https://sourceware.org/bugzilla/show_bug.cgi?id=34802
Bug ID: 34802
Summary: GNU ld misplaces a valid 4-GiB-aligned common symbol
after a 32-bit shift
Product: binutils
Version: 2.47
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 17122
--> https://sourceware.org/bugzilla/attachment.cgi?id=17122&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 assembler-produced ELF64 COMMON alignment of 2^32 makes current GNU ld shift
an unsigned 32-bit value by 32 in bfd_generic_define_common_symbol; fail-fast
UBSan aborts, while sanitizer-recovery and plain current/released builds can
place the symbol at +8 modulo its requested alignment. The one-field 2^31
control is clean and correctly aligned.
Reproduction
============
1. Download and extract
`bfd-generic-common-alignment-shift-ubsan-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
===============
An assembler-produced ELF64 COMMON alignment of 2^32 makes current GNU ld shift
an unsigned 32-bit value by 32 in bfd_generic_define_common_symbol; fail-fast
UBSan aborts, while sanitizer-recovery and plain current/released builds can
place the symbol at +8 modulo its requested alignment. The one-field 2^31
control is clean and correctly aligned.
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.
--
You are receiving this mail because:
You are on the CC list for the bug.
