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<br> 从Platform Builder来看,Windows CE支持相当多CPU,但现在市场上实际销售的PDA几乎全部采用ARM芯片。arm是一个RISC构架的32位微处理器,它一次有16个可见的寄存器:r0-r15。其中r0-r7是通用寄存器并可以做任何目的;r8-r12也是通用寄存器,但是在切换到FIQ模式的时候,使用它们的影子(shadow)寄存器;最后这三个是特殊寄存器:<br> <br> r13 (sp) - 堆栈指针<br> r14 (lr) - 链接寄存器<br> r15 (pc/psr) - 程序计数器/状态寄存器<br> <br> IDAPro和调试器里都是用别名表示。和其它RISC指令类似,arm指令主要有分支(branch)指令、载入和存储指令和其它指令等,除了载入和存储指令,其它指令都是不能直接操作内存的,而且载入和存储指令操作的是4字节类型,那么内存地址必须要求4字节对齐,这也是RISC指令和CISC指令差异比较大的地方,在操作字符串的时候相对就比较麻烦。arm指令一个很有趣的地方就是可以直接修改访问pc寄存器,这样如果写shellcode的话就不必象SPARC或PowerPC一样需要多条指令来定位自身。<br> <br> 另外Windows CE默认使用的字节序是little-endian。<br> <br> --[ 2. Windows CE核心结构<br> <br> Windows CE是一个32位的操作系统,所以其虚拟内存的大小是4GB(2的32次方)。Windows CE把这4GB虚拟内存空间分为低地址2GB和高地址2GB。应用程序使用的地址空间是低地址2GB,高地址2GB专供Windows CE内核使用。在Windows CE 3.0源码的PRIVATE/WINCEOS/COREOS/NK/INC/nkarm.h头文件里有一些有趣的信息:<br> <br> /* High memory layout<br> *<br> * This structure is mapped in at the end of the 4GB virtual<br> * address space.<br> *<br> * 0xFFFD0000 - first level page table (uncached) (2nd half is r/o)<br> * 0xFFFD4000 - disabled for protection<br> * 0xFFFE0000 - second level page tables (uncached)<br> * 0xFFFE4000 - disabled for protection<br> * 0xFFFF0000 - exception vectors<br> * 0xFFFF0400 - not used (r/o)<br> * 0xFFFF1000 - disabled for protection<br> * 0xFFFF2000 - r/o (physical overlaps with vectors)<br> * 0xFFFF2400 - Interrupt stack (1k)<br> * 0xFFFF2800 - r/o (physical overlaps with Abort stack & FIQ stack)<br> * 0xFFFF3000 - disabled for protection<br> * 0xFFFF4000 - r/o (physical memory overlaps with vectors & intr. stack & FIQ stack)<br> * 0xFFFF4900 - Abort stack (2k - 256 bytes)<br> *&n<br> <br> bsp; 0xFFFF5000 - disabled for protection<br> * 0xFFFF6000 - r/o (physical memory overlaps with vectors & intr. stack)<br> * 0xFFFF6800 - FIQ stack (256 bytes)<br> * 0xFFFF6900 - r/o (physical memory overlaps with Abort stack)<br> * 0xFFFF7000 - disabled<br> * 0xFFFFC000 - kernel stack<br> * 0xFFFFC800 - KDataStruct<br> * 0xFFFFCC00 - disabled for protection (2nd level page table for 0xFFF00000)<br> */<br> <br> typedef struct arm_HIGH {<br> ulong firstPT[4096]; // 0xFFFD0000: 1st level page table<br> PAGETBL aPT[16]; // 0xFFFD4000: 2nd level page tables<br> char reserved2[0x20000-0x4000-16*sizeof(PAGETBL)];<br> <br> char exVectors[0x400]; // 0xFFFF0000: exception vectors<br> char reserved3[0x2400-0x400];<br> <br> char intrStack[0x400]; // 0xFFFF2400: interrupt stack<br> char reserved4[0x4900-0x2800];<br> <br> char abortStack[0x700]; // 0xFFFF4900: abort stack<br> char reserved5[0x6800-0x5000];<br> <br> char fiqStack[0x100]; // 0xFFFF6800: FIQ stack<br> char reserved6[0xC000-0x6900];<br> <br> char kStack[0x800]; // 0xFFFFC000: kernel stack<br> struct KDataStruct kdata; &<br> <br> nbsp; // 0xFFFFC800: kernel data page<br> } arm_HIGH;<br> <br> 其中KDataStruct的结构非常重要而且有意思,有些类似Win32下的PEB结构,定义了系统各种重要的信息:<br> <br> struct KDataStruct {<br> LPDWORD lpvTls; /* 0x000 Current thread local storage pointer */<br> HANDLE ahSys[NUM_SYS_HANDLES]; /* 0x004 If this moves, change kapi.h */<br> // NUM_SYS_HANDLES == 32 : PUBLIC/COMMON/SDK/INC/kfuncs.h<br> 0x004 SH_WIN32<br> 0x008 SH_CURTHREAD<br> 0x00c SH_CURPROC<br> 0x010 SH_KWIN32<br> 0x044 SH_GDI<br> 0x048 SH_WMGR<br> 0x04c SH_WNET<br> 0x050 SH_COMM<br> 0x054 SH_FILESYS_APIS<br> 0x058 SH_SHELL<br> 0x05c