- "bitflags",
+ "bitflags 1.2.1",
  "bytes",
  "derive_more",
  "futures-core",
@@ -120,7 +120,7 @@ dependencies = [
  "actix-tls",
  "actix-utils",
  "base64 0.12.3",
- "bitflags",
+ "bitflags 1.2.1",
  "brotli2",
  "bytes",
  "cookie",
@@ -280,7 +280,7 @@ dependencies = [
  "actix-codec",
  "actix-rt",
  "actix-service",
- "bitflags",
+ "bitflags 1.2.1",
  "bytes",
  "either",
  "futures",
@@ -382,6 +382,12 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ee2a4ec343196209d6594e19543ae87a39f96d5534d7174822a3ad825dd6ed7e"
 
+[[package]]
+name = "adler32"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "567b077b825e468cc974f0020d4082ee6e03132512f207ef1a02fd5d00d1f32d"
+
 [[package]]
 name = "aho-corasick"
 version = "0.7.13"
@@ -496,6 +502,15 @@ version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1b20b618342cf9891c292c4f5ac2cde7287cc5c87e87e9c769d617793607dec1"
 
+[[package]]
+name = "base64"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "30e93c03064e7590d0466209155251b90c22e37fab1daf2771582598b5827557"
+dependencies = [
+ "byteorder",
+]
+
 [[package]]
 name = "base64"
 version = "0.9.3"
@@ -539,6 +554,12 @@ dependencies = [
  "getrandom",
 ]
 
+[[package]]
+name = "bitflags"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aad18937a628ec6abcd26d1489012cc0e18c21798210f491af69ded9b881106d"
+
 [[package]]
 name = "bitflags"
 version = "1.2.1"
@@ -642,6 +663,12 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e3b5ca7a04898ad4bcd41c90c5285445ff5b791899bb1b0abdd2a2aa791211d7"
 
+[[package]]
+name = "bytemuck"
+version = "1.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "db7a1029718df60331e557c9e83a55523c955e5dd2a7bfeffad6bbd50b538ae9"
+
 [[package]]
 name = "byteorder"
 version = "1.3.4"
@@ -663,6 +690,26 @@ dependencies = [
  "bytes",
 ]
 
+[[package]]
+name = "c_vec"
+version = "1.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8a318911dce53b5f1ca6539c44f5342c632269f0fa7ea3e35f32458c27a7c30"
+
+[[package]]
+name = "captcha"
+version = "0.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4d060a3be43adb2fe89d3448e9a193149806139b1ce99281865fcab7aeaf04ed"
+dependencies = [
+ "base64 0.5.2",
+ "image",
+ "lodepng",
+ "rand 0.3.23",
+ "serde_json",
+ "time 0.1.43",
+]
+
 [[package]]
 name = "cc"
 version = "1.0.58"
@@ -695,7 +742,7 @@ checksum = "bdfa80d47f954d53a35a64987ca1422f495b8d6483c0fe9f7117b36c2a792129"
 dependencies = [
  "ansi_term",
  "atty",
- "bitflags",
+ "bitflags 1.2.1",
  "strsim 0.8.0",
  "textwrap",
  "unicode-width",
@@ -708,7 +755,7 @@ version = "0.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
 dependencies = [
- "bitflags",
+ "bitflags 1.2.1",
 ]
 
 [[package]]
@@ -717,9 +764,15 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4344512281c643ae7638bbabc3af17a11307803ec8f0fcad9fae512a8bf36467"
 dependencies = [
- "bitflags",
+ "bitflags 1.2.1",
 ]
 
+[[package]]
+name = "color_quant"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0dbbb57365263e881e805dc77d94697c9118fd94d8da011240555aa7b23445bd"
+
 [[package]]
 name = "comrak"
 version = "0.7.0"
@@ -806,6 +859,43 @@ dependencies = [
  "crossbeam-utils",
 ]
 
