[ Sorry for the additional email on this patch; trying to consolidate comments now. ]
On Tue, Sep 15, 2020 at 11:16PM +0200, Andrey Konovalov wrote: > Provide implementation of KASAN functions required for the hardware > tag-based mode. Those include core functions for memory and pointer > tagging (tags_hw.c) and bug reporting (report_tags_hw.c). Also adapt > common KASAN code to support the new mode. > > Signed-off-by: Andrey Konovalov <[email protected]> > Signed-off-by: Vincenzo Frascino <[email protected]> > --- > Change-Id: I8a8689ba098174a4d0ef3f1d008178387c80ee1c > --- > arch/arm64/include/asm/memory.h | 4 +- > arch/arm64/kernel/setup.c | 1 - > include/linux/kasan.h | 6 +-- > include/linux/mm.h | 2 +- > include/linux/page-flags-layout.h | 2 +- > mm/kasan/Makefile | 5 ++ > mm/kasan/common.c | 14 +++--- > mm/kasan/kasan.h | 17 +++++-- > mm/kasan/report_tags_hw.c | 47 +++++++++++++++++++ > mm/kasan/report_tags_sw.c | 2 +- > mm/kasan/shadow.c | 2 +- > mm/kasan/tags_hw.c | 78 +++++++++++++++++++++++++++++++ > mm/kasan/tags_sw.c | 2 +- > 13 files changed, 162 insertions(+), 20 deletions(-) > create mode 100644 mm/kasan/report_tags_hw.c > create mode 100644 mm/kasan/tags_hw.c [...] > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > index 41c7f1105eaa..412a23d1546b 100644 > --- a/mm/kasan/common.c > +++ b/mm/kasan/common.c > @@ -118,7 +118,7 @@ void kasan_free_pages(struct page *page, unsigned int > order) > */ > static inline unsigned int optimal_redzone(unsigned int object_size) > { > - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) > + if (!IS_ENABLED(CONFIG_KASAN_GENERIC)) > return 0; > > return > @@ -183,14 +183,14 @@ size_t kasan_metadata_size(struct kmem_cache *cache) > struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache, > const void *object) > { > - return (void *)object + cache->kasan_info.alloc_meta_offset; > + return (void *)reset_tag(object) + cache->kasan_info.alloc_meta_offset; > } > > struct kasan_free_meta *get_free_info(struct kmem_cache *cache, > const void *object) > { > BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32); > - return (void *)object + cache->kasan_info.free_meta_offset; > + return (void *)reset_tag(object) + cache->kasan_info.free_meta_offset; > } > > void kasan_poison_slab(struct page *page) > @@ -272,7 +272,8 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache > *cache, > alloc_info = get_alloc_info(cache, object); > __memset(alloc_info, 0, sizeof(*alloc_info)); Suggested edit below (assuming the line-break wasn't intentional; this should still be within checkpatch.pl's 100 col limit): ------ - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || - IS_ENABLED(CONFIG_KASAN_HW_TAGS)) + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || IS_ENABLED(CONFIG_KASAN_HW_TAGS)) object = set_tag(object, assign_tag(cache, object, true, false)); @@ -343,8 +342,7 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, redzone_end = round_up((unsigned long)object + cache->object_size, KASAN_GRANULE_SIZE); - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || - IS_ENABLED(CONFIG_KASAN_HW_TAGS)) + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || IS_ENABLED(CONFIG_KASAN_HW_TAGS)) tag = assign_tag(cache, object, false, keep_tag); ------ > - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || > + IS_ENABLED(CONFIG_KASAN_HW_TAGS)) > object = set_tag(object, > assign_tag(cache, object, true, false)); > > @@ -342,10 +343,11 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, > const void *object, > redzone_end = round_up((unsigned long)object + cache->object_size, > KASAN_GRANULE_SIZE); > > - if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) > + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || > + IS_ENABLED(CONFIG_KASAN_HW_TAGS)) > tag = assign_tag(cache, object, false, keep_tag); > > - /* Tag is ignored in set_tag without CONFIG_KASAN_SW_TAGS */ > + /* Tag is ignored in set_tag without CONFIG_KASAN_SW/HW_TAGS */ > kasan_unpoison_memory(set_tag(object, tag), size); > kasan_poison_memory((void *)redzone_start, redzone_end - redzone_start, > KASAN_KMALLOC_REDZONE); [...] > diff --git a/mm/kasan/report_tags_hw.c b/mm/kasan/report_tags_hw.c > new file mode 100644 > index 000000000000..c2f73c46279a > --- /dev/null > +++ b/mm/kasan/report_tags_hw.c > @@ -0,0 +1,47 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * This file contains hardware tag-based KASAN specific error reporting code. > + * > + * Copyright (c) 2020 Google, Inc. > + * Author: Andrey Konovalov <[email protected]> > + * > + * 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. > + * I do not think we put the "This program is ..." preamble in new files anymore. It should be covered by SPDX tag above. > + */ > + > +#include <linux/kasan.h> > +#include <linux/kernel.h> > +#include <linux/memory.h> > +#include <linux/mm.h> > +#include <linux/string.h> > +#include <linux/types.h> [...] > diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c > index 4888084ecdfc..ca69726adf8f 100644 > --- a/mm/kasan/shadow.c > +++ b/mm/kasan/shadow.c > @@ -111,7 +111,7 @@ void kasan_unpoison_memory(const void *address, size_t > size) > > if (IS_ENABLED(CONFIG_KASAN_SW_TAGS)) > *shadow = tag; > - else > + else /* CONFIG_KASAN_GENERIC */ > *shadow = size & KASAN_GRANULE_MASK; > } > } > diff --git a/mm/kasan/tags_hw.c b/mm/kasan/tags_hw.c > new file mode 100644 > index 000000000000..c93d43379e39 > --- /dev/null > +++ b/mm/kasan/tags_hw.c > @@ -0,0 +1,78 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * This file contains core hardware tag-based KASAN code. > + * > + * Copyright (c) 2020 Google, Inc. > + * Author: Andrey Konovalov <[email protected]> > + * > + * 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. > + * I do not think we put the "This program is ..." preamble in new files anymore. It should be covered by SPDX tag above. > + */ > + > +#include <linux/kasan.h> > +#include <linux/kernel.h> > +#include <linux/memory.h> > +#include <linux/mm.h> > +#include <linux/string.h> > +#include <linux/types.h> > + > +#include "kasan.h" > + > +void kasan_init_tags(void) > +{ > + init_tags(KASAN_TAG_MAX); > +} > + > +void *kasan_reset_tag(const void *addr) > +{ > + return reset_tag(addr); > +} > + To help readability, would this edit be ok? ------ void kasan_poison_memory(const void *address, size_t size, u8 value) { - set_mem_tag_range(reset_tag(address), - round_up(size, KASAN_GRANULE_SIZE), value); + set_mem_tag_range(reset_tag(address), round_up(size, KASAN_GRANULE_SIZE), value); } void kasan_unpoison_memory(const void *address, size_t size) { - set_mem_tag_range(reset_tag(address), - round_up(size, KASAN_GRANULE_SIZE), get_tag(address)); + set_mem_tag_range(reset_tag(address), round_up(size, KASAN_GRANULE_SIZE), get_tag(address)); } ------ > +void kasan_poison_memory(const void *address, size_t size, u8 value) > +{ > + set_mem_tag_range(reset_tag(address), > + round_up(size, KASAN_GRANULE_SIZE), value); > +} > + > +void kasan_unpoison_memory(const void *address, size_t size) > +{ > + set_mem_tag_range(reset_tag(address), > + round_up(size, KASAN_GRANULE_SIZE), get_tag(address)); > +} > + > +u8 random_tag(void) > +{ > + return get_random_tag(); > +} > + > +bool check_invalid_free(void *addr) > +{ > + u8 ptr_tag = get_tag(addr); > + u8 mem_tag = get_mem_tag(addr); > + Why not just: ------ - if (shadow_byte == KASAN_TAG_INVALID) - return true; - if (tag != KASAN_TAG_KERNEL && tag != shadow_byte) - return true; - return false; + return shadow_byte == KASAN_TAG_INVALID || + (tag != KASAN_TAG_KERNEL && tag != shadow_byte); } ------ > + if (mem_tag == KASAN_TAG_INVALID) > + return true; > + if (ptr_tag != KASAN_TAG_KERNEL && ptr_tag != mem_tag) > + return true; > + return false; > +} > + Thanks, -- Marco
