https://sourceware.org/bugzilla/show_bug.cgi?id=34793
Bug ID: 34793
Summary: GNU ld shifts a negative value while decoding a valid
SLEB128 CIE field
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 17113
--> https://sourceware.org/bugzilla/attachment.cgi?id=17113&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 GNU-as x86-64 ET_REL with a complete CIE/FDE and canonical two-byte SLEB128
data-alignment factor -128 makes current and released UBSan GNU ld evaluate a
signed left shift of -1 in read_sleb128 at bfd/elf-eh-frame.c:135 and abort; a
-64 boundary control is clean, while optimized BFD produces the intended
output.
Reproduction
============
1. Download and extract
`bfd-eh-frame-sleb128-negative-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
===============
A GNU-as x86-64 ET_REL with a complete CIE/FDE and canonical two-byte SLEB128
data-alignment factor -128 makes current and released UBSan GNU ld evaluate a
signed left shift of -1 in read_sleb128 at bfd/elf-eh-frame.c:135 and abort; a
-64 boundary control is clean, while optimized BFD produces the intended
output.
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.
