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/*
* Copyright (c) 2015, Vsevolod Stakhov
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR ''AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "printf_check.h"
#include "clang/AST/AST.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include <unordered_map>
using namespace clang;
namespace rspamd {
class PrintfCheckVisitor::impl {
std::unordered_map<std::string, int> printf_functions;
ASTContext *pcontext;
public:
impl (ASTContext *_ctx) : pcontext(_ctx)
{
/* name -> format string position */
printf_functions = {
{"rspamd_printf", 0},
{"rspamd_default_log_function", 4},
{"rspamd_snprintf", 2},
{"rspamd_fprintf", 1}
};
};
bool VisitCallExpr (CallExpr *E)
{
auto callee = dyn_cast<NamedDecl> (E->getCalleeDecl ());
if (callee == NULL) {
llvm::errs () << "Bad callee\n";
return false;
}
auto fname = callee->getNameAsString ();
auto pos_it = printf_functions.find (fname);
if (pos_it != printf_functions.end ()) {
const auto args = E->getArgs ();
auto pos = pos_it->second;
auto query = args[pos];
if (!query->isEvaluatable (*pcontext)) {
llvm::errs () << "Cannot evaluate query\n";
return false;
}
clang::Expr::EvalResult r;
if (!query->EvaluateAsRValue (r, *pcontext)) {
llvm::errs () << "Cannot evaluate query\n";
return false;
}
auto qval = dyn_cast<StringLiteral> (
r.Val.getLValueBase ().get<const Expr *> ());
if (qval) {
llvm::errs () << "query string: "
<< qval->getString () << "\n";
}
for (auto i = pos + 1; i < E->getNumArgs (); i++) {
auto arg = args[i];
if (arg) {
auto type = arg->getType ().split ().Ty;
type->dump ();
}
}
}
return true;
}
};
PrintfCheckVisitor::PrintfCheckVisitor (ASTContext *ctx) :
pimpl { new impl(ctx) }
{
}
PrintfCheckVisitor::~PrintfCheckVisitor ()
{
}
bool PrintfCheckVisitor::VisitCallExpr (clang::CallExpr *E)
{
return pimpl->VisitCallExpr (E);
}
};
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