diff options
author | Alex Shi <alex.shi@linaro.org> | 2016-04-14 09:27:55 +0800 |
---|---|---|
committer | Alex Shi <alex.shi@linaro.org> | 2016-04-14 09:27:55 +0800 |
commit | c789ced3a2a574ae52495c913a918e34d32d7bdd (patch) | |
tree | 872d7347125f6388d0d66c7a264a950070b3fd54 | |
parent | bd8f852bb489f067898cdd7cb08f65bd7f5a7e0a (diff) | |
parent | 4c88271f57519108a32181ba7aa600becf85729c (diff) |
Merge branch 'linux-linaro-lsk-v4.1' into linux-linaro-lsk-v4.1-android
-rw-r--r-- | arch/x86/include/asm/kasan.h | 3 | ||||
-rw-r--r-- | arch/x86/mm/kasan_init_64.c | 125 | ||||
-rw-r--r-- | include/linux/compiler-gcc.h | 153 | ||||
-rw-r--r-- | include/linux/compiler-gcc3.h | 23 | ||||
-rw-r--r-- | include/linux/compiler-gcc4.h | 91 | ||||
-rw-r--r-- | include/linux/compiler-gcc5.h | 67 | ||||
-rw-r--r-- | include/linux/compiler.h | 74 | ||||
-rw-r--r-- | include/linux/kasan.h | 10 | ||||
-rw-r--r-- | mm/kasan/Makefile | 2 | ||||
-rw-r--r-- | mm/kasan/kasan.c | 41 | ||||
-rw-r--r-- | mm/kasan/kasan.h | 6 | ||||
-rw-r--r-- | mm/kasan/kasan_init.c | 152 | ||||
-rw-r--r-- | mm/kasan/report.c | 113 |
13 files changed, 482 insertions, 378 deletions
diff --git a/arch/x86/include/asm/kasan.h b/arch/x86/include/asm/kasan.h index 74a2a8dc9908..1410b567ecde 100644 --- a/arch/x86/include/asm/kasan.h +++ b/arch/x86/include/asm/kasan.h @@ -1,6 +1,9 @@ #ifndef _ASM_X86_KASAN_H #define _ASM_X86_KASAN_H +#include <linux/const.h> +#define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL) + /* * Compiler uses shadow offset assuming that addresses start * from 0. Kernel addresses don't start from 0, so shadow diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index 9a54dbe98064..caf175745141 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -11,20 +11,6 @@ extern pgd_t early_level4_pgt[PTRS_PER_PGD]; extern struct range pfn_mapped[E820_X_MAX]; -static pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss; -static pmd_t kasan_zero_pmd[PTRS_PER_PMD] __page_aligned_bss; -static pte_t kasan_zero_pte[PTRS_PER_PTE] __page_aligned_bss; - -/* - * This page used as early shadow. We don't use empty_zero_page - * at early stages, stack instrumentation could write some garbage - * to this page. - * Latter we reuse it as zero shadow for large ranges of memory - * that allowed to access, but not instrumented by kasan - * (vmalloc/vmemmap ...). - */ -static unsigned char kasan_zero_page[PAGE_SIZE] __page_aligned_bss; - static int __init map_range(struct range *range) { unsigned long start; @@ -61,106 +47,6 @@ static void __init kasan_map_early_shadow(pgd_t *pgd) } } -static int __init zero_pte_populate(pmd_t *pmd, unsigned long addr, - unsigned long end) -{ - pte_t *pte = pte_offset_kernel(pmd, addr); - - while (addr + PAGE_SIZE <= end) { - WARN_ON(!pte_none(*pte)); - set_pte(pte, __pte(__pa_nodebug(kasan_zero_page) - | __PAGE_KERNEL_RO)); - addr += PAGE_SIZE; - pte = pte_offset_kernel(pmd, addr); - } - return 0; -} - -static int __init zero_pmd_populate(pud_t *pud, unsigned long addr, - unsigned long end) -{ - int ret = 0; - pmd_t *pmd = pmd_offset(pud, addr); - - while (IS_ALIGNED(addr, PMD_SIZE) && addr + PMD_SIZE <= end) { - WARN_ON(!pmd_none(*pmd)); - set_pmd(pmd, __pmd(__pa_nodebug(kasan_zero_pte) - | _KERNPG_TABLE)); - addr += PMD_SIZE; - pmd = pmd_offset(pud, addr); - } - if (addr < end) { - if (pmd_none(*pmd)) { - void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE); - if (!p) - return -ENOMEM; - set_pmd(pmd, __pmd(__pa_nodebug(p) | _KERNPG_TABLE)); - } - ret = zero_pte_populate(pmd, addr, end); - } - return ret; -} - - -static int __init zero_pud_populate(pgd_t *pgd, unsigned long addr, - unsigned long end) -{ - int ret = 0; - pud_t *pud = pud_offset(pgd, addr); - - while (IS_ALIGNED(addr, PUD_SIZE) && addr + PUD_SIZE <= end) { - WARN_ON(!pud_none(*pud)); - set_pud(pud, __pud(__pa_nodebug(kasan_zero_pmd) - | _KERNPG_TABLE)); - addr += PUD_SIZE; - pud = pud_offset(pgd, addr); - } - - if (addr < end) { - if (pud_none(*pud)) { - void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE); - if (!p) - return -ENOMEM; - set_pud(pud, __pud(__pa_nodebug(p) | _KERNPG_TABLE)); - } - ret = zero_pmd_populate(pud, addr, end); - } - return ret; -} - -static int __init zero_pgd_populate(unsigned long addr, unsigned long end) -{ - int ret = 0; - pgd_t *pgd = pgd_offset_k(addr); - - while (IS_ALIGNED(addr, PGDIR_SIZE) && addr + PGDIR_SIZE <= end) { - WARN_ON(!pgd_none(*pgd)); - set_pgd(pgd, __pgd(__pa_nodebug(kasan_zero_pud) - | _KERNPG_TABLE)); - addr += PGDIR_SIZE; - pgd = pgd_offset_k(addr); - } - - if (addr < end) { - if (pgd_none(*pgd)) { - void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE); - if (!p) - return -ENOMEM; - set_pgd(pgd, __pgd(__pa_nodebug(p) | _KERNPG_TABLE)); - } - ret = zero_pud_populate(pgd, addr, end); - } - return ret; -} - - -static void __init populate_zero_shadow(const void *start, const void *end) -{ - if (zero_pgd_populate((unsigned long)start, (unsigned long)end)) - panic("kasan: unable to map zero shadow!"); -} - - #ifdef CONFIG_KASAN_INLINE static int kasan_die_handler(struct notifier_block *self, unsigned long val, @@ -212,7 +98,7 @@ void __init kasan_init(void) clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); - populate_zero_shadow((void *)KASAN_SHADOW_START, + kasan_populate_zero_shadow((void *)KASAN_SHADOW_START, kasan_mem_to_shadow((void *)PAGE_OFFSET)); for (i = 0; i < E820_X_MAX; i++) { @@ -222,14 +108,15 @@ void __init kasan_init(void) if (map_range(&pfn_mapped[i])) panic("kasan: unable to allocate shadow!"); } - populate_zero_shadow(kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM), - kasan_mem_to_shadow((void *)__START_KERNEL_map)); + kasan_populate_zero_shadow( + kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM), + kasan_mem_to_shadow((void *)__START_KERNEL_map)); vmemmap_populate((unsigned long)kasan_mem_to_shadow(_stext), (unsigned long)kasan_mem_to_shadow(_end), NUMA_NO_NODE); - populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END), + kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END), (void *)KASAN_SHADOW_END); memset(kasan_zero_page, 0, PAGE_SIZE); @@ -237,4 +124,6 @@ void __init kasan_init(void) load_cr3(init_level4_pgt); __flush_tlb_all(); init_task.kasan_depth = 0; + + pr_info("KernelAddressSanitizer initialized\n"); } diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 371e560d13cf..824df0cea651 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -115,15 +115,160 @@ #define __maybe_unused __attribute__((unused)) #define __always_unused __attribute__((unused)) -#define __gcc_header(x) #x -#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h) -#define gcc_header(x) _gcc_header(x) -#include gcc_header(__GNUC__) +/* gcc version specific checks */ + +#if GCC_VERSION < 30200 +# error Sorry, your compiler is too old - please upgrade it. +#endif + +#if GCC_VERSION < 30300 +# define __used __attribute__((__unused__)) +#else +# define __used __attribute__((__used__)) +#endif + +#ifdef CONFIG_GCOV_KERNEL +# if GCC_VERSION < 30400 +# error "GCOV profiling support for gcc versions below 3.4 not included" +# endif /* __GNUC_MINOR__ */ +#endif /* CONFIG_GCOV_KERNEL */ + +#if GCC_VERSION >= 30400 +#define __must_check __attribute__((warn_unused_result)) +#endif + +#if GCC_VERSION >= 40000 + +/* GCC 4.1.[01] miscompiles __weak */ +#ifdef __KERNEL__ +# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101 +# error Your version of gcc miscompiles the __weak directive +# endif +#endif + +#define __used __attribute__((__used__)) +#define __compiler_offsetof(a, b) \ + __builtin_offsetof(a, b) + +#if GCC_VERSION >= 40100 && GCC_VERSION < 40600 +# define __compiletime_object_size(obj) __builtin_object_size(obj, 0) +#endif + +#if GCC_VERSION >= 40300 +/* Mark functions as cold. gcc will assume any path leading to a call + * to them will be unlikely. This means a lot of manual unlikely()s + * are unnecessary now for any paths leading to the usual suspects + * like BUG(), printk(), panic() etc. [but let's keep them for now for + * older compilers] + * + * Early snapshots of gcc 4.3 don't support this and we can't detect this + * in the preprocessor, but we can live with this because they're unreleased. + * Maketime probing would be overkill here. + * + * gcc also has a __attribute__((__hot__)) to move hot functions into + * a special section, but I don't see any sense in this right now in + * the kernel context + */ +#define __cold __attribute__((__cold__)) + +#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) + +#ifndef __CHECKER__ +# define __compiletime_warning(message) __attribute__((warning(message))) +# define __compiletime_error(message) __attribute__((error(message))) +#endif /* __CHECKER__ */ +#endif /* GCC_VERSION >= 40300 */ + +#if GCC_VERSION >= 40500 +/* + * Mark a position in code as unreachable. This can be used to + * suppress control flow warnings after asm blocks that transfer + * control elsewhere. + * + * Early snapshots of gcc 4.5 don't support this and we can't detect + * this in the preprocessor, but we can live with this because they're + * unreleased. Really, we need to have autoconf for the kernel. + */ +#define unreachable() __builtin_unreachable() + +/* Mark a function definition as prohibited from being cloned. */ +#define __noclone __attribute__((__noclone__)) + +#endif /* GCC_VERSION >= 40500 */ + +#if GCC_VERSION >= 40600 +/* + * When used with Link Time Optimization, gcc can