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Standardize the filename of Archive Entries so path traversal characters cannot be used to manipulate file output location #171

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Standardize the filename of Archive Entries so path traversal characters cannot be used to manipulate file output location #171

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10 changes: 10 additions & 0 deletions ZipZap.xcodeproj/project.pbxproj
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,8 @@
5BC58CA618745940002FAE04 /* large-test-encrypted-standard.zip in Resources */ = {isa = PBXBuildFile; fileRef = 5BC58CA418745940002FAE04 /* large-test-encrypted-standard.zip */; };
5BC58CA718745940002FAE04 /* small-test-encrypted-standard.zip in Resources */ = {isa = PBXBuildFile; fileRef = 5BC58CA518745940002FAE04 /* small-test-encrypted-standard.zip */; };
5BC58CAC18745D22002FAE04 /* ZZStandardCryptoEngine.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 5B50392E187069E4002B2B12 /* ZZStandardCryptoEngine.cpp */; };
5F2CE0DE20C0B2D900B558EC /* path-traversal.zip in Resources */ = {isa = PBXBuildFile; fileRef = 5F2CE0DD20C0B2D900B558EC /* path-traversal.zip */; };
5F2CE0E120C0B3F900B558EC /* ZZPathTraversalUnzipTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 5F2CE0E020C0B3F900B558EC /* ZZPathTraversalUnzipTests.m */; };
BF8624AD1BB7495200C12EEE /* ZZAESDecryptInputStream.mm in Sources */ = {isa = PBXBuildFile; fileRef = D8ABBF3D18883528002858BE /* ZZAESDecryptInputStream.mm */; };
BF8624AE1BB7495200C12EEE /* ZZArchive.mm in Sources */ = {isa = PBXBuildFile; fileRef = D899CFDB162C608300112F49 /* ZZArchive.mm */; };
BF8624AF1BB7495200C12EEE /* ZZArchiveEntry.m in Sources */ = {isa = PBXBuildFile; fileRef = D899CFD9162C608300112F49 /* ZZArchiveEntry.m */; };
Expand Down Expand Up @@ -242,6 +244,9 @@
5B50393218707C36002B2B12 /* ZZStandardDecryptInputStream.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ZZStandardDecryptInputStream.h; sourceTree = "<group>"; };
5BC58CA418745940002FAE04 /* large-test-encrypted-standard.zip */ = {isa = PBXFileReference; lastKnownFileType = archive.zip; path = "large-test-encrypted-standard.zip"; sourceTree = "<group>"; };
5BC58CA518745940002FAE04 /* small-test-encrypted-standard.zip */ = {isa = PBXFileReference; lastKnownFileType = archive.zip; path = "small-test-encrypted-standard.zip"; sourceTree = "<group>"; };
5F2CE0DD20C0B2D900B558EC /* path-traversal.zip */ = {isa = PBXFileReference; lastKnownFileType = archive.zip; path = "path-traversal.zip"; sourceTree = "<group>"; };
5F2CE0DF20C0B3F900B558EC /* ZZPathTraversalUnzipTests.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ZZPathTraversalUnzipTests.h; sourceTree = "<group>"; };
5F2CE0E020C0B3F900B558EC /* ZZPathTraversalUnzipTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = ZZPathTraversalUnzipTests.m; sourceTree = "<group>"; };
BF8624CB1BB7495200C12EEE /* ZipZap.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = ZipZap.framework; sourceTree = BUILT_PRODUCTS_DIR; };
BF8624EF1BB74B1F00C12EEE /* libZipZap.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = libZipZap.a; sourceTree = BUILT_PRODUCTS_DIR; };
D804E4C8187645FE00289404 /* ZZDataProvider.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ZZDataProvider.h; sourceTree = "<group>"; };
Expand Down Expand Up @@ -447,6 +452,7 @@
5BC58CA318745940002FAE04 /* assets */ = {
isa = PBXGroup;
children = (
5F2CE0DD20C0B2D900B558EC /* path-traversal.zip */,
D87BA1AA1B3D5B2900ED7EB3 /* dog.jpg */,
D87BA1AB1B3D5B2900ED7EB3 /* dog.png */,
D8E366EA188832C0009F3008 /* large-test-encrypted-aes128.zip */,
Expand Down Expand Up @@ -543,6 +549,8 @@
D8B83A7E19B7D3A700CF72B6 /* ZZZipOldTests.h */,
D8B83A7C19B7D39200CF72B6 /* ZZZipOldTests.m */,
D899D01F162F6C9700112F49 /* ZZZipTests.h */,
5F2CE0DF20C0B3F900B558EC /* ZZPathTraversalUnzipTests.h */,
5F2CE0E020C0B3F900B558EC /* ZZPathTraversalUnzipTests.m */,
D899D020162F6C9700112F49 /* ZZZipTests.m */,
D899CF9E162C5EC100112F49 /* Supporting Files */,
);
Expand Down Expand Up @@ -813,6 +821,7 @@
buildActionMask = 2147483647;
files = (
D8E366F5188832C0009F3008 /* small-test-encrypted-aes256.zip in Resources */,
5F2CE0DE20C0B2D900B558EC /* path-traversal.zip in Resources */,
D899CFA2162C5EC100112F49 /* InfoPlist.strings in Resources */,
D8E366F0188832C0009F3008 /* large-test-encrypted-aes128.zip in Resources */,
D8E366F2188832C0009F3008 /* large-test-encrypted-aes256.zip in Resources */,
Expand Down Expand Up @@ -952,6 +961,7 @@
D899D01A162CCF9700112F49 /* ZZUnzipTests.m in Sources */,
D8B83A7719B7CBB400CF72B6 /* ZZZipNewTests.m in Sources */,
D8B83A7D19B7D39200CF72B6 /* ZZZipOldTests.m in Sources */,
5F2CE0E120C0B3F900B558EC /* ZZPathTraversalUnzipTests.m in Sources */,
D899D021162F6C9700112F49 /* ZZZipTests.m in Sources */,
);
runOnlyForDeploymentPostprocessing = 0;
Expand Down
11 changes: 8 additions & 3 deletions ZipZap/ZZOldArchiveEntry.mm
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Expand Up @@ -250,9 +250,14 @@ - (BOOL)check:(out NSError**)error

