From 19f1c3acf8f4431982355b2e8a78e42b884dd788 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Thu, 24 Mar 2022 18:11:20 -0700 Subject: kasan, vmalloc: unpoison VM_ALLOC pages after mapping Make KASAN unpoison vmalloc mappings after they have been mapped in when it's possible: for vmalloc() (indentified via VM_ALLOC) and vm_map_ram(). The reasons for this are: - For vmalloc() and vm_map_ram(): pages don't get unpoisoned in case mapping them fails. - For vmalloc(): HW_TAGS KASAN needs pages to be mapped to set tags via kasan_unpoison_vmalloc(). As a part of these changes, the return value of __vmalloc_node_range() is changed to area->addr. This is a non-functional change, as __vmalloc_area_node() returns area->addr anyway. Link: https://lkml.kernel.org/r/fcb98980e6fcd3c4be6acdcb5d6110898ef28548.1643047180.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Acked-by: Marco Elver Cc: Andrey Ryabinin Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Evgenii Stepanov Cc: Mark Rutland Cc: Peter Collingbourne Cc: Vincenzo Frascino Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmalloc.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-) (limited to 'mm/vmalloc.c') diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 8530d86c3e58..8da8501db942 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2231,14 +2231,15 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node) mem = (void *)addr; } - mem = kasan_unpoison_vmalloc(mem, size); - if (vmap_pages_range(addr, addr + size, PAGE_KERNEL, pages, PAGE_SHIFT) < 0) { vm_unmap_ram(mem, count); return NULL; } + /* Mark the pages as accessible, now that they are mapped. */ + mem = kasan_unpoison_vmalloc(mem, size); + return mem; } EXPORT_SYMBOL(vm_map_ram); @@ -2466,7 +2467,14 @@ static struct vm_struct *__get_vm_area_node(unsigned long size, setup_vmalloc_vm(area, va, flags, caller); - area->addr = kasan_unpoison_vmalloc(area->addr, requested_size); + /* + * Mark pages for non-VM_ALLOC mappings as accessible. Do it now as a + * best-effort approach, as they can be mapped outside of vmalloc code. + * For VM_ALLOC mappings, the pages are marked as accessible after + * getting mapped in __vmalloc_node_range(). + */ + if (!(flags & VM_ALLOC)) + area->addr = kasan_unpoison_vmalloc(area->addr, requested_size); return area; } @@ -3075,7 +3083,7 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, const void *caller) { struct vm_struct *area; - void *addr; + void *ret; unsigned long real_size = size; unsigned long real_align = align; unsigned int shift = PAGE_SHIFT; @@ -3137,10 +3145,13 @@ again: prot = arch_vmap_pgprot_tagged(prot); /* Allocate physical pages and map them into vmalloc space. */ - addr = __vmalloc_area_node(area, gfp_mask, prot, shift, node); - if (!addr) + ret = __vmalloc_area_node(area, gfp_mask, prot, shift, node); + if (!ret) goto fail; + /* Mark the pages as accessible, now that they are mapped. */ + area->addr = kasan_unpoison_vmalloc(area->addr, real_size); + /* * In this function, newly allocated vm_struct has VM_UNINITIALIZED * flag. It means that vm_struct is not fully initialized. @@ -3152,7 +3163,7 @@ again: if (!(vm_flags & VM_DEFER_KMEMLEAK)) kmemleak_vmalloc(area, size, gfp_mask); - return addr; + return area->addr; fail: if (shift > PAGE_SHIFT) { @@ -3836,7 +3847,10 @@ retry: } spin_unlock(&vmap_area_lock); - /* mark allocated areas as accessible */ + /* + * Mark allocated areas as accessible. Do it now as a best-effort + * approach, as they can be mapped outside of vmalloc code. + */ for (area = 0; area < nr_vms; area++) vms[area]->addr = kasan_unpoison_vmalloc(vms[area]->addr, vms[area]->size); -- cgit v1.2.3