Fix up and clean up base64 & aes code.

core/c/base64.c

@@ -78,37 +78,35 @@ static const unsigned char pr2six[256] =
                 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
         };
 
-size_t Base64decode_len(const char *bufcoded) {
+size_t mpw_base64_decode_max(const char *b64Text) {
 
-    size_t nbytesdecoded;
+    register const uint8_t *bufin;
-    register const unsigned char *bufin;
     register int nprbytes;
 
-    bufin = (const unsigned char *)bufcoded;
+    bufin = (uint8_t *)b64Text;
     while (pr2six[*(bufin++)] <= 63);
 
-    nprbytes = (int)(bufin - (const unsigned char *)bufcoded) - 1;
+    nprbytes = (int)(bufin - (uint8_t *)b64Text) - 1;
-    nbytesdecoded = (size_t)(((nprbytes + 3) / 4) * 3);
+    return (size_t)(((nprbytes + 3) / 4) * 3);
-
-    return nbytesdecoded;
 }
 
-int Base64decode(uint8_t *bufplain, const char *bufcoded) {
+int mpw_base64_decode(uint8_t *plainBuf, size_t plainMax, const char *b64Text) {
 
-    int nbytesdecoded;
+    register const uint8_t *bufin;
-    register const unsigned char *bufin;
+    register uint8_t *bufout;
-    register unsigned char *bufout;
     register int nprbytes;
 
-    bufin = (const unsigned char *)bufcoded;
+    bufin = (uint8_t *)b64Text;
     while (pr2six[*(bufin++)] <= 63);
-    nprbytes = (int)(bufin - (const unsigned char *)bufcoded) - 1;
+    nprbytes = (int)(bufin - (uint8_t *)b64Text) - 1;
-    nbytesdecoded = ((nprbytes + 3) / 4) * 3;
 
-    bufout = bufplain;
+    bufout = plainBuf;
-    bufin = (const unsigned char *)bufcoded;
+    bufin = (uint8_t *)b64Text;
 
     while (nprbytes > 4) {
+        if (bufout + 2 >= plainBuf + plainMax)
+            return -1;
+
         *(bufout++) = (pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
         *(bufout++) = (pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
         *(bufout++) = (pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
@@ -118,54 +116,67 @@ int Base64decode(uint8_t *bufplain, const char *bufcoded) {
 
     /* Note: (nprbytes == 1) would be an error, so just ingore that case */
     if (nprbytes > 1) {
+        if (bufout >= plainBuf + plainMax)
+            return -1;
         *(bufout++) = (pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
     }
     if (nprbytes > 2) {
+        if (bufout >= plainBuf + plainMax)
+            return -1;
         *(bufout++) = (pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
     }
     if (nprbytes > 3) {
+        if (bufout >= plainBuf + plainMax)
+            return -1;
         *(bufout++) = (pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
     }
 
-    nbytesdecoded -= (4 - nprbytes) & 3;
+    return (int)(bufout - plainBuf);
-    return nbytesdecoded;
 }
 
 static const char basis_64[] =
         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 
-size_t Base64encode_len(size_t len) {
+size_t mpw_base64_encode_max(size_t plainSize) {
 
-    return ((len + 2) / 3 * 4);
+    // Every 3 plain bytes yield 4 b64 chars => len = 4 * ceil(plainSize / 3)
+    return 4 /*chars*/ * (plainSize + 3 /*bytes*/ - 1) / 3 /*bytes*/;
 }
 
-int Base64encode(char *encoded, const uint8_t *string, size_t len) {
+int mpw_base64_encode(char *b64Text, size_t b64Max, const uint8_t *plainBuf, size_t plainSize) {
 
     int i;
     char *p;
 
