Reject IPv4-mapped/compatible IPv6 forms of local hosts as unsafe proxies#1697
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Reject IPv4-mapped/compatible IPv6 forms of local hosts as unsafe proxies#1697jax-0n-git wants to merge 1 commit into
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…xies `isLocalOnlyHost` rejected loopback / link-local / this-network proxy endpoints in their IPv4 (`127.0.0.1`, `169.254.x`) and plain-IPv6 (`::1`, `fe80::/10`) spellings, but the IPv6 branch only matched those literal shapes. The same machine-local endpoints written as IPv4-mapped (`::ffff:127.0.0.1`, `::ffff:169.254.1.1`) or IPv4-compatible (`::127.0.0.1`) IPv6 addresses slipped through the check and were accepted as "safe" remote proxy hosts. Decode the embedded IPv4 address from the mapped (`::ffff:a.b.c.d`) and compatible (`::a.b.c.d`) forms and apply the same IPv4 local-host rules to it, via a shared `isLocalOnlyIPv4` helper. Adds a test target for OsaurusNetworking with coverage for the mapped/compatible local hosts, the existing plain spellings (regression), and genuinely-remote hosts (including a public IPv4-mapped address, which must still be accepted). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Summary
isLocalOnlyHostrejects loopback / link-local / this-network proxy endpoints in their IPv4 (127.0.0.1,169.254.x) and plain-IPv6 (::1,fe80::/10) spellings, but the IPv6 branch only matched those literal shapes. The same machine-local endpoints written as IPv4-mapped (::ffff:127.0.0.1,::ffff:169.254.1.1) or IPv4-compatible (::127.0.0.1) IPv6 addresses slipped through and were accepted as "safe" remote proxy hosts.This decodes the embedded IPv4 address from the mapped (
::ffff:a.b.c.d) and compatible (::a.b.c.d) forms and applies the same IPv4 local-host rules to it, via a sharedisLocalOnlyIPv4helper. The change only ever rejects more hosts (the fail-safe direction for a security guard); genuinely-remote addresses — including a public IPv4-mapped address like::ffff:8.8.8.8— stay accepted. The IPv4-compatible branch also rejects the reserved low::0.xrange as non-routable, which is the safe direction.Coupling: open #1693 also edits
GlobalProxyConfiguration.swiftand adds the sameOsaurusNetworkingTeststarget. Whichever lands second needs a trivial rebase to de-dupe thePackage.swifttest-target block; the test files have distinct names and don't conflict.Changes
Test Plan
swift testinPackages/OsaurusNetworking(all green) +swift-format lint --strictclean. New test target covers the mapped/compatible local hosts (rejected after fix), the existing plain spellings (regression), and genuinely-remote hosts including a public IPv4-mapped address (still accepted). No MLX/GUI dependency.