testing/kernel-cache-tests/pageablekc-vtable-patching/test.py

   1 #!/usr/bin/python2.7
   2
   3 import os
   4 import KernelCollection
   5
   6 # This verifies that a kext can patch vtables against another kext
   7 # We put foo.kext in the base KC so that the patch slot in bar.kext has to know to use the correct fixup level in the fixup chain
   8
   9 def check(kernel_cache):
  10     kernel_cache.buildKernelCollection("x86_64", "/pageablekc-vtable-patching/main.kc", "/pageablekc-vtable-patching/main.kernel", "/pageablekc-vtable-patching/extensions", ["com.apple.foo"], [])
  11     kernel_cache.analyze("/pageablekc-vtable-patching/main.kc", ["-layout", "-arch", "x86_64"])
  12
  13     assert len(kernel_cache.dictionary()["dylibs"]) == 2
  14     assert kernel_cache.dictionary()["dylibs"][0]["name"] == "com.apple.kernel"
  15     assert kernel_cache.dictionary()["dylibs"][1]["name"] == "com.apple.foo"
  16
  17     # Get the addresses for the symbols we are looking at.  This will make it easier to work out the fixup slots
  18     kernel_cache.analyze("/pageablekc-vtable-patching/main.kc", ["-symbols", "-arch", "x86_64"])
  19
  20     # From foo, we want to know where the vtable is, and the foo() and fooUsed0() slots in that vtable
  21     # Foo::foo()
  22     assert kernel_cache.dictionary()["dylibs"][1]["global-symbols"][6]["name"] == "__ZN3Foo3fooEv"
  23     assert kernel_cache.dictionary()["dylibs"][1]["global-symbols"][6]["vmAddr"] == "0x16ED0"
  24     # Foo::fooUsed0()
  25     assert kernel_cache.dictionary()["dylibs"][1]["global-symbols"][7]["name"] == "__ZN3Foo8fooUsed0Ev"
  26     assert kernel_cache.dictionary()["dylibs"][1]["global-symbols"][7]["vmAddr"] == "0x16EF0"
  27
  28
  29     # Check the fixups
  30     kernel_cache.analyze("/pageablekc-vtable-patching/main.kc", ["-fixups", "-arch", "x86_64"])
  31
  32     # In vtable for Foo, we match the entry for Foo::foo() by looking for its value on the RHS of the fixup
  33     assert kernel_cache.dictionary()["fixups"]["0x1D150"] == "kc(0) + 0x16ED0"
  34     # Then the following fixup should be to Foo::fooUsed0()
  35     assert kernel_cache.dictionary()["fixups"]["0x1D158"] == "kc(0) + 0x16EF0"
  36
  37
  38     # -----------------------------------------------------------
  39     # Now build an pageable cache using the baseline kernel collection
  40     kernel_cache.buildPageableKernelCollection("x86_64", "/pageablekc-vtable-patching/pageable.kc", "/pageablekc-vtable-patching/main.kc", "/pageablekc-vtable-patching/extensions", ["com.apple.bar"], [])
  41     kernel_cache.analyze("/pageablekc-vtable-patching/pageable.kc", ["-layout", "-arch", "x86_64"])
  42
  43     assert len(kernel_cache.dictionary()["dylibs"]) == 1
  44     assert kernel_cache.dictionary()["dylibs"][0]["name"] == "com.apple.bar"
  45
  46
  47     # Get the addresses for the symbols we are looking at.  This will make it easier to work out the fixup slots
  48     kernel_cache.analyze("/pageablekc-vtable-patching/pageable.kc", ["-symbols", "-arch", "x86_64"])
  49
  50     # From bar, find the vtable and its override of foo()
  51     # Bar::foo()
  52     assert kernel_cache.dictionary()["dylibs"][0]["global-symbols"][3]["name"] == "__ZN3Bar3fooEv"
  53     assert kernel_cache.dictionary()["dylibs"][0]["global-symbols"][3]["vmAddr"] == "0x4F10"
  54
  55
  56     # Check the fixups
  57     kernel_cache.analyze("/pageablekc-vtable-patching/pageable.kc", ["-fixups", "-arch", "x86_64"])
  58
  59     # In bar, again match the entry for its Bar::foo() symbol
  60     assert kernel_cache.dictionary()["dylibs"][0]["fixups"]["0x8150"] == "kc(1) + 0x4F10"
  61     # And if the patching was correct, then following entry should be to Foo::fooUsed0()
  62     assert kernel_cache.dictionary()["dylibs"][0]["fixups"]["0x8158"] == "kc(0) + 0x12EF0"
  63
  64
  65 # [~]> xcrun -sdk macosx.internal cc -arch x86_64 -Wl,-static -mkernel -nostdlib -Wl,-e,__start -Wl,-pie main.cpp -Wl,-pagezero_size,0x0 -o main.kernel -Wl,-image_base,0x10000 -Wl,-segaddr,__HIB,0x4000 -Wl,-add_split_seg_info -Wl,-install_name,/usr/lib/swift/split.seg.v2.hack -iwithsysroot /System/Library/Frameworks/Kernel.framework/Headers -Wl,-sectcreate,__LINKINFO,__symbolsets,SymbolSets.plist -Wl,-segprot,__LINKINFO,r--,r--
  66 # [~]> xcrun -sdk macosx.internal cc -arch x86_64 -Wl,-kext -mkernel -nostdlib -Wl,-add_split_seg_info -Wl,-no_data_const foo.cpp -o extensions/foo.kext/foo -iwithsysroot /System/Library/Frameworks/Kernel.framework/Headers -DFOO_USED=1
  67 # [~]> xcrun -sdk macosx.internal cc -arch x86_64 -Wl,-kext -mkernel -nostdlib -Wl,-add_split_seg_info -Wl,-data_const bar.cpp -o extensions/bar.kext/bar -iwithsysroot /System/Library/Frameworks/Kernel.framework/Headers
  68 # [~]> rm -r extensions/*.kext/*.ld
  69