diff --git a/deps/vmprofiler b/deps/vmprofiler
index b018ca7..c5df133 160000
--- a/deps/vmprofiler
+++ b/deps/vmprofiler
@@ -1 +1 @@
-Subproject commit b018ca7999b7a5bd372f56fad4d11f1f9033f255
+Subproject commit c5df1338acfb22485387e4b96d26051640b3a931
diff --git a/include/vmemu_t.hpp b/include/vmemu_t.hpp
index c2a838a..3b63cf8 100644
--- a/include/vmemu_t.hpp
+++ b/include/vmemu_t.hpp
@@ -24,13 +24,22 @@ class emu_t {
uc_engine* uc;
const vm::vmctx_t* m_vm;
zydis_reg_t vip, vsp;
+
+ ///
+ /// current code trace...
+ ///
vm::instrs::hndlr_trace_t cc_trace;
+
+ ///
+ /// current virtual code block...
+ /// block...
+ ///
vm::instrs::vblk_t* cc_blk;
///
- /// set to true when emulating the vm enter...
+ /// current code virtual routine...
///
- bool m_vm_enter;
+ vm::instrs::vrtn_t* cc_vrtn;
///
/// unicorn engine hook
@@ -80,13 +89,21 @@ class emu_t {
static void int_callback(uc_engine* uc, std::uint32_t intno, emu_t* obj);
///
- /// determines if there is a JCC in the virtual instruction stream, if there
- /// is returns a pair of image based addresses for both of the branches...
+ /// determines if its possible that the virtual instruction stream contains a
+ /// virtual JCC...
+ ///
+ /// this simply checks to see if there are at least 3 LCONST that load 64bit
+ /// constant values...
+ ///
+ /// it also checks if the last 2 LCONST's load image based addresses which
+ /// land inside of executable sections...
+ ///
+ /// this function cannot be used to determine if there is a virtual branch or
+ /// not... it is only a useful/preliminary function...
///
/// vector of virtual instructions...
- /// returns a pair of imaged based addresses, one for each branch
- /// address... if there is no jcc then it returns nothing...
- std::optional> has_jcc(
- std::vector& vinstrs);
+ /// returns true if there is at least 3 LCONST in the virtual
+ /// instruction stream that load 64bit values...
+ bool could_have_jcc(std::vector& vinstrs);
};
} // namespace vm
diff --git a/src/vmemu_t.cpp b/src/vmemu_t.cpp
index 2f60b3e..b14fa3b 100644
--- a/src/vmemu_t.cpp
+++ b/src/vmemu_t.cpp
@@ -78,12 +78,12 @@ bool emu_t::emulate(std::uint32_t vmenter_rva, vm::instrs::vrtn_t& vrtn) {
cc_trace.m_vip = vip;
cc_trace.m_vsp = vsp;
vrtn.m_rva = vmenter_rva;
- m_vm_enter = true;
vm::instrs::vblk_t blk;
blk.m_vip = {0ull, 0ull};
- blk.m_cpu = {nullptr, nullptr};
+
cc_blk = &blk;
+ cc_vrtn = &vrtn;
std::printf("> beginning execution at = %p\n", rip);
if ((err = uc_emu_start(uc, rip, 0ull, 0ull, 0ull))) {
@@ -91,9 +91,9 @@ bool emu_t::emulate(std::uint32_t vmenter_rva, vm::instrs::vrtn_t& vrtn) {
return false;
}
- std::printf("> blk address = %p\n", blk.m_vip.img_base);
- const auto jcc_result = has_jcc(blk.m_vinstrs);
- std::printf("> jcc result = %d\n", jcc_result.has_value());
+ std::printf(
+ "> blk_%p, number of virtual instructions = %d, could have a jcc = %d\n",
+ blk.m_vip.img_base, blk.m_vinstrs.size(), could_have_jcc(blk.m_vinstrs));
return true;
}
@@ -148,18 +148,17 @@ bool emu_t::code_exec_callback(uc_engine* uc,
if (instr.mnemonic == ZYDIS_MNEMONIC_INVALID)
return false;
- // save the current cpu's context (all register values and such)...
- // create a new emu_instr_t with this information... this info will be used by
- // profiles to grab decrypted values and such...
- uc_context* cpu_ctx;
- uc_context_alloc(obj->uc, &cpu_ctx);
- uc_context_save(obj->uc, cpu_ctx);
+ uc_context* ctx;
+ uc_context_alloc(uc, &ctx);
+ uc_context_save(uc, ctx);
- std::uint8_t* stack = reinterpret_cast(malloc(STACK_SIZE));
- uc_mem_read(uc, STACK_BASE, stack, STACK_SIZE);
+ // if this is the first instruction of this handler then save the stack...
