Add more checks to fseeks in CFX_FolderFontInfo
Bug: chromium:770890
Change-Id: Iee532d76aabc0763a835c203344455ba07c6e82c
Reviewed-on: https://pdfium-review.googlesource.com/15930
Reviewed-by: Ryan Harrison <rharrison@chromium.org>
Commit-Queue: Nicolás Peña Moreno <npm@chromium.org>
diff --git a/core/fxge/cfx_folderfontinfo.cpp b/core/fxge/cfx_folderfontinfo.cpp
index 1ee9ea7..6b564f8 100644
--- a/core/fxge/cfx_folderfontinfo.cpp
+++ b/core/fxge/cfx_folderfontinfo.cpp
@@ -54,13 +54,17 @@
ByteString FPDF_LoadTableFromTT(FILE* pFile,
const uint8_t* pTables,
uint32_t nTables,
- uint32_t tag) {
+ uint32_t tag,
+ uint32_t fileSize) {
for (uint32_t i = 0; i < nTables; i++) {
const uint8_t* p = pTables + i * 16;
if (GET_TT_LONG(p) == tag) {
uint32_t offset = GET_TT_LONG(p + 8);
uint32_t size = GET_TT_LONG(p + 12);
- fseek(pFile, offset, SEEK_SET);
+ if (offset > std::numeric_limits<uint32_t>::max() - size ||
+ offset + size > fileSize || fseek(pFile, offset, SEEK_SET) < 0) {
+ return ByteString();
+ }
return FPDF_ReadStringFromFile(pFile, size);
}
}
@@ -199,9 +203,8 @@
FILE* pFile,
uint32_t filesize,
uint32_t offset) {
- fseek(pFile, offset, SEEK_SET);
char buffer[16];
- if (!fread(buffer, 12, 1, pFile))
+ if (fseek(pFile, offset, SEEK_SET) < 0 || !fread(buffer, 12, 1, pFile))
return;
uint32_t nTables = GET_TT_SHORT(buffer + 4);
@@ -209,8 +212,8 @@
if (tables.IsEmpty())
return;
- ByteString names =
- FPDF_LoadTableFromTT(pFile, tables.raw_str(), nTables, 0x6e616d65);
+ ByteString names = FPDF_LoadTableFromTT(pFile, tables.raw_str(), nTables,
+ 0x6e616d65, filesize);
if (names.IsEmpty())
return;
@@ -227,8 +230,8 @@
auto pInfo = pdfium::MakeUnique<FontFaceInfo>(path, facename, tables, offset,
filesize);
- ByteString os2 =
- FPDF_LoadTableFromTT(pFile, tables.raw_str(), nTables, 0x4f532f32);
+ ByteString os2 = FPDF_LoadTableFromTT(pFile, tables.raw_str(), nTables,
+ 0x4f532f32, filesize);
if (os2.GetLength() >= 86) {
const uint8_t* p = os2.raw_str() + 78;
uint32_t codepages = GET_TT_LONG(p);