726f45b33d
When attempting to set all flags except trap flag, the EFLAGS value should be 0x00244ED7, I've tested this on Windows and here https://ideone.com/WQAvk1 which is presumably Linux. Unicorn however has the value 0x00000ED7, bits 11-21 are not set. Bit 21 is the ID bit indicating whether or not CPUID is available.
107 lines
2.7 KiB
C
107 lines
2.7 KiB
C
#include <stdlib.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <inttypes.h>
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#include <assert.h>
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#include <unicorn/unicorn.h>
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#define X86_CODE32 "\x9C\x68\xFF\xFE\xFF\xFF\x9D\x9C\x58\x9D" // pushf; push ffffffeff; popf; pushf; pop eax; popf
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#define ADDRESS 0x1000000
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#define PAGE_8K (1 << 13)
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#define PAGE_4K (1 << 12)
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#define TARGET_PAGE_MASK ~(PAGE_4K - 1)
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#define TARGET_PAGE_PREPARE(addr) (((addr) + PAGE_4K - 1) & TARGET_PAGE_MASK)
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#define TARGET_PAGE_ALIGN(addr) (addr - (TARGET_PAGE_PREPARE(addr) - addr) & TARGET_PAGE_MASK)
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unsigned int realEflags()
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{
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unsigned int val = 0;
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unsigned int i = 0xFFFFFEFF; //attempt to set ALL bits except trap flag.
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__asm__("pushf\n\t"
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"push %0\n\t"
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"popf\n\t"
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"pushf\n\t"
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"pop %0\n\t"
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"popf"
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: "=r"(val)
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: "r"(i)
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: "%0");
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printf("Real system eflags: 0x%08X\n", val);
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return val;
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}
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static void VM_exec()
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{
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uc_engine *uc;
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uc_err err;
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unsigned int r_eax, eflags, r_esp, realflags = 0;
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r_eax = 0;
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r_esp = ADDRESS+0x100; //some safe distance from main code.
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eflags = 0x00000206;
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// Initialize emulator in X86-32bit mode
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err = uc_open(UC_ARCH_X86, UC_MODE_32, &uc);
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if(err)
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{
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printf("Failed on uc_open() with error returned: %s\n", uc_strerror(err));
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return;
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}
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err = uc_mem_map(uc, ADDRESS, (2 * 1024 * 1024), UC_PROT_ALL);
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if(err != UC_ERR_OK)
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{
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printf("Failed to map memory %s\n", uc_strerror(err));
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return;
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}
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// write machine code to be emulated to memory
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err = uc_mem_write(uc, ADDRESS, X86_CODE32, sizeof(X86_CODE32) - 1);
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if(err != UC_ERR_OK)
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{
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printf("Failed to write emulation code to memory, quit!: %s(len %lu)\n", uc_strerror(err), sizeof(X86_CODE32) - 1);
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return;
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}
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// initialize machine registers
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uc_reg_write(uc, UC_X86_REG_EAX, &r_eax);
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uc_reg_write(uc, UC_X86_REG_ESP, &r_esp); //make stack pointer point to already mapped memory so we don't need to hook.
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uc_reg_write(uc, UC_X86_REG_EFLAGS, &eflags);
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// emulate machine code in infinite time
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err = uc_emu_start(uc, ADDRESS, ADDRESS + (sizeof(X86_CODE32) - 1), 0, 0);
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if(err)
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{
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printf("Failed on uc_emu_start() with error returned %u: %s\n", err, uc_strerror(err));
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uc_close(uc);
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return;
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}
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uc_reg_read(uc, UC_X86_REG_EAX, &r_eax);
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uc_reg_read(uc, UC_X86_REG_EFLAGS, &eflags);
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uc_close(uc);
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printf(">>> Emulation done. Below is the CPU context\n");
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printf(">>> EAX = 0x%08X\n", r_eax);
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printf(">>> EFLAGS = 0x%08X\n", eflags);
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realflags = realEflags();
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assert(r_eax == realflags);
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puts("Unicorn EFLAGS match expected system eflags");
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}
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int main(int argc, char *argv[])
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{
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VM_exec();
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return 0;
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}
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