From: Kristina Martsenko <kristina.martsenko@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Adam Wallis <awallis@codeaurora.org>,
Amit Kachhap <Amit.Kachhap@arm.com>,
Andrew Jones <drjones@redhat.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Arnd Bergmann <arnd@arndb.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Christoffer Dall <christoffer.dall@arm.com>,
Dave P Martin <Dave.Martin@arm.com>,
Jacob Bramley <jacob.bramley@arm.com>,
Kees Cook <keescook@chromium.org>,
Marc Zyngier <marc.zyngier@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ramana Radhakrishnan <ramana.radhakrishnan@arm.com>,
"Suzuki K . Poulose" <suzuki.poulose@arm.com>,
Will Deacon <will.deacon@arm.com>,
kvmarm@lists.cs.columbia.edu, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [RFC 14/17] arm64: unwind: strip PAC from kernel addresses
Date: Fri, 5 Oct 2018 09:47:51 +0100 [thread overview]
Message-ID: <20181005084754.20950-15-kristina.martsenko@arm.com> (raw)
In-Reply-To: <20181005084754.20950-1-kristina.martsenko@arm.com>
From: Mark Rutland <mark.rutland@arm.com>
When we enable pointer authentication in the kernel, LR values saved to
the stack will have a PAC which we must strip in order to retrieve the
real return address.
Strip PACs when unwinding the stack in order to account for this.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
---
arch/arm64/include/asm/pointer_auth.h | 10 +++++++---
arch/arm64/kernel/ptrace.c | 2 +-
arch/arm64/kernel/stacktrace.c | 3 +++
3 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h
index 5e40533f4ea2..e60f225d9fa2 100644
--- a/arch/arm64/include/asm/pointer_auth.h
+++ b/arch/arm64/include/asm/pointer_auth.h
@@ -55,12 +55,16 @@ static inline void ptrauth_keys_switch(struct ptrauth_keys *keys)
* The EL0 pointer bits used by a pointer authentication code.
* This is dependent on TBI0 being enabled, or bits 63:56 would also apply.
*/
-#define ptrauth_pac_mask() GENMASK(54, VA_BITS)
+#define ptrauth_pac_mask_ttbr0() GENMASK(54, VA_BITS)
+
+#define ptrauth_pac_mask_ttbr1() (GENMASK(63, 56) | GENMASK(54, VA_BITS))
-/* Only valid for EL0 TTBR0 instruction pointers */
static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr)
{
- return ptr & ~ptrauth_pac_mask();
+ if (ptr & BIT_ULL(55))
+ return ptr | ptrauth_pac_mask_ttbr1();
+ else
+ return ptr & ~ptrauth_pac_mask_ttbr0();
}
#define ptrauth_task_init_user(tsk) \
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index cb8246f8c603..bf4d6d384e4f 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -970,7 +970,7 @@ static int pac_mask_get(struct task_struct *target,
* depending on TCR_EL1.TBID*, which we may make use of in future, so
* we expose separate masks.
*/
- unsigned long mask = ptrauth_pac_mask();
+ unsigned long mask = ptrauth_pac_mask_ttbr0();
struct user_pac_mask uregs = {
.data_mask = mask,
.insn_mask = mask,
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 4989f7ea1e59..44f6a64a8006 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -24,6 +24,7 @@
#include <linux/stacktrace.h>
#include <asm/irq.h>
+#include <asm/pointer_auth.h>
#include <asm/stack_pointer.h>
#include <asm/stacktrace.h>
@@ -56,6 +57,8 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8));
+ frame->pc = ptrauth_strip_insn_pac(frame->pc);
+
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (tsk->ret_stack &&
(frame->pc == (unsigned long)return_to_handler)) {
