code review 6456045: syscall: workaround accept() bug on Darwin

syscall: workaround accept() bug on Darwin

Darwin kernels have a bug in accept() where error result from
an internal call is not checked and socket is accepted instead
of ECONNABORTED error. However, such sockets have no sockaddr,
which results in EAFNOSUPPORT error from anyToSockaddr, making
Go http servers running on Mac OS X easily susceptible to
denial of service from simple port scans with nmap.
Fixes issue 3849.

[snaury, 2012-07-26 17:57:20]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://go.googlecode.com/hg/

[adg, 2012-07-26 23:26:27]

LGTM

I'll leave it a couple of days before I submit in case anyone else wants to
weigh in

[mikio, 2012-07-28 12:07:27]

LGTM

http://codereview.appspot.com/6456045/diff/5001/src/pkg/syscall/syscall_bsd.go
File src/pkg/syscall/syscall_bsd.go (right):

http://codereview.appspot.com/6456045/diff/5001/src/pkg/syscall/syscall_bsd.g...
src/pkg/syscall/syscall_bsd.go:306: if len == 0 {
Also you could state that the bug depends on darwin explicitly like:
const darwin := runtime.GO == "darwin"
if darwin && len == 0 {

[adg, 2012-07-29 23:02:43]

*** Submitted as http://code.google.com/p/go/source/detail?r=0eae95b0307a ***

syscall: workaround accept() bug on Darwin

Darwin kernels have a bug in accept() where error result from
an internal call is not checked and socket is accepted instead
of ECONNABORTED error. However, such sockets have no sockaddr,
which results in EAFNOSUPPORT error from anyToSockaddr, making
Go http servers running on Mac OS X easily susceptible to
denial of service from simple port scans with nmap.
Fixes issue 3849.

R=golang-dev, adg, mikioh.mikioh
CC=golang-dev
http://codereview.appspot.com/6456045

Committer: Andrew Gerrand <adg@golang.org>

[rsc, 2012-07-29 23:36:40]

mikioh's comment did not get done. I will send it in as a separate CL.