From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v4 2/2] powerpc/64: add stack protector support
Date: Wed, 26 Sep 2018 11:40:40 +0000 (UTC) [thread overview]
Message-ID: <439f9fbadb382553446153b2b3a1f6dbbe229505.1537961921.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <d6c43ab708bf9ae1266c745fece457ed2da43d7c.1537961921.git.christophe.leroy@c-s.fr>
On PPC64, as register r13 points to the paca_struct at all time,
this patch adds a copy of the canary there, which is copied at
task_switch.
That new canary is then used by using the following GCC options:
-mstack-protector-guard=tls
-mstack-protector-guard-reg=r13
-mstack-protector-guard-offset=offsetof(struct paca_struct, canary))
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/Kconfig | 2 +-
arch/powerpc/Makefile | 8 ++++++++
arch/powerpc/include/asm/paca.h | 3 +++
arch/powerpc/include/asm/stackprotector.h | 3 +++
arch/powerpc/kernel/asm-offsets.c | 3 +++
arch/powerpc/kernel/entry_64.S | 4 ++++
6 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 3bcb05929931..602eea723624 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -180,7 +180,7 @@ config PPC
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
select HAVE_CBPF_JIT if !PPC64
- select HAVE_STACKPROTECTOR if $(cc-option,-mstack-protector-guard=tls) && PPC32
+ select HAVE_STACKPROTECTOR if $(cc-option,-mstack-protector-guard=tls)
select HAVE_CONTEXT_TRACKING if PPC64
select HAVE_DEBUG_KMEMLEAK
select HAVE_DEBUG_STACKOVERFLOW
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 45b8eb4d8fe7..81552c7b46eb 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -113,7 +113,11 @@ KBUILD_ARFLAGS += --target=elf$(BITS)-$(GNUTARGET)
endif
cflags-$(CONFIG_STACKPROTECTOR) += -mstack-protector-guard=tls
+ifdef CONFIG_PPC64
+cflags-$(CONFIG_STACKPROTECTOR) += -mstack-protector-guard-reg=r13
+else
cflags-$(CONFIG_STACKPROTECTOR) += -mstack-protector-guard-reg=r2
+endif
LDFLAGS_vmlinux-y := -Bstatic
LDFLAGS_vmlinux-$(CONFIG_RELOCATABLE) := -pie
@@ -411,8 +415,12 @@ ifdef CONFIG_STACKPROTECTOR
prepare: stack_protector_prepare
stack_protector_prepare: prepare0
+ifdef CONFIG_PPC64
+ $(eval KBUILD_CFLAGS += -mstack-protector-guard-offset=$(shell awk '{if ($$2 == "PACA_CANARY") print $$3;}' include/generated/asm-offsets.h))
+else
$(eval KBUILD_CFLAGS += -mstack-protector-guard-offset=$(shell awk '{if ($$2 == "TASK_CANARY") print $$3;}' include/generated/asm-offsets.h))
endif
+endif
# Use the file '.tmp_gas_check' for binutils tests, as gas won't output
# to stdout and these checks are run even on install targets.
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index 6d6b3706232c..98d883e58945 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -246,6 +246,9 @@ struct paca_struct {
struct slb_entry *mce_faulty_slbs;
u16 slb_save_cache_ptr;
#endif /* CONFIG_PPC_BOOK3S_64 */
+#ifdef CONFIG_STACKPROTECTOR
+ unsigned long canary;
+#endif
} ____cacheline_aligned;
extern struct paca_struct **paca_ptrs;
diff --git a/arch/powerpc/include/asm/stackprotector.h b/arch/powerpc/include/asm/stackprotector.h
index 263e2aab1862..e81991955c0d 100644
--- a/arch/powerpc/include/asm/stackprotector.h
+++ b/arch/powerpc/include/asm/stackprotector.h
@@ -29,6 +29,9 @@ static __always_inline void boot_init_stack_canary(void)
canary ^= LINUX_VERSION_CODE;
current->stack_canary = canary;
+#ifdef CONFIG_PPC64
+ get_paca()->canary = canary;
+#endif
}
#endif /* _ASM_STACKPROTECTOR_H */
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index a992f7a53cf3..773dee55b3f6 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -81,6 +81,9 @@ int main(void)
OFFSET(MM, task_struct, mm);
#ifdef CONFIG_STACKPROTECTOR
OFFSET(TASK_CANARY, task_struct, stack_canary);
+#ifdef CONFIG_PPC64
+ OFFSET(PACA_CANARY, paca_struct, canary);
+#endif
#endif
OFFSET(MMCONTEXTID, mm_struct, context.id);
#ifdef CONFIG_PPC64
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 77a888bfcb53..573fa879d785 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -624,6 +624,10 @@ _GLOBAL(_switch)
addi r6,r4,-THREAD /* Convert THREAD to 'current' */
std r6,PACACURRENT(r13) /* Set new 'current' */
+#if defined(CONFIG_STACKPROTECTOR)
+ ld r6, TASK_CANARY(r6)
+ std r6, PACA_CANARY(r13)
+#endif
ld r8,KSP(r4) /* new stack pointer */
#ifdef CONFIG_PPC_BOOK3S_64
--
2.13.3
next prev parent reply other threads:[~2018-09-26 11:40 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-26 11:40 [PATCH v4 1/2] powerpc/32: add stack protector support Christophe Leroy
2018-09-26 11:40 ` Christophe Leroy [this message]
2018-09-26 19:16 ` Segher Boessenkool
2018-09-27 6:20 ` Christophe LEROY
2018-09-27 7:45 ` Segher Boessenkool
2018-09-27 11:51 ` Christophe LEROY
2018-09-28 12:56 ` Michael Ellerman
2018-09-28 16:26 ` Segher Boessenkool
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=439f9fbadb382553446153b2b3a1f6dbbe229505.1537961921.git.christophe.leroy@c-s.fr \
--to=christophe.leroy@c-s.fr \
--cc=benh@kernel.crashing.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=paulus@samba.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;
as well as URLs for NNTP newsgroup(s).