Add space-escaping to path parts of lxc.mount.entry lines in generated lxc.conf, allowing for spaces in mount point names

Fixes #2802

lxc_template.go

@@ -1,6 +1,7 @@
 package docker
 
 import (
+	"strings"
 	"text/template"
 )
 
@@ -31,8 +32,8 @@ lxc.rootfs = {{$ROOTFS}}
 
 {{if and .HostnamePath .HostsPath}}
 # enable domain name support
-lxc.mount.entry = {{.HostnamePath}} {{$ROOTFS}}/etc/hostname none bind,ro 0 0
-lxc.mount.entry = {{.HostsPath}} {{$ROOTFS}}/etc/hosts none bind,ro 0 0
+lxc.mount.entry = {{escapeFstabSpaces .HostnamePath}} {{escapeFstabSpaces $ROOTFS}}/etc/hostname none bind,ro 0 0
+lxc.mount.entry = {{escapeFstabSpaces .HostsPath}} {{escapeFstabSpaces $ROOTFS}}/etc/hosts none bind,ro 0 0
 {{end}}
 
 # use a dedicated pts for the container (and limit the number of pseudo terminal
@@ -84,27 +85,27 @@ lxc.cgroup.devices.allow = c 10:200 rwm
 lxc.pivotdir = lxc_putold
 #  WARNING: procfs is a known attack vector and should probably be disabled
 #           if your userspace allows it. eg. see http://blog.zx2c4.com/749
-lxc.mount.entry = proc {{$ROOTFS}}/proc proc nosuid,nodev,noexec 0 0
+lxc.mount.entry = proc {{escapeFstabSpaces $ROOTFS}}/proc proc nosuid,nodev,noexec 0 0
 #  WARNING: sysfs is a known attack vector and should probably be disabled
 #           if your userspace allows it. eg. see http://bit.ly/T9CkqJ
-lxc.mount.entry = sysfs {{$ROOTFS}}/sys sysfs nosuid,nodev,noexec 0 0
-lxc.mount.entry = devpts {{$ROOTFS}}/dev/pts devpts newinstance,ptmxmode=0666,nosuid,noexec 0 0
-#lxc.mount.entry = varrun {{$ROOTFS}}/var/run tmpfs mode=755,size=4096k,nosuid,nodev,noexec 0 0
-#lxc.mount.entry = varlock {{$ROOTFS}}/var/lock tmpfs size=1024k,nosuid,nodev,noexec 0 0
-lxc.mount.entry = shm {{$ROOTFS}}/dev/shm tmpfs size=65536k,nosuid,nodev,noexec 0 0
+lxc.mount.entry = sysfs {{escapeFstabSpaces $ROOTFS}}/sys sysfs nosuid,nodev,noexec 0 0
+lxc.mount.entry = devpts {{escapeFstabSpaces $ROOTFS}}/dev/pts devpts newinstance,ptmxmode=0666,nosuid,noexec 0 0
+#lxc.mount.entry = varrun {{escapeFstabSpaces $ROOTFS}}/var/run tmpfs mode=755,size=4096k,nosuid,nodev,noexec 0 0
+#lxc.mount.entry = varlock {{escapeFstabSpaces $ROOTFS}}/var/lock tmpfs size=1024k,nosuid,nodev,noexec 0 0
+lxc.mount.entry = shm {{escapeFstabSpaces $ROOTFS}}/dev/shm tmpfs size=65536k,nosuid,nodev,noexec 0 0
 
 # Inject dockerinit
-lxc.mount.entry = {{.SysInitPath}} {{$ROOTFS}}/.dockerinit none bind,ro 0 0
+lxc.mount.entry = {{escapeFstabSpaces .SysInitPath}} {{escapeFstabSpaces $ROOTFS}}/.dockerinit none bind,ro 0 0
 
 # Inject env
-lxc.mount.entry = {{.EnvConfigPath}} {{$ROOTFS}}/.dockerenv none bind,ro 0 0
+lxc.mount.entry = {{escapeFstabSpaces .EnvConfigPath}} {{escapeFstabSpaces $ROOTFS}}/.dockerenv none bind,ro 0 0
 
 # In order to get a working DNS environment, mount bind (ro) the host's /etc/resolv.conf into the container
-lxc.mount.entry = {{.ResolvConfPath}} {{$ROOTFS}}/etc/resolv.conf none bind,ro 0 0
+lxc.mount.entry = {{escapeFstabSpaces .ResolvConfPath}} {{escapeFstabSpaces $ROOTFS}}/etc/resolv.conf none bind,ro 0 0
 {{if .Volumes}}
 {{ $rw := .VolumesRW }}
 {{range $virtualPath, $realPath := .Volumes}}
-lxc.mount.entry = {{$realPath}} {{$ROOTFS}}/{{$virtualPath}} none bind,{{ if index $rw $virtualPath }}rw{{else}}ro{{end}} 0 0
+lxc.mount.entry = {{escapeFstabSpaces $realPath}} {{escapeFstabSpaces $ROOTFS}}/{{escapeFstabSpaces $virtualPath}} none bind,{{ if index $rw $virtualPath }}rw{{else}}ro{{end}} 0 0
 {{end}}
 {{end}}
 
@@ -144,6 +145,12 @@ lxc.cgroup.cpu.shares = {{.Config.CpuShares}}
 
 var LxcTemplateCompiled *template.Template
 
+// Escape spaces in strings according to the fstab documentation, which is the
+// format for "lxc.mount.entry" lines in lxc.conf. See also "man 5 fstab".
+func escapeFstabSpaces(field string) string {
+	return strings.Replace(field, " ", "\\040", -1)
+}
+
 func getMemorySwap(config *Config) int64 {
 	// By default, MemorySwap is set to twice the size of RAM.
 	// If you want to omit MemorySwap, set it to `-1'.
@@ -167,6 +174,7 @@ func init() {
 		"getMemorySwap":   getMemorySwap,
 		"getHostConfig":   getHostConfig,
 		"getCapabilities": getCapabilities,
+		"escapeFstabSpaces": escapeFstabSpaces,
 	}
 	LxcTemplateCompiled, err = template.New("lxc").Funcs(funcMap).Parse(LxcTemplate)
 	if err != nil {