The patch titled
Subject: kasan, arm64: reset pointer tags of vmapped stacks
has been removed from the -mm tree. Its filename was
kasan-arm64-reset-pointer-tags-of-vmapped-stacks.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan, arm64: reset pointer tags of vmapped stacks
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.
[andreyknvl@xxxxxxxxxx: fix case when a stack is retrieved from cached_stacks]
Link: https://lkml.kernel.org/r/f50c5f96ef896d7936192c888b0c0a7674e33184.1644943792.git.andreyknvl@xxxxxxxxxx
[dan.carpenter@xxxxxxxxxx: remove unnecessary check in alloc_thread_stack_node()]
Link: https://lkml.kernel.org/r/20220301080706.GB17208@kili
Link: https://lkml.kernel.org/r/698c5ab21743c796d46c15d075b9481825973e34.1643047180.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Acked-by: Marco Elver <elver@xxxxxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Peter Collingbourne <pcc@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/vmap_stack.h | 5 ++++-
kernel/fork.c | 11 ++++++-----
2 files changed, 10 insertions(+), 6 deletions(-)
--- a/arch/arm64/include/asm/vmap_stack.h~kasan-arm64-reset-pointer-tags-of-vmapped-stacks
+++ a/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 */
--- a/kernel/fork.c~kasan-arm64-reset-pointer-tags-of-vmapped-stacks
+++ a/kernel/fork.c
@@ -286,11 +286,13 @@ static int alloc_thread_stack_node(struc
if (!s)
continue;
- /* Mark stack accessible for KASAN. */
+ /* Reset stack metadata. */
kasan_unpoison_range(s->addr, THREAD_SIZE);
+ stack = kasan_reset_tag(s->addr);
+
/* Clear stale pointers from reused stack. */
- memset(s->addr, 0, THREAD_SIZE);
+ memset(stack, 0, THREAD_SIZE);
if (memcg_charge_kernel_stack(s)) {
vfree(s->addr);
@@ -298,7 +300,7 @@ static int alloc_thread_stack_node(struc
}
tsk->stack_vm_area = s;
- tsk->stack = s->addr;
+ tsk->stack = stack;
return 0;
}
@@ -326,8 +328,7 @@ static int alloc_thread_stack_node(struc
* so cache the vm_struct.
*/
tsk->stack_vm_area = vm;
- if (stack)
- stack = kasan_reset_tag(stack);
+ stack = kasan_reset_tag(stack);
tsk->stack = stack;
return 0;
}
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
stacktrace-add-interface-based-on-shadow-call-stack.patch
arm64-scs-save-scs_sp-values-per-cpu-when-switching-stacks.patch
arm64-implement-stack_trace_save_shadow.patch
kasan-use-stack_trace_save_shadow.patch
