From 314afb287e00653f682161817972a9809e61789f Mon Sep 17 00:00:00 2001
From: Knut Ahlers <knut@ahlers.me>
Date: Fri, 14 Apr 2023 13:06:14 +0200
Subject: [PATCH] Breaking: Replace deprecated / archived crypto library (#80)

---
 README.md             |  2 +-
 cli_create.sh         | 34 +++++++++++++-------------
 cli_get.sh            | 14 +++++------
 src/app.vue           | 56 ++++++++++++++++++++++++-------------------
 src/crypto.js         | 35 +++++++++++++++++++++++++++
 src/package-lock.json |  6 -----
 src/package.json      |  1 -
 7 files changed, 93 insertions(+), 55 deletions(-)
 create mode 100644 src/crypto.js

diff --git a/README.md b/README.md
index dafbf89..95f11f2 100644
--- a/README.md
+++ b/README.md
@@ -36,7 +36,7 @@ As `ots` is designed to never let the server know the secret you are sharing you
 This is slightly more complex as you first need to encrypt your secret before sending it to the API but in this case you can be sure the server will in no case be able to access the secret. Especially if you are using ots.fyi (my public hosted instance) you should not trust me with your secret but use an encrypted secret:
 
 ```console
-# echo "my password" | openssl aes-256-cbc -base64 -pass pass:mypass -md md5
+# echo "my password" | openssl aes-256-cbc -base64 -pass pass:mypass -iter 300000 -md sha512
 U2FsdGVkX18wJtHr6YpTe8QrvMUUdaLZ+JMBNi1OvOQ=
 
 # curl -X POST -H 'content-type: application/json' -i -s -d '{"secret": "U2FsdGVkX18wJtHr6YpTe8QrvMUUdaLZ+JMBNi1OvOQ="}' https://ots.fyi/api/create
diff --git a/cli_create.sh b/cli_create.sh
index 4529c8e..69f9bce 100644
--- a/cli_create.sh
+++ b/cli_create.sh
@@ -1,36 +1,38 @@
 #!/bin/bash
 set -euo pipefail
 
+: ${INSTANCE:=https://ots.fyi} # Where to reach the API of the instance (omit trailing slash)
+
 deps=(curl jq)
 for cmd in "${deps[@]}"; do
-	which ${cmd} >/dev/null || {
-		echo "'${cmd}' util is required for this script"
-		exit 1
-	}
+  which ${cmd} >/dev/null || {
+    echo "'${cmd}' util is required for this script"
+    exit 1
+  }
 done
 
 # Get secret from CLI argument
 SECRET=${1:-}
 [[ -n $SECRET ]] || {
-	echo "Usage: $0 'secret to share'"
-	exit 1
+  echo "Usage: $0 'secret to share'"
+  exit 1
 }
 
-# Generate a random 8 character password
-pass=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | head -c 8 || true)
+# Generate a random 20 character password
+pass=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | head -c 20 || true)
 
 # Encrypt the secret
-ciphertext=$(echo "${SECRET}" | openssl aes-256-cbc -base64 -pass "pass:${pass}" -md md5 2>/dev/null)
+ciphertext=$(echo "${SECRET}" | openssl aes-256-cbc -base64 -pass "pass:${pass}" -iter 300000 -md sha512 2>/dev/null)
 
 # Create a secret and extract the secret ID
 id=$(
-	curl -sSf \
-		-X POST \
-		-H 'content-type: application/json' \
-		-d "$(jq --arg secret "${ciphertext}" -cn '{"secret": $secret}')" \
-		https://ots.fyi/api/create |
-		jq -r '.secret_id'
+  curl -sSf \
+    -X POST \
+    -H 'content-type: application/json' \
+    -d "$(jq --arg secret "${ciphertext}" -cn '{"secret": $secret}')" \
+    "${INSTANCE}/api/create" |
+    jq -r '.secret_id'
 )
 
 # Display URL to user
-echo -e "Secret is now available at:\nhttps://ots.fyi/#${id}%7C${pass}"
+echo -e "Secret is now available at:\n${INSTANCE}/#${id}%7C${pass}"
