From: Will Deacon <will.deacon@arm•com>
To: Andrey Konovalov <andreyknvl@google•com>
Cc: Mark Rutland <mark.rutland@arm•com>,
Kate Stewart <kstewart@linuxfoundation•org>,
linux-doc@vger•kernel.org,
Catalin Marinas <catalin.marinas@arm•com>,
Paul Lawrence <paullawrence@google•com>,
linux-mm@kvack•org, Alexander Potapenko <glider@google•com>,
Chintan Pandya <cpandya@codeaurora•org>,
Christoph Lameter <cl@linux•com>, Ingo Molnar <mingo@kernel•org>,
Jacob Bramley <Jacob.Bramley@arm•com>,
Ruben Ayrapetyan <Ruben.Ayrapetyan@arm•com>,
Mark Brand <markbrand@google•com>,
kasan-dev@googlegroups•com, linux-sparse@vger•kernel.org,
Geert Uytterhoeven <geert@linux-m68k•org>,
linux-arm-kernel@lists•infradead.org,
Andrey Ryabinin <aryabinin@virtuozzo•com>,
Dave Martin <dave.martin@arm•com>,
Evgeniy Stepanov <eugenis@google•com>,
Vishwath Mohan <vishwath@google•com>,
Arnd Bergmann <arnd@arndb•de>,
linux-kbuild@vger•kernel.org, Marc Zyngier <marc.zyngier@arm•com>,
Ramana Radhakrishnan <Ramana.Radhakrishnan@arm•com>,
Mike Rapoport <rppt@linux•vnet.ibm.com>,
Dmitry Vyukov <dvyukov@google•com>,
Kostya Serebryany <kcc@google•com>, Jann Horn <jannh@google•com>,
Ard Biesheuvel <ard.biesheuvel@linaro•org>,
Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
Nick Desaulniers <ndesaulniers@google•com>,
linux-kernel@vger•kernel.org,
"Eric W . Biederman" <ebiederm@xmission•com>,
Lee Smith <Lee.Smith@arm•com>,
Andrew Morton <akpm@linux-foundation•org>,
"Kirill A . Shutemov" <kirill.shutemov@linux•intel.com>
Subject: Re: [PATCH v12 20/25] kasan, arm64: add brk handler for inline instrumentation
Date: Thu, 29 Nov 2018 18:01:38 +0000 [thread overview]
Message-ID: <20181129180138.GB4318@arm.com> (raw)
In-Reply-To: <e825441eda1dbbbb7f583f826a66c94e6f88316a.1543337629.git.andreyknvl@google.com>
On Tue, Nov 27, 2018 at 05:55:38PM +0100, Andrey Konovalov wrote:
> Tag-based KASAN inline instrumentation mode (which embeds checks of shadow
> memory into the generated code, instead of inserting a callback) generates
> a brk instruction when a tag mismatch is detected.
>
> This commit adds a tag-based KASAN specific brk handler, that decodes the
> immediate value passed to the brk instructions (to extract information
> about the memory access that triggered the mismatch), reads the register
> values (x0 contains the guilty address) and reports the bug.
