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  1. JDK
  2. JDK-6832374

(reflect) malformed signature can cause parser to go into infinite loop

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Details

    • Bug
    • Resolution: Fixed
    • P3
    • 8
    • 6u10
    • core-libs
    • b04
    • x86
    • linux
    • Verified

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      Description

        FULL PRODUCT VERSION :
        $ java -version
        java version "1.5.0_16"
        $ java -version
        openjdk version "1.7.0-internal"
        1.6.0_12-b04
        (I think you'll find this is in about every version of java.)

        ADDITIONAL OS VERSION INFORMATION :
        All OSes.

        A DESCRIPTION OF THE PROBLEM :
        A logic error in SignatureParser.java makes it possible for a malformed signature to push the JVM into an infinite loop, which only ends when heap is exhausted.

        STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
        Compile and run the attached program.

        EXPECTED VERSUS ACTUAL BEHAVIOR :
        EXPECTED -
        Something like "parse error, malformed method descriptor."
        ACTUAL -
        <twiddle twiddle twiddle> boom.

        ERROR MESSAGES/STACK TRACES THAT OCCUR :
        Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
        at java.util.ArrayList.ensureCapacity(ArrayList.java:169)
        at java.util.ArrayList.add(ArrayList.java:351)
        at sun.reflect.generics.parser.SignatureParser.parseFormalTypeParameters(SignatureParser.java:190)
        at sun.reflect.generics.parser.SignatureParser.parseZeroOrMoreFormalTypeParameters(SignatureParser.java:177)
        at sun.reflect.generics.parser.SignatureParser.parseMethodTypeSignature(SignatureParser.java:436)
        at sun.reflect.generics.parser.SignatureParser.parseMethodSig(SignatureParser.java:141)
        at SigP.main(SigP.java:8)


        REPRODUCIBILITY :
        This bug can be reproduced always.

        ---------- BEGIN SOURCE ----------
        import sun.reflect.generics.parser.SignatureParser;

        public class SigP {
          public static void main(String[] args) {
            SignatureParser sp = SignatureParser.make();
            String sig = "<T:Lscala/tools/nsc/symtab/Names;Lscala/tools/nsc/symtab/Symbols;Lscala/tools/nsc/symtab/Types;Lscala/tools/nsc/symtab/Scopes;Lscala/tools/nsc/symtab/Definitions;Lscala/tools/nsc/symtab/Constants;Lscala/tools/nsc/symtab/BaseTypeSeqs;Lscala/tools/nsc/symtab/InfoTransformers;Lscala/tools/nsc/symtab/StdNames;Lscala/tools/nsc/symtab/AnnotationInfos;Lscala/tools/nsc/symtab/AnnotationCheckers;Lscala/tools/nsc/ast/Trees;Lscala/ScalaObject.Symbol;>(TT;Lscala/tools/nsc/symtab/Names;Lscala/tools/nsc/symtab/Symbols;Lscala/tools/nsc/symtab/Types;Lscala/tools/nsc/symtab/Scopes;Lscala/tools/nsc/symtab/Definitions;Lscala/tools/nsc/symtab/Constants;Lscala/tools/nsc/symtab/BaseTypeSeqs;Lscala/tools/nsc/symtab/InfoTransformers;Lscala/tools/nsc/symtab/StdNames;Lscala/tools/nsc/symtab/AnnotationInfos;Lscala/tools/nsc/symtab/AnnotationCheckers;Lscala/tools/nsc/ast/Trees;Lscala/ScalaObject.Type;)TT;";
            
            sp.parseMethodSig(sig);
          }
        }
        ---------- END SOURCE ----------

        CUSTOMER SUBMITTED WORKAROUND :
          Fix SignatureParser and rebuild the jdk. The exploitable logic around line 210:

        while (current() != '>') {
        ftps.add(parseFormalTypeParameter());
        }

        It is possible for parseFormalTypeParameter() not to advance the input, so this will loop indefinitely, allocating new empty type parameters until it exhausts its rope.

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                darcy Joe Darcy
                ndcosta Nelson Dcosta (Inactive)
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