-    p = encoded;
+    p = b64Text;
-    for (i = 0; i < len - 2; i += 3) {
+    for (i = 0; i < plainSize - 2; i += 3) {
-        *p++ = basis_64[(string[i] >> 2) & 0x3F];
+        if (p >= b64Text + b64Max)
-        *p++ = basis_64[((string[i] & 0x3) << 4) |
+            return -1;
-                        ((string[i + 1] & 0xF0) >> 4)];
+
-        *p++ = basis_64[((string[i + 1] & 0xF) << 2) |
+        *p++ = basis_64[(plainBuf[i] >> 2) & 0x3F];
-                        ((string[i + 2] & 0xC0) >> 6)];
+        *p++ = basis_64[((plainBuf[i] & 0x3) << 4) |
-        *p++ = basis_64[string[i + 2] & 0x3F];
+                        ((plainBuf[i + 1] & 0xF0) >> 4)];
+        *p++ = basis_64[((plainBuf[i + 1] & 0xF) << 2) |
+                        ((plainBuf[i + 2] & 0xC0) >> 6)];
+        *p++ = basis_64[plainBuf[i + 2] & 0x3F];
     }
-    if (i < len) {
+    if (i < plainSize) {
-        *p++ = basis_64[(string[i] >> 2) & 0x3F];
+        if (p + 3 >= b64Text + b64Max)
-        if (i == (len - 1)) {
+            return -1;
-            *p++ = basis_64[((string[i] & 0x3) << 4)];
+
+        *p++ = basis_64[(plainBuf[i] >> 2) & 0x3F];
+        if (i == (plainSize - 1)) {
+            *p++ = basis_64[((plainBuf[i] & 0x3) << 4)];
             *p++ = '=';
         }
         else {
-            *p++ = basis_64[((string[i] & 0x3) << 4) |
+            *p++ = basis_64[((plainBuf[i] & 0x3) << 4) |
-                            ((string[i + 1] & 0xF0) >> 4)];
+                            ((plainBuf[i + 1] & 0xF0) >> 4)];
-            *p++ = basis_64[((string[i + 1] & 0xF) << 2)];
+            *p++ = basis_64[((plainBuf[i + 1] & 0xF) << 2)];
         }
         *p++ = '=';
     }
 
-    return (int)(p - encoded);
+    *p = '\0';
+    return (int)(p - b64Text);
 }

core/c/base64.h

@@ -57,8 +57,23 @@
 #include <stddef.h>
 #include <stdint.h>
 
-size_t Base64decode_len(const char *bufcoded);
+/**
-int Base64decode(uint8_t *bufplain, const char *bufcoded);
+ * @return The amount of bytes needed to decode the given b64Text.
+ */
+size_t mpw_base64_decode_max(const char *b64Text);
+/** Decodes a base-64 encoded string into a plain byte buffer.
+  * @param plainMax the maximum amount of bytes to write to plainBuf.
+  * @return The amount of bytes that were written to plainBuf or -1 if this amount would have exceeded plainMax.
+  */
+int mpw_base64_decode(uint8_t *plainBuf, size_t plainMax, const char *b64Text);
 
-size_t Base64encode_len(size_t len);
+/**
-int Base64encode(char *encoded, const uint8_t *string, size_t len);
+ * @return The amount of characters needed to encode a plainBuf of the given size as base-64 (excluding the terminating NUL).
+ */
+size_t mpw_base64_encode_max(size_t plainSize);
+/** Encodes a plain byte buffer into a base-64 encoded string.
+  * @param b64Max the maximum amount of characters to write to b64Text, excluding the terminating NUL.
+  * @return The amount of characters that were written to b64Text, excluding the terminating NUL
+  *         or -1 if this amount would have exceeded b64Max.
+  */
+int mpw_base64_encode(char *b64Text, size_t b64Max, const uint8_t *plainBuf, size_t plainSize);

core/c/mpw-algorithm_v0.c

@@ -157,16 +157,22 @@ const char *mpw_encrypt_v0(
         MPMasterKey masterKey, const char *plainText) {
 
