[openpyxl]: fix exception control for internal error (#8616)

Fix exception handling for issues.
48488 (https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=48488)
48506 (https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=48506)y

projects/openpyxl/fuzz_comment.py

@@ -24,20 +24,29 @@ def TestInput(data):
 
     wb = Workbook()
     ws = wb.active
-    
+
     #Set Comment
     c1 = ws['A1'].comment
-    c1 = Comment(fdp.ConsumeString(10),fdp.ConsumeString(10))
+    c1 = Comment(fdp.ConsumeUnicodeNoSurrogates(10),
+        fdp.ConsumeUnicodeNoSurrogates(10))
     c1.width = 300
     c1.height = 50
     ws['A1'].comment = c1
 
     #Double assign comment
-    c2 = Comment(fdp.ConsumeString(10),fdp.ConsumeString(10))
+    c2 = Comment(fdp.ConsumeUnicodeNoSurrogates(10),
+        fdp.ConsumeUnicodeNoSurrogates(10))
     ws['B1'].comment = c2
     ws['C1'].comment = c2
 
-    wb.save('%s.xlsx'%fdp.ConsumeString(10))
+    try:
+        wb.save('%s.xlsx'%fdp.ConsumeUnicodeNoSurrogates(10))
+    except ValueError as e:
+        if "embedded null byte" not in str(e):
+            raise e
+    except FileNotFoundError:
+       # Expected for corrupted file name
+       pass
 
 def main():
     atheris.Setup(sys.argv, TestInput, enable_python_coverage=True)

projects/openpyxl/fuzz_formulae.py

@@ -17,17 +17,24 @@
 import atheris
 import sys
 with atheris.instrument_imports():
-    from openpyxl.formula import Tokenizer
-    from openpyxl.formula.translate import Translator
+    from openpyxl.formula.tokenizer import *
+    from openpyxl.formula.translate import *
 
 def TestInput(data):
     fdp = atheris.FuzzedDataProvider(data)
 
-    #Initial tokenizer for random string and process it
-    Tokenizer(fdp.ConsumeString(200))
+    try:
+        #Initial tokenizer for random string and process it
+        Tokenizer(fdp.ConsumeString(200))
 
-    #Translate random string formulae
-    Translator(fdp.ConsumeString(200), origin="A1").translate_formula("B2")
+        #Translate random string formulae
+        Translator(fdp.ConsumeString(200), origin="A1").translate_formula("B2")
+    except IndexError as e:
+        if 'empty list' not in str(e):
+            raise e
+    except (TokenizerError, TranslatorError):
+        # Internal error handling is expected
+        pass
 
 def main():
     atheris.Setup(sys.argv, TestInput, enable_python_coverage=True)