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")
ZydisCalcAbsoluteAddress(const ZydisDecodedInstruction * instruction,const ZydisDecodedOperand * operand,ZyanU64 runtime_address,ZyanU64 * result_address)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
ZydisCalcAbsoluteAddressEx(const ZydisDecodedInstruction * instruction,const ZydisDecodedOperand * operand,ZyanU64 runtime_address,const ZydisRegisterContext * register_context,ZyanU64 * result_address)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_REGISTER) &&
137 ((operand->type != ZYDIS_OPERAND_TYPE_MEMORY) ||
138 ((operand->mem.base == ZYDIS_REGISTER_NONE) &&
139 (operand->mem.index == ZYDIS_REGISTER_NONE)) ||
140 (operand->mem.base == ZYDIS_REGISTER_EIP) ||
141 (operand->mem.base == ZYDIS_REGISTER_RIP)))
142 {
143 return ZydisCalcAbsoluteAddress(instruction, operand, runtime_address, result_address);
144 }
145
146 ZyanU64 value;
147 if (operand->type == ZYDIS_OPERAND_TYPE_REGISTER)
148 {
149 value = register_context->values[operand->reg.value];
150 }
151 else if (operand->type == ZYDIS_OPERAND_TYPE_MEMORY)
152 {
153 value = operand->mem.disp.value;
154 if (operand->mem.base)
155 {
156 value += register_context->values[operand->mem.base];
157 }
158 if (operand->mem.index)
159 {
160 value += register_context->values[operand->mem.index] * operand->mem.scale;
161 }
162 }
163 else
164 {
165 return ZYAN_STATUS_INVALID_ARGUMENT;
166 }
167
168 switch (instruction->address_width)
169 {
170 case 16:
171 *result_address = value & 0x000000000000FFFF;
172 return ZYAN_STATUS_SUCCESS;
173 case 32:
174 *result_address = value & 0x00000000FFFFFFFF;
175 return ZYAN_STATUS_SUCCESS;
176 case 64:
177 *result_address = value;
178 return ZYAN_STATUS_SUCCESS;
179 default:
180 return ZYAN_STATUS_INVALID_ARGUMENT;
181 }
182 }
183
184 /* ============================================================================================== */
185