     // Encrypt
-    dbg( "-- encrypting plainText: %s\n", plainText );
     size_t bufSize = strlen( plainText );
     const uint8_t *cipherBuf = mpw_aes_encrypt( masterKey, MPMasterKeySize, (const uint8_t *)plainText, bufSize );
-    dbg( "--   cipherBuf: %lu bytes = ", bufSize );
+    if (!cipherBuf) {
-    printb( cipherBuf, bufSize );
+        err( "AES encryption error: %s\n", strerror( errno ) );
+        return NULL;
+    }
+
 
     // Base64-encode
-    char *cipherText = calloc( 1, Base64encode_len( bufSize ) + 1 );
+    size_t b64Max = mpw_base64_encode_max( bufSize );
-    Base64encode( cipherText, cipherBuf, bufSize );
+    char *cipherText = calloc( 1, b64Max + 1 );
-    dbg( "--   b64 encoded -> cipherText: %s\n", cipherText );
+    if (mpw_base64_encode( cipherText, b64Max, cipherBuf, bufSize ) < 0) {
+        err( "Base64 encoding error." );
+        mpw_free_string( cipherText );
+        cipherText = NULL;
+    }
     mpw_free( cipherBuf, bufSize );
 
     return cipherText;
@@ -176,17 +182,19 @@ const char *mpw_decrypt_v0(
         MPMasterKey masterKey, const char *cipherText) {
 
     // Base64-decode
-    dbg( "-- decrypting cipherText: %s\n", cipherText );
+    size_t bufSize = mpw_base64_decode_max( cipherText );
-    size_t bufSize = Base64decode_len( cipherText ) + 1;
     uint8_t *cipherBuf = calloc( 1, bufSize );
-    Base64decode( cipherBuf, cipherText );
+    if ((bufSize = (size_t)mpw_base64_decode( cipherBuf, bufSize, cipherText )) < 0) {
-    dbg( "--   b64 decoded: %lu bytes = ", bufSize );
+        err( "Base64 decoding error." );
-    printb( cipherBuf, bufSize );
+        mpw_free( cipherBuf, mpw_base64_decode_max( cipherText ) );
+        return NULL;
+    }
 
 
     // Decrypt
     const char *plainText = (const char *)mpw_aes_decrypt( masterKey, MPMasterKeySize, cipherBuf, bufSize );
-    dbg( "--   decrypted -> plainText: %s\n", plainText );
+    if (!plainText)
+        err( "AES decryption error: %s\n", strerror( errno ) );
     mpw_free( cipherBuf, bufSize );
 
     return plainText;

core/c/mpw-util.c

@@ -185,19 +185,22 @@ static uint8_t const *mpw_aes(bool encrypt, const uint8_t *key, const size_t key
     if (!key || keySize < crypto_stream_KEYBYTES)
         return NULL;
 
-    uint8_t cipherKey[crypto_stream_KEYBYTES];
-    memcpy( cipherKey, key, sizeof( cipherKey ) );
-
     uint8_t nonce[crypto_stream_NONCEBYTES];
     bzero( (void *)nonce, sizeof( nonce ) );
 
     if (encrypt) {
         uint8_t *const cipherBuf = malloc( bufSize );
-        crypto_stream_aes128ctr_xor( cipherBuf, buf, bufSize, nonce, cipherKey );
+        if (crypto_stream_aes128ctr_xor( cipherBuf, buf, bufSize, nonce, key ) != 0) {
+            mpw_free( cipherBuf, bufSize );
+            return NULL;
+        }
         return cipherBuf;
     } else {
         uint8_t *const plainBuf = malloc( bufSize );
-        crypto_stream_aes128ctr( plainBuf, bufSize, nonce, cipherKey );
+        if (crypto_stream_aes128ctr( plainBuf, bufSize, nonce, key ) != 0) {
+            mpw_free( plainBuf, bufSize );
+            return NULL;
+        }
         for (size_t c = 0; c < bufSize; ++c)
             plainBuf[c] = buf[c] ^ plainBuf[c];
         return plainBuf;