diff --git a/cli_get.sh b/cli_get.sh
index 137fa93..03ce712 100644
--- a/cli_get.sh
+++ b/cli_get.sh
@@ -3,17 +3,17 @@ set -euo pipefail
 
 deps=(curl jq)
 for cmd in "${deps[@]}"; do
-	which ${cmd} >/dev/null || {
-		echo "'${cmd}' util is required for this script"
-		exit 1
-	}
+  which ${cmd} >/dev/null || {
+    echo "'${cmd}' util is required for this script"
+    exit 1
+  }
 done
 
 # Get URL from CLI argument
 url="${1:-}"
 [[ -n $url ]] || {
-	echo "Usage: $0 'URL to get the secret'"
-	exit 1
+  echo "Usage: $0 'URL to get the secret'"
+  exit 1
 }
 # normalize url and extract parts
 url="${url/|/%7C}"
@@ -25,4 +25,4 @@ geturl="${host}/api/get/${id}"
 
 # fetch secret and decrypt to STDOUT
 curl -sSf "${geturl}" | jq -r ".secret" |
-	openssl aes-256-cbc -base64 -pass "pass:${pass}" -md md5 -d 2>/dev/null
+  openssl aes-256-cbc -base64 -pass "pass:${pass}" -iter 300000 -md sha512 -d 2>/dev/null
diff --git a/src/app.vue b/src/app.vue
index eecb07c..e78037b 100644
--- a/src/app.vue
+++ b/src/app.vue
@@ -166,7 +166,7 @@
 
 <script>
 import axios from 'axios'
-import AES from 'gibberish-aes/src/gibberish-aes'
+import crypto from './crypto.js'
 
 const passwordCharset = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
 const passwordLength = 20
@@ -218,27 +218,26 @@ export default {
       this.securePassword = [...window.crypto.getRandomValues(new Uint8Array(passwordLength))]
         .map(n => passwordCharset[n % passwordCharset.length])
         .join('')
-      const secret = AES.enc(this.secret, this.securePassword)
+      crypto.enc(this.secret, this.securePassword)
+        .then(secret => axios.post('api/create', { secret })
+          .then(resp => {
+            this.secretId = resp.data.secret_id
+            this.secret = ''
 
-      axios.post('api/create', { secret })
-        .then(resp => {
-          this.secretId = resp.data.secret_id
-          this.secret = ''
-
-          // Give the interface a moment to transistion and focus
-          window.setTimeout(() => this.$refs.secretUrl.focus(), 100)
-        })
-        .catch(err => {
-          switch (err.response.status) {
-          case 404:
+            // Give the interface a moment to transistion and focus
+            window.setTimeout(() => this.$refs.secretUrl.focus(), 100)
+          })
+          .catch(err => {
+            switch (err.response.status) {
+            case 404:
             // Mock for interface testing
-            this.secretId = 'foobar'
-            break
-          default:
-            this.error = this.$t('alert-something-went-wrong')
-            this.showError = true
-          }
-        })
+              this.secretId = 'foobar'
+              break
+            default:
+              this.error = this.$t('alert-something-went-wrong')
+              this.showError = true
+            }
+          }))
 
       return false
     },
@@ -267,11 +266,20 @@ export default {
     requestSecret() {
       axios.get(`api/get/${this.secretId}`)
         .then(resp => {
-          let secret = resp.data.secret
-          if (this.securePassword) {
-            secret = AES.dec(secret, this.securePassword)
+          const secret = resp.data.secret
+          if (!this.securePassword) {
+            this.secret = secret
+            return
           }
