From 9fc284427c96cc2e89c51f79080f16c44a10594d Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Mon, 26 Apr 2021 11:11:59 +0200
Subject: [PATCH] wolfssl: handle SSL_write() returns 0 for error

Reported-by: Timo Lange

Closes #6967
---
 lib/vtls/wolfssl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/vtls/wolfssl.c b/lib/vtls/wolfssl.c
index a0afe7418..a16612015 100644
--- a/lib/vtls/wolfssl.c
+++ b/lib/vtls/wolfssl.c
@@ -786,7 +786,7 @@ static ssize_t wolfssl_send(struct Curl_easy *data,
   int memlen = (len > (size_t)INT_MAX) ? INT_MAX : (int)len;
   int rc = SSL_write(backend->handle, mem, memlen);
 
-  if(rc < 0) {
+  if(rc <= 0) {
     int err = SSL_get_error(backend->handle, rc);
 
     switch(err) {