| Message ID | 1a2b5e3047faf05e5c11a9080c3f97a9b9b4c383.1639432170.git.andreyknvl@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kasan, vmalloc, arm64: add vmalloc tagging support for SW/HW_TAGS | expand |
On Mon, Dec 13, 2021 at 10:54 PM <andrey.konovalov@linux.dev> wrote: > > From: Andrey Konovalov <andreyknvl@google.com> > > Make KASAN unpoison vmalloc mappings after that have been mapped in > when it's possible: for vmalloc() (indentified via VM_ALLOC) and > vm_map_ram(). The subject says "don't unpoison VM_ALLOC pages", whereas the description says "unpoison VM_ALLOC pages", or am I missing something? > 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(). > > Signed-off-by: Andrey Konovalov <andreyknvl@google.com> > > --- > > Changes v2->v3: > - Update patch description. > --- > mm/vmalloc.c | 26 ++++++++++++++++++++++---- > 1 file changed, 22 insertions(+), 4 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 58bd2f7f86d7..9a6862e274df 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2208,14 +2208,15 @@ 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 after they were mapped in. */ > + mem = kasan_unpoison_vmalloc(mem, size); > + > return mem; > } > EXPORT_SYMBOL(vm_map_ram); > @@ -2443,7 +2444,14 @@ 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); > + /* > + * For VM_ALLOC mappings, __vmalloc_node_range() mark the pages as > + * accessible after they are mapped in. > + * Otherwise, as the pages can be mapped outside of vmalloc code, > + * mark them now as a best-effort approach. > + */ > + if (!(flags & VM_ALLOC)) > + area->addr = kasan_unpoison_vmalloc(area->addr, requested_size); > > return area; > } > @@ -3104,6 +3112,12 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, > if (!addr) > goto fail; > > + /* > + * Mark the pages for VM_ALLOC mappings as accessible after they were > + * mapped in. > + */ > + addr = kasan_unpoison_vmalloc(addr, real_size); > + > /* > * In this function, newly allocated vm_struct has VM_UNINITIALIZED > * flag. It means that vm_struct is not fully initialized. > @@ -3799,7 +3813,11 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets, > } > spin_unlock(&vmap_area_lock); > > - /* mark allocated areas as accessible */ > + /* > + * Mark allocated areas as accessible. > + * As the pages are mapped outside of vmalloc code, > + * mark them now as a best-effort approach. > + */ > for (area = 0; area < nr_vms; area++) > vms[area]->addr = kasan_unpoison_vmalloc(vms[area]->addr, > vms[area]->size); > -- > 2.25.1 > > -- > You received this message because you are subscribed to the Google Groups "kasan-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/1a2b5e3047faf05e5c11a9080c3f97a9b9b4c383.1639432170.git.andreyknvl%40google.com.
On Thu, Dec 16, 2021 at 8:08 PM Alexander Potapenko <glider@google.com> wrote: > > On Mon, Dec 13, 2021 at 10:54 PM <andrey.konovalov@linux.dev> wrote: > > > > From: Andrey Konovalov <andreyknvl@google.com> > > > > Make KASAN unpoison vmalloc mappings after that have been mapped in > > when it's possible: for vmalloc() (indentified via VM_ALLOC) and > > vm_map_ram(). > > The subject says "don't unpoison VM_ALLOC pages", whereas the > description says "unpoison VM_ALLOC pages", or am I missing something? Yes :) The title says "don't unpoison *before*", and the body says "unpoison *after*". I'll reword the changelog in v4 to make it less confusing. Thanks!
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 58bd2f7f86d7..9a6862e274df 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2208,14 +2208,15 @@ 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 after they were mapped in. */ + mem = kasan_unpoison_vmalloc(mem, size); + return mem; } EXPORT_SYMBOL(vm_map_ram); @@ -2443,7 +2444,14 @@ 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); + /* + * For VM_ALLOC mappings, __vmalloc_node_range() mark the pages as + * accessible after they are mapped in. + * Otherwise, as the pages can be mapped outside of vmalloc code, + * mark them now as a best-effort approach. + */ + if (!(flags & VM_ALLOC)) + area->addr = kasan_unpoison_vmalloc(area->addr, requested_size); return area; } @@ -3104,6 +3112,12 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, if (!addr) goto fail; + /* + * Mark the pages for VM_ALLOC mappings as accessible after they were + * mapped in. + */ + addr = kasan_unpoison_vmalloc(addr, real_size); + /* * In this function, newly allocated vm_struct has VM_UNINITIALIZED * flag. It means that vm_struct is not fully initialized. @@ -3799,7 +3813,11 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets, } spin_unlock(&vmap_area_lock); - /* mark allocated areas as accessible */ + /* + * Mark allocated areas as accessible. + * As the pages are mapped outside of vmalloc code, + * mark them now as a best-effort approach. + */ for (area = 0; area < nr_vms; area++) vms[area]->addr = kasan_unpoison_vmalloc(vms[area]->addr, vms[area]->size);