| Message ID | bc9f6cb3df24eb076a6d99f91f97820718f3e29e.1639432170.git.andreyknvl@google.com (mailing list archive) |
|---|---|
| State | New |
| 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> > > 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 > arch_alloc_vmap_stack(). > > 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> > > --- > > Changes v2->v3: > - Add this patch. > --- > arch/arm64/include/asm/vmap_stack.h | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/vmap_stack.h b/arch/arm64/include/asm/vmap_stack.h > index 894e031b28d2..20873099c035 100644 > --- a/arch/arm64/include/asm/vmap_stack.h > +++ b/arch/arm64/include/asm/vmap_stack.h > @@ -17,10 +17,13 @@ > */ > static inline unsigned long *arch_alloc_vmap_stack(size_t stack_size, int node) > { > + void *p; > + > BUILD_BUG_ON(!IS_ENABLED(CONFIG_VMAP_STACK)); > > - return __vmalloc_node(stack_size, THREAD_ALIGN, THREADINFO_GFP, node, > + p = __vmalloc_node(stack_size, THREAD_ALIGN, THREADINFO_GFP, node, > __builtin_return_address(0)); > + return kasan_reset_tag(p); > } > > #endif /* __ASM_VMAP_STACK_H */ > -- > 2.25.1 > Catalin, Vincenzo, This is a new patch added in v3. Could you PTAL? Thanks!
On Mon, Dec 13, 2021 at 10:54:19PM +0100, 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 > arch_alloc_vmap_stack(). > > 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> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm64/include/asm/vmap_stack.h b/arch/arm64/include/asm/vmap_stack.h index 894e031b28d2..20873099c035 100644 --- a/arch/arm64/include/asm/vmap_stack.h +++ b/arch/arm64/include/asm/vmap_stack.h @@ -17,10 +17,13 @@ */ static inline unsigned long *arch_alloc_vmap_stack(size_t stack_size, int node) { + void *p; + BUILD_BUG_ON(!IS_ENABLED(CONFIG_VMAP_STACK)); - return __vmalloc_node(stack_size, THREAD_ALIGN, THREADINFO_GFP, node, + p = __vmalloc_node(stack_size, THREAD_ALIGN, THREADINFO_GFP, node, __builtin_return_address(0)); + return kasan_reset_tag(p); } #endif /* __ASM_VMAP_STACK_H */