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linux-next/include/linux/kasan-checks.h
Andrey Konovalov 611806b4bf kasan: fix bug detection via ksize for HW_TAGS mode
The currently existing kasan_check_read/write() annotations are intended
to be used for kernel modules that have KASAN compiler instrumentation
disabled. Thus, they are only relevant for the software KASAN modes that
rely on compiler instrumentation.

However there's another use case for these annotations: ksize() checks
that the object passed to it is indeed accessible before unpoisoning the
whole object. This is currently done via __kasan_check_read(), which is
compiled away for the hardware tag-based mode that doesn't rely on
compiler instrumentation. This leads to KASAN missing detecting some
memory corruptions.

Provide another annotation called kasan_check_byte() that is available
for all KASAN modes. As the implementation rename and reuse
kasan_check_invalid_free(). Use this new annotation in ksize().
To avoid having ksize() as the top frame in the reported stack trace
pass _RET_IP_ to __kasan_check_byte().

Also add a new ksize_uaf() test that checks that a use-after-free is
detected via ksize() itself, and via plain accesses that happen later.

Link: https://linux-review.googlesource.com/id/Iaabf771881d0f9ce1b969f2a62938e99d3308ec5
Link: https://lkml.kernel.org/r/f32ad74a60b28d8402482a38476f02bb7600f620.1610733117.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-24 13:38:31 -08:00

51 lines
1.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_KASAN_CHECKS_H
#define _LINUX_KASAN_CHECKS_H
#include <linux/types.h>
/*
* The annotations present in this file are only relevant for the software
* KASAN modes that rely on compiler instrumentation, and will be optimized
* away for the hardware tag-based KASAN mode. Use kasan_check_byte() instead.
*/
/*
* __kasan_check_*: Always available when KASAN is enabled. This may be used
* even in compilation units that selectively disable KASAN, but must use KASAN
* to validate access to an address. Never use these in header files!
*/
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
bool __kasan_check_read(const volatile void *p, unsigned int size);
bool __kasan_check_write(const volatile void *p, unsigned int size);
#else
static inline bool __kasan_check_read(const volatile void *p, unsigned int size)
{
return true;
}
static inline bool __kasan_check_write(const volatile void *p, unsigned int size)
{
return true;
}
#endif
/*
* kasan_check_*: Only available when the particular compilation unit has KASAN
* instrumentation enabled. May be used in header files.
*/
#ifdef __SANITIZE_ADDRESS__
#define kasan_check_read __kasan_check_read
#define kasan_check_write __kasan_check_write
#else
static inline bool kasan_check_read(const volatile void *p, unsigned int size)
{
return true;
}
static inline bool kasan_check_write(const volatile void *p, unsigned int size)
{
return true;
}
#endif
#endif