linux-kernel - [PATCH v2 2/2] mm: usercopy: Warn vmalloc/module address in check_heap

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Message-ID: <20211225120621.13908-3-wangkefeng.wang@huawei.com>
Date:   Sat, 25 Dec 2021 20:06:21 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Kees Cook <keescook@...omium.org>,
        Laura Abbott <labbott@...hat.com>,
        "Mark Rutland" <mark.rutland@....com>, <linux-mm@...ck.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        <linux-kernel@...r.kernel.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        "Paul Mackerras" <paulus@...ba.org>,
        <linuxppc-dev@...ts.ozlabs.org>
CC:     Nicholas Piggin <npiggin@...il.com>,
        Kefeng Wang <wangkefeng.wang@...wei.com>
Subject: [PATCH v2 2/2] mm: usercopy: Warn vmalloc/module address in check_heap_object()

virt_addr_valid() could be insufficient to validate the virt addr
on some architecture, which could lead to potential BUG which has
been found on arm64/powerpc64.

Let's add WARN_ON to check if the virt addr is passed virt_addr_valid()
but is a vmalloc/module address.

Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
---
 mm/usercopy.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/usercopy.c b/mm/usercopy.c
index b3de3c4eefba..ce83e0b137dd 100644
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -228,6 +228,8 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
 	if (!virt_addr_valid(ptr))
 		return;
 
+	WARN_ON_ONCE(is_vmalloc_or_module_addr(ptr));
+
 	/*
 	 * When CONFIG_HIGHMEM=y, kmap_to_page() will give either the
 	 * highmem page or fallback to virt_to_page(). The following
-- 
2.26.2