libs/zydis/src/Utils.c

   1 /***************************************************************************************************
   2
   3   Zyan Disassembler Library (Zydis)
   4
   5   Original Author : Florian Bernd
   6
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in all
  15  * copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE.
  24
  25 ***************************************************************************************************/
  26
  27 #include <Zycore/LibC.h>
  28 #include <Zydis/Utils.h>
  29
  30 /* ============================================================================================== */
  31 /* Exported functions                                                                             */
  32 /* ============================================================================================== */
  33
  34 /* ---------------------------------------------------------------------------------------------- */
  35 /* Address calculation                                                                            */
  36 /* ---------------------------------------------------------------------------------------------- */
  37
  38 // Signed integer overflow is expected behavior in this function, for wrapping around the
  39 // instruction pointer on jumps right at the end of the address space.
  40 ZYAN_NO_SANITIZE("signed-integer-overflow")
  41 ZyanStatus ZydisCalcAbsoluteAddress(const ZydisDecodedInstruction* instruction,
  42     const ZydisDecodedOperand* operand, ZyanU64 runtime_address, ZyanU64* result_address)
  43 {
  44     if (!instruction || !operand || !result_address)
  45     {
  46         return ZYAN_STATUS_INVALID_ARGUMENT;
  47     }
  48
  49     switch (operand->type)
  50     {
  51     case ZYDIS_OPERAND_TYPE_MEMORY:
  52         if (!operand->mem.disp.has_displacement)
  53         {
  54             return ZYAN_STATUS_INVALID_ARGUMENT;
  55         }
  56         if (operand->mem.base == ZYDIS_REGISTER_EIP)
  57         {
  58             *result_address = ((ZyanU32)runtime_address + instruction->length +
  59                 (ZyanU32)operand->mem.disp.value);
  60             return ZYAN_STATUS_SUCCESS;
  61         }
  62         if (operand->mem.base == ZYDIS_REGISTER_RIP)
  63         {
  64             *result_address = (ZyanU64)(runtime_address + instruction->length +
  65                 operand->mem.disp.value);
  66             return ZYAN_STATUS_SUCCESS;
  67         }
  68         if ((operand->mem.base == ZYDIS_REGISTER_NONE) &&
  69             (operand->mem.index == ZYDIS_REGISTER_NONE))
  70         {
  71             switch (instruction->address_width)
  72             {
  73             case 16:
  74                 *result_address = (ZyanU64)operand->mem.disp.value & 0x000000000000FFFF;
  75                 return ZYAN_STATUS_SUCCESS;
  76             case 32:
  77                 *result_address = (ZyanU64)operand->mem.disp.value & 0x00000000FFFFFFFF;
  78                 return ZYAN_STATUS_SUCCESS;
  79             case 64:
  80                 *result_address = (ZyanU64)operand->mem.disp.value;
  81                 return ZYAN_STATUS_SUCCESS;
  82             default:
  83                 return ZYAN_STATUS_INVALID_ARGUMENT;
  84             }
  85         }
  86         break;
  87     case ZYDIS_OPERAND_TYPE_IMMEDIATE:
  88         if (operand->imm.is_signed && operand->imm.is_relative)
  89         {
  90             *result_address = (ZyanU64)((ZyanI64)runtime_address + instruction->length +
  91                 operand->imm.value.s);
  92             switch (instruction->machine_mode)
  93             {
  94             case ZYDIS_MACHINE_MODE_LONG_COMPAT_16:
  95             case ZYDIS_MACHINE_MODE_LEGACY_16:
  96             case ZYDIS_MACHINE_MODE_REAL_16:
  97             case ZYDIS_MACHINE_MODE_LONG_COMPAT_32:
  98             case ZYDIS_MACHINE_MODE_LEGACY_32:
  99                 // `XBEGIN` is a special case as it doesn't truncate computed address
 100                 // This behavior is documented by Intel (SDM Vol. 2C):
 101                 // Use of the 16-bit operand size does not cause this address to be truncated to
 102                 // 16 bits, unlike a near jump to a relative offset.
 103                 if ((instruction->operand_width == 16) &&
 104                     (instruction->mnemonic != ZYDIS_MNEMONIC_XBEGIN))
 105                 {
 106                     *result_address &= 0xFFFF;
 107                 }
 108                 break;
 109             case ZYDIS_MACHINE_MODE_LONG_64:
 110                 break;
 111             default:
 112                 return ZYAN_STATUS_INVALID_ARGUMENT;
 113             }
 114             return ZYAN_STATUS_SUCCESS;
 115         }
 116         break;
 117     default:
 118         break;
 119     }
 120
 121     return ZYAN_STATUS_INVALID_ARGUMENT;
 122 }
 123
 124 ZyanStatus ZydisCalcAbsoluteAddressEx(const ZydisDecodedInstruction* instruction,
 125     const ZydisDecodedOperand* operand, ZyanU64 runtime_address,
 126     const ZydisRegisterContext* register_context, ZyanU64* result_address)
 127 {
 128     // TODO: Test this with AGEN/MIB operands
 129     // TODO: Add support for Gather/Scatter instructions
 130
 131     if (!instruction || !operand || !register_context || !result_address)
 132     {
 133         return ZYAN_STATUS_INVALID_ARGUMENT;
 134     }
 135
 136     if ((operand->type != ZYDIS_OPERAND_TYPE_MEMORY) ||
 137         ((operand->mem.base == ZYDIS_REGISTER_NONE) &&
 138          (operand->mem.index == ZYDIS_REGISTER_NONE)) ||
 139         (operand->mem.base == ZYDIS_REGISTER_EIP) ||
 140         (operand->mem.base == ZYDIS_REGISTER_RIP))
 141     {
 142         return ZydisCalcAbsoluteAddress(instruction, operand, runtime_address, result_address);
 143     }
 144
 145     ZyanU64 value = operand->mem.disp.value;
 146     if (operand->mem.base)
 147     {
 148         value += register_context->values[operand->mem.base];
 149     }
 150     if (operand->mem.index)
 151     {
 152         value += register_context->values[operand->mem.index] * operand->mem.scale;
 153     }
 154
 155     switch (instruction->address_width)
 156     {
 157     case 16:
 158         *result_address = value & 0x000000000000FFFF;
 159         return ZYAN_STATUS_SUCCESS;
 160     case 32:
 161         *result_address = value & 0x00000000FFFFFFFF;
 162         return ZYAN_STATUS_SUCCESS;
 163     case 64:
 164         *result_address = value;
 165         return ZYAN_STATUS_SUCCESS;
 166     default:
 167         return ZYAN_STATUS_INVALID_ARGUMENT;
 168     }
 169 }
 170
 171 /* ============================================================================================== */