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authordsinclair <dsinclair@chromium.org>2016-09-21 12:49:36 -0700
committerCommit bot <commit-bot@chromium.org>2016-09-21 12:49:36 -0700
commitc0f60dc29db66262bbc0082fcd51170a570b0d1f (patch)
tree48b53ab54770ab7dc1766d1f94e2b1cfdc386d43 /core/fpdfapi
parent81d92f8ffc5e632ade8c507b8f2e34c5fe3ca902 (diff)
downloadpdfium-c0f60dc29db66262bbc0082fcd51170a570b0d1f.tar.xz
Check for overflow in CMap_GetCode.
Given a large enough value for the character code it's possible to overflow the conversion to an int. This Cl updates the code to guard against overflow. BUG=chromium:648739 Review-Url: https://codereview.chromium.org/2358023002
Diffstat (limited to 'core/fpdfapi')
-rw-r--r--core/fpdfapi/fpdf_font/fpdf_font_cid.cpp16
-rw-r--r--core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp5
2 files changed, 16 insertions, 5 deletions
diff --git a/core/fpdfapi/fpdf_font/fpdf_font_cid.cpp b/core/fpdfapi/fpdf_font/fpdf_font_cid.cpp
index 3f95ec4a96..96c1ef5753 100644
--- a/core/fpdfapi/fpdf_font/fpdf_font_cid.cpp
+++ b/core/fpdfapi/fpdf_font/fpdf_font_cid.cpp
@@ -441,16 +441,22 @@ void CPDF_CMapParser::ParseWord(const CFX_ByteStringC& word) {
// Static.
uint32_t CPDF_CMapParser::CMap_GetCode(const CFX_ByteStringC& word) {
- int num = 0;
+ pdfium::base::CheckedNumeric<uint32_t> num = 0;
if (word.GetAt(0) == '<') {
- for (int i = 1; i < word.GetLength() && std::isxdigit(word.GetAt(i)); ++i)
+ for (int i = 1; i < word.GetLength() && std::isxdigit(word.GetAt(i)); ++i) {
num = num * 16 + FXSYS_toHexDigit(word.GetAt(i));
- return num;
+ if (!num.IsValid())
+ return 0;
+ }
+ return num.ValueOrDie();
}
- for (int i = 0; i < word.GetLength() && std::isdigit(word.GetAt(i)); ++i)
+ for (int i = 0; i < word.GetLength() && std::isdigit(word.GetAt(i)); ++i) {
num = num * 10 + FXSYS_toDecimalDigit(static_cast<FX_WCHAR>(word.GetAt(i)));
- return num;
+ if (!num.IsValid())
+ return 0;
+ }
+ return num.ValueOrDie();
}
// Static.
diff --git a/core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp b/core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp
index ccf49ee46a..ec05df5226 100644
--- a/core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp
+++ b/core/fpdfapi/fpdf_font/fpdf_font_cid_unittest.cpp
@@ -28,6 +28,11 @@ TEST(fpdf_font_cid, CMap_GetCode) {
EXPECT_EQ(12u, CPDF_CMapParser::CMap_GetCode("12"));
EXPECT_EQ(12u, CPDF_CMapParser::CMap_GetCode("12d"));
EXPECT_EQ(128u, CPDF_CMapParser::CMap_GetCode("128"));
+
+ EXPECT_EQ(4294967295u, CPDF_CMapParser::CMap_GetCode("<FFFFFFFF"));
+
+ // Overflow a uint32_t.
+ EXPECT_EQ(0u, CPDF_CMapParser::CMap_GetCode("<100000000"));
}
TEST(fpdf_font_cid, CMap_GetCodeRange) {