- (NSString*)fileNameWithEncoding:(NSStringEncoding)encoding
{
return [[NSString alloc] initWithBytes:_centralFileHeader->fileName()
length:_centralFileHeader->fileNameLength
encoding:encoding];
// Sanitize path traversal characters if they're present in the file name to prevent directory backtracking. Ignoring these characters mimicks the default behavior of the Unarchiving tool on macOS.
NSString *rawFilePath = [[NSString alloc] initWithBytes:_centralFileHeader->fileName() length:_centralFileHeader->fileNameLength encoding:encoding];

// Add URL percent encoding to the path as it may contain non-english accented characters that would break NSURL
rawFilePath = [rawFilePath stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];

// Standardize the URL (remove any path oddities) before removing the percent encoding
return [[[[NSURL URLWithString:rawFilePath] standardizedURL] absoluteString] stringByRemovingPercentEncoding];
}

- (BOOL)checkEncryptionAndCompression:(out NSError**)error
Expand Down
12 changes: 12 additions & 0 deletions ZipZapTests/ZZPathTraversalUnzipTests.h
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Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
//
// ZZPathTraversalUnzipTests.h
// ZipZapTests
//
// Created by Ethan Arbuckle on 5/31/18.
//

#import <XCTest/XCTest.h>

@interface ZZPathTraversalUnzipTests : XCTestCase

@end
27 changes: 27 additions & 0 deletions ZipZapTests/ZZPathTraversalUnzipTests.m
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Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
//
// ZZPathTraversalUnzipTests.m
// ZipZapTests
//
// Created by Ethan Arbuckle on 5/31/18.
//

#import "ZZPathTraversalUnzipTests.h"
#import <ZipZap/ZipZap.h>

@implementation ZZPathTraversalUnzipTests

- (void)testExtractingZipContainingPathTraversalEntries
{
// This zip archive contains a file titled '../../../../../../../../../../..//tmp/test.txt'. ZipZap should ignore the path traversing and write the file to "tmp/test.txt"
ZZArchive* zipFile = [ZZArchive archiveWithURL:[[NSBundle bundleForClass:self.class] URLForResource:@"path-traversal" withExtension:@"zip"] error:nil];

for (NSUInteger index = 0, count = zipFile.entries.count; index < count; ++index)
{
ZZArchiveEntry* nextEntry = zipFile.entries[index];

// Assert that the entry does not begin with '..'
XCTAssertFalse([[[nextEntry fileName] substringToIndex:2] isEqualToString:@".."]);
}
}

@end
Binary file added ZipZapTests/assets/path-traversal.zip
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