--
2.11.0
next prev parent reply other threads:[~2018-10-05 8:50 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-05 8:47 [PATCH 00/17] ARMv8.3 pointer authentication support Kristina Martsenko
2018-10-05 8:47 ` [PATCH v5 01/17] arm64: add pointer authentication register bits Kristina Martsenko
2018-10-11 16:28 ` Will Deacon
2018-10-12 8:53 ` Mark Rutland
2018-10-12 8:56 ` Will Deacon
2018-10-12 9:50 ` Mark Rutland
2018-10-05 8:47 ` [PATCH v5 02/17] arm64/kvm: consistently handle host HCR_EL2 flags Kristina Martsenko
2018-10-05 8:47 ` [PATCH v5 03/17] arm64/kvm: hide ptrauth from guests Kristina Martsenko
2018-10-05 8:47 ` [PATCH v5 04/17] arm64: Don't trap host pointer auth use to EL2 Kristina Martsenko
2018-10-05 8:47 ` [PATCH v5 05/17] arm64/cpufeature: detect pointer authentication Kristina Martsenko
2018-10-05 8:47 ` [PATCH v5 06/17] asm-generic: mm_hooks: allow hooks to be overridden individually Kristina Martsenko
2018-10-05 8:47 ` [PATCH v5 07/17] arm64: add basic pointer authentication support Kristina Martsenko
2018-10-11 16:00 ` Suzuki K Poulose
2018-10-19 11:15 ` Catalin Marinas
2018-10-19 11:24 ` Will Deacon
2018-10-19 15:36 ` Kees Cook
2018-10-19 15:49 ` Will Deacon
2018-10-19 16:05 ` Kees Cook
2018-10-19 16:16 ` Will Deacon
2018-10-19 15:54 ` Mark Rutland
2018-10-19 16:49 ` Cyrill Gorcunov
2018-11-14 18:11 ` Will Deacon
2018-11-15 10:25 ` Dave Martin
2018-10-23 8:36 ` Ramana Radhakrishnan
2018-10-23 10:20 ` Will Deacon
2018-10-05 8:47 ` [PATCH v5 08/17] arm64: expose user PAC bit positions via ptrace Kristina Martsenko
2018-10-05 8:47 ` [PATCH v5 09/17] arm64: perf: strip PAC when unwinding userspace Kristina Martsenko
2018-10-05 8:47 ` [PATCH v5 10/17] arm64: enable pointer authentication Kristina Martsenko
2018-10-05 8:47 ` [PATCH v5 11/17] arm64: docs: document " Kristina Martsenko
2018-10-05 9:04 ` Ramana Radhakrishnan
2018-10-16 16:14 ` Kristina Martsenko
2018-10-19 11:35 ` Catalin Marinas
2018-10-19 11:47 ` Marc Zyngier
2018-10-19 12:22 ` Will Deacon
2018-10-19 14:42 ` Kristina Martsenko
2018-10-19 15:10 ` Catalin Marinas
2018-10-19 17:45 ` Will Deacon
2018-11-02 6:02 ` Jon Masters
2018-10-24 10:56 ` Ramana Radhakrishnan
2018-10-15 22:35 ` Kees Cook
2018-11-02 9:46 ` Ramana Radhakrishnan
2018-10-05 8:47 ` [RFC 12/17] arm64: move ptrauth keys to thread_info Kristina Martsenko
2018-10-19 11:38 ` Catalin Marinas
2018-10-05 8:47 ` [RFC 13/17] arm64: install user ptrauth keys at kernel exit time Kristina Martsenko
2018-10-05 8:47 ` Kristina Martsenko [this message]
2018-10-05 8:47 ` [RFC 15/17] arm64: enable ptrauth earlier Kristina Martsenko
2018-10-06 12:51 ` Amit Kachhap
2018-10-05 8:47 ` [RFC 16/17] arm64: initialize and switch ptrauth kernel keys Kristina Martsenko
2018-10-06 12:56 ` Amit Kachhap
2018-10-05 8:47 ` [RFC 17/17] arm64: compile the kernel with ptrauth -msign-return-address Kristina Martsenko
2018-10-05 9:01 ` Ramana Radhakrishnan
2018-10-11 14:00 ` Kristina Martsenko
2018-10-11 14:23 ` Vladimir Murzin
2018-10-15 22:38 ` Kees Cook
2018-10-15 22:42 ` [PATCH 00/17] ARMv8.3 pointer authentication support Kees Cook
2018-11-13 16:17 ` Kristina Martsenko
2018-11-13 23:09 ` Kees Cook
2018-11-14 15:54 ` Kristina Martsenko
2018-11-14 21:47 ` Mark Rutland
2018-11-14 22:48 ` Kees Cook
2018-10-19 12:36 ` Will Deacon
2018-10-23 8:39 ` Ramana Radhakrishnan
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