Move FIRAppEnvironmentUtil.m to third_party directory (#89)

1 files changed, 233 insertions, 0 deletions

diff --git a/Firebase/Core/third_party/FIRAppEnvironmentUtil.m b/Firebase/Core/third_party/FIRAppEnvironmentUtil.m
new file mode 100644
index 0000000..64c85d9
--- /dev/null
+++ b/Firebase/Core/third_party/FIRAppEnvironmentUtil.m
@@ -0,0 +1,233 @@
+// Copyright 2017 Google
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import <Foundation/Foundation.h>
+
+#import "FIRAppEnvironmentUtil.h"
+
+#import <dlfcn.h>
+#import <mach-o/dyld.h>
+#import <sys/utsname.h>
+
+/// The encryption info struct and constants are missing from the iPhoneSimulator SDK, but not from
+/// the iPhoneOS or Mac OS X SDKs. Since one doesn't ever ship a Simulator binary, we'll just
+/// provide the definitions here.
+#if TARGET_OS_SIMULATOR && !defined(LC_ENCRYPTION_INFO)
+#define LC_ENCRYPTION_INFO 0x21
+struct encryption_info_command {
+  uint32_t cmd;
+  uint32_t cmdsize;
+  uint32_t cryptoff;
+  uint32_t cryptsize;
+  uint32_t cryptid;
+};
+#endif
+
+@implementation FIRAppEnvironmentUtil
+
+/// The file name of the sandbox receipt. This is available on iOS >= 8.0
+static NSString *const kFIRAIdentitySandboxReceiptFileName = @"sandboxReceipt";
+
+/// The following copyright from Landon J. Fuller applies to the isAppEncrypted function.
+///
+/// Copyright (c) 2017 Landon J. Fuller <landon@landonf.org>
+/// All rights reserved.
+///
+/// Permission is hereby granted, free of charge, to any person obtaining a copy of this software
+/// and associated documentation files (the "Software"), to deal in the Software without
+/// restriction, including without limitation the rights to use, copy, modify, merge, publish,
+/// distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the
+/// Software is furnished to do so, subject to the following conditions:
+///
+/// The above copyright notice and this permission notice shall be included in all copies or
+/// substantial portions of the Software.
+///
+/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
+/// BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+/// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+/// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+/// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+///
+/// Comment from <a href="http://iphonedevwiki.net/index.php/Crack_prevention">iPhone Dev Wiki
+/// Crack Prevention</a>:
+/// App Store binaries are signed by both their developer and Apple. This encrypts the binary so
+/// that decryption keys are needed in order to make the binary readable. When iOS executes the
+/// binary, the decryption keys are used to decrypt the binary into a readable state where it is
+/// then loaded into memory and executed. iOS can tell the encryption status of a binary via the
+/// cryptid structure member of LC_ENCRYPTION_INFO MachO load command. If cryptid is a non-zero
+/// value then the binary is encrypted.
+///
+/// 'Cracking' works by letting the kernel decrypt the binary then siphoning the decrypted data into
+/// a new binary file, resigning, and repackaging. This will only work on jailbroken devices as
+/// codesignature validation has been removed. Resigning takes place because while the codesignature
+/// doesn't have to be valid thanks to the jailbreak, it does have to be in place unless you have
+/// AppSync or similar to disable codesignature checks.
+///
+/// More information at <a href="http://landonf.org/2009/02/index.html">Landon Fuller's blog</a>
+static BOOL isAppEncrypted() {
+  const struct mach_header *executableHeader = NULL;
+  for (uint32_t i = 0; i < _dyld_image_count(); i++) {
+    const struct mach_header *header = _dyld_get_image_header(i);
+    if (header && header->filetype == MH_EXECUTE) {
+      executableHeader = header;
+      break;
+    }
+  }
+
+  if (!executableHeader) {
+    return NO;
+  }
+
+  BOOL is64bit = (executableHeader->magic == MH_MAGIC_64);
+  uintptr_t cursor = (uintptr_t)executableHeader +
+      (is64bit ? sizeof(struct mach_header_64) : sizeof(struct mach_header));
+  const struct segment_command *segmentCommand = NULL;
+  uint32_t i = 0;
+
+  while (i++ < executableHeader->ncmds) {
+    segmentCommand = (struct segment_command *)cursor;
+
+    if (!segmentCommand) {
+      continue;
+    }
+
+    if ((!is64bit && segmentCommand->cmd == LC_ENCRYPTION_INFO) ||
+        (is64bit && segmentCommand->cmd == LC_ENCRYPTION_INFO_64)) {
+      if (is64bit) {
+        struct encryption_info_command_64 *cryptCmd =
+            (struct encryption_info_command_64 *)segmentCommand;
+        return cryptCmd && cryptCmd->cryptid != 0;
+      } else {
+        struct encryption_info_command *cryptCmd = (struct encryption_info_command *)segmentCommand;
+        return cryptCmd && cryptCmd->cryptid != 0;
+      }
+    }
+    cursor += segmentCommand->cmdsize;
+  }
+
+  return NO;
+}
+
++ (BOOL)isFromAppStore {
+  static dispatch_once_t isEncryptedOnce;
+  static BOOL isEncrypted = NO;
+
+  dispatch_once(&isEncryptedOnce, ^{
+    isEncrypted = isAppEncrypted();
+  });
+
+  if ([FIRAppEnvironmentUtil isSimulator]) {
+    return NO;
+  }
+  if ([FIRAppEnvironmentUtil hasSCInfoFolder]) {
+    // When iTunes downloads a .ipa, it also gets a customized .sinf file which is added to the
+    // main SC_Info directory.
