064f89156f
Once tag-based KASAN modes start tagging vmalloc() allocations, kernel stacks start getting tagged if CONFIG_VMAP_STACK is enabled. Reset the tag of kernel stack pointers after allocation in arch_alloc_vmap_stack(). For SW_TAGS KASAN, when CONFIG_KASAN_STACK is enabled, the instrumentation can't handle the SP register being tagged. For HW_TAGS KASAN, there's no instrumentation-related issues. However, the impact of having a tagged SP register needs to be properly evaluated, so keep it non-tagged for now. Note, that the memory for the stack allocation still gets tagged to catch vmalloc-into-stack out-of-bounds accesses. Link: https://lkml.kernel.org/r/698c5ab21743c796d46c15d075b9481825973e34.1643047180.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> (cherry picked from commit 54f7bbc3786b67625b02fe067a91478fc3f39caa git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git akpm) Bug: 217222520 Change-Id: Ie273a7bbde12a28b26c49d94795733f289a0c150 Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
30 lines
739 B
C
30 lines
739 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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// Copyright (C) 2017 Arm Ltd.
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#ifndef __ASM_VMAP_STACK_H
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#define __ASM_VMAP_STACK_H
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#include <linux/bug.h>
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#include <linux/gfp.h>
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#include <linux/kconfig.h>
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#include <linux/vmalloc.h>
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#include <linux/pgtable.h>
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#include <asm/memory.h>
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#include <asm/thread_info.h>
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/*
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* To ensure that VMAP'd stack overflow detection works correctly, all VMAP'd
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* stacks need to have the same alignment.
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*/
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static inline unsigned long *arch_alloc_vmap_stack(size_t stack_size, int node)
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{
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void *p;
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BUILD_BUG_ON(!IS_ENABLED(CONFIG_VMAP_STACK));
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p = __vmalloc_node(stack_size, THREAD_ALIGN, THREADINFO_GFP, node,
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__builtin_return_address(0));
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return kasan_reset_tag(p);
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}
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#endif /* __ASM_VMAP_STACK_H */
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