https://sourceware.org/bugzilla/show_bug.cgi?id=34816

            Bug ID: 34816
           Summary: GNU ld MIPS dereferences a NULL symbol-hash array
                    after an empty-symbol-table diagnostic
           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 17136
  --> https://sourceware.org/bugzilla/attachment.cgi?id=17136&action=edit
repro

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
=======

An ELF32 MIPS relocation against a zero-sized symbol table is diagnosed as
malformed during relocation scanning, but GNU ld continues into final
relocation and indexes a NULL elf_sym_hashes array at elfxx-mips.c:10559;
current ASan/UBSan attributes a zero-page read, unsanitized current and
released GNU ld 2.46 SIGSEGV in all tested link modes, the one-byte
populated-symbol-table control passes, and LLD rejects the malformed trigger
cleanly.

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

1. Download and extract
`bfd-mips-empty-symtab-null-hash-array-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:

       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
===============

An ELF32 MIPS relocation against a zero-sized symbol table is diagnosed as
malformed during relocation scanning, but GNU ld continues into final
relocation and indexes a NULL elf_sym_hashes array at elfxx-mips.c:10559;
current ASan/UBSan attributes a zero-page read, unsanitized current and
released GNU ld 2.46 SIGSEGV in all tested link modes, the one-byte
populated-symbol-table control passes, and LLD rejects the malformed trigger
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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