From: Jian Cai <jiancai@google.com>
To: unlisted-recipients:; (no To-header on input)
Cc: ndesaulniers@google.com, manojgupta@google.com,
llozano@google.com, clang-built-linux@googlegroups.com,
"Jian Cai" <jiancai@google.com>,
"Nathan Chancellor" <nathan@kernel.org>,
"David Laight" <David.Laight@aculab.com>,
"Will Deacon" <will@kernel.org>,
"Russell King" <linux@armlinux.org.uk>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"James Morris" <jmorris@namei.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Masahiro Yamada" <masahiroy@kernel.org>,
"Kees Cook" <keescook@chromium.org>,
"Ard Biesheuvel" <ardb@kernel.org>,
"Andreas Färber" <afaerber@suse.de>,
"Ingo Molnar" <mingo@kernel.org>,
"Linus Walleij" <linus.walleij@linaro.org>,
"Marc Zyngier" <maz@kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Mike Rapoport" <rppt@kernel.org>,
"Mark Rutland" <mark.rutland@arm.com>,
"David Brazdil" <dbrazdil@google.com>,
"James Morse" <james.morse@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: [PATCH v4] ARM: Implement SLS mitigation
Date: Fri, 19 Feb 2021 15:08:13 -0800 [thread overview]
Message-ID: <20210219230841.875875-1-jiancai@google.com> (raw)
In-Reply-To: <20210219201852.3213914-1-jiancai@google.com>
This patch adds CONFIG_HARDEN_SLS_ALL that can be used to turn on
-mharden-sls=all, which mitigates the straight-line speculation
vulnerability, speculative execution of the instruction following some
unconditional jumps. Notice -mharden-sls= has other options as below,
and this config turns on the strongest option.
all: enable all mitigations against Straight Line Speculation that are implemented.
none: disable all mitigations against Straight Line Speculation.
retbr: enable the mitigation against Straight Line Speculation for RET and BR instructions.
blr: enable the mitigation against Straight Line Speculation for BLR instructions.
Links:
https://reviews.llvm.org/D93221
https://reviews.llvm.org/D81404
https://developer.arm.com/support/arm-security-updates/speculative-processor-vulnerability/downloads/straight-line-speculation
https://developer.arm.com/support/arm-security-updates/speculative-processor-vulnerability/frequently-asked-questions#SLS2
Suggested-by: Manoj Gupta <manojgupta@google.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: David Laight <David.Laight@aculab.com>
Suggested-by: Will Deacon <will@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Jian Cai <jiancai@google.com>
---
Changes v3 -> v4:
Address Nathan's comment and replace def_bool with depends on in
HARDEN_SLS_ALL.
arch/arm/Makefile | 4 ++++
arch/arm/include/asm/vmlinux.lds.h | 4 ++++
arch/arm/kernel/vmlinux.lds.S | 1 +
arch/arm64/Makefile | 4 ++++
arch/arm64/kernel/vmlinux.lds.S | 5 +++++
security/Kconfig.hardening | 10 ++++++++++
6 files changed, 28 insertions(+)
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 4aaec9599e8a..11d89ef32da9 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -48,6 +48,10 @@ CHECKFLAGS += -D__ARMEL__
KBUILD_LDFLAGS += -EL
endif
+ifeq ($(CONFIG_HARDEN_SLS_ALL), y)
+KBUILD_CFLAGS += -mharden-sls=all
+endif
+
#
# The Scalar Replacement of Aggregates (SRA) optimization pass in GCC 4.9 and
# later may result in code being generated that handles signed short and signed
diff --git a/arch/arm/include/asm/vmlinux.lds.h b/arch/arm/include/asm/vmlinux.lds.h
index 4a91428c324d..c7f9717511ca 100644
--- a/arch/arm/include/asm/vmlinux.lds.h
