From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 94A731FB7 for ; Fri, 25 Mar 2022 01:11:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D277C340EC; Fri, 25 Mar 2022 01:11:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1648170668; bh=WB80sFaBxyAUXBG5EJJVF/0zD2Pwiyr+4hsi276rbCI=; h=Date:To:From:In-Reply-To:Subject:From; b=AxSGhCLZoKYIKvIWV/SU2NGHBQOa+jFZJ1kcvW0yXhsJiVpQohyS4p0VNq2mki3gE Ty3DZx36eaoyVr7ufH0kErgJj233FZP3NQAWh8zROu+q4sHoNTa302Aaj6ng1Ri9h2 083QdsYNQsvJOOpLm1ZESjvs8Zom6/TscQkxzCCM= Date: Thu, 24 Mar 2022 18:11:07 -0700 To: will@kernel.org,vincenzo.frascino@arm.com,ryabinin.a.a@gmail.com,pcc@google.com,mark.rutland@arm.com,glider@google.com,eugenis@google.com,elver@google.com,dvyukov@google.com,catalin.marinas@arm.com,andreyknvl@google.com,akpm@linux-foundation.org,patches@lists.linux.dev,linux-mm@kvack.org,mm-commits@vger.kernel.org,torvalds@linux-foundation.org,akpm@linux-foundation.org From: Andrew Morton In-Reply-To: <20220324180758.96b1ac7e17675d6bc474485e@linux-foundation.org> Subject: [patch 051/114] kasan, fork: reset pointer tags of vmapped stacks Message-Id: <20220325011108.5D277C340EC@smtp.kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: From: Andrey Konovalov Subject: 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 Reviewed-by: Alexander Potapenko Acked-by: Marco Elver Cc: Andrey Ryabinin Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Evgenii Stepanov Cc: Mark Rutland Cc: Peter Collingbourne Cc: Vincenzo Frascino Cc: Will Deacon Signed-off-by: Andrew Morton --- kernel/fork.c | 2 ++ 1 file changed, 2 insertions(+) --- a/kernel/fork.c~kasan-fork-reset-pointer-tags-of-vmapped-stacks +++ a/kernel/fork.c @@ -326,6 +326,8 @@ static int alloc_thread_stack_node(struc * so cache the vm_struct. */ tsk->stack_vm_area = vm; + if (stack) + stack = kasan_reset_tag(stack); tsk->stack = stack; return 0; } _