SH_DEVMGR_APIS<br> 0x060 SH_TAPI<br> 0x064 SH_PATCHER<br> 0x06c SH_SERVICES<br> <br> char bResched; /* 0x084 reschedule flag */<br> char cNest; /* 0x085 kernel exception nesting */<br> char bPowerOff; /* 0x086 TRUE during "power off" processing */<br> char bProfileOn;&nb<br> <br> sp; /* 0x087 TRUE if profiling enabled */<br> ulong unused; /* 0x088 unused */<br> ulong rsvd2; /* 0x08c was DiffMSec */<br> PPROCESS pCurPrc; /* 0x090 ptr to current PROCESS struct */<br> PTHREAD pCurThd; /* 0x094 ptr to current THREAD struct */<br> DWORD dwKCRes; /* 0x098 */<br> ulong handleBase; /* 0x09c handle table base address */<br> PSECTION aSections[64]; /* 0x0a0 section table for virutal memory */<br> LPEVENT alpeIntrEvents[SYSINTR_MAX_DEVICES];/* 0x1a0 */<br> LPVOID alpvIntrData[SYSINTR_MAX_DEVICES]; /* 0x220 */<br> ulong pAPIReturn; /* 0x2a0 direct API return address for kernel mode */<br> uchar *pMap; /* 0x2a4 ptr to MemoryMap array */<br> DWORD dwInDebugger; /* 0x2a8 !0 when in debugger */<br> PTHREAD pCurFPUOwner; /* 0x2ac current FPU owner */<br> PPROCESS pCpuASIDPrc; /* 0x2b0 current ASID proc */<br> long nMemForPT; /* 0x2b4 - Memory used for PageTables */<br> <br> long alPad[18]; /* 0x2b8 - padding */<br> <br> DWORD aInfo[32]; /* 0x300 - misc. kernel info */<br> // PUBLIC/COMMON/OAK/INC/pkfuncs.h<br> 0x300 KINX_PROCARRAY address of process array<br> 0x304 KINX_PAGESIZE system page size<br> 0x308 KINX_PFN_SHIFT shift for page # in PTE<br> 0x30c KINX_PFN_MASK mask for page # in PTE<br> 0x310 KINX_PAGEFREE # of free physical pages<br> 0x314 KINX_SYSPAGES # of pages used by kernel<br> 0x318 KINX_KHEAP ptr to kernel heap array<br> 0x31c KINX_SECTIONS ptr to SectionTable array<br> 0x320 KINX_MEMINFO ptr to system MemoryInfo struct<br> 0x324 KINX_MODULES ptr to module list<br> 0x328 KINX_DLL_LOW lower bound of DLL shared space<br> 0x32c KINX_NUMPAGES total # of RAM pages<br> 0x330 KINX_PTOC &nb<br> sp; ptr to ROM table of contents<br> 0x334 KINX_KDATA_ADDR kernel mode version of KData<br> 0x338 KINX_GWESHEAPINFO Current amount of gwes heap in use<br> 0x33c KINX_TIMEZONEBIAS Fast timezone bias info<br> 0x340 KINX_PENDEVENTS bit mask for pending interrupt events<br> 0x344 KINX_KERNRESERVE number of kernel reserved pages<br> 0x348 KINX_API_MASK bit mask for registered api sets<br> 0x34c KINX_NLS_CP hiword OEM code page, loword ANSI code page<br> 0x350 KINX_NLS_SYSLOC Default System locale<br> 0x354 KINX_NLS_USERLOC Default User locale<br> 0x358 KINX_HEAP_WASTE Kernel heap wasted space<br> 0x35c KINX_DEBUGGER For use by debugger for protocol communication<br> 0x360 KINX_APISETS APIset pointers<br> 0x364 KINX_MINPAGEFREE water mark of the minimum number of free pages<br> 0x368 KINX_CELOGSTATUS CeLog status flags<br> 0x36c KINX_NKSECTION Address of NKSection<br> 0x370 KINX_PWR_EVTS Events to be set after power on<br> 0x37c KINX_NKSIG last entry of KINFO -- signature when NK is ready<br> <br> /* 0x380 - interlocked api code */<br> /* 0x400 - end */<br> }<br> <br> Win32下可以通过PEB结构定位kernel32.dll的基址,然后通过PE文件结构查找Windows API。在Windows CE下,coredll.dll的作用相当于Win32的kernel32.dll,由于KDataStruct结构开始于0xFFFFC800,偏移0x324的aInfo[KINX_MODULES]是一个指向模块链表的指针,通过这个链表能否找到coredll.dll模块呢?让我们来看一下模块的结构:<br> <br> // PRIVATE/WINCEOS/COREOS/NK/INC/kernel.h<br> typedef struct Module { < |
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