optimize away C functions or + * variables which are referenced only from assembly code. __visible tells the + * optimizer that something else uses this function or variable, thus preventing + * this. + */ +#define __visible __attribute__((externally_visible)) +#endif + + +#if GCC_VERSION >= 40900 && !defined(__CHECKER__) +/* + * __assume_aligned(n, k): Tell the optimizer that the returned + * pointer can be assumed to be k modulo n. The second argument is + * optional (default 0), so we use a variadic macro to make the + * shorthand. + * + * Beware: Do not apply this to functions which may return + * ERR_PTRs. Also, it is probably unwise to apply it to functions + * returning extra information in the low bits (but in that case the + * compiler should see some alignment anyway, when the return value is + * massaged by 'flags = ptr & 3; ptr &= ~3;'). + */ +#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) +#endif + +/* + * GCC 'asm goto' miscompiles certain code sequences: + * + * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 + * + * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. + * + * (asm goto is automatically volatile - the naming reflects this.) + */ +#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) + +#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP +#if GCC_VERSION >= 40400 +#define __HAVE_BUILTIN_BSWAP32__ +#define __HAVE_BUILTIN_BSWAP64__ +#endif +#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600) +#define __HAVE_BUILTIN_BSWAP16__ +#endif +#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */ + +#if GCC_VERSION >= 50000 +#define KASAN_ABI_VERSION 4 +#elif GCC_VERSION >= 40902 +#define KASAN_ABI_VERSION 3 +#endif + +#if GCC_VERSION >= 40902 +/* + * Tell the compiler that address safety instrumentation (KASAN) + * should not be applied to that function. + * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 + */ +#define __no_sanitize_address __attribute__((no_sanitize_address)) +#endif + +#endif /* gcc version >= 40000 specific checks */ #if !defined(__noclone) #define __noclone /* not needed */ #endif +#if !defined(__no_sanitize_address) +#define __no_sanitize_address +#endif + /* * A trick to suppress uninitialized variable warning without generating any * code diff --git a/include/linux/compiler-gcc3.h b/include/linux/compiler-gcc3.h deleted file mode 100644 index 7d89febe4d79..000000000000 --- a/include/linux/compiler-gcc3.h +++ /dev/null @@ -1,23 +0,0 @@ -#ifndef __LINUX_COMPILER_H -#error "Please don't include <linux/compiler-gcc3.h> directly, include <linux/compiler.h> instead." -#endif - -#if GCC_VERSION < 30200 -# error Sorry, your compiler is too old - please upgrade it. -#endif - -#if GCC_VERSION >= 30300 -# define __used __attribute__((__used__)) -#else -# define __used __attribute__((__unused__)) -#endif - -#if GCC_VERSION >= 30400 -#define __must_check __attribute__((warn_unused_result)) -#endif - -#ifdef CONFIG_GCOV_KERNEL -# if GCC_VERSION < 30400 -# error "GCOV profiling support for gcc versions below 3.4 not included" -# endif /* __GNUC_MINOR__ */ -#endif /* CONFIG_GCOV_KERNEL */ diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h deleted file mode 100644 index 769e19864632..000000000000 --- a/include/linux/compiler-gcc4.h +++ /dev/null @@ -1,91 +0,0 @@ -#ifndef __LINUX_COMPILER_H -#error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead." -#endif - -/* GCC 4.1.[01] miscompiles __weak */ -#ifdef __KERNEL__ -# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101 -# error Your version of gcc miscompiles the __weak directive -# endif -#endif - -#define __used __attribute__((__used__)) -#define __must_check __attribute__((warn_unused_result)) -#define __compiler_offsetof(a,b) __builtin_offsetof(a,b) - -#if GCC_VERSION >= 40100 && GCC_VERSION < 40600 -# define __compiletime_object_size(obj) __builtin_object_size(obj, 0) -#endif - -#if GCC_VERSION >= 40300 -/* Mark functions as cold. gcc will assume any path leading to a call - to them will be unlikely. This means a lot of manual unlikely()s - are unnecessary now for any paths leading to the usual suspects - like BUG(), printk(), panic() etc. [but let's keep them for now for - older compilers] - - Early snapshots of gcc 4.3 don't support this and we can't detect this - in the preprocessor, but we can live with this because they're unreleased. - Maketime probing would be overkill here. - - gcc also has a __attribute__((__hot__)) to move hot functions into - a special section, but I don't see any sense in this right now in - the kernel context */ -#define __cold __attribute__((__cold__)) - -#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) - -#ifndef __CHECKER__ -# define __compiletime_warning(message) __attribute__((warning(message))) -# define __compiletime_error(message) __attribute__((error(message))) -#endif /* __CHECKER__ */ -#endif /* GCC_VERSION >= 40300 */ - -#if GCC_VERSION >= 40500 -/* - * Mark a position in code as unreachable. This can be used to - * suppress control flow warnings after asm blocks that transfer - * control elsewhere. - * - * Early snapshots of gcc 4.5 don't support this and we can't detect - * this in the preprocessor, but we can live with this because they're - * unreleased. Really, we need to have autoconf for the kernel. - */ -#define unreachable() __builtin_unreachable() - -/* Mark a function definition as prohibited from being cloned. */ -#define __noclone __attribute__((__noclone__)) - -#endif /* GCC_VERSION >= 40500 */ - -#if GCC_VERSION >= 40600 -/* - * Tell the optimizer that something else uses this function or variable. - */ -#define __visible __attribute__((externally_visible)) -#endif - -/* - * GCC 'asm goto' miscompiles certain code sequences: - * - * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 - * - * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. - * - * (asm goto is automatically volatile - the naming reflects this.) - */ -#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) - -#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP -#if GCC_VERSION >= 40400 -#define __HAVE_BUILTIN_BSWAP32__ -#define __HAVE_BUILTIN_BSWAP64__ -#endif -#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600) -#define __HAVE_BUILTIN_BSWAP16__ -#endif -#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */ - -#if GCC_VERSION >= 40902 -#define KASAN_ABI_VERSION 3 -#endif diff --git a/include/linux/compiler-gcc5.h b/include/linux/compiler-gcc5.h deleted file mode 100644 index efee493714eb..000000000000 --- a/include/linux/compiler-gcc5.h +++ /dev/null @@ -1,67 +0,0 @@ -#ifndef __LINUX_COMPILER_H -#error "Please don't include <linux/compiler-gcc5.h> directly, include <linux/compiler.h> instead." -#endif - -#define __used __attribute__((__used__)) -#define __must_check __attribute__((warn_unused_result)) -#define __compiler_offsetof(a, b) __builtin_offsetof(a, b) - -/* Mark functions as cold. gcc will assume any path leading to a call - to them will be unlikely. This means a lot of manual unlikely()s - are unnecessary now for any paths leading to the usual suspects - like BUG(), printk(), panic() etc. [but let's keep them for now for - older compilers] - - Early snapshots of gcc 4.3 don't support this and we can't detect this - in the preprocessor, but we can live with this because they're unreleased. - Maketime probing would be overkill here. - - gcc also has a __attribute__((__hot__)) to move hot functions into - a special section, but I don't see any sense in this right now in - the kernel context */ -#define __cold __attribute__((__cold__)) - -#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__) - -#ifndef __CHECKER__ -# define __compiletime_warning(message) __attribute__((warning(message))) -# define __compiletime_error(message) __attribute__((error(message))) -#endif /* __CHECKER__ */ - -/* - * Mark a position in code as unreachable. This can be used to - * suppress control flow warnings after asm blocks that transfer - * control elsewhere. - * - * Early snapshots of gcc 4.5 don't support this and we can't detect - * this in the preprocessor, but we can live with this because they're - * unreleased. Really, we need to have autoconf for the kernel. - */ -#define unreachable() __builtin_unreachable() - -/* Mark a function definition as prohibited from being cloned. */ -#define __noclone __attribute__((__noclone__)) - -/* - * Tell the optimizer that something else uses this function or variable. - */ -#define __visible __attribute__((externally_visible)) - -/* - * GCC 'asm goto' miscompiles certain code sequences: - * - * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 - * - * Work it around via a compiler barrier quirk suggested by Jakub Jelinek. - * - * (asm goto is automatically volatile - the naming reflects this.) - */ -#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) - -#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP -#define __HAVE_BUILTIN_BSWAP32__ -#define __HAVE_BUILTIN_BSWAP64__ -#define __HAVE_BUILTIN_BSWAP16__ -#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */ - -#define KASAN_ABI_VERSION 4 diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 99728072e536..98be9bdb2105 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -196,19 +196,45 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); #include <uapi/linux/types.h> -static __always_inline void __read_once_size(const volatile void *p, void *res, int size) +#define __READ_ONCE_SIZE \ +({ \ + switch (size) { \ + case 1: *(__u8 *)res = *(volatile __u8 *)p; break; \ + case 2: *(__u16 *)res = *(volatile __u16 *)p; break; \ + case 4: *(__u32 *)res = *(volatile __u32 *)p; break; \ + case 8: *(__u64 *)res = *(volatile __u64 *)p; break; \ + default: \ + barrier(); \ + __builtin_memcpy((void *)res, (const void *)p, size); \ + barrier(); \ + } \ +}) + +static __always_inline +void __read_once_size(const volatile void *p, void *res, int size) { - switch (size) { - case 1: *(__u8 *)res = *(volatile __u8 *)p; break; - case 2: *(__u16 *)res = *(volatile __u16 *)p; break; - case 4: *(__u32 *)res = *(volatile __u32 *)p; break; - case 8: *(__u64 *)res = *(volatile __u64 *)p; break; - default: - barrier(); - __builtin_memcpy((void *)res, (const void *)p, size); - barrier(); - } + __READ_ONCE_SIZE; +} + +#ifdef CONFIG_KASAN +/* + * This function is not 'inline' because __no_sanitize_address confilcts + * with inlining. Attempt to inline it may cause a build failure. + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 + * '__maybe_unused' allows us to avoid defined-but-not-used warnings. + */ +static __no_sanitize_address __maybe_unused +void __read_once_size_nocheck(const volatile void *p, void *res, int size) +{ + __READ_ONCE_SIZE; +} +#else +static __always_inline +void __read_once_size_nocheck(const volatile void *p, void *res, int size) +{ + __READ_ONCE_SIZE; } +#endif static __always_inline void __write_once_size(volatile void *p, void *res, int size) { @@ -246,8 +272,22 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s * required ordering. */ -#define READ_ONCE(x) \ - ({ union { typeof(x) __val; char __c[1]; } __u; __read_once_size(&(x), __u.__c, sizeof(x)); __u.__val; }) +#define __READ_ONCE(x, check) \ +({ \ + union { typeof(x) __val; char __c[1]; } __u; \ + if (check) \ + __read_once_size(&(x), __u.__c, sizeof(x)); \ + else \ + __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \ + __u.__val; \ +}) +#define READ_ONCE(x) __READ_ONCE(x, 1) + +/* + * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need + * to hide memory access from KASAN. + */ +#define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0) #define WRITE_ONCE(x, val) \ ({ typeof(x) __val = (val); __write_once_size(&(x), &__val, sizeof(__val)); __val; }) @@ -370,6 +410,14 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s #define __visible #endif +/* + * Assume alignment of return value. + */ +#ifndef __assume_aligned +#define __assume_aligned(a, ...) +#endif + + /* Are two types/vars the same type (ignoring qualifiers)? */ #ifndef __same_type # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index 5486d777b706..4b9f85c963d0 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -10,11 +10,19 @@ struct vm_struct; #ifdef CONFIG_KASAN #define KASAN_SHADOW_SCALE_SHIFT 3 -#define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL) #include <asm/kasan.h> +#include <asm/pgtable.h> #include <linux/sched.h> +extern unsigned char kasan_zero_page[PAGE_SIZE]; +extern pte_t kasan_zero_pte[PTRS_PER_PTE]; +extern pmd_t kasan_zero_pmd[PTRS_PER_PMD]; +extern pud_t kasan_zero_pud[PTRS_PER_PUD]; + +void kasan_populate_zero_shadow(const void *shadow_start, + const void *shadow_end); + static inline void *kasan_mem_to_shadow(const void *addr) { return (void *)((unsigned long)addr >> KASAN_SHADOW_SCALE_SHIFT) diff --git a/mm/kasan/Makefile b/mm/kasan/Makefile index bd837b8c2f41..64710148941e 100644 --- a/mm/kasan/Makefile +++ b/mm/kasan/Makefile @@ -5,4 +5,4 @@ CFLAGS_REMOVE_kasan.o = -pg # see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533 CFLAGS_kasan.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector) -obj-y := kasan.o report.o +obj-y := kasan.o report.o kasan_init.o diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 6c513a63ea84..81a2f4596f35 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -4,7 +4,7 @@ * Copyright (c) 2014 Samsung Electronics Co., Ltd. * Author: Andrey Ryabinin <a.ryabinin@samsung.com> * - * Some of code borrowed from https://github.com/xairy/linux by + * Some code borrowed from https://github.com/xairy/kasan-prototype by * Andrey Konovalov <adech.fo@gmail.com> * * This program is free software; you can redistribute it and/or modify @@ -19,6 +19,7 @@ #include <linux/export.h> #include <linux/init.h> #include <linux/kernel.h> +#include <linux/kmemleak.h> #include <linux/memblock.h> #include <linux/memory.h> #include <linux/mm.h> @@ -86,6 +87,11 @@ static __always_inline bool memory_is_poisoned_2(unsigned long addr) if (memory_is_poisoned_1(addr + 1)) return true; + /* + * If single shadow byte covers 2-byte access, we don't + * need to do anything more. Otherwise, test the first + * shadow byte. + */ if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0)) return