Created attachment 716539 [details]
stunnel log

Description of problem:
When running the stunnel as daemon with config read from stdin file descriptor, the first connection always fails. This happens if stunnel is used on either server or client side.

Version-Release number of selected component (if applicable):
stunnel-4.29-2.el6.x86_64

How reproducible:
always

Steps to Reproduce:
1. SERVER="debug = 7
cert = $PWD/server.crt
key = $PWD/server.key
verify = 0
pid = $PWD/server.pid
output = $PWD/server.log
[server]
accept = 10001
connect = 10000
"
2. create server SSL certificate (server.crt) and key (server.key) in current working directory
3. echo foo > file.txt
4. stunnel -fd 0 <<< "$SERVER"
5. python -m SimpleHTTPServer 10000 &
6. curl -k https://localhost:10001/file.txt
7. curl -k https://localhost:10001/file.txt
  
Actual results:
first curl (6.) prints:
---
curl: (35) SSL connect error
---
second curl (7.) prints:
---
localhost.localdomain - - [26/Mar/2013 14:58:23] "GET /file.txt HTTP/1.1" 200 -
foo
---

Expected results:
Both curl runs are successful.

Additional info:
I. stunnel log attached. The timescale is:
2013.03.26 15:06:49 - startup
2013.03.26 15:06:55 - first (failing) curl connection
2013.03.26 15:07:01 - second (working) curl connection
2013.03.26 15:07:06 - exit

II. If the same config is loaded from a file, the first connection works well. This can be achieved by modifying stunnel execution (4.) as follows:
printf "$SERVER" > server.conf; stunnel server.conf

III. This bug appears to be already fixed upstream, as it is no longer an issue in the current upstream version (4.56)