diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/kasan/hw_tags.c | 7 | ||||
| -rw-r--r-- | mm/kasan/shadow.c | 8 | ||||
| -rw-r--r-- | mm/vmalloc.c | 49 |
3 files changed, 44 insertions, 20 deletions
diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index 21104fd51872..2e9378a4f07f 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -247,6 +247,13 @@ void *__kasan_unpoison_vmalloc(const void *start, unsigned long size, if (!(flags & KASAN_VMALLOC_VM_ALLOC)) return (void *)start; + /* + * Don't tag executable memory. + * The kernel doesn't tolerate having the PC register tagged. + */ + if (!(flags & KASAN_VMALLOC_PROT_NORMAL)) + return (void *)start; + tag = kasan_random_tag(); start = set_tag(start, tag); diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c index b958babc8fed..a4f07de21771 100644 --- a/mm/kasan/shadow.c +++ b/mm/kasan/shadow.c @@ -488,6 +488,14 @@ void *__kasan_unpoison_vmalloc(const void *start, unsigned long size, if (!is_vmalloc_or_module_addr(start)) return (void *)start; + /* + * Don't tag executable memory with the tag-based mode. + * The kernel doesn't tolerate having the PC register tagged. + */ + if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) && + !(flags & KASAN_VMALLOC_PROT_NORMAL)) + return (void *)start; + start = set_tag(start, kasan_random_tag()); kasan_unpoison(start, size, false); return (void *)start; diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 185ab3e27d13..e163372d3967 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2242,7 +2242,7 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node) * With hardware tag-based KASAN, marking is skipped for * non-VM_ALLOC mappings, see __kasan_unpoison_vmalloc(). */ - mem = kasan_unpoison_vmalloc(mem, size, KASAN_VMALLOC_NONE); + mem = kasan_unpoison_vmalloc(mem, size, KASAN_VMALLOC_PROT_NORMAL); return mem; } @@ -2481,7 +2481,7 @@ static struct vm_struct *__get_vm_area_node(unsigned long size, */ if (!(flags & VM_ALLOC)) area->addr = kasan_unpoison_vmalloc(area->addr, requested_size, - KASAN_VMALLOC_NONE); + KASAN_VMALLOC_PROT_NORMAL); return area; } @@ -3091,7 +3091,7 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, { struct vm_struct *area; void *ret; - kasan_vmalloc_flags_t kasan_flags; + kasan_vmalloc_flags_t kasan_flags = KASAN_VMALLOC_NONE; unsigned long real_size = size; unsigned long real_align = align; unsigned int shift = PAGE_SHIFT; @@ -3144,21 +3144,28 @@ again: goto fail; } - /* Prepare arguments for __vmalloc_area_node(). */ - if (kasan_hw_tags_enabled() && - pgprot_val(prot) == pgprot_val(PAGE_KERNEL)) { - /* - * Modify protection bits to allow tagging. - * This must be done before mapping in __vmalloc_area_node(). - */ - prot = arch_vmap_pgprot_tagged(prot); + /* + * Prepare arguments for __vmalloc_area_node() and + * kasan_unpoison_vmalloc(). + */ + if (pgprot_val(prot) == pgprot_val(PAGE_KERNEL)) { + if (kasan_hw_tags_enabled()) { + /* + * Modify protection bits to allow tagging. + * This must be done before mapping. + */ + prot = arch_vmap_pgprot_tagged(prot); - /* - * Skip page_alloc poisoning and zeroing for physical pages - * backing VM_ALLOC mapping. Memory is instead poisoned and - * zeroed by kasan_unpoison_vmalloc(). - */ - gfp_mask |= __GFP_SKIP_KASAN_UNPOISON | __GFP_SKIP_ZERO; + /* + * Skip page_alloc poisoning and zeroing for physical + * pages backing VM_ALLOC mapping. Memory is instead + * poisoned and zeroed by kasan_unpoison_vmalloc(). + */ + gfp_mask |= __GFP_SKIP_KASAN_UNPOISON | __GFP_SKIP_ZERO; + } + + /* Take note that the mapping is PAGE_KERNEL. */ + kasan_flags |= KASAN_VMALLOC_PROT_NORMAL; } /* Allocate physical pages and map them into vmalloc space. */ @@ -3172,10 +3179,13 @@ again: * (except for the should_skip_init() check) to make sure that memory * is initialized under the same conditions regardless of the enabled * KASAN mode. + * Tag-based KASAN modes only assign tags to normal non-executable + * allocations, see __kasan_unpoison_vmalloc(). */ - kasan_flags = KASAN_VMALLOC_VM_ALLOC; + kasan_flags |= KASAN_VMALLOC_VM_ALLOC; if (!want_init_on_free() && want_init_on_alloc(gfp_mask)) kasan_flags |= KASAN_VMALLOC_INIT; + /* KASAN_VMALLOC_PROT_NORMAL already set if required. */ area->addr = kasan_unpoison_vmalloc(area->addr, real_size, kasan_flags); /* @@ -3881,8 +3891,7 @@ retry: */ for (area = 0; area < nr_vms; area++) vms[area]->addr = kasan_unpoison_vmalloc(vms[area]->addr, - vms[area]->size, - KASAN_VMALLOC_NONE); + vms[area]->size, KASAN_VMALLOC_PROT_NORMAL); kfree(vas); return vms; |