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authorDan Sinclair <dsinclair@chromium.org>2018-05-15 18:59:46 +0000
committerChromium commit bot <commit-bot@chromium.org>2018-05-15 18:59:46 +0000
commit6137483528225c1dc102db44fb2c2bce6c256534 (patch)
tree8dc95914968969ce433665d08a2d60bda1cfb953 /core/fxcrt
parent6595905a9e6080cfc9a99310b597d66463a7eb2f (diff)
downloadpdfium-6137483528225c1dc102db44fb2c2bce6c256534.tar.xz
Cap size of exponent when converting floats
When detecting the exponent on a floating point number, cap the maximum amount we'll multiply by otherwise we can get excessivly large numbers. Bug: chromium:843074 Change-Id: I6a8d1b4c20b66e305d2727f464119b1e74beb699 Reviewed-on: https://pdfium-review.googlesource.com/32570 Reviewed-by: Henrique Nakashima <hnakashima@chromium.org> Commit-Queue: dsinclair <dsinclair@chromium.org>
Diffstat (limited to 'core/fxcrt')
-rw-r--r--core/fxcrt/fx_extension.cpp17
-rw-r--r--core/fxcrt/fx_extension_unittest.cpp8
2 files changed, 22 insertions, 3 deletions
diff --git a/core/fxcrt/fx_extension.cpp b/core/fxcrt/fx_extension.cpp
index b1f2a95d62..a27e0279c6 100644
--- a/core/fxcrt/fx_extension.cpp
+++ b/core/fxcrt/fx_extension.cpp
@@ -6,13 +6,15 @@
#include "core/fxcrt/fx_extension.h"
-#include "core/fxcrt/fx_fallthrough.h"
-
#include <algorithm>
#include <cwctype>
+#include <limits>
+
+#include "core/fxcrt/fx_fallthrough.h"
float FXSYS_wcstof(const wchar_t* pwsStr, int32_t iLength, int32_t* pUsedLen) {
ASSERT(pwsStr);
+
if (iLength < 0)
iLength = static_cast<int32_t>(wcslen(pwsStr));
if (iLength == 0)
@@ -62,13 +64,22 @@ float FXSYS_wcstof(const wchar_t* pwsStr, int32_t iLength, int32_t* pUsedLen) {
++iUsedLen;
}
- size_t exp_value = 0;
+ int32_t exp_value = 0;
while (iUsedLen < iLength) {
wchar_t wch = pwsStr[iUsedLen];
if (!std::iswdigit(wch))
break;
exp_value = exp_value * 10.0f + (wch - L'0');
+ // Exponent is outside the valid range, fail.
+ if ((negative_exponent &&
+ -exp_value < std::numeric_limits<float>::min_exponent10) ||
+ (!negative_exponent &&
+ exp_value > std::numeric_limits<float>::max_exponent10)) {
+ *pUsedLen = 0;
+ return 0.0f;
+ }
+
++iUsedLen;
}
diff --git a/core/fxcrt/fx_extension_unittest.cpp b/core/fxcrt/fx_extension_unittest.cpp
index f7e07c7c65..155b7014b7 100644
--- a/core/fxcrt/fx_extension_unittest.cpp
+++ b/core/fxcrt/fx_extension_unittest.cpp
@@ -134,6 +134,14 @@ TEST(fxcrt, FXSYS_wcstof) {
EXPECT_FLOAT_EQ(1.234e10f, FXSYS_wcstof(L"1.234E10", 8, &used_len));
EXPECT_EQ(8, used_len);
+ used_len = 0;
+ EXPECT_FLOAT_EQ(0.0f, FXSYS_wcstof(L"1.234E100000000000000", 21, &used_len));
+ EXPECT_EQ(0, used_len);
+
+ used_len = 0;
+ EXPECT_FLOAT_EQ(0.0f, FXSYS_wcstof(L"1.234E-128", 21, &used_len));
+ EXPECT_EQ(0, used_len);
+
// TODO(dsinclair): This should round as per IEEE 64-bit values.
// EXPECT_EQ(L"123456789.01234567", FXSYS_wcstof(L"123456789.012345678"));
used_len = 0;