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Revert strict IPv6 validation in URL #1258

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Merged
merged 1 commit into from
Apr 23, 2025
Merged

Revert strict IPv6 validation in URL #1258

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47 changes: 2 additions & 45 deletions Sources/FoundationEssentials/URL/URLParser.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -435,41 +435,6 @@ internal struct RFC3986Parser {
return validate(string: password, component: .password, percentEncodingAllowed: percentEncodingAllowed)
}

private static func isIPvFuture(_ innerHost: some StringProtocol) -> Bool {
// precondition: IP-literal == "[" innerHost [ "%25" zoneID ] "]"
var iter = innerHost.utf8.makeIterator()
guard iter.next() == UInt8(ascii: "v") else { return false }
guard let second = iter.next(), second.isValidHexDigit else { return false }
while let next = iter.next() {
if next.isValidHexDigit { continue }
if next == ._dot { return true }
return false
}
return false
}

/// Only checks that the characters are allowed in an IPv6 address.
/// Does not validate the format of the IPv6 address.
private static func validateIPv6Address(_ address: some StringProtocol) -> Bool {
let isValid = address.utf8.withContiguousStorageIfAvailable {
$0.allSatisfy { $0.isValidHexDigit || $0 == UInt8(ascii: ":") || $0 == UInt8(ascii: ".") }
}
if let isValid {
return isValid
}
#if FOUNDATION_FRAMEWORK
if let fastCharacters = address._ns._fastCharacterContents() {
let charsBuffer = UnsafeBufferPointer(start: fastCharacters, count: address._ns.length)
return charsBuffer.allSatisfy {
guard $0 < 128 else { return false }
let v = UInt8($0)
return v.isValidHexDigit || v == UInt8(ascii: ":") || v == UInt8(ascii: ".")
}
}
#endif
return address.utf8.allSatisfy { $0.isValidHexDigit || $0 == UInt8(ascii: ":") || $0 == UInt8(ascii: ".") }
}

/// Validates an IP-literal host string that has leading and trailing brackets.
/// If the host string contains a zone ID delimiter "%", this must be percent encoded to "%25" to be valid.
/// The zone ID may contain any `reg_name` characters, including percent-encoding.
Expand All @@ -483,11 +448,7 @@ internal struct RFC3986Parser {

guard let percentIndex = utf8.firstIndex(of: UInt8(ascii: "%")) else {
// There is no zoneID, so the whole innerHost must be the IP-literal address.
if isIPvFuture(innerHost) {
return validate(string: innerHost, component: .hostIPvFuture, percentEncodingAllowed: false)
} else {
return validateIPv6Address(innerHost)
}
return validate(string: innerHost, component: .hostIPvFuture, percentEncodingAllowed: false)
}

// The first "%" in an IP-literal must be the zone ID delimiter.
Expand All @@ -503,11 +464,7 @@ internal struct RFC3986Parser {
return false
}

if isIPvFuture(innerHost) {
return validate(string: innerHost[..<percentIndex], component: .hostIPvFuture, percentEncodingAllowed: false) && validate(string: innerHost[innerHost.index(after: twoAfterIndex)...], component: .hostZoneID)
} else {
return validateIPv6Address(innerHost[..<percentIndex]) && validate(string: innerHost[innerHost.index(after: twoAfterIndex)...], component: .hostZoneID)
}
return validate(string: innerHost[..<percentIndex], component: .hostIPvFuture, percentEncodingAllowed: false) && validate(string: innerHost[innerHost.index(after: twoAfterIndex)...], component: .hostZoneID)
}

private static func validate(host: some StringProtocol, knownIPLiteral: Bool = false) -> Bool {
Expand Down
5 changes: 5 additions & 0 deletions Tests/FoundationEssentialsTests/URLTests.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -884,6 +884,11 @@ final class URLTests : XCTestCase {
XCTAssertEqual(url.host, "fe80::a%100%CustomZone")
XCTAssertEqual(url.host(percentEncoded: true), "fe80::a%25100%25CustomZone")
XCTAssertEqual(url.host(percentEncoded: false), "fe80::a%100%CustomZone")

// Make sure an IP-literal with invalid characters `{` and `}`
// returns `nil` even if we can percent-encode the zone-ID.
let invalid = URL(string: "http://[{Invalid}%100%EncodableZone]")
XCTAssertNil(invalid)
}

#if !os(Windows)
Expand Down