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This patch adds arch specific code for kernel address sanitizer (see Documentation/kasan.txt). 1/8 of kernel addresses reserved for shadow memory. There was no big enough hole for this, so virtual addresses for shadow were stolen from vmalloc area. At early boot stage the whole shadow region populated with just one physical page (kasan_zero_page). Later, this page reused as readonly zero shadow for some memory that KASan currently don't track (vmalloc). After mapping the physical memory, pages for shadow memory are allocated and mapped. Functions like memset/memmove/memcpy do a lot of memory accesses. If bad pointer passed to one of these function it is important to catch this. Compiler's instrumentation cannot do this since these functions are written in assembly. KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in name, so we could call non-instrumented variant if needed. Some files built without kasan instrumentation (e.g. mm/slub.c). Original mem* function replaced (via #define) with prefixed variants to disable memory access checks for such files. Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Tested-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
69 lines
2.1 KiB
C
69 lines
2.1 KiB
C
/*
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* Copyright (C) 2013 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __ASM_STRING_H
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#define __ASM_STRING_H
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#define __HAVE_ARCH_STRRCHR
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extern char *strrchr(const char *, int c);
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#define __HAVE_ARCH_STRCHR
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extern char *strchr(const char *, int c);
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#define __HAVE_ARCH_STRCMP
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extern int strcmp(const char *, const char *);
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#define __HAVE_ARCH_STRNCMP
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extern int strncmp(const char *, const char *, __kernel_size_t);
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#define __HAVE_ARCH_STRLEN
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extern __kernel_size_t strlen(const char *);
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#define __HAVE_ARCH_STRNLEN
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extern __kernel_size_t strnlen(const char *, __kernel_size_t);
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#define __HAVE_ARCH_MEMCPY
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extern void *memcpy(void *, const void *, __kernel_size_t);
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extern void *__memcpy(void *, const void *, __kernel_size_t);
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#define __HAVE_ARCH_MEMMOVE
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extern void *memmove(void *, const void *, __kernel_size_t);
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extern void *__memmove(void *, const void *, __kernel_size_t);
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#define __HAVE_ARCH_MEMCHR
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extern void *memchr(const void *, int, __kernel_size_t);
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#define __HAVE_ARCH_MEMSET
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extern void *memset(void *, int, __kernel_size_t);
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extern void *__memset(void *, int, __kernel_size_t);
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#define __HAVE_ARCH_MEMCMP
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extern int memcmp(const void *, const void *, size_t);
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#if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__)
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/*
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* For files that are not instrumented (e.g. mm/slub.c) we
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* should use not instrumented version of mem* functions.
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*/
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#define memcpy(dst, src, len) __memcpy(dst, src, len)
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#define memmove(dst, src, len) __memmove(dst, src, len)
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#define memset(s, c, n) __memset(s, c, n)
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#endif
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#endif
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