From 1d1b2b1509646e07ab4a984c7622fa002a0fcdb7 Mon Sep 17 00:00:00 2001
From: Daniel J Walsh <dwalsh@redhat.com>
Date: Thu, 3 Feb 2022 18:33:22 -0500
Subject: Update containers/buildah v1.24.1

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>
---
 .../docker/go-connections/sockets/unix_socket.go   | 116 +++++++++++++++++++--
 1 file changed, 105 insertions(+), 11 deletions(-)

(limited to 'vendor/github.com/docker/go-connections/sockets/unix_socket.go')

diff --git a/vendor/github.com/docker/go-connections/sockets/unix_socket.go b/vendor/github.com/docker/go-connections/sockets/unix_socket.go
index a8b5dbb6f..e7591e6ed 100644
--- a/vendor/github.com/docker/go-connections/sockets/unix_socket.go
+++ b/vendor/github.com/docker/go-connections/sockets/unix_socket.go
@@ -1,5 +1,51 @@
 // +build !windows
 
+/*
+Package sockets is a simple unix domain socket wrapper.
+
+Usage
+
+For example:
+
+	import(
+		"fmt"
+		"net"
+		"os"
+		"github.com/docker/go-connections/sockets"
+	)
+
+	func main() {
+		l, err := sockets.NewUnixSocketWithOpts("/path/to/sockets",
+			sockets.WithChown(0,0),sockets.WithChmod(0660))
+		if err != nil {
+			panic(err)
+		}
+		echoStr := "hello"
+
+		go func() {
+			for {
+				conn, err := l.Accept()
+				if err != nil {
+					return
+				}
+				conn.Write([]byte(echoStr))
+				conn.Close()
+			}
+		}()
+
+		conn, err := net.Dial("unix", path)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		buf := make([]byte, 5)
+		if _, err := conn.Read(buf); err != nil {
+			panic(err)
+		} else if string(buf) != echoStr {
+			panic(fmt.Errorf("Msg may lost"))
+		}
+	}
+*/
 package sockets
 
 import (
@@ -8,25 +54,73 @@ import (
 	"syscall"
 )
 
-// NewUnixSocket creates a unix socket with the specified path and group.
-func NewUnixSocket(path string, gid int) (net.Listener, error) {
+// SockOption sets up socket file's creating option
+type SockOption func(string) error
+
+// WithChown modifies the socket file's uid and gid
+func WithChown(uid, gid int) SockOption {
+	return func(path string) error {
+		if err := os.Chown(path, uid, gid); err != nil {
+			return err
+		}
+		return nil
+	}
+}
+
+// WithChmod modifies socket file's access mode.
+func WithChmod(mask os.FileMode) SockOption {
+	return func(path string) error {
+		if err := os.Chmod(path, mask); err != nil {
+			return err
+		}
+		return nil
+	}
+}
+
+// NewUnixSocketWithOpts creates a unix socket with the specified options.
+// By default, socket permissions are 0000 (i.e.: no access for anyone); pass
+// WithChmod() and WithChown() to set the desired ownership and permissions.
+//
+// This function temporarily changes the system's "umask" to 0777 to work around
+// a race condition between creating the socket and setting its permissions. While
+// this should only be for a short duration, it may affect other processes that
+// create files/directories during that period.
+func NewUnixSocketWithOpts(path string, opts ...SockOption) (net.Listener, error) {
 	if err := syscall.Unlink(path); err != nil && !os.IsNotExist(err) {
 		return nil, err
 	}
-	mask := syscall.Umask(0777)
-	defer syscall.Umask(mask)
 
+	// net.Listen does not allow for permissions to be set. As a result, when
+	// specifying custom permissions ("WithChmod()"), there is a short time
+	// between creating the socket and applying the permissions, during which
+	// the socket permissions are Less restrictive than desired.
+	//
+	// To work around this limitation of net.Listen(), we temporarily set the
+	// umask to 0777, which forces the socket to be created with 000 permissions
+	// (i.e.: no access for anyone). After that, WithChmod() must be used to set
+	// the desired permissions.
+	//
+	// We don't use "defer" here, to reset the umask to its original value as soon
+	// as possible. Ideally we'd be able to detect if WithChmod() was passed as
+	// an option, and skip changing umask if default permissions are used.
+	origUmask := syscall.Umask(0777)
 	l, err := net.Listen("unix", path)
+	syscall.Umask(origUmask)
 	if err != nil {
 		return nil, err
 	}
-	if err := os.Chown(path, 0, gid); err != nil {
-		l.Close()
-		return nil, err
-	}
-	if err := os.Chmod(path, 0660); err != nil {
-		l.Close()
-		return nil, err
+
+	for _, op := range opts {
+		if err := op(path); err != nil {
+			_ = l.Close()
+			return nil, err
+		}
 	}
+
 	return l, nil
 }
+
+// NewUnixSocket creates a unix socket with the specified path and group.
+func NewUnixSocket(path string, gid int) (net.Listener, error) {
+	return NewUnixSocketWithOpts(path, WithChown(0, gid), WithChmod(0660))
+}
-- 
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