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fix: validate CIDR prefix lengths in match #212

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Merged
whitequark merged 2 commits into from
Sep 1, 2026
+45 −0
Merged

fix: validate CIDR prefix lengths in match #212

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3e4d853
fix: validate CIDR prefix lengths in match
fasrm Sep 1, 2026
2e48170
test: reformat CIDR prefix validation cases
fasrm Sep 1, 2026
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10 changes: 10 additions & 0 deletions lib/ipaddr.js
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Original file line number Diff line number Diff line change
Expand Up @@ -108,6 +108,16 @@ function matchCIDR (first, second, partSize, cidrBits) {
throw new Error('ipaddr: cannot match CIDR for objects with different lengths');
}

const maxCidrBits = first.length * partSize;

if (
!Number.isInteger(cidrBits) ||
cidrBits < 0 ||
cidrBits > maxCidrBits
) {
throw new Error('ipaddr: invalid CIDR prefix length');
}

let part = 0;
let shift;

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35 changes: 35 additions & 0 deletions test/ipaddr.test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -106,6 +106,19 @@ describe('ipaddr', () => {
equal(addr.match(addr, 32), true);
})

it('rejects invalid IPv4 CIDR prefix lengths in match', () => {
const address = IPv4.parse('8.8.8.8');
const network = IPv4.parse('192.168.1.0');

throws(() => address.match(network, -1));
throws(() => address.match(network, -0.5));
throws(() => address.match(network, NaN));
throws(() => address.match(network, Infinity));
throws(() => address.match(network, -Infinity));
throws(() => address.match(network, 24.9));
throws(() => address.match(network, 33));
})

it('parses CIDR reversible', () => {
equal(parseCIDR('1.2.3.4/24').toString(), '1.2.3.4/24');
equal(parseCIDR('::1%zone/24').toString(), '::1%zone/24');
Expand Down Expand Up @@ -179,6 +192,19 @@ describe('ipaddr', () => {
});
})

it('rejects invalid IPv6 CIDR prefix lengths in match', () => {
const address = IPv6.parse('2001:db8::1');
const network = IPv6.parse('2001:db8::');

throws(() => address.match(network, -1));
throws(() => address.match(network, -0.5));
throws(() => address.match(network, NaN));
throws(() => address.match(network, Infinity));
throws(() => address.match(network, -Infinity));
throws(() => address.match(network, 64.9));
throws(() => address.match(network, 129));
})

it('can construct IPv6 from 8bit parts', () => {
doesNotThrow(() => {
new IPv6([0x20, 0x01, 0xd, 0xb8, 0xf5, 0x3a, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]);
Expand Down Expand Up @@ -566,6 +592,15 @@ describe('ipaddr', () => {
equal(subnetMatch(new IPv6([0x2001, 1, 2, 3, 0, 0, 0, 1]), rangelist, false), 'dual64');
})

it('subnetMatch rejects invalid CIDR prefix lengths', () => {
const address = IPv4.parse('8.8.8.8');
const network = IPv4.parse('192.168.1.0');

throws(() => subnetMatch(address, { internal: [network, -1] }, 'external'));
throws(() => subnetMatch(address, { internal: [network, NaN] }, 'external'));
throws(() => subnetMatch(address, { internal: [network, Infinity] }, 'external'));
})

it('is able to determine IP address type from byte array input', () => {
equal(fromByteArray([0x7f, 0, 0, 1]).kind(), 'ipv4');
equal(fromByteArray([0x20, 0x01, 0xd, 0xb8, 0xf5, 0x3a, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]).kind(), 'ipv6');
Expand Down