+[[package]]
+name = "crossbeam-deque"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f02af974daeee82218205558e51ec8768b48cf524bd01d550abe5573a608285"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+ "maybe-uninit",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "058ed274caafc1f60c4997b5fc07bf7dc7cca454af7c6e81edffe5f33f70dace"
+dependencies = [
+ "autocfg 1.0.0",
+ "cfg-if",
+ "crossbeam-utils",
+ "lazy_static",
+ "maybe-uninit",
+ "memoffset",
+ "scopeguard",
+]
+
+[[package]]
+name = "crossbeam-queue"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "774ba60a54c213d409d5353bda12d49cd68d14e45036a285234c8d6f91f92570"
+dependencies = [
+ "cfg-if",
+ "crossbeam-utils",
+ "maybe-uninit",
+]
+
 [[package]]
 name = "crossbeam-utils"
 version = "0.7.2"
@@ -852,6 +942,16 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "deflate"
+version = "0.7.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "707b6a7b384888a70c8d2e8650b3e60170dfc6a67bb4aa67b6dfca57af4bedb4"
+dependencies = [
+ "adler32",
+ "byteorder",
+]
+
 [[package]]
 name = "derive_builder"
 version = "0.9.0"
@@ -894,7 +994,7 @@ version = "1.4.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3e2de9deab977a153492a1468d1b1c0662c1cf39e5ea87d0c060ecd59ef18d8c"
 dependencies = [
- "bitflags",
+ "bitflags 1.2.1",
  "byteorder",
  "chrono",
  "diesel_derives",
@@ -1072,6 +1172,15 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "enum_primitive"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be4551092f4d519593039259a9ed8daedf0da12e5109c5280338073eaeb81180"
+dependencies = [
+ "num-traits 0.1.43",
+]
+
 [[package]]
 name = "env_logger"
 version = "0.7.1"
@@ -1167,7 +1276,7 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2e9763c69ebaae630ba35f74888db465e49e259ba1bc0eda7d06f4a067615d82"
 dependencies = [
- "bitflags",
+ "bitflags 1.2.1",
  "fuchsia-zircon-sys",
 ]
 
@@ -1311,6 +1420,16 @@ dependencies = [
  "wasi",
 ]
 
+[[package]]
+name = "gif"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2e41945ba23db3bf51b24756d73d81acb4f28d85c3dccc32c6fae904438c25f"
+dependencies = [
+ "color_quant",
+ "lzw",
+]
+
 [[package]]
 name = "gimli"
 version = "0.22.0"
@@ -1455,6 +1574,23 @@ dependencies = [
  "unicode-normalization",
 ]
 
+[[package]]
+name = "image"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1c3f4f5ea213ed9899eca760a8a14091d4b82d33e27cf8ced336ff730e9f6da8"
+dependencies = [
+ "byteorder",
+ "enum_primitive",
+ "gif",
+ "jpeg-decoder",
+ "num-iter",
+ "num-rational",
+ "num-traits 0.1.43",
+ "png",
+ "scoped_threadpool",
+]
+
 [[package]]
 name = "indexmap"
 version = "1.5.0"
@@ -1465,6 +1601,12 @@ dependencies = [
  "hashbrown",
 ]
 
+[[package]]
+name = "inflate"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d1238524675af3938a7c74980899535854b88ba07907bb1c944abe5b8fc437e5"
+
 [[package]]
 name = "instant"
 version = "0.1.6"
@@ -1507,6 +1649,16 @@ version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc6f3ad7b9d11a0c00842ff8de1b60ee58661048eb8049ed33c73594f359d7e6"
 
+[[package]]
+name = "jpeg-decoder"
+version = "0.1.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc797adac5f083b8ff0ca6f6294a999393d76e197c36488e2ef732c4715f6fa3"
+dependencies = [
+ "byteorder",
+ "rayon",
+]
+
 [[package]]
 name = "js-sys"
 version = "0.3.42"
@@ -1585,6 +1737,7 @@ dependencies = [
  "awc",
  "base64 0.12.3",
  "bcrypt",
+ "captcha",
  "chrono",
  "diesel",
  "diesel_migrations",
@@ -1673,7 +1826,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "db65c6da02e61f55dae90a0ae427b2a5f6b3e8db09f58d10efab23af92592616"
 dependencies = [
  "arrayvec",
- "bitflags",
+ "bitflags 1.2.1",
  "cfg-if",
  "ryu",
  "static_assertions",
@@ -1719,6 +1872,18 @@ dependencies = [
  "scopeguard",
 ]
 
+[[package]]
+name = "lodepng"
+version = "1.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ac1dfdf85b7d5dea61a620e12c051a72078189366a0b3c0ab331e30847def2f"
+dependencies = [
+ "c_vec",
+ "cc",
+ "libc",
+ "rgb",
+]
+
 [[package]]
 name = "log"
 version = "0.4.11"
@@ -1737,6 +1902,12 @@ dependencies = [
  "linked-hash-map 0.5.3",
 ]
 
+[[package]]
+name = "lzw"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d947cbb889ed21c2a84be6ffbaebf5b4e0f4340638cba0444907e38b56be084"
+
 [[package]]
 name = "maplit"
 version = "1.0.2"
@@ -1755,12 +1926,27 @@ version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7ffc5c5338469d4d3ea17d269fa8ea3512ad247247c30bd2df69e68309ed0a08"
 
