From d98c9e83b5e7ca78175df1b13ac4a6d460d3962d Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Tue, 17 Dec 2019 20:51:38 -0800 Subject: kasan: fix crashes on access to memory mapped by vm_map_ram() With CONFIG_KASAN_VMALLOC=y any use of memory obtained via vm_map_ram() will crash because there is no shadow backing that memory. Instead of sprinkling additional kasan_populate_vmalloc() calls all over the vmalloc code, move it into alloc_vmap_area(). This will fix vm_map_ram() and simplify the code a bit. [aryabinin@virtuozzo.com: v2] Link: http://lkml.kernel.org/r/20191205095942.1761-1-aryabinin@virtuozzo.comLink: http://lkml.kernel.org/r/20191204204534.32202-1-aryabinin@virtuozzo.com Fixes: 3c5c3cfb9ef4 ("kasan: support backing vmalloc space with real shadow memory") Signed-off-by: Andrey Ryabinin Reported-by: Dmitry Vyukov Reviewed-by: Uladzislau Rezki (Sony) Cc: Daniel Axtens Cc: Alexander Potapenko Cc: Daniel Axtens Cc: Qian Cai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/kasan/common.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) (limited to 'mm/kasan') diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 2fa710bb6358..e04e73603dfc 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -778,15 +778,17 @@ static int kasan_populate_vmalloc_pte(pte_t *ptep, unsigned long addr, return 0; } -int kasan_populate_vmalloc(unsigned long requested_size, struct vm_struct *area) +int kasan_populate_vmalloc(unsigned long addr, unsigned long size) { unsigned long shadow_start, shadow_end; int ret; - shadow_start = (unsigned long)kasan_mem_to_shadow(area->addr); + if (!is_vmalloc_or_module_addr((void *)addr)) + return 0; + + shadow_start = (unsigned long)kasan_mem_to_shadow((void *)addr); shadow_start = ALIGN_DOWN(shadow_start, PAGE_SIZE); - shadow_end = (unsigned long)kasan_mem_to_shadow(area->addr + - area->size); + shadow_end = (unsigned long)kasan_mem_to_shadow((void *)addr + size); shadow_end = ALIGN(shadow_end, PAGE_SIZE); ret = apply_to_page_range(&init_mm, shadow_start, @@ -797,10 +799,6 @@ int kasan_populate_vmalloc(unsigned long requested_size, struct vm_struct *area) flush_cache_vmap(shadow_start, shadow_end); - kasan_unpoison_shadow(area->addr, requested_size); - - area->flags |= VM_KASAN; - /* * We need to be careful about inter-cpu effects here. Consider: * @@ -843,12 +841,23 @@ int kasan_populate_vmalloc(unsigned long requested_size, struct vm_struct *area) * Poison the shadow for a vmalloc region. Called as part of the * freeing process at the time the region is freed. */ -void kasan_poison_vmalloc(void *start, unsigned long size) +void kasan_poison_vmalloc(const void *start, unsigned long size) { + if (!is_vmalloc_or_module_addr(start)) + return; + size = round_up(size, KASAN_SHADOW_SCALE_SIZE); kasan_poison_shadow(start, size, KASAN_VMALLOC_INVALID); } +void kasan_unpoison_vmalloc(const void *start, unsigned long size) +{ + if (!is_vmalloc_or_module_addr(start)) + return; + + kasan_unpoison_shadow(start, size); +} + static int kasan_depopulate_vmalloc_pte(pte_t *ptep, unsigned long addr, void *unused) { -- cgit v1.2.3