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[6.2] Prevent accessing unicode scalar element with incorrect index. (#1214) #1219

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merged 1 commit into from
May 15, 2025
Merged

[6.2] Prevent accessing unicode scalar element with incorrect index. (#1214) #1219

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26 changes: 16 additions & 10 deletions Sources/SwiftDocC/Utility/ValidatedURL.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -179,23 +179,29 @@ private extension StringProtocol {
func addingPercentEncodingIfNeeded(withAllowedCharacters allowedCharacters: CharacterSet) -> String? {
var needsPercentEncoding: Bool {
for (index, character) in unicodeScalars.indexed() where !allowedCharacters.contains(character) {
// Check if the character "%" represents a percent encoded URL.
// Any other disallowed character is an indication that this substring needs percent encoding.
if character == "%" {
// % isn't allowed in a URL fragment but it is also the escape character for percent encoding.
let firstFollowingIndex = unicodeScalars.index(after: index)
let secondFollowingIndex = unicodeScalars.index(after: firstFollowingIndex)

guard secondFollowingIndex < unicodeScalars.endIndex else {
guard self.distance(from: index, to: self.endIndex) >= 2 else {
// There's not two characters after the "%". This "%" can't represent a percent encoded character.
return true
}
// If either of the two following characters aren't hex digits, the "%" doesn't represent a
return !Character(unicodeScalars[firstFollowingIndex]).isHexDigit
|| !Character(unicodeScalars[secondFollowingIndex]).isHexDigit
let firstFollowingIndex = self.index(after: index)
let secondFollowingIndex = self.index(after: firstFollowingIndex)

} else {
// Any other disallowed character is an indication that this substring needs percent encoding.
return true
// Check if the next two characthers represent a percent encoded
// URL.
// If either of the two following characters aren't hex digits,
// the "%" doesn't represent a percent encoded character.
if Character(unicodeScalars[firstFollowingIndex]).isHexDigit,
Character(unicodeScalars[secondFollowingIndex]).isHexDigit
{
// Later characters in the string might require percentage encoding.
continue
}
}
return true
}
return false
}
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48 changes: 32 additions & 16 deletions Tests/SwiftDocCTests/Utility/ValidatedURLTests.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,14 @@ class ValidatedURLTests: XCTestCase {
}

func testQueryIsPartOfPathForAuthoredLinks() throws {

func validate(linkText: String, expectedPath: String, expectedFragment: String? = nil,file: StaticString = #filePath, line: UInt = #line) throws {
let validated = try XCTUnwrap(ValidatedURL(parsingAuthoredLink: linkText), "Failed to parse \(linkText.singleQuoted) as authored link")
XCTAssertNil(validated.components.queryItems, "Authored documentation links don't include query items", file: file, line: line)
XCTAssertEqual(validated.components.path, expectedPath, file: file, line: line)
XCTAssertEqual(validated.components.fragment, expectedFragment, file: file, line: line)
}

// Test return type disambiguation
for linkText in [
"SymbolName/memberName()->Int?",
Expand All @@ -91,14 +99,8 @@ class ValidatedURLTests: XCTestCase {
? "/SymbolName/memberName()->Int?"
: "SymbolName/memberName()->Int?"

let validated = try XCTUnwrap(ValidatedURL(parsingAuthoredLink: linkText), "Failed to parse \(linkText.singleQuoted) as authored link")
XCTAssertNil(validated.components.queryItems, "Authored documentation links don't include query items")
XCTAssertEqual(validated.components.path, expectedPath)

let validatedWithHeading = try XCTUnwrap(ValidatedURL(parsingAuthoredLink: linkText + "#Heading-Name"), "Failed to parse '\(linkText)#Heading-Name' as authored link")
XCTAssertNil(validatedWithHeading.components.queryItems, "Authored documentation links don't include query items")
XCTAssertEqual(validatedWithHeading.components.path, expectedPath)
XCTAssertEqual(validatedWithHeading.components.fragment, "Heading-Name")
try validate(linkText: linkText, expectedPath: expectedPath)
try validate(linkText: linkText + "#Heading-Name", expectedPath: expectedPath, expectedFragment: "Heading-Name")
}

// Test parameter type disambiguation
Expand All @@ -111,15 +113,29 @@ class ValidatedURLTests: XCTestCase {
? "/SymbolName/memberName(with:and:)-(Int?,_)"
: "SymbolName/memberName(with:and:)-(Int?,_)"

let validated = try XCTUnwrap(ValidatedURL(parsingAuthoredLink: linkText), "Failed to parse \(linkText.singleQuoted) as authored link")
XCTAssertNil(validated.components.queryItems, "Authored documentation links don't include query items")
XCTAssertEqual(validated.components.path, expectedPath)

let validatedWithHeading = try XCTUnwrap(ValidatedURL(parsingAuthoredLink: linkText + "#Heading-Name"), "Failed to parse '\(linkText)#Heading-Name' as authored link")
XCTAssertNil(validatedWithHeading.components.queryItems, "Authored documentation links don't include query items")
XCTAssertEqual(validatedWithHeading.components.path, expectedPath)
XCTAssertEqual(validatedWithHeading.components.fragment, "Heading-Name")
try validate(linkText: linkText, expectedPath: expectedPath)
try validate(linkText: linkText + "#Heading-Name", expectedPath: expectedPath, expectedFragment: "Heading-Name")
}

// Test parameter with percent encoding
var linkText = "doc://com.example.test/docc=Whats%20New&version=DocC&Title=[Update]"
var expectedPath = "/docc=Whats%20New&version=DocC&Title=[Update]"
try validate(linkText: linkText, expectedPath: expectedPath)

// Test parameter with percent encoding at the end of the URL
linkText = "doc://com.example.test/docc=Whats%20New&version=DocC&Title=[Update]%20"
expectedPath = "/docc=Whats%20New&version=DocC&Title=[Update]%20"
try validate(linkText: linkText, expectedPath: expectedPath)

// Test parameter without percent encoding
linkText = "doc://com.example.test/docc=WhatsNew&version=DocC&Title=[Update]"
expectedPath = "/docc=WhatsNew&version=DocC&Title=[Update]"
try validate(linkText: linkText, expectedPath: expectedPath)

// Test parameter with special characters
linkText = "doc://com.example.test/テスト"
expectedPath = "/テスト"
try validate(linkText: linkText, expectedPath: expectedPath)
}

func testEscapedFragment() throws {
Expand Down