FiSHLiM: Support for CBC mode + more commands (#2347)

1 files changed, 70 insertions, 0 deletions

diff --git a/plugins/fishlim/utils.c b/plugins/fishlim/utils.c
new file mode 100644
index 00000000..5af87404
--- /dev/null
+++ b/plugins/fishlim/utils.c
@@ -0,0 +1,70 @@
+/*
+
+  Copyright (c) 2020 <bakasura@protonmail.ch>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+  THE SOFTWARE.
+
+*/
+
+#include "utils.h"
+
+/**
+ * Calculate the length of Base64-encoded string
+ *
+ * @param plaintext_len Size of clear text to encode
+ * @return Size of encoded string
+ */
+unsigned long base64_len(size_t plaintext_len) {
+    int length_unpadded = (4 * plaintext_len) / 3;
+    /* Add padding */
+    return length_unpadded % 4 != 0 ? length_unpadded + (4 - length_unpadded % 4) : length_unpadded;
+}
+
+/**
+ * Calculate the length of BlowcryptBase64-encoded string
+ *
+ * @param plaintext_len Size of clear text to encode
+ * @return Size of encoded string
+ */
+unsigned long base64_fish_len(size_t plaintext_len) {
+    int length_unpadded = (12 * plaintext_len) / 8;
+    /* Add padding */
+    return length_unpadded % 12 != 0 ? length_unpadded + (12 - length_unpadded % 12) : length_unpadded;
+}
+
+/**
+ * Calculate the length of fish-encrypted string in CBC mode
+ *
+ * @param plaintext_len  Size of clear text to encode
+ * @return Size of encoded string
+ */
+unsigned long cbc_len(size_t plaintext_len) {
+    /*IV + DATA + Zero Padding */
+    return base64_len(8 + (plaintext_len % 8 != 0 ? plaintext_len + 8 - (plaintext_len % 8) : plaintext_len));
+}
+
+/**
+ * Calculate the length of fish-encrypted string in ECB mode
+ *
+ * @param plaintext_len  Size of clear text to encode
+ * @return Size of encoded string
+ */
+unsigned long ecb_len(size_t plaintext_len) {
+    return base64_fish_len(plaintext_len);
+}
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