diff --git a/ChangeLog b/ChangeLog
index c0759b2..95383ab 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -10,7 +10,9 @@
    * Remove some redundant code in bignum.c. Contributed by Alexey Skalozub.
    * Support cmake build where Mbed TLS is a subproject. Fix
      contributed independently by Matthieu Volat and Arne Schwabe.
-
+   * Add a pre-verify callback to ssl.h to receive notification before
+     the X.509 chain building. Contributed by Nick Wilson.
+     
 = mbed TLS 2.8.0 branch released 2018-03-16
 
 Default behavior changes
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index fa5ae2f..131e4ba 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -636,11 +636,11 @@
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
     /** Callback to receive notification before X.509 chain building        */
     mbedtls_ssl_pre_verify_t *f_pre_vrfy;
-    void *p_pre_vrfy;               /*!< context for pre-verify calllback   */
+    void *p_pre_vrfy;               /*!< context for pre-verify callback    */
 
     /** Callback to customize X.509 certificate chain verification          */
     int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *);
-    void *p_vrfy;                   /*!< context for X.509 verify calllback */
+    void *p_vrfy;                   /*!< context for X.509 verify callback  */
 #endif
 
 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
@@ -1104,7 +1104,7 @@
  */
 void mbedtls_ssl_conf_pre_verify( mbedtls_ssl_config *conf,
                          mbedtls_ssl_pre_verify_t *f_pre_vrfy,
-                         void *p_pre_vrfy);
+                         void *p_pre_vrfy );
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
 
 /**
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index c87b370..b2bb964 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -5888,8 +5888,8 @@
                          mbedtls_ssl_pre_verify_t *f_pre_vrfy,
                          void *p_pre_vrfy)
 {
-  conf->f_pre_vrfy = f_pre_vrfy;
-  conf->p_pre_vrfy = p_pre_vrfy;
+    conf->f_pre_vrfy = f_pre_vrfy;
+    conf->p_pre_vrfy = p_pre_vrfy;
 }
 #endif /* MBEDTLS_X509_CRT_PARSE_C */