+[[package]]
+name = "maybe-uninit"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60302e4db3a61da70c0cb7991976248362f30319e88850c487b9b95bbf059e00"
+
 [[package]]
 name = "memchr"
 version = "2.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3728d817d99e5ac407411fa471ff9800a778d88a24685968b36824eaf4bee400"
 
+[[package]]
+name = "memoffset"
+version = "0.5.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c198b026e1bbf08a937e94c6c60f9ec4a2267f5b0d2eec9c1b21b061ce2be55f"
+dependencies = [
+ "autocfg 1.0.0",
+]
+
 [[package]]
 name = "migrations_internals"
 version = "1.4.1"
@@ -1920,6 +2106,27 @@ dependencies = [
  "num-traits 0.2.12",
 ]
 
+[[package]]
+name = "num-iter"
+version = "0.1.41"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a6e6b7c748f995c4c29c5f5ae0248536e04a5739927c74ec0fa564805094b9f"
+dependencies = [
+ "autocfg 1.0.0",
+ "num-integer",
+ "num-traits 0.2.12",
+]
+
+[[package]]
+name = "num-rational"
+version = "0.1.42"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee314c74bd753fc86b4780aa9475da469155f3848473a261d2d18e35245a784e"
+dependencies = [
+ "num-integer",
+ "num-traits 0.2.12",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.1.43"
@@ -1978,7 +2185,7 @@ version = "0.10.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8d575eff3665419f9b83678ff2815858ad9d11567e082f5ac1814baba4e2bcb4"
 dependencies = [
- "bitflags",
+ "bitflags 1.2.1",
  "cfg-if",
  "foreign-types",
  "lazy_static",
@@ -2153,6 +2360,18 @@ version = "0.3.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d36492546b6af1463394d46f0c834346f31548646f6ba10849802c9c9a27ac33"
 
+[[package]]
+name = "png"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "48f397b84083c2753ba53c7b56ad023edb94512b2885ffe227c66ff7edb61868"
+dependencies = [
+ "bitflags 0.7.0",
+ "deflate",
+ "inflate",
+ "num-iter",
+]
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.8"
@@ -2225,6 +2444,16 @@ dependencies = [
  "scheduled-thread-pool",
 ]
 
+[[package]]
+name = "rand"
+version = "0.3.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "64ac302d8f83c0c1974bf758f6b041c6c8ada916fbb44a609158ca8b064cc76c"
+dependencies = [
+ "libc",
+ "rand 0.4.6",
+]
+
 [[package]]
 name = "rand"
 version = "0.4.6"
@@ -2385,6 +2614,31 @@ dependencies = [
  "rand_core 0.3.1",
 ]
 
+[[package]]
+name = "rayon"
+version = "1.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62f02856753d04e03e26929f820d0a0a337ebe71f849801eea335d464b349080"
+dependencies = [
+ "autocfg 1.0.0",
+ "crossbeam-deque",
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e92e15d89083484e11353891f1af602cc661426deb9564c298b270c726973280"
+dependencies = [
+ "crossbeam-deque",
+ "crossbeam-queue",
+ "crossbeam-utils",
+ "lazy_static",
+ "num_cpus",
+]
+
 [[package]]
 name = "rdrand"
 version = "0.4.0"
@@ -2437,6 +2691,15 @@ dependencies = [
  "quick-error",
 ]
 
+[[package]]
+name = "rgb"
+version = "0.8.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90ef54b45ae131327a88597e2463fee4098ad6c88ba7b6af4b3987db8aad4098"
+dependencies = [
+ "bytemuck",
+]
+
 [[package]]
 name = "ring"
 version = "0.16.15"
@@ -2521,6 +2784,12 @@ dependencies = [
  "parking_lot 0.11.0",
 ]
 
+[[package]]
+name = "scoped_threadpool"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d51f5df5af43ab3f1360b429fa5e0152ac5ce8c0bd6485cae490332e96846a8"
+
 [[package]]
 name = "scopeguard"
 version = "1.1.0"
@@ -2543,7 +2812,7 @@ version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "64808902d7d99f78eaddd2b4e2509713babc3dc3c85ad6f4c447680f3c01e535"
 dependencies = [
- "bitflags",
+ "bitflags 1.2.1",
  "core-foundation",
  "core-foundation-sys",
  "libc",

server/Cargo.toml

@@ -51,3 +51,4 @@ itertools = "0.9.0"
 uuid = { version = "0.8", features = ["serde", "v4"] }
 sha2 = "0.9"
 async-trait = "0.1.36"
+captcha = "0.0.7"

server/config/defaults.hjson

@@ -59,6 +59,10 @@
     # comma seperated list of instances with which federation is allowed
     allowed_instances: ""
   }
+  captcha: {
+    enabled: true
+    difficulty: medium # Can be easy, medium, or hard
+  }
 #  # email sending configuration
 #  email: {
 #    # hostname and port of the smtp server

server/lemmy_utils/src/settings.rs

@@ -17,6 +17,7 @@ pub struct Settings {
   pub rate_limit: RateLimitConfig,
   pub email: Option<EmailConfig>,
   pub federation: Federation,
+  pub captcha: CaptchaConfig,
 }
 