+++ b/arch/arm/include/asm/vmlinux.lds.h
@@ -145,3 +145,7 @@
__edtcm_data = .; \
} \
. = __dtcm_start + SIZEOF(.data_dtcm);
+
+#define SLS_TEXT \
+ ALIGN_FUNCTION(); \
+ *(.text.__llvm_slsblr_thunk_*)
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index f7f4620d59c3..e71f2bc97bae 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -63,6 +63,7 @@ SECTIONS
.text : { /* Real text segment */
_stext = .; /* Text and read-only data */
ARM_TEXT
+ SLS_TEXT
}
#ifdef CONFIG_DEBUG_ALIGN_RODATA
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 90309208bb28..ca7299b356a9 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -34,6 +34,10 @@ $(warning LSE atomics not supported by binutils)
endif
endif
+ifeq ($(CONFIG_HARDEN_SLS_ALL), y)
+KBUILD_CFLAGS += -mharden-sls=all
+endif
+
cc_has_k_constraint := $(call try-run,echo \
'int main(void) { \
asm volatile("and w0, w0, %w0" :: "K" (4294967295)); \
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 4c0b0c89ad59..f8912e42ffcd 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -93,6 +93,10 @@ jiffies = jiffies_64;
#define TRAMP_TEXT
#endif
+#define SLS_TEXT \
+ ALIGN_FUNCTION(); \
+ *(.text.__llvm_slsblr_thunk_*)
+
/*
* The size of the PE/COFF section that covers the kernel image, which
* runs from _stext to _edata, must be a round multiple of the PE/COFF
@@ -144,6 +148,7 @@ SECTIONS
HIBERNATE_TEXT
TRAMP_TEXT
*(.fixup)
+ SLS_TEXT
*(.gnu.warning)
. = ALIGN(16);
*(.got) /* Global offset table */
diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
index 269967c4fc1b..146b75a79d9e 100644
--- a/security/Kconfig.hardening
+++ b/security/Kconfig.hardening
@@ -121,6 +121,16 @@ choice
endchoice
+config HARDEN_SLS_ALL
+ bool "enable SLS vulnerability hardening"
+ default n
+ depends on $(cc-option,-mharden-sls=all)
+ help
+ Enables straight-line speculation vulnerability hardening on ARM and ARM64
+ architectures. It inserts speculation barrier sequences (SB or DSB+ISB
+ depending on the target architecture) after RET and BR, and replacing
+ BLR with BL+BR sequence.
+
config GCC_PLUGIN_STRUCTLEAK_VERBOSE
bool "Report forcefully initialized variables"
depends on GCC_PLUGIN_STRUCTLEAK
--
2.30.0.617.g56c4b15f3c-goog
next prev parent reply other threads:[~2021-02-19 23:10 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-12 5:14 [PATCH] ARM: Implement Clang's SLS mitigation Jian Cai
2021-02-12 5:55 ` Nathan Chancellor
2021-02-12 10:41 ` David Laight
2021-02-12 19:52 ` [PATCH v2] " Jian Cai
2021-02-17 9:49 ` Will Deacon
2021-02-17 11:05 ` David Laight
2021-03-25 14:01 ` Linus Walleij
2021-02-17 18:20 ` Nick Desaulniers
2021-02-19 20:18 ` [PATCH v3] ARM: Implement " Jian Cai
2021-02-19 20:30 ` Nathan Chancellor
2021-02-19 23:08 ` Jian Cai [this message]
2021-02-21 10:13 ` [PATCH v4] " Russell King - ARM Linux admin
2021-02-22 11:58 ` Will Deacon
2021-02-22 21:50 ` Jian Cai
2021-02-23 10:04 ` Will Deacon
2021-03-03 15:18 ` Linus Walleij
2021-03-03 15:29 ` David Laight
2021-03-03 15:31 ` Linus Walleij
2021-02-23 2:31 ` [PATCH v5] " Jian Cai
2021-02-23 2:35 ` Jian Cai
2021-03-03 15:04 ` Linus Walleij
2021-03-04 23:22 ` Jian Cai
2021-03-06 12:25 ` Linus Walleij
2021-03-10 4:43 ` Jian Cai
2021-03-22 11:45 ` Linus Walleij
2021-03-23 22:39 ` Jian Cai
2021-03-05 0:53 ` [PATCH v6] " Jian Cai
2021-03-05 9:52 ` Will Deacon
2021-03-06 12:27 ` Linus Walleij
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