libnet/i/defaultipam: improve address pools validation

akerouanton · akerouanton · commit 37ba8240131b · 2024-05-22T08:33:13.000+02:00
Nothing was validating whether address pools' `base` prefix
were larger than the target subnet `size` they're associated to. As
such invalid address pools would yield no subnet, the error could go
unnoticed.

Signed-off-by: Albin Kerouanton &lt;albinker@gmail.com&gt;
diff --git a/libnetwork/ipams/defaultipam/allocator.go b/libnetwork/ipams/defaultipam/allocator.go
@@ -95,6 +95,9 @@ func splitByIPFamily(s []*ipamutils.NetworkToSplit) ([]*ipamutils.NetworkToSplit
 		if !n.Base.IsValid() || n.Size == 0 {
 			return []*ipamutils.NetworkToSplit{}, []*ipamutils.NetworkToSplit{}, fmt.Errorf("network at index %d (%v) is not in canonical form", i, n)
 		}
+		if n.Base.Bits() > n.Size {
+			return []*ipamutils.NetworkToSplit{}, []*ipamutils.NetworkToSplit{}, fmt.Errorf("network at index %d (%v) has a smaller prefix (/%d) than the target size of that pool (/%d)", i, n, n.Base.Bits(), n.Size)
+		}
 
 		n.Base, _ = n.Base.Addr().Unmap().Prefix(n.Base.Bits())
 

Original file line number	Diff line number	Diff line change
`@@ -95,6 +95,9 @@ func splitByIPFamily(s []ipamutils.NetworkToSplit) ([]ipamutils.NetworkToSplit`
`95`	`95`	`if !n.Base.IsValid() \|\| n.Size == 0 {`
`96`	`96`	`return []ipamutils.NetworkToSplit{}, []ipamutils.NetworkToSplit{}, fmt.Errorf("network at index %d (%v) is not in canonical form", i, n)`
`97`	`97`	`}`
	`98`	`+ if n.Base.Bits() > n.Size {`
	`99`	`+ return []ipamutils.NetworkToSplit{}, []ipamutils.NetworkToSplit{}, fmt.Errorf("network at index %d (%v) has a smaller prefix (/%d) than the target size of that pool (/%d)", i, n, n.Base.Bits(), n.Size)`
	`100`	`+ }`
`98`	`101`
`99`	`102`	`n.Base, _ = n.Base.Addr().Unmap().Prefix(n.Base.Bits())`
`100`	`103`