https://sourceware.org/bugzilla/show_bug.cgi?id=34449
Bug ID: 34449
Summary: ld: SEGV in elf_x86_64_common_section_index
(bfd/elf64-x86-64.c:6093) via malformed common symbol
with `-r`
Product: binutils
Version: 2.47
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: ld
Assignee: unassigned at sourceware dot org
Reporter: 2722900221 at qq dot com
Target Milestone: ---
Created attachment 16881
--> https://sourceware.org/bugzilla/attachment.cgi?id=16881&action=edit
PoC
Summary
During relocatable link (`-r`), `elf_x86_64_common_section_index`
(`bfd/elf64-x86-64.c:6093`) dereferences a NULL `sec` while computing the
common-section index for an output symbol (called from `elf_link_output_extsym`
→ `bfd_hash_traverse` → `_bfd_elf_final_link`). `elf_section_flags(sec)` on the
NULL pointer crashes.
Affected Version
- binutils 2.47 (release tarball, version date `20260726`) — reproduced.
- Originally triaged on dev snapshot `2.47.50.20260722` (commit `640a79623`).
Reproduction
Build (ASAN):
CC=gcc CFLAGS='-g -O1 -fsanitize=address -fno-omit-frame-pointer -fno-common' \
LDFLAGS='-fsanitize=address' \
./configure --disable-gdb --disable-gdbserver --disable-sim --disable-cet \
--disable-werror --disable-nls --enable-targets=x86_64-linux-gnu
MAKEINFO=true
make -j
Run:
export
ASAN_OPTIONS="abort_on_error=0:symbolize=1:detect_leaks=0:allocator_may_return_null=1:halt_on_error=1"
ld -r -o /dev/null bug_0.o
Error Log
==64971==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000008 (pc
0x55a11ccb37ed bp 0x7ffdc898b0d0 sp 0x7ffdc898b0d0 T0)
The signal is caused by a READ memory access.
#0 elf_x86_64_common_section_index
/home/user/build/binutils-2.47/bfd/elf64-x86-64.c:6093
#1 elf_link_output_extsym
/home/user/build/binutils-2.47/bfd/elflink.c:10941
#2 bfd_hash_traverse
/home/user/build/binutils-2.47/bfd/hash.c:814
#3 _bfd_elf_final_link
/home/user/build/binutils-2.47/bfd/elflink.c:13380
#4 ldwrite
/home/user/build/binutils-2.47/ld/ldwrite.c:548
SUMMARY: AddressSanitizer: SEGV
/home/user/build/binutils-2.47/bfd/elf64-x86-64.c:6093 in
elf_x86_64_common_section_index
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