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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>
- #include <vector>
- #include <sstream>
- #include <ctype.h>
-
- using namespace clang;
-
- namespace rspamd {
- struct PrintfArgChecker;
-
- static bool cstring_arg_handler (const Expr *arg,
- struct PrintfArgChecker *ctx);
- static bool int_arg_handler (const Expr *arg,
- struct PrintfArgChecker *ctx);
- static bool long_arg_handler (const Expr *arg,
- struct PrintfArgChecker *ctx);
- static bool size_arg_handler (const Expr *arg,
- struct PrintfArgChecker *ctx);
- static bool char_arg_handler (const Expr *arg,
- struct PrintfArgChecker *ctx);
- static bool double_arg_handler (const Expr *arg,
- struct PrintfArgChecker *ctx);
- static bool long_double_arg_handler (const Expr *arg,
- struct PrintfArgChecker *ctx);
-
- using arg_parser_t = bool (*) (const Expr *, struct PrintfArgChecker *);
-
- static void
- print_error (const std::string &err, const Expr *e, const ASTContext *ast)
- {
- auto const &sm = ast->getSourceManager ();
- auto loc = e->getExprLoc ();
- llvm::errs() << err << " at " << loc.printToString (sm) << "\n";
- }
-
- struct PrintfArgChecker {
- private:
- arg_parser_t parser;
- public:
- int width;
- int precision;
- bool is_unsigned;
- ASTContext *past;
-
- PrintfArgChecker (arg_parser_t _p, ASTContext *_ast) :
- parser(_p), past(_ast)
- {
- width = 0;
- precision = 0;
- is_unsigned = false;
- }
- virtual ~PrintfArgChecker () {}
-
- bool operator () (const Expr *e)
- {
- return parser (e, this);
- }
- };
-
- class PrintfCheckVisitor::impl {
- std::unordered_map<std::string, int> printf_functions;
- ASTContext *pcontext;
-
- std::unique_ptr<PrintfArgChecker> parseFlags (const std::string &flags)
- {
- auto type = flags.back();
-
- switch (type) {
- case 's':
- return llvm::make_unique<PrintfArgChecker>(cstring_arg_handler,
- this->pcontext);
- case 'd':
- return llvm::make_unique<PrintfArgChecker>(int_arg_handler,
- this->pcontext);
- case 'z':
- return llvm::make_unique<PrintfArgChecker> (size_arg_handler,
- this->pcontext);
- case 'l':
- return llvm::make_unique<PrintfArgChecker> (long_arg_handler,
- this->pcontext);
- case 'f':
- case 'g':
- return llvm::make_unique<PrintfArgChecker> (double_arg_handler,
- this->pcontext);
- case 'F':
- case 'G':
- return llvm::make_unique<PrintfArgChecker> (long_double_arg_handler,
- this->pcontext);
- case 'c':
- return llvm::make_unique<PrintfArgChecker> (char_arg_handler,
- this->pcontext);
- default:
- llvm::errs () << "unknown parser flag: " << type << "\n";
- break;
- }
-
- return nullptr;
- }
-
- std::shared_ptr<std::vector<PrintfArgChecker> >
- genParsers (const StringRef query)
- {
- enum {
- ignore_chars = 0,
- read_percent,
- read_width,
- read_precision,
- read_arg
- } state = ignore_chars;
- int width, precision;
- std::string flags;
-
- auto res = std::make_shared<std::vector<PrintfArgChecker> >();
-
- for (const auto c : query) {
- switch (state) {
- case ignore_chars:
- if (c == '%') {
- state = read_percent;
- flags.clear ();
- width = precision = 0;
- }
- break;
- case read_percent:
- if (isdigit (c)) {
- state = read_width;
- width = c - '0';
- }
- else if (c == '.') {
- state = read_precision;
- precision = c - '0';
- }
- else if (c == '*') {
- /* %*s - need integer argument */
- res->emplace_back (int_arg_handler, this->pcontext);
- state = read_arg;
- }
- else if (c == '%') {
- /* Percent character, ignore */
- state = ignore_chars;
- }
- else {
- flags.push_back (c);
- state = read_arg;
- }
- break;
- case read_width:
- if (isdigit (c)) {
- width *= 10;
- width += c - '0';
- }
- else if (c == '.') {
- state = read_precision;
- precision = c - '0';
- }
- else {
- flags.push_back (c);
- state = read_arg;
- }
- break;
- case read_precision:
- if (isdigit (c)) {
- precision *= 10;
- precision += c - '0';
- }
- else if (c == '*') {
- res->emplace_back (int_arg_handler, this->pcontext);
- state = read_arg;
- }
- else {
- flags.push_back (c);
