linux-kernel - [PATCH] riscv/efistub: Ensure GP-relative addressing is not used

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: <42c63cb9-87d0-49db-9af8-95771b186684@siemens.com>
Date: Fri, 12 Jan 2024 19:37:29 +0100
From: Jan Kiszka <jan.kiszka@...mens.com>
To: Ard Biesheuvel <ardb@...nel.org>, Palmer Dabbelt <palmer@...osinc.com>
Cc: linux-efi <linux-efi@...r.kernel.org>,
 Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH] riscv/efistub: Ensure GP-relative addressing is not used

From: Jan Kiszka <jan.kiszka@...mens.com>

The cflags for the RISC-V efistub were missing -mno-relax, thus were
under the risk that the compiler could use GP-relative addressing. That
happened for _edata with binutils-2.41 and kernel 6.1, causing the
relocation to fail due to an invalid kernel_size in handle_kernel_image.
It was not yet observed with newer versions, but that may just be luck.

Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
---

Something like this should go to stable as well, but we will need 
rebased patches.

 drivers/firmware/efi/libstub/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 06964a3c130f..d561d7de46a9 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -28,7 +28,7 @@ cflags-$(CONFIG_ARM)		+= -DEFI_HAVE_STRLEN -DEFI_HAVE_STRNLEN \
 				   -DEFI_HAVE_MEMCHR -DEFI_HAVE_STRRCHR \
 				   -DEFI_HAVE_STRCMP -fno-builtin -fpic \
 				   $(call cc-option,-mno-single-pic-base)
-cflags-$(CONFIG_RISCV)		+= -fpic -DNO_ALTERNATIVE
+cflags-$(CONFIG_RISCV)		+= -fpic -DNO_ALTERNATIVE -mno-relax
 cflags-$(CONFIG_LOONGARCH)	+= -fpie
 
 cflags-$(CONFIG_EFI_PARAMS_FROM_FDT)	+= -I$(srctree)/scripts/dtc/libfdt
-- 
2.35.3