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3429055f04
Provide a hook that can be used by custom memcpy implementations to tell KMSAN that the metadata needs to be copied. Without that, false positive reports are possible in the cases where KMSAN fails to intercept memory initialization. Link: https://lore.kernel.org/all/3b7dbd88-0861-4638-b2d2-911c97a4cadf@I-love.SAKURA.ne.jp/ Link: https://lkml.kernel.org/r/20240320101851.2589698-1-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Marco Elver <elver@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
99 lines
2.9 KiB
C
99 lines
2.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* KMSAN checks to be used for one-off annotations in subsystems.
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*
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* Copyright (C) 2017-2022 Google LLC
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* Author: Alexander Potapenko <glider@google.com>
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*
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*/
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#ifndef _LINUX_KMSAN_CHECKS_H
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#define _LINUX_KMSAN_CHECKS_H
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#include <linux/types.h>
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#ifdef CONFIG_KMSAN
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/**
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* kmsan_poison_memory() - Mark the memory range as uninitialized.
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* @address: address to start with.
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* @size: size of buffer to poison.
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* @flags: GFP flags for allocations done by this function.
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*
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* Until other data is written to this range, KMSAN will treat it as
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* uninitialized. Error reports for this memory will reference the call site of
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* kmsan_poison_memory() as origin.
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*/
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void kmsan_poison_memory(const void *address, size_t size, gfp_t flags);
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/**
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* kmsan_unpoison_memory() - Mark the memory range as initialized.
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* @address: address to start with.
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* @size: size of buffer to unpoison.
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*
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* Until other data is written to this range, KMSAN will treat it as
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* initialized.
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*/
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void kmsan_unpoison_memory(const void *address, size_t size);
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/**
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* kmsan_check_memory() - Check the memory range for being initialized.
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* @address: address to start with.
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* @size: size of buffer to check.
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*
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* If any piece of the given range is marked as uninitialized, KMSAN will report
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* an error.
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*/
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void kmsan_check_memory(const void *address, size_t size);
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/**
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* kmsan_copy_to_user() - Notify KMSAN about a data transfer to userspace.
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* @to: destination address in the userspace.
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* @from: source address in the kernel.
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* @to_copy: number of bytes to copy.
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* @left: number of bytes not copied.
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*
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* If this is a real userspace data transfer, KMSAN checks the bytes that were
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* actually copied to ensure there was no information leak. If @to belongs to
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* the kernel space (which is possible for compat syscalls), KMSAN just copies
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* the metadata.
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*/
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void kmsan_copy_to_user(void __user *to, const void *from, size_t to_copy,
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size_t left);
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/**
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* kmsan_memmove() - Notify KMSAN about a data copy within kernel.
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* @to: destination address in the kernel.
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* @from: source address in the kernel.
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* @size: number of bytes to copy.
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*
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* Invoked after non-instrumented version (e.g. implemented using assembly
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* code) of memmove()/memcpy() is called, in order to copy KMSAN's metadata.
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*/
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void kmsan_memmove(void *to, const void *from, size_t to_copy);
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#else
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static inline void kmsan_poison_memory(const void *address, size_t size,
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gfp_t flags)
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{
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}
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static inline void kmsan_unpoison_memory(const void *address, size_t size)
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{
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}
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static inline void kmsan_check_memory(const void *address, size_t size)
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{
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}
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static inline void kmsan_copy_to_user(void __user *to, const void *from,
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size_t to_copy, size_t left)
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{
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}
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static inline void kmsan_memmove(void *to, const void *from, size_t to_copy)
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{
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}
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#endif
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#endif /* _LINUX_KMSAN_CHECKS_H */
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