From 242485bcbe53f7ca2abd560573b1030d91bba05c Mon Sep 17 00:00:00 2001
From: an7s <an7s@git.zephyr-software.com>
Date: Fri, 6 Oct 2017 13:06:45 +0000
Subject: [PATCH] Add to utility functions
Former-commit-id: 526d027a802518d2d85366d426b4f5309c2568ae
---
libIRDB/include/util/params.hpp | 4 +-
libIRDB/src/util/params.cpp | 146 ++++++++++++++++++++++++++++----
2 files changed, 131 insertions(+), 19 deletions(-)
diff --git a/libIRDB/include/util/params.hpp b/libIRDB/include/util/params.hpp
index de6006c13..2c9861055 100644
--- a/libIRDB/include/util/params.hpp
+++ b/libIRDB/include/util/params.hpp
@@ -2,6 +2,8 @@
#define _PARAMS_H
extern bool IsParameterWrite(const libIRDB::FileIR_t *firp, libIRDB::Instruction_t* insn, std::string& output_dst);
-extern bool CallFollows(libIRDB::FileIR_t *firp, libIRDB::Instruction_t* insn, const std::string& arg_str);
+extern bool CallFollows(const libIRDB::FileIR_t *firp, libIRDB::Instruction_t* insn, const std::string& arg_str, const std::string & = "");
+extern bool LeaFlowsIntoCall(const libIRDB::FileIR_t *firp, libIRDB::Instruction_t* insn);
+extern bool LeaFlowsIntoPrintf(const libIRDB::FileIR_t *firp, libIRDB::Instruction_t* insn);
#endif
diff --git a/libIRDB/src/util/params.cpp b/libIRDB/src/util/params.cpp
index 3829a0ea9..3db2c7cd5 100644
--- a/libIRDB/src/util/params.cpp
+++ b/libIRDB/src/util/params.cpp
@@ -29,7 +29,7 @@ using namespace std;
// Does instruction potentially write to a parameter to a call?
bool libIRDB::IsParameterWrite(const FileIR_t *firp, Instruction_t* insn, string& output_dst)
{
- DISASM d;
+ auto d=DISASM({0});
insn->Disassemble(d);
if(d.Argument1.AccessMode!=WRITE)
{
@@ -93,49 +93,159 @@ bool libIRDB::IsParameterWrite(const FileIR_t *firp, Instruction_t* insn, string
return false;
}
-// is instruction originally a call?
-static bool IsOrWasCall(const FileIR_t *firp, Instruction_t* insn)
+//
+// we look for:
+// (1) call instruction
+// (2) call converted to push/jmp pair
+//
+static Instruction_t* IsOrWasCall(const FileIR_t *firp, Instruction_t* insn)
{
if (firp == NULL || insn == NULL)
- return false;
+ return NULL;
- DISASM d;
+ auto d=DISASM({0});
insn->Disassemble(d);
if(d.Instruction.Mnemonic == string("call "))
- return true;
- else {
- // call may have been converted to push/jmp in previous phase
- // look for "push64" type reloc
+ {
+ return insn->GetTarget();
+ }
+ else
+ {
+ // look for "push64" or "fix_call_fallthrough" reloc
auto it = std::find_if(insn->GetRelocations().begin(),insn->GetRelocations().end(),[&](const Relocation_t* reloc)
{
return (reloc && ((reloc->GetType() == string("push64")) || reloc->GetType() == string("fix_call_fallthrough")));
});
+ // find actual target
if (it != insn->GetRelocations().end())
- return true;
+ {
+ if (insn->GetTarget())
+ return insn->GetTarget();
+ else if (insn->GetFallthrough())
+ return insn->GetFallthrough()->GetTarget();
+ }
}
return false;
}
// Does a call follow the instruction?
