Fix Cidr::contains_addr for zero length prefixes.

whitequark · whitequark · commit 1e18c03d3452 · 2017-10-30T08:25:32.000Z
diff --git a/src/wire/ipv4.rs b/src/wire/ipv4.rs
@@ -109,6 +109,9 @@ impl Cidr {
     /// Query whether the subnetwork described by this IPv4 CIDR block contains
     /// the given address.
     pub fn contains_addr(&self, addr: &Address) -> bool {
+        // right shift by 32 is not legal
+        if self.prefix_len == 0 { return true }
+
         let shift = 32 - self.prefix_len;
         let self_prefix = NetworkEndian::read_u32(self.address.as_bytes()) >> shift;
         let addr_prefix = NetworkEndian::read_u32(addr.as_bytes()) >> shift;
@@ -832,5 +835,8 @@ mod test {
             |&(a, p)| Cidr::new(Address::new(a[0], a[1], a[2], a[3]), p)) {
             assert!(!cidr.contains_subnet(&subnet));
         }
+
+        let cidr_without_prefix = Cidr::new(cidr.address(), 0);
+        assert!(cidr_without_prefix.contains_addr(&Address::new(127, 0, 0, 1)));
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -109,6 +109,9 @@ impl Cidr {`
`109`	`109`	`/// Query whether the subnetwork described by this IPv4 CIDR block contains`
`110`	`110`	`/// the given address.`
`111`	`111`	`pub fn contains_addr(&self, addr: &Address) -> bool {`
	`112`	`+ // right shift by 32 is not legal`
	`113`	`+ if self.prefix_len == 0 { return true }`
	`114`	`+`
`112`	`115`	`let shift = 32 - self.prefix_len;`
`113`	`116`	`let self_prefix = NetworkEndian::read_u32(self.address.as_bytes()) >> shift;`
`114`	`117`	`let addr_prefix = NetworkEndian::read_u32(addr.as_bytes()) >> shift;`
`@@ -832,5 +835,8 @@ mod test {`
`832`	`835`	`\|&(a, p)\| Cidr::new(Address::new(a[0], a[1], a[2], a[3]), p)) {`
`833`	`836`	`assert!(!cidr.contains_subnet(&subnet));`
`834`	`837`	`}`
	`838`	`+`
	`839`	`+ let cidr_without_prefix = Cidr::new(cidr.address(), 0);`
	`840`	`+ assert!(cidr_without_prefix.contains_addr(&Address::new(127, 0, 0, 1)));`
`835`	`841`	`}`
`836`	`842`	`}`