add error codes & messages to the library

1 files changed, 59 insertions, 17 deletions

diff --git a/src/buffer.c b/src/buffer.c
index b4896f7..71ebad2 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -13,20 +13,40 @@
 
 static unsigned char FULL_BLOCK_PADDING[16] = { 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16 };
 
-size_t aesni_encrypt_buffer_ecb128(
+int aesni_encrypt_buffer_ecb128(
     const void* src,
     size_t src_size,
     void* dest,
-    AesNI_KeySchedule128* key_schedule)
+    size_t* dest_size,
+    AesNI_KeySchedule128* key_schedule,
+    AesNI_ErrorDetails* err_details)
 {
-    size_t rem_size = src_size % 16;
-    size_t padding_size = 16 - rem_size;
-    size_t dest_size = src_size + padding_size;
+    if (dest_size == NULL)
+    {
+        aesni_make_error_null_argument(err_details, "dest_size");
+        return 1;
+    }
+
+    const size_t rem_size = src_size % 16;
+    const size_t padding_size = 16 - rem_size;
+    *dest_size = src_size + padding_size;
 
     if (dest == NULL)
-        return dest_size;
+        return 0;
 
-    size_t src_len = src_size / 16;
+    if (src == NULL)
+    {
+        aesni_make_error_null_argument(err_details, "src");
+        return 1;
+    }
+
+    if (key_schedule == NULL)
+    {
+        aesni_make_error_null_argument(err_details, "key_schedule");
+        return 1;
+    }
+
+    const size_t src_len = src_size / 16;
 
     for (size_t i = 0; i < src_len; ++i, (char*) src += 16, (char*) dest += 16)
     {
@@ -51,10 +71,10 @@ size_t aesni_encrypt_buffer_ecb128(
     AesNI_Block128 ciphertext = aesni_encrypt_block_ecb128(plaintext, key_schedule);
     aesni_store_block128(dest, ciphertext);
 
-    return dest_size;
+    return 0;
 }
 
-static unsigned char get_padding_size(const unsigned char* padding)
+static unsigned char get_pkcs7_padding_size(const unsigned char* padding)
 {
     if (padding[15] < 0x01 || padding[15] > 0x10)
         return 0;
@@ -66,18 +86,38 @@ static unsigned char get_padding_size(const unsigned char* padding)
     return padding[15];
 }
 
-size_t aesni_decrypt_buffer_ecb128(
+int aesni_decrypt_buffer_ecb128(
     const void* src,
     size_t src_size,
     void* dest,
-    AesNI_KeySchedule128* inverted_schedule)
+    size_t* dest_size,
+    AesNI_KeySchedule128* inverted_schedule,
+    AesNI_ErrorDetails* err_details)
 {
-    size_t dest_size = src_size;
+    if (dest_size == NULL)
+    {
+        aesni_make_error_null_argument(err_details, "dest_size");
+        return 1;
+    }
+
+    *dest_size = src_size;
 
     if (dest == NULL)
-        return dest_size;
+        return 0;
+
+    if (src == NULL)
+    {
+        aesni_make_error_null_argument(err_details, "src");
+        return 1;
+    }
 
-    size_t src_len = src_size / 16;
+    if (inverted_schedule == NULL)
+    {
+        aesni_make_error_null_argument(err_details, "inverted_schedule");
+        return 1;
+    }
+
+    const size_t src_len = src_size / 16;
 
     for (size_t i = 0; i < src_len - 1; ++i, (char*) src += 16, (char*) dest += 16)
     {
@@ -91,15 +131,17 @@ size_t aesni_decrypt_buffer_ecb128(
     unsigned char padding[16];
     aesni_store_block128(padding, plaintext);
 
-    unsigned char padding_size = get_padding_size(padding);
+    unsigned char padding_size = get_pkcs7_padding_size(padding);
 
     if (padding_size == 0)
     {
-        return dest_size - 16;
+        aesni_make_error_invalid_pkcs7_padding(err_details);
+        return 1;
     }
     else
     {
         memcpy(dest, padding, 16 - padding_size);
-        return dest_size - padding_size;
+        *dest_size -= padding_size;
+        return 0;
     }
 }