[PDFBOX-3641] ICC_ColorSpace usage is not thread safe

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.4
• Fix Version/s: 2.0.5, 3.0.0 PDFBox
• Component/s: Rendering
• Assignee: Tilman Hausherr
• Reporter: Mike Kaplinskiy
• Created: 28/Dec/16 22:32
• Updated: 26/Oct/19 12:02
• Resolved: 05/Mar/17 08:46

Description

Unfortunately ICC_ColorSpace is not thread safe. Even creating Color instances and passing an ICC_ColorSpace can't be considered thread safe. All color conversion calls lazy initialize a value without a memory barrier: https://github.com/openjdk-mirror/jdk/blob/jdk8u/jdk8u/master/src/share/classes/java/awt/color/ICC_ColorSpace.java#L172 . This seems like a bug in Java, but PDFBox triggers it

PDFBox seems to attempt to initialize colorspaces/colors in a thread-safe way around https://github.com/apache/pdfbox/blob/f419d203ebebc4deb83ba71ef0a0e6bb1ff22c5a/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/graphics/color/PDICCBased.java#L146 , but calls to toRGB/fromRGB aren't synchronized. I think calling all 4 (to/from)(CIEXYZ/RGB) in a locked block should initialize the instances enough to be thread safe.

The symptoms of this problem look like this (exception formatting due to clojure):

                     org.apache.pdfbox.rendering.PDFRenderer.renderImageWithDPI               PDFRenderer.java:   94
                            org.apache.pdfbox.rendering.PDFRenderer.renderImage               PDFRenderer.java:  145
                                org.apache.pdfbox.rendering.PageDrawer.drawPage                PageDrawer.java:  189
                    org.apache.pdfbox.contentstream.PDFStreamEngine.processPage           PDFStreamEngine.java:  149
                  org.apache.pdfbox.contentstream.PDFStreamEngine.processStream           PDFStreamEngine.java:  446
         org.apache.pdfbox.contentstream.PDFStreamEngine.processStreamOperators           PDFStreamEngine.java:  472
                org.apache.pdfbox.contentstream.PDFStreamEngine.processOperator           PDFStreamEngine.java:  815
org.apache.pdfbox.contentstream.operator.color.SetNonStrokingColorSpace.process  SetNonStrokingColorSpace.java:   41
                            org.apache.pdfbox.pdmodel.PDResources.getColorSpace               PDResources.java:  166
                            org.apache.pdfbox.pdmodel.PDResources.getColorSpace               PDResources.java:  196
                   org.apache.pdfbox.pdmodel.graphics.color.PDColorSpace.create              PDColorSpace.java:  182
                     org.apache.pdfbox.pdmodel.graphics.color.PDICCBased.<init>                PDICCBased.java:   89
             org.apache.pdfbox.pdmodel.graphics.color.PDICCBased.loadICCProfile                PDICCBased.java:  145
                                                          java.awt.Color.<init>                     Color.java:  542
                                            java.awt.color.ICC_ColorSpace.toRGB            ICC_ColorSpace.java:  179
java.lang.NullPointerException:

Issue Links

• is related to: PDFBOX-4514 inefficient use of synchronized in PDICCBased.java
• links to: ICC_ColorSpace operations use over 2GB used despite -Xmx200m