>
> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo•com>
> Reviewed-by: Dmitry Vyukov <dvyukov@google•com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google•com>
> ---
> arch/arm64/include/asm/brk-imm.h | 2 +
> arch/arm64/kernel/traps.c | 68 +++++++++++++++++++++++++++++++-
> include/linux/kasan.h | 3 ++
> 3 files changed, 71 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/include/asm/brk-imm.h b/arch/arm64/include/asm/brk-imm.h
> index ed693c5bcec0..2945fe6cd863 100644
> --- a/arch/arm64/include/asm/brk-imm.h
> +++ b/arch/arm64/include/asm/brk-imm.h
> @@ -16,10 +16,12 @@
> * 0x400: for dynamic BRK instruction
> * 0x401: for compile time BRK instruction
> * 0x800: kernel-mode BUG() and WARN() traps
> + * 0x9xx: tag-based KASAN trap (allowed values 0x900 - 0x9ff)
> */
> #define FAULT_BRK_IMM 0x100
> #define KGDB_DYN_DBG_BRK_IMM 0x400
> #define KGDB_COMPILED_DBG_BRK_IMM 0x401
> #define BUG_BRK_IMM 0x800
> +#define KASAN_BRK_IMM 0x900
>
> #endif
> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
> index 5f4d9acb32f5..04bdc53716ef 100644
> --- a/arch/arm64/kernel/traps.c
> +++ b/arch/arm64/kernel/traps.c
> @@ -35,6 +35,7 @@
> #include <linux/sizes.h>
> #include <linux/syscalls.h>
> #include <linux/mm_types.h>
> +#include <linux/kasan.h>
>
> #include <asm/atomic.h>
> #include <asm/bug.h>
> @@ -284,10 +285,14 @@ void arm64_notify_die(const char *str, struct pt_regs *regs,
> }
> }
>
> -void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size)
> +void __arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size)
> {
> regs->pc += size;
> +}
>
> +void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size)
> +{
> + __arm64_skip_faulting_instruction(regs, size);
> /*
> * If we were single stepping, we want to get the step exception after
> * we return from the trap.
> @@ -959,7 +964,7 @@ static int bug_handler(struct pt_regs *regs, unsigned int esr)
> }
>
> /* If thread survives, skip over the BUG instruction and continue: */
> - arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
> + __arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
Why do you want to avoid the single-step logic here? Given that we're
skipping over the brk instruction, why wouldn't you want that to trigger
a step exception if single-step is enabled?
Will
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next prev parent reply other threads:[~2018-11-29 18:02 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-27 16:55 [PATCH v12 00/25] kasan: add software tag-based mode for arm64 Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 01/25] kasan, mm: change hooks signatures Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 02/25] kasan, slub: handle pointer tags in early_kmem_cache_node_alloc Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 03/25] kasan: move common generic and tag-based code to common.c Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 04/25] kasan: rename source files to reflect the new naming scheme Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 05/25] kasan: add CONFIG_KASAN_GENERIC and CONFIG_KASAN_SW_TAGS Andrey Konovalov
2018-12-04 22:23 ` Max Filippov
2018-12-06 10:19 ` Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 06/25] kasan, arm64: adjust shadow size for tag-based mode Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 07/25] kasan: rename kasan_zero_page to kasan_early_shadow_page Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 08/25] kasan: initialize shadow to 0xff for tag-based mode Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 09/25] arm64: move untagged_addr macro from uaccess.h to memory.h Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 10/25] kasan: add tag related helper functions Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 11/25] kasan, arm64: untag address in _virt_addr_is_linear Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 12/25] kasan: preassign tags to objects with ctors or SLAB_TYPESAFE_BY_RCU Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 13/25] kasan, arm64: fix up fault handling logic Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 14/25] kasan, arm64: enable top byte ignore for the kernel Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 15/25] kasan, mm: perform untagged pointers comparison in krealloc Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 16/25] kasan: split out generic_report.c from report.c Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 17/25] kasan: add bug reporting routines for tag-based mode Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 18/25] mm: move obj_to_index to include/linux/slab_def.h Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 19/25] kasan: add hooks implementation for tag-based mode Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 20/25] kasan, arm64: add brk handler for inline instrumentation Andrey Konovalov
2018-11-29 18:01 ` Will Deacon [this message]
2018-12-06 10:31 ` Andrey Konovalov
2018-12-06 11:11 ` Will Deacon
2018-12-06 12:25 ` Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 21/25] kasan, mm, arm64: tag non slab memory allocated via pagealloc Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 22/25] kasan: add __must_check annotations to kasan hooks Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 23/25] kasan, arm64: select HAVE_ARCH_KASAN_SW_TAGS Andrey Konovalov
2018-11-29 18:01 ` Will Deacon
2018-12-06 10:19 ` Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 24/25] kasan: update documentation Andrey Konovalov
2018-11-27 16:55 ` [PATCH v12 25/25] kasan: add SPDX-License-Identifier mark to source files Andrey Konovalov
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