include/linux/kmsan-checks.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * KMSAN checks to be used for one-off annotations in subsystems.
   4  *
   5  * Copyright (C) 2017-2022 Google LLC
   6  * Author: Alexander Potapenko <glider@google.com>
   7  *
   8  */
   9
  10 #ifndef _LINUX_KMSAN_CHECKS_H
  11 #define _LINUX_KMSAN_CHECKS_H
  12
  13 #include <linux/types.h>
  14
  15 #ifdef CONFIG_KMSAN
  16
  17 /**
  18  * kmsan_poison_memory() - Mark the memory range as uninitialized.
  19  * @address: address to start with.
  20  * @size:    size of buffer to poison.
  21  * @flags:   GFP flags for allocations done by this function.
  22  *
  23  * Until other data is written to this range, KMSAN will treat it as
  24  * uninitialized. Error reports for this memory will reference the call site of
  25  * kmsan_poison_memory() as origin.
  26  */
  27 void kmsan_poison_memory(const void *address, size_t size, gfp_t flags);
  28
  29 /**
  30  * kmsan_unpoison_memory() -  Mark the memory range as initialized.
  31  * @address: address to start with.
  32  * @size:    size of buffer to unpoison.
  33  *
  34  * Until other data is written to this range, KMSAN will treat it as
  35  * initialized.
  36  */
  37 void kmsan_unpoison_memory(const void *address, size_t size);
  38
  39 /**
  40  * kmsan_check_memory() - Check the memory range for being initialized.
  41  * @address: address to start with.
  42  * @size:    size of buffer to check.
  43  *
  44  * If any piece of the given range is marked as uninitialized, KMSAN will report
  45  * an error.
  46  */
  47 void kmsan_check_memory(const void *address, size_t size);
  48
  49 /**
  50  * kmsan_copy_to_user() - Notify KMSAN about a data transfer to userspace.
  51  * @to:      destination address in the userspace.
  52  * @from:    source address in the kernel.
  53  * @to_copy: number of bytes to copy.
  54  * @left:    number of bytes not copied.
  55  *
  56  * If this is a real userspace data transfer, KMSAN checks the bytes that were
  57  * actually copied to ensure there was no information leak. If @to belongs to
  58  * the kernel space (which is possible for compat syscalls), KMSAN just copies
  59  * the metadata.
  60  */
  61 void kmsan_copy_to_user(void __user *to, const void *from, size_t to_copy,
  62                         size_t left);
  63
  64 /**
  65  * kmsan_memmove() - Notify KMSAN about a data copy within kernel.
  66  * @to:   destination address in the kernel.
  67  * @from: source address in the kernel.
  68  * @size: number of bytes to copy.
  69  *
  70  * Invoked after non-instrumented version (e.g. implemented using assembly
  71  * code) of memmove()/memcpy() is called, in order to copy KMSAN's metadata.
  72  */
  73 void kmsan_memmove(void *to, const void *from, size_t to_copy);
  74
  75 #else
  76
  77 static inline void kmsan_poison_memory(const void *address, size_t size,
  78                                        gfp_t flags)
  79 {
  80 }
  81 static inline void kmsan_unpoison_memory(const void *address, size_t size)
  82 {
  83 }
  84 static inline void kmsan_check_memory(const void *address, size_t size)
  85 {
  86 }
  87 static inline void kmsan_copy_to_user(void __user *to, const void *from,
  88                                       size_t to_copy, size_t left)
  89 {
  90 }
  91
  92 static inline void kmsan_memmove(void *to, const void *from, size_t to_copy)
  93 {
  94 }
  95
  96 #endif
  97
  98 #endif /* _LINUX_KMSAN_CHECKS_H */