 #[derive(Debug, Deserialize, Clone)]
@@ -46,6 +47,12 @@ pub struct EmailConfig {
   pub use_tls: bool,
 }
 
+#[derive(Debug, Deserialize, Clone)]
+pub struct CaptchaConfig {
+  pub enabled: bool,
+  pub difficulty: String, // easy, medium, or hard
+}
+
 #[derive(Debug, Deserialize, Clone)]
 pub struct Database {
   pub user: String,

server/src/api/site.rs

@@ -370,6 +370,8 @@ impl Perform for Oper<GetSite> {
         password_verify: setup.admin_password.to_owned(),
         admin: true,
         show_nsfw: true,
+        captcha_uuid: None,
+        captcha_answer: None,
       };
       let login_response = Oper::new(register, self.client.clone())
         .perform(pool, websocket_info.clone())

server/src/api/user.rs

@@ -2,8 +2,9 @@ use crate::{
   api::{claims::Claims, is_admin, APIError, Oper, Perform},
   apub::ApubObjectType,
   blocking,
+  captcha_espeak_wav_base64,
   websocket::{
-    server::{JoinUserRoom, SendAllMessage, SendUserRoomMessage},
+    server::{CaptchaItem, CheckCaptcha, JoinUserRoom, SendAllMessage, SendUserRoomMessage},
     UserOperation,
     WebsocketInfo,
   },
@@ -11,6 +12,8 @@ use crate::{
   LemmyError,
 };
 use bcrypt::verify;
+use captcha::{gen, Difficulty};
+use chrono::Duration;
 use lemmy_db::{
   comment::*,
   comment_view::*,
@@ -66,6 +69,23 @@ pub struct Register {
   pub password_verify: String,
   pub admin: bool,
   pub show_nsfw: bool,
+  pub captcha_uuid: Option<String>,
+  pub captcha_answer: Option<String>,
+}
+
+#[derive(Serialize, Deserialize)]
+pub struct GetCaptcha {}
+
+#[derive(Serialize, Deserialize)]
+pub struct GetCaptchaResponse {
+  ok: Option<CaptchaResponse>,
+}
+
+#[derive(Serialize, Deserialize)]
+pub struct CaptchaResponse {
+  png: String,         // A Base64 encoded png
+  wav: Option<String>, // A Base64 encoded wav audio
+  uuid: String,
 }
 
 #[derive(Serialize, Deserialize)]
@@ -303,7 +323,7 @@ impl Perform for Oper<Register> {
   async fn perform(
     &self,
     pool: &DbPool,
-    _websocket_info: Option<WebsocketInfo>,
+    websocket_info: Option<WebsocketInfo>,
   ) -> Result<LoginResponse, LemmyError> {
     let data: &Register = &self.data;
 
@@ -320,6 +340,31 @@ impl Perform for Oper<Register> {
       return Err(APIError::err("passwords_dont_match").into());
     }
 
+    // If its not the admin, check the captcha
+    if !data.admin && Settings::get().captcha.enabled {
+      match websocket_info {
+        Some(ws) => {
+          let check = ws
+            .chatserver
+            .send(CheckCaptcha {
+              uuid: data
+                .captcha_uuid
+                .to_owned()
+                .unwrap_or_else(|| "".to_string()),
+              answer: data
+                .captcha_answer
+                .to_owned()
+                .unwrap_or_else(|| "".to_string()),
+            })
+            .await?;
+          if !check {
+            return Err(APIError::err("captcha_incorrect").into());
+          }
+        }
+        None => return Err(APIError::err("captcha_incorrect").into()),
+      };
+    }
+
     if let Err(slurs) = slur_check(&data.username) {
       return Err(APIError::err(&slurs_vec_to_str(slurs)).into());
     }
@@ -439,6 +484,54 @@ impl Perform for Oper<Register> {
   }
 }
 
