diff --git a/library/memory_buffer_alloc.c b/library/memory_buffer_alloc.c
index 0d3342d..1cfc27c 100644
--- a/library/memory_buffer_alloc.c
+++ b/library/memory_buffer_alloc.c
@@ -184,7 +184,7 @@
 {
     memory_header *prv = heap.first, *cur;
 
-    if( heap.first == NULL || verify_header( heap.first ) != 0 )
+    if( prv == NULL || verify_header( prv ) != 0 )
     {
 #if defined(MBEDTLS_MEMORY_DEBUG)
         mbedtls_fprintf( stderr, "FATAL: verification of first header "
diff --git a/library/pem.c b/library/pem.c
index d726bd6..7b3ae8d 100644
--- a/library/pem.c
+++ b/library/pem.c
@@ -435,7 +435,8 @@
         return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
     }
 
-    if( use_len != 0 && ( encode_buf = mbedtls_calloc( 1, use_len ) ) == NULL )
+    if( use_len != 0 &&
+        ( ( encode_buf = mbedtls_calloc( 1, use_len ) ) == NULL ) )
         return( MBEDTLS_ERR_PEM_ALLOC_FAILED );
 
     if( ( ret = mbedtls_base64_encode( encode_buf, use_len, &use_len, der_data,
diff --git a/library/x509_crl.c b/library/x509_crl.c
index c302bb2..8f98d8c 100644
--- a/library/x509_crl.c
+++ b/library/x509_crl.c
@@ -257,7 +257,7 @@
 {
     int ret;
     size_t len;
-    unsigned char *p = NULL, *end;
+    unsigned char *p = NULL, *end = NULL;
     mbedtls_x509_buf sig_params1, sig_params2, sig_oid2;
     mbedtls_x509_crl *crl = chain;
 
@@ -294,7 +294,7 @@
     /*
      * Copy raw DER-encoded CRL
      */
-    if( buflen != 0 && ( p = mbedtls_calloc( 1, buflen ) ) == NULL )
+    if( buflen != 0 && ( ( p = mbedtls_calloc( 1, buflen ) ) == NULL ) )
         return( MBEDTLS_ERR_X509_ALLOC_FAILED );
 
     memcpy( p, buf, buflen );