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-rw-r--r--core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp42
-rw-r--r--fpdfsdk/src/fpdfview_embeddertest.cpp8
-rw-r--r--testing/resources/bug_xrefv4_loop.pdf45
3 files changed, 76 insertions, 19 deletions
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
index c6e48e74a2..026247c3aa 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
@@ -374,30 +374,25 @@ FX_BOOL CPDF_Parser::LoadAllCrossRefV4(FX_FILESIZE xrefpos) {
CFX_FileSizeArray CrossRefList, XRefStreamList;
CrossRefList.Add(xrefpos);
XRefStreamList.Add(GetDirectInteger(m_pTrailer, "XRefStm"));
- if (!CheckDirectType(m_pTrailer, "Prev", PDFOBJ_NUMBER)) {
- return FALSE;
- }
- FX_FILESIZE newxrefpos = GetDirectInteger(m_pTrailer, "Prev");
- if (newxrefpos == xrefpos) {
- return FALSE;
- }
- xrefpos = newxrefpos;
+
+ std::set<FX_FILESIZE> seen_xrefpos;
+ seen_xrefpos.insert(xrefpos);
+ // When |m_pTrailer| doesn't have Prev entry or Prev entry value is not
+ // numerical, GetDirectInteger() returns 0. Loading will end.
+ xrefpos = GetDirectInteger(m_pTrailer, "Prev");
while (xrefpos) {
+ // Check for circular references.
+ if (pdfium::ContainsKey(seen_xrefpos, xrefpos))
+ return FALSE;
+ seen_xrefpos.insert(xrefpos);
CrossRefList.InsertAt(0, xrefpos);
LoadCrossRefV4(xrefpos, 0, TRUE);
std::unique_ptr<CPDF_Dictionary, ReleaseDeleter<CPDF_Dictionary>> pDict(
LoadTrailerV4());
if (!pDict)
return FALSE;
+ xrefpos = GetDirectInteger(pDict.get(), "Prev");
- if (!CheckDirectType(pDict.get(), "Prev", PDFOBJ_NUMBER))
- return FALSE;
-
- newxrefpos = GetDirectInteger(pDict.get(), "Prev");
- if (newxrefpos == xrefpos)
- return FALSE;
-
- xrefpos = newxrefpos;
XRefStreamList.InsertAt(0, pDict->GetInteger("XRefStm"));
m_Trailers.Add(pDict.release());
}
@@ -423,17 +418,26 @@ FX_BOOL CPDF_Parser::LoadLinearizedAllCrossRefV4(FX_FILESIZE xrefpos,
CFX_FileSizeArray CrossRefList, XRefStreamList;
CrossRefList.Add(xrefpos);
XRefStreamList.Add(GetDirectInteger(m_pTrailer, "XRefStm"));
+
+ std::set<FX_FILESIZE> seen_xrefpos;
+ seen_xrefpos.insert(xrefpos);
xrefpos = GetDirectInteger(m_pTrailer, "Prev");
while (xrefpos) {
+ // Check for circular references.
+ if (pdfium::ContainsKey(seen_xrefpos, xrefpos))
+ return FALSE;
+ seen_xrefpos.insert(xrefpos);
CrossRefList.InsertAt(0, xrefpos);
LoadCrossRefV4(xrefpos, 0, TRUE);
- CPDF_Dictionary* pDict = LoadTrailerV4();
+ std::unique_ptr<CPDF_Dictionary, ReleaseDeleter<CPDF_Dictionary>> pDict(
+ LoadTrailerV4());
if (!pDict) {
return FALSE;
}
- xrefpos = GetDirectInteger(pDict, "Prev");
+ xrefpos = GetDirectInteger(pDict.get(), "Prev");
+
XRefStreamList.InsertAt(0, pDict->GetInteger("XRefStm"));
- m_Trailers.Add(pDict);
+ m_Trailers.Add(pDict.release());
}
for (int32_t i = 1; i < CrossRefList.GetSize(); i++)
if (!LoadCrossRefV4(CrossRefList[i], XRefStreamList[i], FALSE)) {
diff --git a/fpdfsdk/src/fpdfview_embeddertest.cpp b/fpdfsdk/src/fpdfview_embeddertest.cpp
index 3be96e7aef..0f4666836f 100644
--- a/fpdfsdk/src/fpdfview_embeddertest.cpp
+++ b/fpdfsdk/src/fpdfview_embeddertest.cpp
@@ -204,3 +204,11 @@ TEST_F(FPDFViewEmbeddertest, Crasher_454695) {
TEST_F(FPDFViewEmbeddertest, Hang_298) {
EXPECT_FALSE(OpenDocument("bug_298.pdf"));
}
+
+// Test if the document opens without infinite looping.
+// Previously this test will hang in a loop inside LoadAllCrossRefV4. After
+// the fix, LoadAllCrossRefV4 will return false after detecting a cross
+// reference loop. Cross references will be rebuilt successfully.
+TEST_F(FPDFViewEmbeddertest, CrossRefV4Loop) {
+ EXPECT_TRUE(OpenDocument("bug_xrefv4_loop.pdf"));
+}
diff --git a/testing/resources/bug_xrefv4_loop.pdf b/testing/resources/bug_xrefv4_loop.pdf
new file mode 100644
index 0000000000..c1169773f7
--- /dev/null
+++ b/testing/resources/bug_xrefv4_loop.pdf
@@ -0,0 +1,45 @@
+%PDF-1.7
+% ò¤ô
+1 0 obj <<
+ /Type /Catalog
+ /Pages 2 0 R
+>>
+endobj
+2 0 obj <<
+ /Type /Pages
+ /Count 1
+ /Kids [
+ 3 0 R
+ ]
+>>
+endobj
+3 0 obj <<
+ /Type /Page
+ /Parent 2 0 R
+ /MediaBox [0 0 612 792]
+>>
+endobj
+xref
+0 2
+0000000000 65535 f
+0000000015 00000 n
+trailer <<
+ /Prev 346
+>>
+xref
+2 1
+0000000068 00000 n
+trailer <<
+ /Prev 216
+>>
+xref
+3 1
+0000000139 00000 n
+trailer <<
+ /Size 4
+ /Prev 291
+ /Root 1 0 R
+>>
+startxref
+346
+%%EOF