+#[async_trait::async_trait(?Send)]
+impl Perform for Oper<GetCaptcha> {
+  type Response = GetCaptchaResponse;
+
+  async fn perform(
+    &self,
+    _pool: &DbPool,
+    websocket_info: Option<WebsocketInfo>,
+  ) -> Result<Self::Response, LemmyError> {
+    let captcha_settings = Settings::get().captcha;
+
+    if !captcha_settings.enabled {
+      return Ok(GetCaptchaResponse { ok: None });
+    }
+
+    let captcha = match captcha_settings.difficulty.as_str() {
+      "easy" => gen(Difficulty::Easy),
+      "medium" => gen(Difficulty::Medium),
+      "hard" => gen(Difficulty::Hard),
+      _ => gen(Difficulty::Medium),
+    };
+
+    let answer = captcha.chars_as_string();
+
+    let png_byte_array = captcha.as_png().expect("failed to generate captcha");
+
+    let png = base64::encode(png_byte_array);
+
+    let uuid = uuid::Uuid::new_v4().to_string();
+
+    let wav = captcha_espeak_wav_base64(&answer).ok();
+
+    let captcha_item = CaptchaItem {
+      answer,
+      uuid: uuid.to_owned(),
+      expires: naive_now() + Duration::minutes(10), // expires in 10 minutes
+    };
+
+    if let Some(ws) = websocket_info {
+      ws.chatserver.do_send(captcha_item);
+    }
+
+    Ok(GetCaptchaResponse {
+      ok: Some(CaptchaResponse { png, uuid, wav }),
+    })
+  }
+}
+
 #[async_trait::async_trait(?Send)]
 impl Perform for Oper<SaveUserSettings> {
   type Response = LoginResponse;

server/src/lib.rs

@@ -7,7 +7,9 @@ pub extern crate lazy_static;
 pub extern crate failure;
 pub extern crate actix;
 pub extern crate actix_web;
+pub extern crate base64;
 pub extern crate bcrypt;
+pub extern crate captcha;
 pub extern crate chrono;
 pub extern crate diesel;
 pub extern crate dotenv;
@@ -35,6 +37,7 @@ use lemmy_utils::{get_apub_protocol_string, settings::Settings};
 use log::error;
 use percent_encoding::{utf8_percent_encode, NON_ALPHANUMERIC};
 use serde::Deserialize;
+use std::process::Command;
 
 pub type DbPool = diesel::r2d2::Pool<diesel::r2d2::ConnectionManager<diesel::PgConnection>>;
 pub type ConnectionId = usize;
@@ -224,9 +227,56 @@ where
   Ok(res)
 }
 
+pub fn captcha_espeak_wav_base64(captcha: &str) -> Result<String, LemmyError> {
+  let mut built_text = String::new();
+
+  // Building proper speech text for espeak
+  for mut c in captcha.chars() {
+    let new_str = if c.is_alphabetic() {
+      if c.is_lowercase() {
+        c.make_ascii_uppercase();
+        format!("lower case {} ... ", c)
+      } else {
+        c.make_ascii_uppercase();
+        format!("capital {} ... ", c)
+      }
+    } else {
+      format!("{} ...", c)
+    };
+
+    built_text.push_str(&new_str);
+  }
+
+  espeak_wav_base64(&built_text)
+}
+
+pub fn espeak_wav_base64(text: &str) -> Result<String, LemmyError> {
+  // Make a temp file path
+  let uuid = uuid::Uuid::new_v4().to_string();
+  let file_path = format!("/tmp/lemmy_espeak_{}.wav", &uuid);
+
+  // Write the wav file
+  Command::new("espeak")
+    .arg("-w")
+    .arg(&file_path)
+    .arg(text)
+    .status()?;
+
+  // Read the wav file bytes
+  let bytes = std::fs::read(&file_path)?;
+
+  // Delete the file
+  std::fs::remove_file(file_path)?;
+
+  // Convert to base64
+  let base64 = base64::encode(bytes);
+
+  Ok(base64)
+}
+
 #[cfg(test)]
 mod tests {
-  use crate::is_image_content_type;
+  use crate::{captcha_espeak_wav_base64, is_image_content_type};
 
   #[test]
   fn test_image() {
@@ -241,6 +291,11 @@ mod tests {
     });
   }
 
+  #[test]
+  fn test_espeak() {
+    assert!(captcha_espeak_wav_base64("WxRt2l").is_ok())
+  }
+
   // These helped with testing
   // #[test]
   // fn test_iframely() {

server/src/routes/api.rs

@@ -140,6 +140,7 @@ pub fn config(cfg: &mut web::ServiceConfig, rate_limit: &RateLimit) {
           .route("/ban", web::post().to(route_post::<BanUser>))
           // Account actions. I don't like that they're in /user maybe /accounts
           .route("/login", web::post().to(route_post::<Login>))
+          .route("/get_captcha", web::get().to(route_post::<GetCaptcha>))
           .route(
             "/delete_account",
             web::post().to(route_post::<DeleteAccount>),

server/src/websocket/mod.rs

@@ -20,6 +20,7 @@ use std::{
 pub enum UserOperation {
   Login,
   Register,
+  GetCaptcha,
   CreateCommunity,
   CreatePost,
   ListCommunities,

server/src/websocket/server.rs

@@ -16,6 +16,7 @@ use crate::{
   UserId,
 };
 use actix_web::client::Client;
+use lemmy_db::naive_now;
 
