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Incorrect assumption with golang net package causes Overlapping IP

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using a len(net.IP) to check for ipv4 or ipv6 is a bad idea.
And that was exactly done in NetworkOverlaps() function with the
assumption that any ipv4 net.IP will be of 4 bytes. Golang Net package
makes no such assumptions.

This assumption actually broke a particular use-case where the
NetworkOverlaps fails to identify a genuine overlap and that causes
datapath issues.

With this fix, we explicitely check for v4 or v6

Signed-off-by: Madhu Venugopal <madhu@docker.com>
This commit is contained in:
Madhu Venugopal 2015-05-04 22:31:16 -07:00
parent 2979369c45
commit d4851b95ec
2 changed files with 4 additions and 2 deletions
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2
libnetwork/drivers/bridge/setup_ipv4.go
View file

@ -35,7 +35,7 @@ func init() {
log.Errorf("Failed to parse address %s", addr)
continue
}
net.IP = ip
net.IP = ip.To4()
bridgeNetworks = append(bridgeNetworks, net)
}
}

4
libnetwork/netutils/utils.go
View file

@ -192,7 +192,9 @@ func CheckRouteOverlaps(toCheck *net.IPNet) error {
// NetworkOverlaps detects overlap between one IPNet and another
func NetworkOverlaps(netX *net.IPNet, netY *net.IPNet) bool {
if len(netX.IP) == len(netY.IP) {
// Check if both netX and netY are ipv4 or ipv6
if (netX.IP.To4() != nil && netY.IP.To4() != nil) ||
(netX.IP.To4() == nil && netY.IP.To4() == nil) {
if firstIP, _ := NetworkRange(netX); netY.Contains(firstIP) {
return true
}