From 7605b2ab5ea2cdd619fafbe5eea981f689865676 Mon Sep 17 00:00:00 2001
From: flu0r1ne <flu0r1ne@flu0r1ne.net>
Date: Sun, 27 Aug 2023 04:17:54 -0500
Subject: Encode key in base32 to exclude the Unix path sep

---
 src/crypto/curve25519.c |  4 +++-
 src/crypto/pubkey.c     | 50 +++++++++++++++++++++++++++++++++++++++++++++++--
 src/crypto/pubkey.hpp   |  7 +++++--
 3 files changed, 56 insertions(+), 5 deletions(-)

(limited to 'src/crypto')

diff --git a/src/crypto/curve25519.c b/src/crypto/curve25519.c
index 7121d1e..2f6f5d6 100644
--- a/src/crypto/curve25519.c
+++ b/src/crypto/curve25519.c
@@ -79,7 +79,9 @@ static noinline void memzero_explicit(void *s, size_t count)
 	asm volatile("": :"r"(s) : "memory");
 }
 
-#ifdef __SIZEOF_INT128__
+#ifdef __EMSCRIPTEN__
+#include "curve25519-fiat32.h"
+#elif __SIZEOF_INT128__
 #include "curve25519-hacl64.h"
 #else
 #include "curve25519-fiat32.h"
diff --git a/src/crypto/pubkey.c b/src/crypto/pubkey.c
index 1224b07..f43dbfc 100644
--- a/src/crypto/pubkey.c
+++ b/src/crypto/pubkey.c
@@ -1,9 +1,43 @@
 #include "curve25519.h"
 #include "encoding.h"
 
-int wg_pubkey_base64(char const * privkey, char * base64) {
+#define WG_KEY_LEN_BASE32 (((WG_KEY_LEN + 4) / 5) * 8 + 1)
+#define WG_KEY_LEN_BASE64 ((((WG_KEY_LEN) + 2) / 3) * 4 + 1)
+
+static inline void encode_base32(char dest[static 8], const uint8_t src[static 5]) {
+	const uint8_t input[] = {
+		  src[0] >> 3,
+		((src[0] & 0x07) << 2) | (src[1] >> 6),
+		 (src[1] & 0x3F) >> 1,
+		((src[1] & 0x01) << 4) | (src[2] >> 4),
+		((src[2] & 0x0F) << 1) | (src[3] >> 7),
+		 (src[3] & 0x7F) >> 2,
+		((src[3] & 0x03) << 3) | (src[4] >> 5),
+		  src[4] & 0x1F
+	};
+
+	for(unsigned int i = 0; i < 8; i++)
+		dest[i] = 'A' + input[i] - (((25 - input[i]) >> 8) & 41);
+}
+
+void key_to_base32(char base32[static WG_KEY_LEN_BASE32], const uint8_t key[static WG_KEY_LEN])
+{
+	unsigned int i;
+
+	for (i = 0; i < WG_KEY_LEN / 5; ++i)
+		encode_base32(&base32[i * 8], &key[i * 5]);
+	encode_base32(&base32[i * 8], (const uint8_t[]){ key[i * 5 + 0], key[i * 5 + 1], 0, 0, 0 });
+	base32[WG_KEY_LEN_BASE32 - 5] = '=';
+	base32[WG_KEY_LEN_BASE32 - 4] = '=';
+	base32[WG_KEY_LEN_BASE32 - 3] = '=';
+	base32[WG_KEY_LEN_BASE32 - 2] = '=';
+	base32[WG_KEY_LEN_BASE32 - 1] = '\0';
+}
+
+int wg_pubkey_base32(char const * privkey, char * base32) {
 
 	uint8_t key[WG_KEY_LEN] __attribute((aligned(sizeof(uintptr_t))));
+	char base64[WG_KEY_LEN_BASE64];
 
 	int i;
 	for(i = 0; privkey[i] && i < WG_KEY_LEN_BASE64 - 1; i++)
@@ -21,7 +55,19 @@ int wg_pubkey_base64(char const * privkey, char * base64) {
 
 	curve25519_generate_public(key, key);
 
-	key_to_base64(base64, key);
+	key_to_base32(base32, key);
+
+	return 0;
+}
+
+int wg_key_convert_base32(char const * base64, char * base32) {
+	uint8_t key[WG_KEY_LEN] __attribute((aligned(sizeof(uintptr_t))));
+
+	if(!key_from_base64(key, base64)) {
+		return 1;
+	}
+
+	key_to_base32(base32, key);
 
 	return 0;
 }
diff --git a/src/crypto/pubkey.hpp b/src/crypto/pubkey.hpp
index 8596431..cb1f794 100644
--- a/src/crypto/pubkey.hpp
+++ b/src/crypto/pubkey.hpp
@@ -5,18 +5,21 @@ extern "C" {
 #endif
 
 #define WG_KEY_LEN_BASE64 ((((WG_KEY_LEN) + 2) / 3) * 4 + 1)
+#define WG_KEY_LEN_BASE32 (((WG_KEY_LEN + 4) / 5) * 8 + 1)
 
 /*
  * wg_pubkey_base64 is a C++-compatible wrapper for the curve25519 public-key
  * derivation routines used natively in `wg(8)`
  *
  * PRIVKEY: a c-style string containing the base64-encoded private key
- * BASE64:  a c-style string of capacity WG_KEY_LEN_BASE64 containing the
+ * BASE32:  a c-style string of capacity WG_KEY_LEN_BASE64 containing the
  * encoded public key
  *
  * returns: 0 on success
  *          > 0 when an error occurs (due to improper key formatting)
  */
-int wg_pubkey_base64(char const * privkey, char * base64);
+int wg_pubkey_base32(char const * privkey, char * base32);
+
+int wg_key_convert_base32(char const * base64, char * base32);
 
 }
-- 
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