Context check bypass to enable opening shared-object libraries
Techniques to bypass system context checks to facilitate opening shared-object libraries are disclosed herein. In at least one implementation, a copy of a header of a shared-object library loaded by a runtime system is created. The header of the shared-object library loaded by the runtime system is patched with code configured to call an open function, wherein the code patched into the header of the shared-object library executes and calls the open function from the shared-object library loaded by the runtime system, the call to the open function is recognized as within a context of the runtime system, and the shared-object library is allowed to be opened. A pointer to the shared-object library opened in memory is received, and the header of the shared-object library is restored to an original version using the copy of the header of the shared-object library.
1. A method to bypass system context checks to facilitate opening shared-object libraries, the method comprising:
creating a copy of a header of a shared-object library loaded by a runtime system;
patching the header of the shared-object library loaded by the runtime system with code configured to call an open function, wherein the code patched into the header of the shared-object library executes and calls the open function from the shared-object library loaded by the runtime system, the call to the open function is recognized as within a context of the runtime system, and the shared-object library is allowed to be opened;
receiving a pointer to the shared-object library opened in memory; and
restoring the header of the shared-object library to an original version using the copy of the header of the shared-object library.
2. The method of claim 1 further comprising determining where the shared-object library is located in the memory.
3. The method of claim 2 wherein determining where the shared-object library is located in the memory comprises determining a base memory address of the shared-object library based on a call address of the shared-object library.
4. The method of claim 3 further comprising marking a paging of the base memory address of the shared-object library as writable.
5. The method of claim 1 wherein the open function comprises a dlopen function.
6. The method of claim 1 wherein the call to the open function is recognized as within the context of the runtime system and the shared-object library is allowed to be opened based on a return address of the call to the open function being within the context of the runtime system.
7. The method of claim 1 wherein receiving the pointer to the shared-object library opened in memory comprises receiving the pointer to the shared-object library opened in memory returned from the call to the open function from the shared-object library loaded by the runtime system.
8. One or more computer-readable storage media having program instructions stored thereon to bypass system context checks to facilitate opening shared-object libraries, wherein the program instructions, when executed by a computing system, direct the computing system to at least:
create a copy of a header of a shared-object library loaded by a runtime system;
patch the header of the shared-object library loaded by the runtime system with code configured to call an open function, wherein the code patched into the header of the shared-object library executes and calls the open function from the shared-object library loaded by the runtime system, the call to the open function is recognized as within a context of the runtime system, and the shared-object library is allowed to be opened;
receive a pointer to the shared-object library opened in memory; and
restore the header of the shared-object library to an original version using the copy of the header of the shared-object library.
9. The one or more computer-readable storage media of claim 8 wherein the program instructions further direct the computing system to determine where the shared-object library is located in the memory.
10. The one or more computer-readable storage media of claim 9 wherein the program instructions direct the computing system to determine where the shared-object library is located in the memory by directing the computing system to determine a base memory address of the shared-object library based on a call address of the shared-object library.
11. The one or more computer-readable storage media of claim 10 wherein the program instructions further direct the computing system to mark a paging of the base memory address of the shared-object library as writable.
12. The one or more computer-readable storage media of claim 8 wherein the open function comprises a dlopen function.
13. The one or more computer-readable storage media of claim 8 wherein the call to the open function is recognized as within the context of the runtime system and the shared-object library is allowed to be opened based on a return address of the call to the open function being within the context of the runtime system.
14. The one or more computer-readable storage media of claim 8 wherein the pointer to the shared-object library opened in memory is returned from the call to the open function from the shared-object library loaded by the runtime system.
15. A computing apparatus comprising:
one or more computer-readable storage media;
a processing system operatively coupled with the one or more computer-readable storage media; and
a mobile application stored on the one or more computer-readable storage media and including an embedded control module comprising program instructions that, when executed by the processing system, direct the processing system to at least:
create a copy of a header of a shared-object library loaded by a runtime system;
patch the header of the shared-object library loaded by the runtime system with code configured to call an open function, wherein the code patched into the header of the shared-object library executes and calls the open function from the shared-object library loaded by the runtime system, the call to the open function is recognized as within a context of the runtime system, and the shared-object library is allowed to be opened;
receive a pointer to the shared-object library opened in memory; and
restore the header of the shared-object library to an original version using the copy of the header of the shared-object library.
16. The computing apparatus of claim 15 wherein the program instructions further direct the processing system to determine where the shared-object library is located in the memory.
17. The computing apparatus of claim 16 wherein the program instructions direct the processing system to determine where the shared-object library is located in the memory by directing the processing system to determine a base memory address of the shared-object library based on a call address of the shared-object library.
18. The computing apparatus of claim 17 wherein the program instructions further direct the processing system to mark a paging of the base memory address of the shared-object library as writable.
19. The computing apparatus of claim 15 wherein the open function comprises a dlopen function.
20. The computing apparatus of claim 15 wherein the call to the open function is recognized as within the context of the runtime system and the shared-object library is allowed to be opened based on a return address of the call to the open function being within the context of the runtime system.