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From: Amit Daniel Kachhap <amit.kachhap@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Mark Rutland <mark.rutland@arm.com>,
	Kees Cook <keescook@chromium.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Kristina Martsenko <kristina.martsenko@arm.com>,
	Dave Martin <Dave.Martin@arm.com>,
	Mark Brown <broonie@kernel.org>,
	James Morse <james.morse@arm.com>,
	Ramana Radhakrishnan <ramana.radhakrishnan@arm.com>,
	Amit Daniel Kachhap <amit.kachhap@arm.com>,
	Vincenzo Frascino <Vincenzo.Frascino@arm.com>,
	Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH v7 12/17] arm64: unwind: strip PAC from kernel addresses
Date: Fri, 13 Mar 2020 14:34:59 +0530	[thread overview]
Message-ID: <1584090304-18043-13-git-send-email-amit.kachhap@arm.com> (raw)
In-Reply-To: <1584090304-18043-1-git-send-email-amit.kachhap@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.

When function graph tracer is used with patchable-function-entry then
return_to_handler will also have pac bits so strip it too.

Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
[Amit: Re-position ptrauth_strip_insn_pac, comment]
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
---
Changes since v6:
 * Mask PAC bits of return_to_handler in case of FUNCTION_GRAPH_TRACER.

   incase 
 arch/arm64/kernel/stacktrace.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index a336cb1..139679c 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -14,6 +14,7 @@
 #include <linux/stacktrace.h>
 
 #include <asm/irq.h>
+#include <asm/pointer_auth.h>
 #include <asm/stack_pointer.h>
 #include <asm/stacktrace.h>
 
@@ -86,7 +87,7 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	if (tsk->ret_stack &&
-			(frame->pc == (unsigned long)return_to_handler)) {
+		(ptrauth_strip_insn_pac(frame->pc) == (unsigned long)return_to_handler)) {
 		struct ftrace_ret_stack *ret_stack;
 		/*
 		 * This is a case where function graph tracer has
@@ -101,6 +102,8 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
 	}
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
+	frame->pc = ptrauth_strip_insn_pac(frame->pc);
+
 	/*
 	 * Frames created upon entry from EL0 have NULL FP and PC values, so
 	 * don't bother reporting these. Frames created by __noreturn functions
-- 
2.7.4


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  parent reply	other threads:[~2020-03-13  9:09 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-13  9:04 [PATCH v7 00/17] arm64: return address signing Amit Daniel Kachhap
2020-03-13  9:04 ` [PATCH v7 01/17] arm64: cpufeature: Fix meta-capability cpufeature check Amit Daniel Kachhap
2020-03-13  9:04 ` [PATCH v7 02/17] arm64: cpufeature: add pointer auth meta-capabilities Amit Daniel Kachhap
2020-03-13  9:04 ` [PATCH v7 03/17] arm64: rename ptrauth key structures to be user-specific Amit Daniel Kachhap
2020-03-13  9:04 ` [PATCH v7 04/17] arm64: install user ptrauth keys at kernel exit time Amit Daniel Kachhap
2020-03-13  9:04 ` [PATCH v7 05/17] arm64: ptrauth: Add bootup/runtime flags for __cpu_setup Amit Daniel Kachhap
2020-03-13  9:04 ` [PATCH v7 06/17] arm64: cpufeature: Move cpu capability helpers inside C file Amit Daniel Kachhap
2020-03-13  9:04 ` [PATCH v7 07/17] arm64: cpufeature: handle conflicts based on capability Amit Daniel Kachhap
2020-03-13  9:04 ` [PATCH v7 08/17] arm64: enable ptrauth earlier Amit Daniel Kachhap
2020-03-13  9:04 ` [PATCH v7 09/17] arm64: initialize and switch ptrauth kernel keys Amit Daniel Kachhap
2020-03-13  9:04 ` [PATCH v7 10/17] arm64: initialize ptrauth keys for kernel booting task Amit Daniel Kachhap
2020-03-13  9:04 ` [PATCH v7 11/17] arm64: mask PAC bits of __builtin_return_address Amit Daniel Kachhap
2020-03-13  9:04 ` Amit Daniel Kachhap [this message]
2020-03-13  9:05 ` [PATCH v7 13/17] arm64: __show_regs: strip PAC from lr in printk Amit Daniel Kachhap
2020-03-13  9:05 ` [PATCH v7 14/17] arm64: suspend: restore the kernel ptrauth keys Amit Daniel Kachhap
2020-03-13  9:05 ` [PATCH v7 15/17] kconfig: Add support for 'as-option' Amit Daniel Kachhap
2020-03-13  9:05   ` Amit Daniel Kachhap
2020-03-13  9:10   ` Masahiro Yamada
2020-03-13  9:10     ` Masahiro Yamada
2020-03-13  9:14     ` Amit Kachhap
2020-03-13  9:14       ` Amit Kachhap
2020-03-13  9:05 ` [PATCH v7 16/17] arm64: compile the kernel with ptrauth return address signing Amit Daniel Kachhap
2020-03-19 18:19   ` [PATCH] arm64: Kconfig: verify binutils support for ARM64_PTR_AUTH Nick Desaulniers
2020-03-19 18:35     ` Nathan Chancellor
2020-03-20 15:09     ` Catalin Marinas
2020-03-13  9:05 ` [PATCH v7 17/17] lkdtm: arm64: test kernel pointer authentication Amit Daniel Kachhap
2020-03-18 14:32 ` [PATCH v7 00/17] arm64: return address signing Catalin Marinas

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