projectsandcastle

projectsandcastle

Android/Linux for the iPhone

Provided utilities:

• loader/ loads kernel and device tree via pongoOS
• syscfg/ tool to extract configuration information from syscfg partition on devices
• hx-touchd/ touch screen support daemon
• hcdpack/ tool to heuristically extract Bluetooth firmware from binaries

Kernel

Kernel can be obtained from our fork of linux-stable:

https://github.com/corellium/linux-sandcastle

Buildroot

The Sandcastle Linux ramdisk is built using buildroot. Our customizations are here:

https://github.com/corellium/sandcastle-buildroot

Android applications

Installing APKs

You can generally install APK files with adb install foo.apk. However, the following limitations apply:

• pure Java APKs will generally work if they don't need unsupported hardware,
• APKs containing only ARMv7 binaries (32-bit) will not work,
• APKs containing ARMv8 binaries (64-bit) will require a rebuild of those binaries.

Rebuilding binary libraries

Binary libraries need to be built for 16kB page size. First, try these options when the library is linked:

-z common-page-size=0x4000 -z max-page-size=0x4000

If the linker is wrapped with C compiler, most likely you'll need this:

-Wl,-z,common-page-size=0x4000 -Wl,-z,max-page-size=0x4000

To check if stuff went well, use readelf -l on the library:

• if there's no RELRO segment, check that the LOAD segments with different attributes do not occupy the same 16kB page in any place (a good tip-off is 4000 in the ALIGN column on all of them),

• if there is a RELRO segment, make sure that it either starts or ends on a 16kB boundary; sometimes compilers put RELRO at start of the RW segment (and RELRO should then end at a 16k boundary) and sometimes they put it at the end (and RELRO should then start at a 16k boundary).

Basically the idea is that files that are incorrectly built end up having executable, read-write and read-only data in the same 16k page.

If this doesn't help, check the source of the library for blatant uses of 4096, 0x1000 or 12 for PAGE_SIZE, kPageSize, PAGE_SHIFT, PAGE_BITS, etc. (comparatively rare, but Chromium is a good example).