-          this.secret = secret
+
+          crypto.dec(secret, this.securePassword)
+            .then(secret => {
+              this.secret = secret
+            })
+            .catch(() => {
+              this.error = this.$t('alert-something-went-wrong')
+              this.showError = true
+            })
         })
         .catch(err => {
           switch (err.response.status) {
diff --git a/src/crypto.js b/src/crypto.js
new file mode 100644
index 0000000..b68b4c6
--- /dev/null
+++ b/src/crypto.js
@@ -0,0 +1,35 @@
+const opensslBanner = new Uint8Array(new TextEncoder('utf8').encode('Salted__'))
+const pbkdf2Params = { hash: 'SHA-512', iterations: 300000, name: 'PBKDF2' }
+
+function decrypt(passphrase, encData) {
+  const data = new Uint8Array(atob(encData).split('')
+    .map(c => c.charCodeAt(0)))
+
+  return deriveKey(passphrase, data.slice(8, 16))
+    .then(({ iv, key }) => window.crypto.subtle.decrypt({ iv, name: 'AES-CBC' }, key, data.slice(16)))
+    .then(data => new TextDecoder('utf8').decode(data))
+}
+
+function deriveKey(passphrase, salt) {
+  return window.crypto.subtle.importKey('raw', new TextEncoder('utf8').encode(passphrase), 'PBKDF2', false, ['deriveBits'])
+    .then(passwordKey => window.crypto.subtle.deriveBits({ ...pbkdf2Params, salt }, passwordKey, 384))
+    .then(key => window.crypto.subtle.importKey('raw', key.slice(0, 32), { name: 'AES-CBC' }, false, ['encrypt', 'decrypt'])
+      .then(aesKey => ({ iv: key.slice(32, 48), key: aesKey })))
+}
+
+function encrypt(passphrase, salt, plainData) {
+  return deriveKey(passphrase, salt)
+    .then(({ iv, key }) => window.crypto.subtle.encrypt({ iv, name: 'AES-CBC' }, key, new TextEncoder('utf8').encode(plainData)))
+    .then(encData => new Uint8Array([...opensslBanner, ...salt, ...new Uint8Array(encData)]))
+    .then(data => btoa(String.fromCharCode.apply(null, data)))
+}
+
+function generateSalt() {
+  const salt = new Uint8Array(8) // Salt MUST consist of 8 byte
+  return window.crypto.getRandomValues(salt)
+}
+
+export default {
+  dec: (cipherText, passphrase) => decrypt(passphrase, cipherText),
+  enc: (plainText, passphrase) => encrypt(passphrase, generateSalt(), plainText),
+}
diff --git a/src/package-lock.json b/src/package-lock.json
index 76a888b..840b3b1 100644
--- a/src/package-lock.json
+++ b/src/package-lock.json
@@ -10,7 +10,6 @@
         "bootstrap": "^4.6.0",
         "bootstrap-vue": "^2.21.2",
         "bootswatch": "^4.6.0",
-        "gibberish-aes": "^1.0.0",
         "popper.js": "^1.16.1",
         "vue": "^2.6.14",
         "vue-i18n": "^8.25.0"
@@ -3907,11 +3906,6 @@
         "assert-plus": "^1.0.0"
       }
     },
-    "node_modules/gibberish-aes": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/gibberish-aes/-/gibberish-aes-1.0.0.tgz",
-      "integrity": "sha1-9kHEWPuCLgrWHDwN6hWOC5Q+n8U="
-    },
     "node_modules/glob": {
       "version": "7.1.7",
       "resolved": "https://registry.npmjs.org/glob/-/glob-7.1.7.tgz",
diff --git a/src/package.json b/src/package.json
index 5c7c7a7..662e316 100644
--- a/src/package.json
+++ b/src/package.json
@@ -27,7 +27,6 @@
     "bootstrap": "^4.6.0",
     "bootstrap-vue": "^2.21.2",
     "bootswatch": "^4.6.0",
-    "gibberish-aes": "^1.0.0",
     "popper.js": "^1.16.1",
     "vue": "^2.6.14",
     "vue-i18n": "^8.25.0"