diff --git a/src/curl.cpp b/src/curl.cpp
index faf1358..c247bcf 100644
--- a/src/curl.cpp
+++ b/src/curl.cpp
@@ -2595,7 +2595,7 @@ void S3fsCurl::insertV4Headers()
             break;
     }
 
-    if(0 == payload_hash.length()){
+    if(b_infile != NULL && 0 == payload_hash.length()){
         S3FS_PRN_ERR("Failed to make SHA256.");
         // TODO: propagate error
     }
diff --git a/src/openssl_auth.cpp b/src/openssl_auth.cpp
index 7d4a937..5402d58 100644
--- a/src/openssl_auth.cpp
+++ b/src/openssl_auth.cpp
@@ -321,9 +321,13 @@ unsigned char* s3fs_sha256_fd(int fd, off_t start, off_t size)
     off_t          bytes;
     unsigned char* result;
 
+    if(-1 == fd){
+        return NULL;
+    }
     if(-1 == size){
         struct stat st;
         if(-1 == fstat(fd, &st)){
+            S3FS_PRN_ERR("fstat error(%d)", errno);
             return NULL;
         }
         size = st.st_size;