From: Brian Gerst <brgerst@gmail.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Uros Bizjak <ubizjak@gmail.com>, Brian Gerst <brgerst@gmail.com>
Subject: [PATCH 2/9] x86/boot: Disable stack protector for early boot code
Date: Mon, 23 Oct 2023 17:17:23 -0400 [thread overview]
Message-ID: <20231023211730.40566-3-brgerst@gmail.com> (raw)
In-Reply-To: <20231023211730.40566-1-brgerst@gmail.com>
On 64-bit, this will prevent crashes when the canary access is changed
from %gs:40 to %gs:__stack_chk_guard(%rip). RIP-relative addresses from
the identity-mapped early boot code will target the wrong address with
zero-based percpu. KASLR could then shift that address to an unmapped
page causing a crash on boot.
This early boot code runs well before userspace is active and does not
need stack protector enabled.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
arch/x86/kernel/Makefile | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 0000325ab98f..aff619054e17 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -39,6 +39,8 @@ KMSAN_SANITIZE_nmi.o := n
KCOV_INSTRUMENT_head$(BITS).o := n
KCOV_INSTRUMENT_sev.o := n
+CFLAGS_head32.o := -fno-stack-protector
+CFLAGS_head64.o := -fno-stack-protector
CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace
obj-y += head_$(BITS).o
--
2.41.0
next prev parent reply other threads:[~2023-10-23 21:17 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-23 21:17 [PATCH 0/9] x86-64: Stack protector and percpu improvements Brian Gerst
2023-10-23 21:17 ` [PATCH 1/9] x86/stackprotector/32: Remove stack protector test script Brian Gerst
2023-10-23 21:17 ` Brian Gerst [this message]
2023-10-23 21:17 ` [PATCH 3/9] x86/stackprotector/64: Convert stack protector to normal percpu variable Brian Gerst
2023-10-24 12:39 ` Uros Bizjak
2023-10-23 21:17 ` [PATCH 4/9] x86/percpu/64: Remove fixed_percpu_data Brian Gerst
2023-10-24 12:33 ` Uros Bizjak
2023-10-24 14:11 ` Brian Gerst
2023-10-23 21:17 ` [PATCH 5/9] x86/percpu/64: Use relative percpu offsets Brian Gerst
2023-10-24 12:43 ` Uros Bizjak
2023-10-23 21:17 ` [PATCH 6/9] x86/boot/64: Remove inverse relocations Brian Gerst
2023-10-23 21:17 ` [PATCH 7/9] x86/percpu/64: Remove INIT_PER_CPU macros Brian Gerst
2023-10-23 21:17 ` [PATCH 8/9] percpu: Remove PER_CPU_FIRST_SECTION Brian Gerst
2023-10-23 21:17 ` [PATCH 9/9] kallsyms: Remove KALLSYMS_ABSOLUTE_PERCPU Brian Gerst
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20231023211730.40566-3-brgerst@gmail.com \
--to=brgerst@gmail.com \
--cc=bp@alien8.de \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=ubizjak@gmail.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox