| Message ID | c3fa42da7337bc46a4b7a1e772e87bed5ff89850.1640036051.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 20, 2021 at 11:01 PM <andrey.konovalov@linux.dev> wrote: > > From: Andrey Konovalov <andreyknvl@google.com> > > Once tag-based KASAN modes start tagging vmalloc() allocations, > kernel stacks start getting tagged if CONFIG_VMAP_STACK is enabled. > > Reset the tag of kernel stack pointers after allocation in > alloc_thread_stack_node(). > > For SW_TAGS KASAN, when CONFIG_KASAN_STACK is enabled, the > instrumentation can't handle the SP register being tagged. > > For HW_TAGS KASAN, there's no instrumentation-related issues. However, > the impact of having a tagged SP register needs to be properly evaluated, > so keep it non-tagged for now. > > Note, that the memory for the stack allocation still gets tagged to > catch vmalloc-into-stack out-of-bounds accesses. > > Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> > > --- > > Changes v2->v3: > - Update patch description. > --- > kernel/fork.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/fork.c b/kernel/fork.c > index 403b9dbbfb62..4125373dba4e 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -254,6 +254,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node) > * so cache the vm_struct. > */ > if (stack) { > + stack = kasan_reset_tag(stack); > tsk->stack_vm_area = find_vm_area(stack); > tsk->stack = stack; > } > -- > 2.25.1 >
diff --git a/kernel/fork.c b/kernel/fork.c index 403b9dbbfb62..4125373dba4e 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -254,6 +254,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node) * so cache the vm_struct. */ if (stack) { + stack = kasan_reset_tag(stack); tsk->stack_vm_area = find_vm_area(stack); tsk->stack = stack; }