linux-kernel - [PATCH 0/3] kexec: Fix invalid field access

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250827-kbuf_all-v1-0-1df9882bb01a@debian.org>
Date: Wed, 27 Aug 2025 03:42:20 -0700
From: Breno Leitao <leitao@...ian.org>
To: Catalin Marinas <catalin.marinas@....com>, 
 Will Deacon <will@...nel.org>, Andrew Morton <akpm@...ux-foundation.org>, 
 Baoquan He <bhe@...hat.com>, Coiby Xu <coxu@...hat.com>, 
 Paul Walmsley <paul.walmsley@...ive.com>, 
 Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, 
 Alexandre Ghiti <alex@...ti.fr>, Heiko Carstens <hca@...ux.ibm.com>, 
 Vasily Gorbik <gor@...ux.ibm.com>, 
 Alexander Gordeev <agordeev@...ux.ibm.com>, 
 Christian Borntraeger <borntraeger@...ux.ibm.com>, 
 Sven Schnelle <svens@...ux.ibm.com>
Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
 linux-riscv@...ts.infradead.org, linux-s390@...r.kernel.org, 
 Breno Leitao <leitao@...ian.org>, kernel-team@...a.com
Subject: [PATCH 0/3] kexec: Fix invalid field access

The kexec_buf structure was previously declared without initialization.
commit bf454ec31add ("kexec_file: allow to place kexec_buf randomly")
added a field that is always read but not consistently populated by all
architectures. This un-initialized field will contain garbage.

This is also triggering a UBSAN warning when the uninitialized data was
accessed:

	------------[ cut here ]------------
	UBSAN: invalid-load in ./include/linux/kexec.h:210:10
	load of value 252 is not a valid value for type '_Bool'

Zero-initializing kexec_buf at declaration ensures all fields are
cleanly set, preventing future instances of uninitialized memory being
used.

An initial fix was already landed for arm64[0], and this patchset fixes
the problem on the remaining arm64 code and on riscv, as raised by Mark.

Discussions about this problem could be found at[1][2].

Link: https://lore.kernel.org/all/20250826180742.f2471131255ec1c43683ea07@linux-foundation.org/ [0]
Link: https://lore.kernel.org/all/oninomspajhxp4omtdapxnckxydbk2nzmrix7rggmpukpnzadw@c67o7njgdgm3/ [1]
Link: https://lore.kernel.org/all/20250826-akpm-v1-1-3c831f0e3799@debian.org/ [2]

Signed-off-by: Breno Leitao <leitao@...ian.org>
---
Breno Leitao (3):
      arm64: kexec: Initialize kexec_buf struct in load_other_segments()
      riscv: kexec: Initialize kexec_buf struct
      s390: kexec: Initialize kexec_buf struct

 arch/arm64/kernel/machine_kexec_file.c | 2 +-
 arch/riscv/kernel/kexec_elf.c          | 4 ++--
 arch/riscv/kernel/kexec_image.c        | 2 +-
 arch/riscv/kernel/machine_kexec_file.c | 2 +-
 arch/s390/kernel/kexec_elf.c           | 2 +-
 arch/s390/kernel/kexec_image.c         | 2 +-
 arch/s390/kernel/machine_kexec_file.c  | 6 +++---
 7 files changed, 10 insertions(+), 10 deletions(-)
---
base-commit: 3c642997252eef4449cb6b6e02af3dc22515d817
change-id: 20250827-kbuf_all-b9d55c9291eb

Best regards,
--  
Breno Leitao <leitao@...ian.org>