Handle zlib data errors better (fixes #106)

ChangeLog

@@ -1,5 +1,7 @@
 2017-07-29  Jay Berkenbilt  <ejb@ql.org>
 
+	* Handle zlib data errors when decoding streams. Fixes #106.
+
 	* Improve handling of files where the "stream" keyword is not
 	followed by proper line terminators. Fixes #104.
 

libqpdf/Pl_Flate.cc

@@ -157,28 +157,36 @@ Pl_Flate::handleData(unsigned char* data, int len, int flush)
 void
 Pl_Flate::finish()
 {
-    if (this->outbuf)
+    try
     {
-	if (this->initialized)
-	{
-	    z_stream& zstream = *(static_cast<z_stream*>(this->zdata));
-	    unsigned char buf[1];
-	    buf[0] = '\0';
-	    handleData(buf, 0, Z_FINISH);
-	    int err = Z_OK;
-	    if (action == a_deflate)
-	    {
-		err = deflateEnd(&zstream);
-	    }
-	    else
-	    {
-		err = inflateEnd(&zstream);
-	    }
-	    checkError("End", err);
-	}
+        if (this->outbuf)
+        {
+            if (this->initialized)
+            {
+                z_stream& zstream = *(static_cast<z_stream*>(this->zdata));
+                unsigned char buf[1];
+                buf[0] = '\0';
+                handleData(buf, 0, Z_FINISH);
+                int err = Z_OK;
+                if (action == a_deflate)
+                {
+                    err = deflateEnd(&zstream);
+                }
+                else
+                {
+                    err = inflateEnd(&zstream);
+                }
+                checkError("End", err);
+            }
 
-	delete [] this->outbuf;
-	this->outbuf = 0;
+            delete [] this->outbuf;
+            this->outbuf = 0;
+        }
+    }
+    catch (std::exception& e)
+    {
+        this->getNext()->finish();
+        throw e;
     }
     this->getNext()->finish();
 }

libqpdf/QPDF.cc

@@ -2206,7 +2206,7 @@ QPDF::pipeStreamData(int objid, int generation,
             warn(e);
         }
     }
-    catch (std::runtime_error& e)
+    catch (std::exception& e)
     {
         if (! suppress_warnings)
         {
@@ -2218,7 +2218,14 @@ QPDF::pipeStreamData(int objid, int generation,
                          QUtil::int_to_string(generation) + ": " + e.what()));
         }
     }
-    pipeline->finish();
+    try
+    {
+        pipeline->finish();
+    }
+    catch (std::exception&)
+    {
+        // ignore
+    }
     return success;
 }
 

qpdf/qtest/qpdf.test

@@ -206,7 +206,7 @@ $td->runtest("remove page we don't have",
 show_ntests();
 # ----------
 $td->notify("--- Miscellaneous Tests ---");
-$n_tests += 88;
+$n_tests += 89;
 
 $td->runtest("qpdf version",
 	     {$td->COMMAND => "qpdf --version"},
@@ -229,6 +229,7 @@ foreach my $d (
     ["118", "other infinite loop", 2],
     ["119", "other infinite loop", 3],
     ["120", "other infinite loop", 3],
+    ["106", "zlib data error", 3],
     )
 {
     my ($n, $description, $exit_status) = @$d;

qpdf/qtest/qpdf/issue-106.out

@@ -0,0 +1,4 @@
+WARNING: issue-106.pdf (file position 56627): error decoding stream data for object 29 0: stream inflate: inflate: data: incorrect data check
+WARNING: issue-106.pdf (file position 64303): error decoding stream data for object 30 0: stream inflate: inflate: data: incorrect data check
+WARNING: issue-106.pdf (file position 67427): error decoding stream data for object 31 0: stream inflate: inflate: data: incorrect data check
+qpdf: operation succeeded with warnings; resulting file may have some problems