 /// Chat server sends this messages to session
 #[derive(Message)]
@@ -134,6 +135,21 @@ pub struct SessionInfo {
   pub ip: IPAddr,
 }
 
+#[derive(Message, Debug)]
+#[rtype(result = "()")]
+pub struct CaptchaItem {
+  pub uuid: String,
+  pub answer: String,
+  pub expires: chrono::NaiveDateTime,
+}
+
+#[derive(Message)]
+#[rtype(bool)]
+pub struct CheckCaptcha {
+  pub uuid: String,
+  pub answer: String,
+}
+
 /// `ChatServer` manages chat rooms and responsible for coordinating chat
 /// session.
 pub struct ChatServer {
@@ -158,6 +174,9 @@ pub struct ChatServer {
   /// Rate limiting based on rate type and IP addr
   rate_limiter: RateLimit,
 
+  /// A list of the current captchas
+  captchas: Vec<CaptchaItem>,
+
   /// An HTTP Client
   client: Client,
 }
@@ -176,6 +195,7 @@ impl ChatServer {
       rng: rand::thread_rng(),
       pool,
       rate_limiter,
+      captchas: Vec::new(),
       client,
     }
   }
@@ -441,6 +461,7 @@ impl ChatServer {
         // User ops
         UserOperation::Login => do_user_operation::<Login>(args).await,
         UserOperation::Register => do_user_operation::<Register>(args).await,
+        UserOperation::GetCaptcha => do_user_operation::<GetCaptcha>(args).await,
         UserOperation::GetUserDetails => do_user_operation::<GetUserDetails>(args).await,
         UserOperation::GetReplies => do_user_operation::<GetReplies>(args).await,
         UserOperation::AddAdmin => do_user_operation::<AddAdmin>(args).await,
@@ -635,7 +656,7 @@ impl Handler<StandardMessage> for ChatServer {
     Box::pin(async move {
       match fut.await {
         Ok(m) => {
-          info!("Message Sent: {}", m);
+          // info!("Message Sent: {}", m);
           Ok(m)
         }
         Err(e) => {
@@ -774,3 +795,30 @@ where
   };
   Ok(serde_json::to_string(&response)?)
 }
+
+impl Handler<CaptchaItem> for ChatServer {
+  type Result = ();
+
+  fn handle(&mut self, msg: CaptchaItem, _: &mut Context<Self>) {
+    self.captchas.push(msg);
+  }
+}
+
+impl Handler<CheckCaptcha> for ChatServer {
+  type Result = bool;
+
+  fn handle(&mut self, msg: CheckCaptcha, _: &mut Context<Self>) -> Self::Result {
+    // Remove all the ones that are past the expire time
+    self.captchas.retain(|x| x.expires.gt(&naive_now()));
+
+    let check = self
+      .captchas
+      .iter()
+      .any(|r| r.uuid == msg.uuid && r.answer == msg.answer);
+
+    // Remove this uuid so it can't be re-checked (Checks only work once)
+    self.captchas.retain(|x| x.uuid != msg.uuid);
+
+    check
+  }
+}

ui/src/components/create-post.tsx

@@ -110,7 +110,7 @@ export class CreatePost extends Component<any, CreatePostState> {
         return lastLocation.split('/c/')[1];
       }
     }
-    return undefined;
+    return;
   }
 
   handlePostCreate(id: number) {

ui/src/components/login.tsx

@@ -9,6 +9,7 @@ import {
   UserOperation,
   PasswordResetForm,
   GetSiteResponse,
+  GetCaptchaResponse,
   WebSocketJsonResponse,
   Site,
 } from '../interfaces';
@@ -21,11 +22,8 @@ interface State {
   registerForm: RegisterForm;
   loginLoading: boolean;
   registerLoading: boolean;
-  mathQuestion: {
+  captcha: GetCaptchaResponse;
-    a: number;
+  captchaPlaying: boolean;
-    b: number;
-    answer: number;
-  };
   site: Site;
 }
 
@@ -43,14 +41,13 @@ export class Login extends Component<any, State> {
       password_verify: undefined,
       admin: false,
       show_nsfw: false,
+      captcha_uuid: undefined,
+      captcha_answer: undefined,
     },
     loginLoading: false,
     registerLoading: false,
-    mathQuestion: {
+    captcha: undefined,
-      a: Math.floor(Math.random() * 10) + 1,
+    captchaPlaying: false,
-      b: Math.floor(Math.random() * 10) + 1,
-      answer: undefined,
-    },
     site: {
       id: undefined,
       name: undefined,
@@ -81,6 +78,7 @@ export class Login extends Component<any, State> {
       );
 