+ if (!obj->cc_trace.m_instrs.size()) {
+ obj->cc_trace.m_stack = reinterpret_cast(malloc(STACK_SIZE));
+ uc_mem_read(uc, STACK_BASE, obj->cc_trace.m_stack, STACK_SIZE);
+ }
- vm::instrs::emu_instr_t emu_instr{instr, cpu_ctx, stack};
- obj->cc_trace.m_instrs.push_back(emu_instr);
+ obj->cc_trace.m_instrs.push_back({instr, ctx});
// RET or JMP REG means the end of a vm handler...
if (instr.mnemonic == ZYDIS_MNEMONIC_RET ||
@@ -185,33 +184,32 @@ bool emu_t::code_exec_callback(uc_engine* uc,
obj->cc_trace.m_instrs.erase((rva_fetch + 1).base(),
obj->cc_trace.m_instrs.end());
- // extract vip address out of the vm enter trace...
- if (obj->m_vm_enter) {
- auto vip_addr_set = std::find_if(
+ // set the virtual code block vip address information...
+ if (!obj->cc_blk->m_vip.rva || !obj->cc_blk->m_vip.img_base) {
+ auto vip_write = std::find_if(
obj->cc_trace.m_instrs.rbegin(), obj->cc_trace.m_instrs.rend(),
- [&vip = obj->vip](vm::instrs::emu_instr_t& emu_instr) -> bool {
- const auto& i = emu_instr.m_instr;
+ [&vip = obj->vip](vm::instrs::emu_instr_t& instr) -> bool {
+ const auto& i = instr.m_instr;
return i.operands[0].type == ZYDIS_OPERAND_TYPE_REGISTER &&
i.operands[0].reg.value == vip;
});
- // get the cpu context from the instruction after the instruction that
- // writes to vip...
- --vip_addr_set;
-
uc_context* backup;
uc_context_alloc(uc, &backup);
uc_context_save(uc, backup);
- uc_context_restore(uc, vip_addr_set->m_cpu);
+ uc_context_restore(uc, (vip_write - 1)->m_cpu);
+
+ auto uc_reg =
+ vm::instrs::reg_map[vip_write->m_instr.operands[0].reg.value];
std::uintptr_t vip_addr = 0ull;
- uc_reg_read(uc, vm::instrs::reg_map[obj->vip], &vip_addr);
+ uc_reg_read(uc, uc_reg, &vip_addr);
+
obj->cc_blk->m_vip.rva = vip_addr -= obj->m_vm->m_module_base;
obj->cc_blk->m_vip.img_base = vip_addr += obj->m_vm->m_image_base;
uc_context_restore(uc, backup);
uc_context_free(backup);
- obj->m_vm_enter = false;
} else {
const auto vinstr =
vm::instrs::determine(obj->vip, obj->vsp, obj->cc_trace);
@@ -241,21 +239,25 @@ bool emu_t::code_exec_callback(uc_engine* uc,
obj->cc_blk->m_vinstrs.push_back(vinstr);
if (vinstr.mnemonic == vm::instrs::mnemonic_t::jmp) {
- uc_context *b1, *b2;
- uc_context_alloc(uc, &b1);
- uc_context_alloc(uc, &b2);
- uc_context_save(uc, b1);
- uc_context_restore(uc, obj->cc_trace.m_instrs.begin()->m_cpu);
- uc_context_save(uc, b2);
- uc_context_restore(uc, b1);
+ uc_context *backup, *copy;
- std::uint8_t* stack =
- reinterpret_cast(malloc(STACK_SIZE));
+ // backup current unicorn-engine context...
+ uc_context_alloc(uc, &backup);
+ uc_context_alloc(uc, ©);
+ uc_context_save(uc, backup);
- std::memcpy(stack, obj->cc_trace.m_instrs.begin()->stack, STACK_SIZE);
+ // make a copy of the first cpu context of the jmp handler...
+ uc_context_restore(uc, obj->cc_trace.m_instrs.begin()->m_cpu);
+ uc_context_save(uc, copy);
+
+ // restore the unicorn-engine context... also free the backup...
+ uc_context_restore(uc, backup);
+ uc_context_free(backup);
- obj->cc_blk->m_cpu.ctx = b2;
- obj->cc_blk->m_cpu.stack = stack;
+ // set current code block virtual jmp instruction information...