false; @@ -103,6 +109,11 @@ static __always_inline bool memory_is_poisoned_4(unsigned long addr) if (memory_is_poisoned_1(addr + 3)) return true; + /* + * If single shadow byte covers 4-byte access, we don't + * need to do anything more. Otherwise, test the first + * shadow byte. + */ if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3)) return false; @@ -120,7 +131,12 @@ static __always_inline bool memory_is_poisoned_8(unsigned long addr) if (memory_is_poisoned_1(addr + 7)) return true; - if (likely(((addr + 7) & KASAN_SHADOW_MASK) >= 7)) + /* + * If single shadow byte covers 8-byte access, we don't + * need to do anything more. Otherwise, test the first + * shadow byte. + */ + if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE))) return false; return unlikely(*(u8 *)shadow_addr); @@ -135,12 +151,16 @@ static __always_inline bool memory_is_poisoned_16(unsigned long addr) if (unlikely(*shadow_addr)) { u16 shadow_first_bytes = *(u16 *)shadow_addr; - s8 last_byte = (addr + 15) & KASAN_SHADOW_MASK; if (unlikely(shadow_first_bytes)) return true; - if (likely(!last_byte)) + /* + * If two shadow bytes covers 16-byte access, we don't + * need to do anything more. Otherwise, test the last + * shadow byte. + */ + if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE))) return false; return memory_is_poisoned_1(addr + 15); @@ -204,7 +224,7 @@ static __always_inline bool memory_is_poisoned_n(unsigned long addr, s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte); if (unlikely(ret != (unsigned long)last_shadow || - ((last_byte & KASAN_SHADOW_MASK) >= *last_shadow))) + ((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow))) return true; } return false; @@ -236,18 +256,12 @@ static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size) static __always_inline void check_memory_region(unsigned long addr, size_t size, bool write) { - struct kasan_access_info info; - if (unlikely(size == 0)) return; if (unlikely((void *)addr < kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) { - info.access_addr = (void *)addr; - info.access_size = size; - info.is_write = write; - info.ip = _RET_IP_; - kasan_report_user_access(&info); + kasan_report(addr, size, write, _RET_IP_); return; } @@ -431,6 +445,7 @@ int kasan_module_alloc(void *addr, size_t size) if (ret) { find_vm_area(addr)->flags |= VM_KASAN; + kmemleak_ignore(ret); return 0; } @@ -525,7 +540,7 @@ static int kasan_mem_notifier(struct notifier_block *nb, static int __init kasan_memhotplug_init(void) { - pr_err("WARNING: KASan doesn't support memory hot-add\n"); + pr_err("WARNING: KASAN doesn't support memory hot-add\n"); pr_err("Memory hot-add will be disabled\n"); hotplug_memory_notifier(kasan_mem_notifier, 0); diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 4986b0acab21..4f6c62e5c21e 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -7,7 +7,6 @@ #define KASAN_SHADOW_MASK (KASAN_SHADOW_SCALE_SIZE - 1) #define KASAN_FREE_PAGE 0xFF /* page was freed */ -#define KASAN_FREE_PAGE 0xFF /* page was freed */ #define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocations */ #define KASAN_KMALLOC_REDZONE 0xFC /* redzone inside slub object */ #define KASAN_KMALLOC_FREE 0xFB /* object was freed (kmem_cache_free/kfree) */ @@ -55,16 +54,13 @@ struct kasan_global { #endif }; -void kasan_report_error(struct kasan_access_info *info); -void kasan_report_user_access(struct kasan_access_info *info); - static inline const void *kasan_shadow_to_mem(const void *shadow_addr) { return (void *)(((unsigned long)shadow_addr - KASAN_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT); } -static inline bool kasan_enabled(void) +static inline bool kasan_report_enabled(void) { return !current->kasan_depth; } diff --git a/mm/kasan/kasan_init.c b/mm/kasan/kasan_init.c new file mode 100644 index 000000000000..3f9a41cf0ac6 --- /dev/null +++ b/mm/kasan/kasan_init.c @@ -0,0 +1,152 @@ +/* + * This file contains some kasan initialization code. + * + * Copyright (c) 2015 Samsung Electronics Co., Ltd. + * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include <linux/bootmem.h> +#include <linux/init.h> +#include <linux/kasan.h> +#include <linux/kernel.h> +#include <linux/memblock.h> +#include <linux/pfn.h> + +#include <asm/page.h> +#include <asm/pgalloc.h> + +/* + * This page serves two purposes: + * - It used as early shadow memory. The entire shadow region populated + * with this page, before we will be able to setup normal shadow memory. + * - Latter it reused it as zero shadow to cover large ranges of memory + * that allowed to access, but not handled by kasan (vmalloc/vmemmap ...). + */ +unsigned char kasan_zero_page[PAGE_SIZE] __page_aligned_bss; + +#if