-bool libIRDB::CallFollows(FileIR_t *firp, Instruction_t* insn, const string& arg_str)
+bool libIRDB::CallFollows(const FileIR_t *firp, Instruction_t* insn, const string& reg_arg_str, const std::string &fn_pattern)
{
+ const std::set<std::string> param_regs = {"rdi", "rsi", "rdx", "rcx", "r8", "r9"};
+ const bool original_is_param_register = param_regs.find(reg_arg_str) != param_regs.end();
+
+ std::set<std::string> live_params;
+ live_params.insert(reg_arg_str);
+
for(Instruction_t* ptr=insn->GetFallthrough(); ptr!=NULL; ptr=ptr->GetFallthrough())
{
- DISASM d;
+ auto d=DISASM({0});
ptr->Disassemble(d);
- if(IsOrWasCall(firp, ptr))
+ long long vo = 0;
+ if (ptr->GetAddress())
+ vo = ptr->GetAddress()->GetVirtualOffset();
+// std::cout << "CallFollows(): " << ptr->getDisassembly() << " @ " << hex << vo << std::endl;
+
+ const auto tgt = IsOrWasCall(firp, ptr);
+
+ if (tgt)
{
- // found it
- return true;
+ if (fn_pattern.size() == 0)
+ {
+ // don't care about function name
+// std::cout << "CallFollows(): yes, parameter to call" << endl;
+ return true;
+ }
+ else
+ {
+ // look for specific function
+
+ // check the target has a function
+ if(tgt->GetFunction()==NULL)
+ return false;
+
+ const auto fname = tgt->GetFunction()->GetName();
+// std::cout << "CallFollows(): yes, parameter to call: function name: " << fname << endl;
+ return fname.find(fn_pattern)!=string::npos;
+ }
}
- // found reference to argstring, assume it's a write and exit
- if(string(d.CompleteInstr).find(arg_str)!= string::npos)
- return false;
+ // found reference to argstring, original code would just stop the search
+ // need more sophisticated heuristic
+ if(string(d.CompleteInstr).find(reg_arg_str)!= string::npos)
+ {
+ if (original_is_param_register)
+ {
+ std::string arg;
+ if (IsParameterWrite(firp, ptr, arg))
+ {
+// std::cout << "CallFollows(): " << ptr->getDisassembly() << ": detected write parameter" << std::endl;
+ if (arg == reg_arg_str)
+ {
+// std::cout << "CallFollows(): " << ptr->getDisassembly() << ": same parameter as original: remove from live list: " << reg_arg_str << std::endl;
+ live_params.erase(reg_arg_str);
+ }
+ else
+ {
+ if (std::string(d.Argument2.ArgMnemonic) == reg_arg_str) {
+// std::cout << "CallFollows(): " << ptr->getDisassembly() << ": copy of original detected: add to live list: " << arg << std::endl;
+ live_params.insert(arg);
+ }
+ }
+ }
+
+ std::cout << "CallFollows(): " << ptr->getDisassembly() << ": #live_param: " << dec << live_params.size() << std::endl;
+ if (live_params.size() == 0)
+ {
+// std::cout << "CallFollows(): not a parameter to call" << endl;
+ return false;
+ }
+ }
+ else
+ {
+// std::cout << "\tassume it's a write and exit" << std::endl;
+ return false;
+ }
+
+ }
}
+// std::cout << "CallFollows(): no more fallthroughs, not a parameter to call" << endl;
return false;
}
+bool libIRDB::LeaFlowsIntoCall(const FileIR_t *firp, Instruction_t* insn)
+{
+ auto d=DISASM({0});
+ insn->Disassemble(d);
+
+ if(string(d.Instruction.Mnemonic)!="lea ")
+ return false;
+
+// std::cout << "LeaFlowsIntoCall(): investigating " << insn->getDisassembly() << endl;
+
+ string param_write;
+ if (!libIRDB::IsParameterWrite(firp, insn, param_write))
+ return false;
+
+ return CallFollows(firp, insn, param_write);
+}
+
+bool libIRDB::LeaFlowsIntoPrintf(const FileIR_t *firp, Instruction_t* insn)
+{
+ auto d=DISASM({0});
+ insn->Disassemble(d);
+
+ if(string(d.Instruction.Mnemonic)!="lea ")
+ return false;
+
+// std::cout << "LeaFlowsIntoCall(): investigating " << insn->getDisassembly() << endl;
+
+ string param_write;
+ if (!libIRDB::IsParameterWrite(firp, insn, param_write))
+ return false;
+
+ return CallFollows(firp, insn, param_write, "printf");
+}
--
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