     WebSocketService.Instance.getSite();
+    WebSocketService.Instance.getCaptcha();
   }
 
   componentWillUnmount() {
@@ -172,6 +170,7 @@ export class Login extends Component<any, State> {
       </div>
     );
   }
+
   registerForm() {
     return (
       <form onSubmit={linkEvent(this, this.handleRegisterSubmit)}>
@@ -258,23 +257,37 @@ export class Login extends Component<any, State> {
             />
           </div>
         </div>
-        <div class="form-group row">
-          <label class="col-sm-10 col-form-label" htmlFor="register-math">
-            {i18n.t('what_is')}{' '}
-            {`${this.state.mathQuestion.a} + ${this.state.mathQuestion.b}?`}
-          </label>
 
-          <div class="col-sm-2">
+        {this.state.captcha && (
+          <div class="form-group row">
+            <label class="col-sm-2" htmlFor="register-captcha">
+              <span class="mr-2">{i18n.t('enter_code')}</span>
+              <button
+                type="button"
+                class="btn btn-secondary"
+                onClick={linkEvent(this, this.handleRegenCaptcha)}
+              >
+                <svg class="icon icon-refresh-cw">
+                  <use xlinkHref="#icon-refresh-cw"></use>
+                </svg>
+              </button>
+            </label>
+            {this.showCaptcha()}
+            <div class="col-sm-6">
               <input
-              type="number"
+                type="text"
-              id="register-math"
                 class="form-control"
-              value={this.state.mathQuestion.answer}
+                id="register-captcha"
-              onInput={linkEvent(this, this.handleMathAnswerChange)}
+                value={this.state.registerForm.captcha_answer}
+                onInput={linkEvent(
+                  this,
+                  this.handleRegisterCaptchaAnswerChange
+                )}
                 required
               />
             </div>
           </div>
+        )}
         {this.state.site.enable_nsfw && (
           <div class="form-group row">
             <div class="col-sm-10">
@@ -295,11 +308,7 @@ export class Login extends Component<any, State> {
         )}
         <div class="form-group row">
           <div class="col-sm-10">
-            <button
+            <button type="submit" class="btn btn-secondary">
-              type="submit"
-              class="btn btn-secondary"
-              disabled={this.mathCheck}
-            >
               {this.state.registerLoading ? (
                 <svg class="icon icon-spinner spin">
                   <use xlinkHref="#icon-spinner"></use>
@@ -314,6 +323,36 @@ export class Login extends Component<any, State> {
     );
   }
 
+  showCaptcha() {
+    return (
+      <div class="col-sm-4">
+        {this.state.captcha.ok && (
+          <>
+            <img
+              class="rounded-top img-fluid"
+              src={this.captchaPngSrc()}
+              style="border-bottom-right-radius: 0; border-bottom-left-radius: 0;"
+            />
+            {this.state.captcha.ok.wav && (
+              <button
+                class="rounded-bottom btn btn-sm btn-secondary btn-block"
+                style="border-top-right-radius: 0; border-top-left-radius: 0;"
+                title={i18n.t('play_captcha_audio')}
+                onClick={linkEvent(this, this.handleCaptchaPlay)}
+                type="button"
+                disabled={this.state.captchaPlaying}
+              >
+                <svg class="icon icon-play">
+                  <use xlinkHref="#icon-play"></use>
+                </svg>
+              </button>
+            )}
+          </>
+        )}
+      </div>
+    );
+  }
+
   handleLoginSubmit(i: Login, event: any) {
     event.preventDefault();
     i.state.loginLoading = true;
@@ -335,11 +374,8 @@ export class Login extends Component<any, State> {
     event.preventDefault();
     i.state.registerLoading = true;
     i.setState(i.state);
-
-    if (!i.mathCheck) {
     WebSocketService.Instance.register(i.state.registerForm);
   }
-  }
 
   handleRegisterUsernameChange(i: Login, event: any) {
     i.state.registerForm.username = event.target.value;
@@ -369,11 +405,16 @@ export class Login extends Component<any, State> {
     i.setState(i.state);
   }
 
-  handleMathAnswerChange(i: Login, event: any) {
+  handleRegisterCaptchaAnswerChange(i: Login, event: any) {
-    i.state.mathQuestion.answer = event.target.value;
+    i.state.registerForm.captcha_answer = event.target.value;
     i.setState(i.state);
   }
 