CONFIG_PGTABLE_LEVELS > 3 +pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss; +#endif +#if CONFIG_PGTABLE_LEVELS > 2 +pmd_t kasan_zero_pmd[PTRS_PER_PMD] __page_aligned_bss; +#endif +pte_t kasan_zero_pte[PTRS_PER_PTE] __page_aligned_bss; + +static __init void *early_alloc(size_t size, int node) +{ + return memblock_virt_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS), + BOOTMEM_ALLOC_ACCESSIBLE, node); +} + +static void __init zero_pte_populate(pmd_t *pmd, unsigned long addr, + unsigned long end) +{ + pte_t *pte = pte_offset_kernel(pmd, addr); + pte_t zero_pte; + + zero_pte = pfn_pte(PFN_DOWN(__pa(kasan_zero_page)), PAGE_KERNEL); + zero_pte = pte_wrprotect(zero_pte); + + while (addr + PAGE_SIZE <= end) { + set_pte_at(&init_mm, addr, pte, zero_pte); + addr += PAGE_SIZE; + pte = pte_offset_kernel(pmd, addr); + } +} + +static void __init zero_pmd_populate(pud_t *pud, unsigned long addr, + unsigned long end) +{ + pmd_t *pmd = pmd_offset(pud, addr); + unsigned long next; + + do { + next = pmd_addr_end(addr, end); + + if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) { + pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte); + continue; + } + + if (pmd_none(*pmd)) { + pmd_populate_kernel(&init_mm, pmd, + early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + } + zero_pte_populate(pmd, addr, next); + } while (pmd++, addr = next, addr != end); +} + +static void __init zero_pud_populate(pgd_t *pgd, unsigned long addr, + unsigned long end) +{ + pud_t *pud = pud_offset(pgd, addr); + unsigned long next; + + do { + next = pud_addr_end(addr, end); + if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) { + pmd_t *pmd; + + pud_populate(&init_mm, pud, kasan_zero_pmd); + pmd = pmd_offset(pud, addr); + pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte); + continue; + } + + if (pud_none(*pud)) { + pud_populate(&init_mm, pud, + early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + } + zero_pmd_populate(pud, addr, next); + } while (pud++, addr = next, addr != end); +} + +/** + * kasan_populate_zero_shadow - populate shadow memory region with + * kasan_zero_page + * @shadow_start - start of the memory range to populate + * @shadow_end - end of the memory range to populate + */ +void __init kasan_populate_zero_shadow(const void *shadow_start, + const void *shadow_end) +{ + unsigned long addr = (unsigned long)shadow_start; + unsigned long end = (unsigned long)shadow_end; + pgd_t *pgd = pgd_offset_k(addr); + unsigned long next; + + do { + next = pgd_addr_end(addr, end); + + if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) { + pud_t *pud; + pmd_t *pmd; + + /* + * kasan_zero_pud should be populated with pmds + * at this moment. + * [pud,pmd]_populate*() below needed only for + * 3,2 - level page tables where we don't have + * puds,pmds, so pgd_populate(), pud_populate() + * is noops. + */ + pgd_populate(&init_mm, pgd, kasan_zero_pud); + pud = pud_offset(pgd, addr); + pud_populate(&init_mm, pud, kasan_zero_pmd); + pmd = pmd_offset(pud, addr); + pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte); + continue; + } + + if (pgd_none(*pgd)) { + pgd_populate(&init_mm, pgd, + early_alloc(PAGE_SIZE, NUMA_NO_NODE)); + } + zero_pud_populate(pgd, addr, next); + } while (pgd++, addr = next, addr != end); +} diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 680ceedf810a..e0b3e94ecdb5 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -4,7 +4,7 @@ * Copyright (c) 2014 Samsung Electronics Co., Ltd. * Author: Andrey Ryabinin <a.ryabinin@samsung.com> * - * Some of code borrowed from https://github.com/xairy/linux by + * Some code borrowed from https://github.com/xairy/kasan-prototype by * Andrey Konovalov <adech.fo@gmail.com> * * This program is free software; you can redistribute it and/or modify @@ -22,6 +22,7 @@ #include <linux/string.h> #include <linux/types.h> #include <linux/kasan.h> +#include <linux/module.h> #include <asm/sections.h> @@ -48,34 +49,49 @@ static const void *find_first_bad_addr(const void *addr, size_t size) static void print_error_description(struct kasan_access_info *info) { - const char *bug_type = "unknown crash"; - u8 shadow_val; + const char *bug_type = "unknown-crash"; + u8 *shadow_addr; info->first_bad_addr = find_first_bad_addr(info->access_addr, info->access_size); - shadow_val = *(u8 *)kasan_mem_to_shadow(info->first_bad_addr); + shadow_addr = (u8 *)kasan_mem_to_shadow(info->first_bad_addr); - switch (shadow_val) { - case KASAN_FREE_PAGE: - case KASAN_KMALLOC_FREE: - bug_type = "use after free"; + /* + * If shadow byte value is in [0, KASAN_SHADOW_SCALE_SIZE) we can look + * at the next shadow byte to determine the type of the bad access. + */ + if (*shadow_addr > 0 && *shadow_addr <= KASAN_SHADOW_SCALE_SIZE - 1) + shadow_addr++; + + switch (*shadow_addr) { + case 0 ... KASAN_SHADOW_SCALE_SIZE - 1: + /* + * In theory it's still possible to see these shadow values + * due to a data race in the kernel code. + */ + bug_type = "out-of-bounds"; break; case KASAN_PAGE_REDZONE: case KASAN_KMALLOC_REDZONE: + bug_type = "slab-out-of-bounds"; + break; case KASAN_GLOBAL_REDZONE: - case 0 ... KASAN_SHADOW_SCALE_SIZE - 1: - bug_type = "out of bounds access"; + bug_type = "global-out-of-bounds"; break; case KASAN_STACK_LEFT: case KASAN_STACK_MID: case KASAN_STACK_RIGHT: case KASAN_STACK_PARTIAL: - bug_type = "out of bounds on stack"; + bug_type = "stack-out-of-bounds"; + break; + case KASAN_FREE_PAGE: + case KASAN_KMALLOC_FREE: + bug_type = "use-after-free"; break; } - pr_err("BUG: KASan: %s in %pS at addr %p\n", + pr_err("BUG: KASAN: %s in %pS at addr %p\n", bug_type, (void *)info->ip, info->access_addr); pr_err("%s of size %zu by task %s/%d\n", @@ -85,9 +101,11 @@ static void print_error_description(struct kasan_access_info *info) static inline bool kernel_or_module_addr(const void *addr) { - return (addr >= (void *)_stext && addr < (void *)_end) - || (addr >= (void *)MODULES_VADDR - && addr < (void *)MODULES_END); + if (addr >= (void *)_stext && addr < (void *)_end) + return true; + if (is_module_address((unsigned long)addr)) + return true; + return false; } static inline bool init_task_stack_addr(const void *addr) @@ -161,15 +179,19 @@ static void print_shadow_for_address(const void *addr) for (i = -SHADOW_ROWS_AROUND_ADDR; i <= SHADOW_ROWS_AROUND_ADDR; i++) { const void *kaddr = kasan_shadow_to_mem(shadow_row); char buffer[4 + (BITS_PER_LONG/8)*2]; + char shadow_buf[SHADOW_BYTES_PER_ROW]; snprintf(buffer, sizeof(buffer), (i == 0) ? ">%p: " : " %p: ", kaddr); - - kasan_disable_current(); + /* + * We should not pass a shadow pointer to generic + * function, because generic functions may try to + * access kasan mapping for the passed address. + */ + memcpy(shadow_buf, shadow_row, SHADOW_BYTES_PER_ROW); print_hex_dump(KERN_ERR, buffer, DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1, - shadow_row, SHADOW_BYTES_PER_ROW, 0); - kasan_enable_current(); + shadow_buf, SHADOW_BYTES_PER_ROW, 0); if (row_is_guilty(shadow_row, shadow)) pr_err("%*c\n", @@ -182,37 +204,43 @@ static void print_shadow_for_address(const void *addr) static DEFINE_SPINLOCK(report_lock); -void kasan_report_error(struct kasan_access_info *info) -{ - unsigned long flags; - - spin_lock_irqsave(&report_lock, flags); - pr_err("=================================" - "=================================\n"); - print_error_description(info); - print_address_description(info); - print_shadow_for_address(info->first_bad_addr); - pr_err("=================================" - "=================================\n"); - spin_unlock_irqrestore(&report_lock, flags); -} - -void kasan_report_user_access(struct kasan_access_info *info) +static void kasan_report_error(struct kasan_access_info *info) { unsigned long flags; + const char *bug_type; + /* + * Make sure we don't end up in loop. + */ + kasan_disable_current(); spin_lock_irqsave(&report_lock, flags); pr_err("=================================" "=================================\n"); - pr_err("BUG: KASan: user-memory-access on address %p\n", - info->access_addr); - pr_err("%s of size %zu by task %s/%d\n", - info->is_write ? "Write" : "Read", - info->access_size, current->comm, task_pid_nr(current)); - dump_stack(); + if (info->access_addr < + kasan_shadow_to_mem((void *)KASAN_SHADOW_START)) { + if ((unsigned long)info->access_addr < PAGE_SIZE) + bug_type = "null-ptr-deref"; + else if ((unsigned long)info->access_addr < TASK_SIZE) + bug_type = "user-memory-access"; + else + bug_type = "wild-memory-access"; + pr_err("BUG: KASAN: %s on address %p\n", + bug_type, info->access_addr); + pr_err("%s of size %zu by task %s/%d\n", + info->is_write ? "Write" : "Read", + info->access_size, current->comm, + task_pid_nr(current)); + dump_stack(); + } else { + print_error_description(info); + print_address_description(info); + print_shadow_for_address(info->first_bad_addr); + } pr_err("=================================" "=================================\n"); + add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); spin_unlock_irqrestore(&report_lock, flags); + kasan_enable_current(); } void kasan_report(unsigned long addr, size_t size, @@ -220,13 +248,14 @@ void kasan_report(unsigned long addr, size_t size, { struct kasan_access_info info; - if (likely(!kasan_enabled())) + if (likely(!kasan_report_enabled())) return; info.access_addr = (void *)addr; info.access_size = size; info.is_write = is_write; info.ip = ip; + kasan_report_error(&info); } |