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Fix IPAddr#private?, #link_local? and #loopback? incorrectly matching public IPv6 addresses as IPv4-mapped #106

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Merged
taketo1113 merged 1 commit into from
Apr 23, 2026
+15 −5
Merged

Fix IPAddr#private?, #link_local? and #loopback? incorrectly matching public IPv6 addresses as IPv4-mapped #106

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10 changes: 5 additions & 5 deletions lib/ipaddr.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -293,7 +293,7 @@ def loopback?
@addr & 0xff000000 == 0x7f000000 # 127.0.0.1/8
when Socket::AF_INET6
@addr == 1 || # ::1
(@addr & 0xffff_0000_0000 == 0xffff_0000_0000 && (
(@addr >> 32 == 0xffff && (
@addr & 0xff000000 == 0x7f000000 # ::ffff:127.0.0.1/8
))
else
Expand All @@ -314,10 +314,10 @@ def private?
@addr & 0xffff0000 == 0xc0a80000 # 192.168.0.0/16
when Socket::AF_INET6
@addr & 0xfe00_0000_0000_0000_0000_0000_0000_0000 == 0xfc00_0000_0000_0000_0000_0000_0000_0000 ||
(@addr & 0xffff_0000_0000 == 0xffff_0000_0000 && (
(@addr >> 32 == 0xffff && (
@addr & 0xff000000 == 0x0a000000 || # ::ffff:10.0.0.0/8
@addr & 0xfff00000 == 0xac100000 || # ::ffff::172.16.0.0/12
@addr & 0xffff0000 == 0xc0a80000 # ::ffff::192.168.0.0/16
@addr & 0xfff00000 == 0xac100000 || # ::ffff:172.16.0.0/12
@addr & 0xffff0000 == 0xc0a80000 # ::ffff:192.168.0.0/16
))
else
raise AddressFamilyError, "unsupported address family"
Expand All @@ -335,7 +335,7 @@ def link_local?
@addr & 0xffff0000 == 0xa9fe0000 # 169.254.0.0/16
when Socket::AF_INET6
@addr & 0xffc0_0000_0000_0000_0000_0000_0000_0000 == 0xfe80_0000_0000_0000_0000_0000_0000_0000 || # fe80::/10
(@addr & 0xffff_0000_0000 == 0xffff_0000_0000 && (
(@addr >> 32 == 0xffff && (
@addr & 0xffff0000 == 0xa9fe0000 # ::ffff:169.254.0.0/16
))
else
Expand Down
10 changes: 10 additions & 0 deletions test/test_ipaddr.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -533,6 +533,9 @@ def test_loopback?
assert_equal(false, IPAddr.new('::ffff:0.0.0.0').loopback?)
assert_equal(false, IPAddr.new('::ffff:192.168.2.0').loopback?)
assert_equal(false, IPAddr.new('::ffff:255.0.0.0').loopback?)

# Global unicast addresses with 0xffff in group 5 must not be mistaken for ::ffff:127.x.x.x
assert_equal(false, IPAddr.new('2001:db8:1:1:0:ffff:7f00:1').loopback?)
end

def test_private?
Expand Down Expand Up @@ -583,6 +586,10 @@ def test_private?
assert_equal(false, IPAddr.new('::ffff:192.169.0.0').private?)

assert_equal(false, IPAddr.new('::ffff:169.254.0.1').private?)

# Global unicast addresses with 0xffff in group 5 must not be mistaken for ::ffff:10/172.16/192.168.x
assert_equal(false, IPAddr.new('2001:718:1404:c8:0:ffff:ac19:c80e').private?)
assert_equal(false, IPAddr.new('2001:db8:1:1:0:ffff:c0a8:1').private?)
end

def test_link_local?
Expand All @@ -609,6 +616,9 @@ def test_link_local?

assert_equal(true, IPAddr.new('::ffff:169.254.1.1').link_local?)
assert_equal(true, IPAddr.new('::ffff:169.254.254.255').link_local?)

# Global unicast addresses with 0xffff in group 5 must not be mistaken for ::ffff:169.254.x.x
assert_equal(false, IPAddr.new('2001:db8:1:1:0:ffff:a9fe:101').link_local?)
end

def test_hash
Expand Down