+  handleRegenCaptcha(_i: Login, _event: any) {
+    event.preventDefault();
+    WebSocketService.Instance.getCaptcha();
+  }
+
   handlePasswordReset(i: Login) {
     event.preventDefault();
     let resetForm: PasswordResetForm = {
@@ -382,11 +423,21 @@ export class Login extends Component<any, State> {
     WebSocketService.Instance.passwordReset(resetForm);
   }
 
-  get mathCheck(): boolean {
+  handleCaptchaPlay(i: Login) {
-    return (
+    event.preventDefault();
-      this.state.mathQuestion.answer !=
+    let snd = new Audio('data:audio/wav;base64,' + i.state.captcha.ok.wav);
-      this.state.mathQuestion.a + this.state.mathQuestion.b
+    snd.play();
-    );
+    i.state.captchaPlaying = true;
+    i.setState(i.state);
+    snd.addEventListener('ended', () => {
+      snd.currentTime = 0;
+      i.state.captchaPlaying = false;
+      i.setState(this.state);
+    });
+  }
+
+  captchaPngSrc() {
+    return `data:image/png;base64,${this.state.captcha.ok.png}`;
   }
 
   parseMessage(msg: WebSocketJsonResponse) {
@@ -394,6 +445,9 @@ export class Login extends Component<any, State> {
     if (msg.error) {
       toast(i18n.t(msg.error), 'danger');
       this.state = this.emptyState;
+      this.state.registerForm.captcha_answer = undefined;
+      // Refetch another captcha
+      WebSocketService.Instance.getCaptcha();
       this.setState(this.state);
       return;
     } else {
@@ -412,6 +466,13 @@ export class Login extends Component<any, State> {
         UserService.Instance.login(data);
         WebSocketService.Instance.userJoin();
         this.props.history.push('/communities');
+      } else if (res.op == UserOperation.GetCaptcha) {
+        let data = res.data as GetCaptchaResponse;
+        if (data.ok) {
+          this.state.captcha = data;
+          this.state.registerForm.captcha_uuid = data.ok.uuid;
+          this.setState(this.state);
+        }
       } else if (res.op == UserOperation.PasswordReset) {
         toast(i18n.t('reset_password_mail_sent'));
       } else if (res.op == UserOperation.GetSite) {

ui/src/components/setup.tsx

@@ -29,6 +29,9 @@ export class Setup extends Component<any, State> {
       password_verify: undefined,
       admin: true,
       show_nsfw: true,
+      // The first admin signup doesn't need a captcha
+      captcha_uuid: '',
+      captcha_answer: '',
     },
     doneRegisteringUser: false,
     userLoading: false,

ui/src/interfaces.ts

@@ -1,6 +1,7 @@
 export enum UserOperation {
   Login,
   Register,
+  GetCaptcha,
   CreateCommunity,
   CreatePost,
   ListCommunities,
@@ -572,6 +573,16 @@ export interface RegisterForm {
   password_verify: string;
   admin: boolean;
   show_nsfw: boolean;
+  captcha_uuid?: string;
+  captcha_answer?: string;
+}
+
+export interface GetCaptchaResponse {
+  ok?: {
+    png: string;
+    wav?: string;
+    uuid: string;
+  };
 }
 
 export interface LoginResponse {
@@ -1010,6 +1021,7 @@ type ResponseType =
   | CommentResponse
   | UserMentionResponse
   | LoginResponse
+  | GetCaptchaResponse
   | GetModlogResponse
   | SearchResponse
   | BanFromCommunityResponse

ui/src/services/WebSocketService.ts

@@ -115,6 +115,10 @@ export class WebSocketService {
     this.ws.send(this.wsSendWrapper(UserOperation.Register, registerForm));
   }
 
+  public getCaptcha() {
+    this.ws.send(this.wsSendWrapper(UserOperation.GetCaptcha, {}));
+  }
+
   public createCommunity(form: CommunityForm) {
     this.setAuth(form);
     this.ws.send(this.wsSendWrapper(UserOperation.CreateCommunity, form));

ui/translations/en.json

@@ -264,6 +264,8 @@
     "password_incorrect": "Password incorrect.",
     "passwords_dont_match": "Passwords do not match.",
     "no_password_reset": "You will not be able to reset your password without an email.",
+    "captcha_incorrect": "Captcha incorrect.",
+    "enter_code": "Enter Code",
     "invalid_username": "Invalid username.",
     "admin_already_created": "Sorry, there's already an admin.",
     "user_already_exists": "User already exists.",
@@ -281,5 +283,6 @@
     "cake_day_title": "Cake day:",
     "cake_day_info": "It's {{ creator_name }}'s cake day today!",
     "invalid_post_title": "Invalid post title",
-    "invalid_url": "Invalid URL."
+    "invalid_url": "Invalid URL.",
+    "play_captcha_audio": "Play Captcha Audio"
 }