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authorAndrey Konovalov <andreyknvl@google.com>2022-03-24 18:11:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-03-24 19:06:47 -0700
commitc08e6a1206e6876c66e0528b3ec717f557b07dd4 (patch)
tree9bf2542aa5b5593c990cef53c0e626c91be468bc /kernel
parent4aff1dc4fb3a5a3be96b6ad8db8348d3e877d7d0 (diff)
kasan, fork: 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 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. Link: https://lkml.kernel.org/r/c6c96f012371ecd80e1936509ebcd3b07a5956f7.1643047180.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> Acked-by: Marco Elver <elver@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/fork.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 834af51ed397..ce0ffe48937f 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -326,6 +326,8 @@ static int alloc_thread_stack_node(struct task_struct *tsk, int node)
* so cache the vm_struct.
*/
tsk->stack_vm_area = vm;
+ if (stack)
+ stack = kasan_reset_tag(stack);
tsk->stack = stack;
return 0;
}