+ obj->cc_blk->m_jmp.ctx = copy;
+ obj->cc_blk->m_jmp.stack = new std::uint8_t[STACK_SIZE];
+ uc_mem_read(uc, STACK_BASE, obj->cc_blk->m_jmp.stack, STACK_SIZE);
}
if (vinstr.mnemonic == vm::instrs::mnemonic_t::jmp ||
@@ -267,9 +269,9 @@ bool emu_t::code_exec_callback(uc_engine* uc,
std::for_each(obj->cc_trace.m_instrs.begin(), obj->cc_trace.m_instrs.end(),
[&](const vm::instrs::emu_instr_t& instr) {
uc_context_free(instr.m_cpu);
- free(instr.stack);
});
+ free(obj->cc_trace.m_stack);
obj->cc_trace.m_instrs.clear();
}
return true;
@@ -314,49 +316,51 @@ void emu_t::invalid_mem(uc_engine* uc,
}
}
-std::optional> emu_t::has_jcc(
- std::vector& vinstrs) {
- if (vinstrs.back().mnemonic == vm::instrs::mnemonic_t::vmexit)
- return {};
-
- // number of LCONST virtual instructions which load 64bit imm's...
- const std::uint32_t lconst_num = std::accumulate(
- vinstrs.begin(), vinstrs.end(), 0,
- [&](std::uint32_t val, vm::instrs::vinstr_t& v) -> std::uint32_t {
- return v.mnemonic == vm::instrs::mnemonic_t::lconst && v.imm.size == 64
- ? ++val
- : val;
- });
-
- if (lconst_num < 3)
- return {};
-
- const auto lconst1 = std::find_if(
- vinstrs.rbegin(), vinstrs.rend(), [&](vm::instrs::vinstr_t& v) -> bool {
- return v.mnemonic == vm::instrs::mnemonic_t::lconst && v.imm.size == 64;
- });
-
- const auto lconst2 = std::find_if(
- lconst1 + 1, vinstrs.rend(), [&](vm::instrs::vinstr_t& v) -> bool {
- return v.mnemonic == vm::instrs::mnemonic_t::lconst && v.imm.size == 64;
- });
-
- static const auto exec_callbk = [&](uc_engine* uc, uint64_t address,
- uint32_t size, emu_t* obj) {};
-
- uc_context *backup, *br1, *br2;
- uc_context_alloc(uc, &backup);
- uc_context_alloc(uc, &br1);
- uc_context_alloc(uc, &br2);
- uc_context_save(uc, backup);
-
- uc_context_restore(uc, cc_blk->m_cpu.ctx);
- uc_mem_write(uc, STACK_BASE, cc_blk->m_cpu.stack, STACK_SIZE);
-
- uc_context_restore(uc, backup);
- uc_context_free(backup);
- uc_context_free(br1);
- uc_context_free(br2);
- return {};
+bool emu_t::could_have_jcc(std::vector& vinstrs) {
+ // check to see if there is at least 3 LCONST %i64's
+ if (std::accumulate(
+ vinstrs.begin(), vinstrs.end(), 0u,
+ [&](std::uint32_t val, vm::instrs::vinstr_t& v) -> std::uint32_t {
+ return v.mnemonic == vm::instrs::mnemonic_t::lconst &&
+ v.imm.size == 64
+ ? ++val
+ : val;
+ }) < 3)
+ return false;
+
+ // extract the lconst64's out of the virtual instruction stream...
+ static const auto lconst64_chk = [&](vm::instrs::vinstr_t& v) -> bool {
+ return v.mnemonic == vm::instrs::mnemonic_t::lconst && v.imm.size == 64;
+ };
+
+ const auto lconst1 =
+ std::find_if(vinstrs.rbegin(), vinstrs.rend(), lconst64_chk);
+
+ if (lconst1 == vinstrs.rend())
+ return false;
+
+ const auto lconst2 = std::find_if(lconst1 + 1, vinstrs.rend(), lconst64_chk);
+
+ if (lconst2 == vinstrs.rend())
+ return false;
+
+ // check to see if the imm val is inside of the image...
+ if (lconst1->imm.val > m_vm->m_image_base + m_vm->m_image_size ||
+ lconst1->imm.val < m_vm->m_image_base ||
+ lconst2->imm.val > m_vm->m_image_base + m_vm->m_image_size ||
+ lconst2->imm.val < m_vm->m_image_base)
+ return false;
+
+ // check to see if the imm's points to something inside of an executable
+ // section...
+ if (!vm::utils::scn::executable(
+ m_vm->m_module_base,
+ (lconst1->imm.val - m_vm->m_image_base) + m_vm->m_module_base) ||
+ !vm::utils::scn::executable(
+ m_vm->m_module_base,
+ (lconst2->imm.val - m_vm->m_image_base) + m_vm->m_module_base))
+ return false;
+
+ return true;
}
} // namespace vm
\ No newline at end of file