add getter for max output size

src/internal.c

@@ -11138,6 +11138,9 @@ const char* wolfSSL_ERR_reason_error_string(unsigned long e)
     case DTLS_EXPORT_VER_E:
         return "Version needs updated after code change or version mismatch";
 
+    case INPUT_SIZE_E:
+        return "Input size too large Error";
+
     default :
         return "unknown error number";
     }

src/ssl.c

@@ -619,16 +619,20 @@ int wolfSSL_GetObjectSize(void)
 #endif
 
 
-/* return record layer size of plaintext input size */
-int wolfSSL_GetOutputSize(WOLFSSL* ssl, int inSz)
+/* return max record layer size plaintext input size */
+int wolfSSL_GetMaxOutputSize(WOLFSSL* ssl)
 {
     int maxSize = OUTPUT_RECORD_SIZE;
 
-    if (ssl == NULL || inSz < 0)
+    WOLFSSL_ENTER("wolfSSL_GetMaxOutputSize");
+
+    if (ssl == NULL)
         return BAD_FUNC_ARG;
 
-    if (ssl->options.handShakeState != HANDSHAKE_DONE)
+    if (ssl->options.handShakeState != HANDSHAKE_DONE) {
+        WOLFSSL_MSG("Handshake not complete yet");
         return BAD_FUNC_ARG;
+    }
 
 #ifdef HAVE_MAX_FRAGMENT
     maxSize = min(maxSize, ssl->max_fragment);
@@ -640,9 +644,26 @@ int wolfSSL_GetOutputSize(WOLFSSL* ssl, int inSz)
     }
 #endif
 
-    if (inSz > maxSize)
+    return maxSize;
+}
+
+
+/* return record layer size of plaintext input size */
+int wolfSSL_GetOutputSize(WOLFSSL* ssl, int inSz)
+{
+    int maxSize;
+
+    WOLFSSL_ENTER("wolfSSL_GetOutputSize");
+
+    if (inSz < 0)
         return BAD_FUNC_ARG;
 
+    maxSize = wolfSSL_GetMaxOutputSize(ssl);
+    if (maxSize < 0)
+        return maxSize;   /* error */
+    if (inSz > maxSize)
+        return INPUT_SIZE_E;
+
     return BuildMessage(ssl, NULL, 0, NULL, inSz, application_data, 0, 1);
 }
 

wolfssl/error-ssl.h

@@ -148,6 +148,7 @@ enum wolfSSL_ErrorCodes {
     ECC_KEY_SIZE_E               = -410,   /* ECC key too small */
 
     DTLS_EXPORT_VER_E            = -411,   /* export version error */
+    INPUT_SIZE_E                 = -412,   /* input size too big error */
     /* add strings to wolfSSL_ERR_reason_error_string in internal.c !!!!! */
 
     /* begin negotiation parameter errors */

wolfssl/ssl.h

@@ -1143,6 +1143,7 @@ WOLFSSL_API int wolfSSL_CTX_SetMinVersion(WOLFSSL_CTX* ctx, int version);
 WOLFSSL_API int wolfSSL_SetMinVersion(WOLFSSL* ssl, int version);
 WOLFSSL_API int wolfSSL_GetObjectSize(void);  /* object size based on build */
 WOLFSSL_API int wolfSSL_GetOutputSize(WOLFSSL*, int);
+WOLFSSL_API int wolfSSL_GetMaxOutputSize(WOLFSSL*);
 WOLFSSL_API int wolfSSL_SetVersion(WOLFSSL* ssl, int version);
 WOLFSSL_API int wolfSSL_KeyPemToDer(const unsigned char*, int,
                                     unsigned char*, int, const char*);