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 PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Tue, 25 Oct 2022 17:12:41 +0300 From: Evgeniy Baskov <baskov@...ras.ru> To: Ard Biesheuvel <ardb@...nel.org> Cc: Evgeniy Baskov <baskov@...ras.ru>, Borislav Petkov <bp@...en8.de>, Andy Lutomirski <luto@...nel.org>, Dave Hansen <dave.hansen@...ux.intel.com>, Ingo Molnar <mingo@...hat.com>, Peter Zijlstra <peterz@...radead.org>, Thomas Gleixner <tglx@...utronix.de>, Alexey Khoroshilov <khoroshilov@...ras.ru>, Peter Jones <pjones@...hat.com>, lvc-project@...uxtesting.org, x86@...nel.org, linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org, linux-hardening@...r.kernel.org Subject: [PATCH v2 03/23] x86/boot: Set cr0 to known state in trampoline Ensure WP bit to be set to prevent boot code from writing to non-writable memory pages. Signed-off-by: Evgeniy Baskov <baskov@...ras.ru> --- arch/x86/boot/compressed/head_64.S | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index d33f060900d2..2a4372b84fc8 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -684,9 +684,8 @@ SYM_CODE_START(trampoline_32bit_src) pushl $__KERNEL_CS pushl %eax - /* Enable paging again. */ - movl %cr0, %eax - btsl $X86_CR0_PG_BIT, %eax + /* Enable paging and set CR0 to known state (this also sets WP flag) */ + movl $CR0_STATE, %eax movl %eax, %cr0 lret -- 2.37.4
Powered by blists - more mailing lists