- state = read_arg;
- }
- break;
- case read_arg:
- if (!isalpha (c)) {
- auto handler = parseFlags (flags);
-
- if (handler) {
- auto handler_copy = *handler;
- handler_copy.precision = precision;
- handler_copy.width = width;
- res->emplace_back (std::move (handler_copy));
- }
- else {
- llvm::errs () << "invalid modifier\n";
- return nullptr;
- }
- state = ignore_chars;
- }
- else {
- flags.push_back (c);
- }
- break;
- }
- }
-
- if (state == read_arg) {
- auto handler = parseFlags (flags);
-
- if (handler) {
- auto handler_copy = *handler;
- handler_copy.precision = precision;
- handler_copy.width = width;
- res->emplace_back (std::move (handler_copy));
- }
- else {
- llvm::errs () << "invalid modifier\n";
- return nullptr;
- }
- }
-
- return res;
- }
- 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 () << "Bad or absent query string\n";
- return false;
- }
-
- auto parsers = genParsers (qval->getString ());
-
- if (parsers) {
- if (parsers->size () != E->getNumArgs () - (pos + 1)) {
- std::ostringstream err_buf;
- err_buf << "number of arguments for " << fname
- << " missmatches query string '" <<
- qval->getString().str()
- << "', expected " << parsers->size () << " args"
- << ", got " << (E->getNumArgs () - (pos + 1))
- << " args";
- print_error (err_buf.str (), E, this->pcontext);
-
- return false;
- }
- else {
- for (auto i = pos + 1; i < E->getNumArgs (); i++) {
- auto arg = args[i];
-
- if (arg) {
- if (!parsers->at(i - (pos + 1))(arg)) {
- return false;
- }
- }
- }
- }
- }
- }
-
- return true;
- }
- };
-
- PrintfCheckVisitor::PrintfCheckVisitor (ASTContext *ctx) :
- pimpl { new impl(ctx) }
- {
- }
-
- PrintfCheckVisitor::~PrintfCheckVisitor ()
- {
- }
-
- bool PrintfCheckVisitor::VisitCallExpr (clang::CallExpr *E)
- {
- return pimpl->VisitCallExpr (E);
- }
-
- /* Type handlers */
- static bool
- cstring_arg_handler (const Expr *arg, struct PrintfArgChecker *ctx)
- {
- auto type = arg->getType ().split ().Ty;
-
- if (!type->isPointerType ()) {
- print_error (
- std::string ("bad string argument for %s: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
-
- auto ptr_type = type->getPointeeType().split().Ty;
-
- if (!ptr_type->isCharType ()) {
- /* We might have gchar * here */
- auto desugared_type = ptr_type->getUnqualifiedDesugaredType ();
-
- if (!desugared_type || !desugared_type->isCharType ()) {
- if (desugared_type) {
- desugared_type->dump ();
- }
- print_error (
- std::string ("bad string argument for %s: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
- }
-
- return true;
- }
-
- static bool
- int_arg_handler (const Expr *arg, struct PrintfArgChecker *ctx)
- {
- auto type = arg->getType ().split ().Ty;
-
- auto desugared_type = type->getUnqualifiedDesugaredType ();
-
- if (!desugared_type->isIntegerType ()) {
- print_error (std::string ("bad integer argument for %d or * arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
- else if (!desugared_type->isBuiltinType ()) {
- print_error (std::string ("bad integer argument for %d or * arg: ") +
- arg->getType ().getAsString(), arg, ctx->past);
- return false;
- }
-
- auto builtin_type = dyn_cast<BuiltinType>(desugared_type);
- auto kind = builtin_type->getKind ();
-
- if (kind != BuiltinType::Kind::UInt &&
- kind != BuiltinType::Kind::Int) {
- print_error (std::string ("bad integer argument for %d or * arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
-
- return true;
- }
-
- static bool
- long_arg_handler (const Expr *arg, struct PrintfArgChecker *ctx)
- {
- auto type = arg->getType ().split ().Ty;
-
- auto desugared_type = type->getUnqualifiedDesugaredType ();
-
- if (!desugared_type->isIntegerType ()) {
- print_error (
- std::string ("bad integer argument for %l arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
- else if (!desugared_type->isBuiltinType ()) {
- print_error (
- std::string ("bad integer argument for %l arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
-
- auto builtin_type = dyn_cast<BuiltinType> (desugared_type);
