From: Tzu-Chiao Yeh <su3g4284zo6y7@gmail.com>
Date: Wed, 2 Sep 2020 02:53:39 +0000 (+0800)
Subject: net/http/fcgi: fix race in child.serve connection read
X-Git-Tag: go1.16beta1~1141
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=7432bee7b372efbbd09b16c4e3176b69fbb6878a;p=gostls13.git

net/http/fcgi: fix race in child.serve connection read

Guards the connection read with a mutex, because typeStdin
asynchronously and concurrently writes to the underlying conn.

Fixes #41167

Change-Id: Ia2610f4fde0bd4b108c54164095ea293980b0301
Reviewed-on: https://go-review.googlesource.com/c/go/+/252417
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
---

diff --git a/src/net/http/fcgi/child.go b/src/net/http/fcgi/child.go
index 30a6b2ce2d..0e91042543 100644
--- a/src/net/http/fcgi/child.go
+++ b/src/net/http/fcgi/child.go
@@ -155,9 +155,12 @@ func (c *child) serve() {
 	defer c.cleanUp()
 	var rec record
 	for {
+		c.conn.mutex.Lock()
 		if err := rec.read(c.conn.rwc); err != nil {
+			c.conn.mutex.Unlock()
 			return
 		}
+		c.conn.mutex.Unlock()
 		if err := c.handleRecord(&rec); err != nil {
 			return
 		}