+    return YES;
+  }
+
+  // For iOS >= 8.0, iTunesMetadata.plist is moved outside of the sandbox. Any attempt to read
+  // the iTunesMetadata.plist outside of the sandbox will be rejected by Apple.
+  // If the app does not contain the sandboxReceipt file which means it is a TestFlight beta, and
+  // it does not contain the embedded.mobileprovision which is stripped out by Apple when the
+  // app is submitted to store, then it is highly likely that it is from Apple Store.
+  return isEncrypted && ![FIRAppEnvironmentUtil isAppStoreReceiptSandbox] &&
+      ![FIRAppEnvironmentUtil hasEmbeddedMobileProvision];
+}
+
++ (BOOL)isAppStoreReceiptSandbox {
+  NSURL *appStoreReceiptURL = [NSBundle mainBundle].appStoreReceiptURL;
+  NSString *appStoreReceiptFileName = appStoreReceiptURL.lastPathComponent;
+  return [appStoreReceiptFileName isEqualToString:kFIRAIdentitySandboxReceiptFileName];
+}
+
++ (BOOL)hasEmbeddedMobileProvision {
+  #if TARGET_OS_IOS
+  return [[NSBundle mainBundle] pathForResource:@"embedded" ofType:@"mobileprovision"].length > 0;
+  #elif TARGET_OS_OSX
+  return NO;
+  #endif
+}
+
++ (BOOL)isSimulator {
+  #if TARGET_OS_IOS
+  NSString *platform = [FIRAppEnvironmentUtil deviceModel];
+  return [platform isEqual:@"x86_64"] || [platform isEqual:@"i386"];
+  #elif TARGET_OS_OSX
+  return NO;
+  #endif
+}
+
++ (NSString *)deviceModel {
+  static dispatch_once_t once;
+  static NSString *deviceModel;
+
+  dispatch_once(&once, ^{
+    struct utsname systemInfo;
+    if (uname(&systemInfo) == 0) {
+      deviceModel = [NSString stringWithUTF8String:systemInfo.machine];
+    }
+  });
+  return deviceModel;
+}
+
++ (NSString *)systemVersion {
+  #if TARGET_OS_IOS
+  return [UIDevice currentDevice].systemVersion;
+  #elif TARGET_OS_OSX
+  return [NSProcessInfo processInfo].operatingSystemVersionString;
+  #endif
+}
+
++ (BOOL)isAppExtension {
+  #if TARGET_OS_IOS
+  // Documented by <a href="https://goo.gl/RRB2Up">Apple</a>
+  BOOL appExtension = [[[NSBundle mainBundle] bundlePath] hasSuffix:@".appex"];
+  return appExtension;
+  #elif TARGET_OS_OSX
+  return NO;
+  #endif
+}
+
+#if TARGET_OS_IOS
++ (UIApplication *)sharedApplication {
+  if ([FIRAppEnvironmentUtil isAppExtension]) {
+    return nil;
+  }
+  id sharedApplication = nil;
+  Class uiApplicationClass = NSClassFromString(@"UIApplication");
+  if (uiApplicationClass &&
+      [uiApplicationClass respondsToSelector:(NSSelectorFromString(@"sharedApplication"))]) {
+    sharedApplication = [uiApplicationClass sharedApplication];
+  }
+  return sharedApplication;
+}
+#elif TARGET_OS_OSX
++ (NSApplication *)sharedApplication {
+  return [NSApplication sharedApplication];
+}
+#endif
+
+#pragma mark - Helper methods
+
++ (BOOL)hasSCInfoFolder {
+  #if TARGET_OS_IOS
+  NSString *bundlePath = [NSBundle mainBundle].bundlePath;
+  NSString *scInfoPath = [bundlePath stringByAppendingPathComponent:@"SC_Info"];
+  return [[NSFileManager defaultManager] fileExistsAtPath:scInfoPath];
+  #elif TARGET_OS_OSX
+  return NO;
+  #endif
+}
+
+@end