- auto kind = builtin_type->getKind ();
-
- if (kind != BuiltinType::Kind::ULong &&
- kind != BuiltinType::Kind::Long) {
- print_error (
- std::string ("bad integer argument for %l arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
-
- return true;
- }
-
- static bool
- char_arg_handler (const Expr *arg, struct PrintfArgChecker *ctx)
- {
- auto type = arg->getType ().split ().Ty;
-
- auto desugared_type = type->getUnqualifiedDesugaredType ();
-
- if (!desugared_type->isCharType ()) {
- print_error (
- std::string ("bad char argument for %c arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
- else if (!desugared_type->isBuiltinType ()) {
- print_error (
- std::string ("bad char argument for %c arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
-
- auto builtin_type = dyn_cast<BuiltinType> (desugared_type);
- auto kind = builtin_type->getKind ();
-
- if (kind != BuiltinType::Kind::UChar &&
- kind != BuiltinType::Kind::SChar) {
- print_error (
- std::string ("bad char argument for %c arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
-
- return true;
- }
-
- static bool
- size_arg_handler (const Expr *arg, struct PrintfArgChecker *ctx)
- {
- auto type = arg->getType ().split ().Ty;
-
- auto desugared_type = type->getUnqualifiedDesugaredType ();
-
- if (!desugared_type->isIntegerType ()) {
- print_error (
- std::string ("bad integer argument for %z arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
- else if (!desugared_type->isBuiltinType ()) {
- print_error (
- std::string ("bad integer argument for %z arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
-
- auto builtin_type = dyn_cast<BuiltinType> (desugared_type);
- auto kind = builtin_type->getKind ();
-
- if (sizeof (size_t) == sizeof (long)) {
- if (kind != BuiltinType::Kind::ULong &&
- kind != BuiltinType::Kind::Long) {
- print_error (
- std::string ("bad integer argument for %z arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
- }
- else if (sizeof (size_t) == sizeof (int)) {
- if (kind != BuiltinType::Kind::UInt &&
- kind != BuiltinType::Kind::Int) {
- print_error (
- std::string ("bad integer argument for %z arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
- }
-
- return true;
- }
-
- static bool
- double_arg_handler (const Expr *arg, struct PrintfArgChecker *ctx)
- {
- auto type = arg->getType ().split ().Ty;
-
- auto desugared_type = type->getUnqualifiedDesugaredType ();
-
- if (!desugared_type->isRealFloatingType ()) {
- print_error (
- std::string ("bad double argument for %f or %g arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
- else if (!desugared_type->isBuiltinType ()) {
- print_error (
- std::string ("bad double argument for %f or %g arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
-
- auto builtin_type = dyn_cast<BuiltinType> (desugared_type);
- auto kind = builtin_type->getKind ();
-
- if (kind != BuiltinType::Kind::Double) {
- print_error (
- std::string ("bad double argument for %f or %g arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
-
- return true;
- }
-
- static bool
- long_double_arg_handler (const Expr *arg, struct PrintfArgChecker *ctx)
- {
- auto type = arg->getType ().split ().Ty;
-
- auto desugared_type = type->getUnqualifiedDesugaredType ();
-
- if (!desugared_type->isRealFloatingType ()) {
- print_error (
- std::string ("bad long double argument for %F or %G arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
- else if (!desugared_type->isBuiltinType ()) {
- print_error (
- std::string ("bad long double argument for %F or %G arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
-
- auto builtin_type = dyn_cast<BuiltinType> (desugared_type);
- auto kind = builtin_type->getKind ();
-
- if (kind != BuiltinType::Kind::LongDouble) {
- print_error (
- std::string ("bad long double argument for %F or %G arg: ") +
- arg->getType ().getAsString (), arg, ctx->past);
- return false;
- }
-
- return true;
- }
- };
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