The Tor Browser: security/sandbox/chromium/base/strings/stringprintf.cc@141e0f1194b1 (annotated)

security/sandbox/chromium/base/strings/stringprintf.cc@141e0f1194b1 (annotated)

security/sandbox/chromium/base/strings/stringprintf.cc

Wed, 31 Dec 2014 07:16:47 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 07:16:47 +0100
branch: TOR_BUG_9701
changeset 3: 141e0f1194b1
permissions: -rw-r--r--

Revert simplistic fix pending revisit of Mozilla integration attempt.

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 #include "base/strings/stringprintf.h"
 #include <errno.h>
 #include "base/scoped_clear_errno.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 namespace base {
 namespace {
 // Overloaded wrappers around vsnprintf and vswprintf. The buf_size parameter
 // is the size of the buffer. These return the number of characters in the
 // formatted string excluding the NUL terminator. If the buffer is not
 // large enough to accommodate the formatted string without truncation, they
 // return the number of characters that would be in the fully-formatted string
 // (vsnprintf, and vswprintf on Windows), or -1 (vswprintf on POSIX platforms).
 inline int vsnprintfT(char* buffer,
                       size_t buf_size,
                       const char* format,
                       va_list argptr) {
   return base::vsnprintf(buffer, buf_size, format, argptr);
 }
 #if !defined(OS_ANDROID)
 inline int vsnprintfT(wchar_t* buffer,
                       size_t buf_size,
                       const wchar_t* format,
                       va_list argptr) {
   return base::vswprintf(buffer, buf_size, format, argptr);
 }
 #endif
 // Templatized backend for StringPrintF/StringAppendF. This does not finalize
 // the va_list, the caller is expected to do that.
 template <class StringType>
 static void StringAppendVT(StringType* dst,
                            const typename StringType::value_type* format,
                            va_list ap) {
   // First try with a small fixed size buffer.
   // This buffer size should be kept in sync with StringUtilTest.GrowBoundary
   // and StringUtilTest.StringPrintfBounds.
   typename StringType::value_type stack_buf[1024];
   va_list ap_copy;
   GG_VA_COPY(ap_copy, ap);
 #if !defined(OS_WIN)
   ScopedClearErrno clear_errno;
 #endif
   int result = vsnprintfT(stack_buf, arraysize(stack_buf), format, ap_copy);
   va_end(ap_copy);
   if (result >= 0 && result < static_cast<int>(arraysize(stack_buf))) {
     // It fit.
     dst->append(stack_buf, result);
     return;
   }
   // Repeatedly increase buffer size until it fits.
   int mem_length = arraysize(stack_buf);
   while (true) {
     if (result < 0) {
 #if !defined(OS_WIN)
       // On Windows, vsnprintfT always returns the number of characters in a
       // fully-formatted string, so if we reach this point, something else is
       // wrong and no amount of buffer-doubling is going to fix it.
       if (errno != 0 && errno != EOVERFLOW)
 #endif
       {
         // If an error other than overflow occurred, it's never going to work.
         DLOG(WARNING) << "Unable to printf the requested string due to error.";
         return;
       }
       // Try doubling the buffer size.
       mem_length *= 2;
     } else {
       // We need exactly "result + 1" characters.
       mem_length = result + 1;
     }
     if (mem_length > 32 * 1024 * 1024) {
       // That should be plenty, don't try anything larger.  This protects
       // against huge allocations when using vsnprintfT implementations that
       // return -1 for reasons other than overflow without setting errno.
       DLOG(WARNING) << "Unable to printf the requested string due to size.";
       return;
     }
     std::vector<typename StringType::value_type> mem_buf(mem_length);
     // NOTE: You can only use a va_list once.  Since we're in a while loop, we
     // need to make a new copy each time so we don't use up the original.
     GG_VA_COPY(ap_copy, ap);
     result = vsnprintfT(&mem_buf[0], mem_length, format, ap_copy);
     va_end(ap_copy);
     if ((result >= 0) && (result < mem_length)) {
       // It fit.
       dst->append(&mem_buf[0], result);
       return;
     }
   }
 }
 }  // namespace
 std::string StringPrintf(const char* format, ...) {
   va_list ap;
   va_start(ap, format);
   std::string result;
   StringAppendV(&result, format, ap);
   va_end(ap);
   return result;
 }
 #if !defined(OS_ANDROID)
 std::wstring StringPrintf(const wchar_t* format, ...) {
   va_list ap;
   va_start(ap, format);
   std::wstring result;
   StringAppendV(&result, format, ap);
   va_end(ap);
   return result;
 }
 #endif
 std::string StringPrintV(const char* format, va_list ap) {
   std::string result;
   StringAppendV(&result, format, ap);
   return result;
 }
 const std::string& SStringPrintf(std::string* dst, const char* format, ...) {
   va_list ap;
   va_start(ap, format);
   dst->clear();
   StringAppendV(dst, format, ap);
   va_end(ap);
   return *dst;
 }
 #if !defined(OS_ANDROID)
 const std::wstring& SStringPrintf(std::wstring* dst,
                                   const wchar_t* format, ...) {
   va_list ap;
   va_start(ap, format);
   dst->clear();
   StringAppendV(dst, format, ap);
   va_end(ap);
   return *dst;
 }
 #endif
 void StringAppendF(std::string* dst, const char* format, ...) {
   va_list ap;
   va_start(ap, format);
   StringAppendV(dst, format, ap);
   va_end(ap);
 }
 #if !defined(OS_ANDROID)
 void StringAppendF(std::wstring* dst, const wchar_t* format, ...) {
   va_list ap;
   va_start(ap, format);
   StringAppendV(dst, format, ap);
   va_end(ap);
 }
 #endif
 void StringAppendV(std::string* dst, const char* format, va_list ap) {
   StringAppendVT(dst, format, ap);
 }
 #if !defined(OS_ANDROID)
 void StringAppendV(std::wstring* dst, const wchar_t* format, va_list ap) {
   StringAppendVT(dst, format, ap);
 }
 #endif
 }  // namespace base

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security/sandbox/chromium/base/strings/stringprintf.cc@141e0f1194b1 (annotated)

security/sandbox/chromium/base/strings/stringprintf.cc