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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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5b301409e8
Make KASAN run on User Mode Linux on x86_64. The UML-specific KASAN initializer uses mmap to map the ~16TB of shadow memory to the location defined by KASAN_SHADOW_OFFSET. kasan_init() utilizes constructors to initialize KASAN before main(). The location of the KASAN shadow memory, starting at KASAN_SHADOW_OFFSET, can be configured using the KASAN_SHADOW_OFFSET option. The default location of this offset is 0x100000000000, which keeps it out-of-the-way even on UML setups with more "physical" memory. For low-memory setups, 0x7fff8000 can be used instead, which fits in an immediate and is therefore faster, as suggested by Dmitry Vyukov. There is usually enough free space at this location; however, it is a config option so that it can be easily changed if needed. Note that, unlike KASAN on other architectures, vmalloc allocations still use the shadow memory allocated upfront, rather than allocating and free-ing it per-vmalloc allocation. If another architecture chooses to go down the same path, we should replace the checks for CONFIG_UML with something more generic, such as: - A CONFIG_KASAN_NO_SHADOW_ALLOC option, which architectures could set - or, a way of having architecture-specific versions of these vmalloc and module shadow memory allocation options. Also note that, while UML supports both KASAN in inline mode (CONFIG_KASAN_INLINE) and static linking (CONFIG_STATIC_LINK), it does not support both at the same time. Signed-off-by: Patricia Alfonso <trishalfonso@google.com> Co-developed-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Signed-off-by: David Gow <davidgow@google.com> Reviewed-by: Johannes Berg <johannes@sipsolutions.net> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Signed-off-by: Richard Weinberger <richard@nod.at>
121 lines
3.2 KiB
C
121 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/types.h>
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#include <linux/module.h>
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/* Some of this are builtin function (some are not but could in the future),
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* so I *must* declare good prototypes for them and then EXPORT them.
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* The kernel code uses the macro defined by include/linux/string.h,
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* so I undef macros; the userspace code does not include that and I
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* add an EXPORT for the glibc one.
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*/
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#undef strlen
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#undef strstr
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#undef memcpy
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#undef memset
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extern size_t strlen(const char *);
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extern void *memmove(void *, const void *, size_t);
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extern void *memset(void *, int, size_t);
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extern int printf(const char *, ...);
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/* If it's not defined, the export is included in lib/string.c.*/
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#ifdef __HAVE_ARCH_STRSTR
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EXPORT_SYMBOL(strstr);
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#endif
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#ifndef __x86_64__
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extern void *memcpy(void *, const void *, size_t);
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EXPORT_SYMBOL(memcpy);
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EXPORT_SYMBOL(memmove);
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EXPORT_SYMBOL(memset);
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#endif
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EXPORT_SYMBOL(printf);
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/* Here, instead, I can provide a fake prototype. Yes, someone cares: genksyms.
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* However, the modules will use the CRC defined *here*, no matter if it is
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* good; so the versions of these symbols will always match
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*/
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#define EXPORT_SYMBOL_PROTO(sym) \
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int sym(void); \
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EXPORT_SYMBOL(sym);
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extern void readdir64(void) __attribute__((weak));
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EXPORT_SYMBOL(readdir64);
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extern void truncate64(void) __attribute__((weak));
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EXPORT_SYMBOL(truncate64);
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#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
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EXPORT_SYMBOL(vsyscall_ehdr);
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EXPORT_SYMBOL(vsyscall_end);
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#endif
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EXPORT_SYMBOL_PROTO(__errno_location);
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EXPORT_SYMBOL_PROTO(access);
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EXPORT_SYMBOL_PROTO(open);
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EXPORT_SYMBOL_PROTO(open64);
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EXPORT_SYMBOL_PROTO(close);
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EXPORT_SYMBOL_PROTO(read);
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EXPORT_SYMBOL_PROTO(write);
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EXPORT_SYMBOL_PROTO(dup2);
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EXPORT_SYMBOL_PROTO(__xstat);
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EXPORT_SYMBOL_PROTO(__lxstat);
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EXPORT_SYMBOL_PROTO(__lxstat64);
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EXPORT_SYMBOL_PROTO(__fxstat64);
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EXPORT_SYMBOL_PROTO(lseek);
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EXPORT_SYMBOL_PROTO(lseek64);
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EXPORT_SYMBOL_PROTO(chown);
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EXPORT_SYMBOL_PROTO(fchown);
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EXPORT_SYMBOL_PROTO(truncate);
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EXPORT_SYMBOL_PROTO(ftruncate64);
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EXPORT_SYMBOL_PROTO(utime);
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EXPORT_SYMBOL_PROTO(utimes);
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EXPORT_SYMBOL_PROTO(futimes);
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EXPORT_SYMBOL_PROTO(chmod);
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EXPORT_SYMBOL_PROTO(fchmod);
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EXPORT_SYMBOL_PROTO(rename);
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EXPORT_SYMBOL_PROTO(__xmknod);
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EXPORT_SYMBOL_PROTO(symlink);
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EXPORT_SYMBOL_PROTO(link);
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EXPORT_SYMBOL_PROTO(unlink);
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EXPORT_SYMBOL_PROTO(readlink);
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EXPORT_SYMBOL_PROTO(mkdir);
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EXPORT_SYMBOL_PROTO(rmdir);
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EXPORT_SYMBOL_PROTO(opendir);
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EXPORT_SYMBOL_PROTO(readdir);
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EXPORT_SYMBOL_PROTO(closedir);
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EXPORT_SYMBOL_PROTO(seekdir);
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EXPORT_SYMBOL_PROTO(telldir);
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EXPORT_SYMBOL_PROTO(ioctl);
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EXPORT_SYMBOL_PROTO(pread64);
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EXPORT_SYMBOL_PROTO(pwrite64);
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EXPORT_SYMBOL_PROTO(statfs);
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EXPORT_SYMBOL_PROTO(statfs64);
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EXPORT_SYMBOL_PROTO(getuid);
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EXPORT_SYMBOL_PROTO(fsync);
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EXPORT_SYMBOL_PROTO(fdatasync);
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EXPORT_SYMBOL_PROTO(lstat64);
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EXPORT_SYMBOL_PROTO(fstat64);
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EXPORT_SYMBOL_PROTO(mknod);
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/* Export symbols used by GCC for the stack protector. */
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extern void __stack_smash_handler(void *) __attribute__((weak));
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EXPORT_SYMBOL(__stack_smash_handler);
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extern long __guard __attribute__((weak));
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EXPORT_SYMBOL(__guard);
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#ifdef _FORTIFY_SOURCE
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extern int __sprintf_chk(char *str, int flag, size_t strlen, const char *format);
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EXPORT_SYMBOL(__sprintf_chk);
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#endif
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