Fix infinite recursion in CPDF_Parser::ParseIndirectObjectAt().

A suitably corrupted file can cause the parser(s) to repeatedly re-read
sections of the file at increasing parser recursion depth until the
stack is exhausted.  There is supposed to be a check for this based upon
the parser "level", but not all call paths pass or update the level as
required.

Much as I hate per-class statics, this introduces one to track the depth
so that the check is enforced no matter how screwy the call path might be
that leads the parser to re-enter itself. This is more palatable than trying
to find all these paths and fix them. We know this is OK since there is
only one thread in here modifying the static.

BUG=451830
R=thestig@chromium.org

Review URL: https://codereview.chromium.org/875263002

1 files changed, 4 insertions, 3 deletions

diff --git a/core/include/fpdfapi/fpdf_parser.h b/core/include/fpdfapi/fpdf_parser.h
index 3f9bda5ad8..e1a0f5cf1a 100644
--- a/core/include/fpdfapi/fpdf_parser.h
+++ b/core/include/fpdfapi/fpdf_parser.h
@@ -261,10 +261,10 @@ public:
         m_Pos = pos;
     }
 
-    CPDF_Object*		GetObject(CPDF_IndirectObjects* pObjList, FX_DWORD objnum, FX_DWORD gennum, int level, struct PARSE_CONTEXT* pContext = NULL, FX_BOOL bDecrypt = TRUE);
+    CPDF_Object*		GetObject(CPDF_IndirectObjects* pObjList, FX_DWORD objnum, FX_DWORD gennum, struct PARSE_CONTEXT* pContext = NULL, FX_BOOL bDecrypt = TRUE);
 
 
-    CPDF_Object*		GetObjectByStrict(CPDF_IndirectObjects* pObjList, FX_DWORD objnum, FX_DWORD gennum, int level, struct PARSE_CONTEXT* pContext = NULL);
+    CPDF_Object*		GetObjectByStrict(CPDF_IndirectObjects* pObjList, FX_DWORD objnum, FX_DWORD gennum, struct PARSE_CONTEXT* pContext = NULL);
 
     int					GetDirectNum();
 
@@ -302,6 +302,8 @@ public:
 
     CFX_ByteString		GetNextWord(FX_BOOL& bIsNumber);
 protected:
+    static const int kParserMaxRecursionDepth = 64;
+    static int s_CurrentRecursionDepth;
 
     virtual FX_BOOL				GetNextChar(FX_BYTE& ch);
 
@@ -520,7 +522,6 @@ public:
         return m_dwFirstPageNo;
     }
 protected:
-
     CPDF_Document*		m_pDocument;
 
     CPDF_SyntaxParser	m_Syntax;