https://sourceware.org/bugzilla/show_bug.cgi?id=34792

            Bug ID: 34792
           Summary: GNU ld performs null-pointer arithmetic for an FDE
                    with no matching CIE
           Product: binutils
           Version: 2.46
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: ld
          Assignee: unassigned at sourceware dot org
          Reporter: basavesh.shivakumar at wsu dot edu
  Target Milestone: ---

Created attachment 17112
  --> https://sourceware.org/bugzilla/attachment.cgi?id=17112&action=edit
reproducer

I'm reporting this bug on behalf of my team: Ananta Srikar Puranam, Emily West,
Dr. Swarn Priya, Dr. Peng Gao and Dr. Basavesh Ammanaghatta Shivakumar.

Summary
=======

A controlled x86-64 ET_REL object whose .eh_frame FDE has no matching CIE makes
current and released GNU ld evaluate local_cies + cie_count with a null base
and zero count at bfd/elf-eh-frame.c:914, causing a deterministic UBSan abort;
a one-byte valid-CIE control links cleanly.

Reproduction
============

1. Download and extract
`bfd-eh-frame-missing-cie-null-pointer-arithmetic-reproducer.tar.gz`.
2. Run the following command with an ld.bfd or all-target `ld-new` binary that
   supports the emulation used by the reproducer:

       LD_BFD=/path/to/ld-new sh repro.sh

The archive contains the fixed input files, independent controls, helper
scripts needed by `repro.sh`, and their checksums. The script uses a temporary
directory and does not modify the source tree.

Observed result
===============

A controlled x86-64 ET_REL object whose .eh_frame FDE has no matching CIE makes
current and released GNU ld evaluate local_cies + cie_count with a null base
and zero count at bfd/elf-eh-frame.c:914, causing a deterministic UBSan abort;
a one-byte valid-CIE control links cleanly.

Expected result
===============

GNU ld should either produce the correct output or reject the input with a
normal diagnostic. It should not crash, hang, execute undefined behavior, read
outside an input-derived allocation, or produce the described malformed
output.

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