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  1. JDK
  2. JDK-6901306

classfile format checker permits array descriptor of more than 255 dims in CONSTANT_NameAndType_info

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    • CPU:
      generic
    • OS:
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      Description

      Draft JVMS 3ed specifies the requirements on array type descriptors in 4.3.2
      section:
        ---Excerpt-from-spec---
        A type descriptor representing an array type is valid only if it represents a
        type with *255 or fewer dimensions*.
        ---End-of-excerpt---

      JVMS section 4.4.6 states as follows:
        ---Excerpt-from-spec---
        CONSTANT_NameAndType_info {
          u1 tag;
          u2 name_index;
          u2 descriptor_index;
        }
        ...
        The items of the CONSTANT_NameAndType_info structure are as follows:
        ...
        descriptor_index

        The value of the descriptor_index item must be a valid index into the
        constant_pool table. The constant_pool entry at that index must be a
        CONSTANT_Utf8_info (4.4.7) structure representing a *valid* field descriptor
        (4.3.2) or method descriptor (4.3.3).
        ---End-of-excerpt---

      However, JVM class format checker does not reject classes with invalid (more
      than 255 dimensions) array type descriptors at the descriptor_index in the
      CONSTANT_NameAndType_info structure.

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              Assignee:
              kamg Keith Mcguigan
              Reporter:
              ygaevsky Yuri Gaevsky
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