From: Kefeng Wang <wangkefeng.wang@huawei.com>
To: <linuxppc-dev@lists.ozlabs.org>, <mpe@ellerman.id.au>,
<benh@kernel.crashing.or>, <paulus@samba.org>,
<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>
Cc: <akpm@linux-foundation.org>, <npiggin@gmail.com>,
<christophe.leroy@csgroup.eu>, <songyuanzheng@huawei.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: [PATCH v4 2/2] powerpc: Fix virt_addr_valid() check
Date: Wed, 16 Feb 2022 20:11:08 +0800 [thread overview]
Message-ID: <20220216121109.157605-2-wangkefeng.wang@huawei.com> (raw)
In-Reply-To: <20220216121109.157605-1-wangkefeng.wang@huawei.com>
When run ethtool eth0 on PowerPC64, the BUG occurred,
usercopy: Kernel memory exposure attempt detected from SLUB object not in SLUB page?! (offset 0, size 1048)!
kernel BUG at mm/usercopy.c:99
...
usercopy_abort+0x64/0xa0 (unreliable)
__check_heap_object+0x168/0x190
__check_object_size+0x1a0/0x200
dev_ethtool+0x2494/0x2b20
dev_ioctl+0x5d0/0x770
sock_do_ioctl+0xf0/0x1d0
sock_ioctl+0x3ec/0x5a0
__se_sys_ioctl+0xf0/0x160
system_call_exception+0xfc/0x1f0
system_call_common+0xf8/0x200
The code shows below,
data = vzalloc(array_size(gstrings.len, ETH_GSTRING_LEN));
copy_to_user(useraddr, data, gstrings.len * ETH_GSTRING_LEN))
The data is alloced by vmalloc(), virt_addr_valid(ptr) will return true
on PowerPC64, which leads to the panic.
As commit 4dd7554a6456 ("powerpc/64: Add VIRTUAL_BUG_ON checks for __va
and __pa addresses") does, make sure the virt addr above PAGE_OFFSET in
the virt_addr_valid() for PowerPC64, also add upper limit check to make
sure the virt is below high_memory.
Meanwhile, for PowerPC32 PAGE_OFFSET is the virtual address of the start
of lowmem, high_memory is the upper low virtual address, the check is
suitable for PowerPC32, this will fix the issue mentioned in commit
602946ec2f90 ("powerpc: Set max_mapnr correctly") too.
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
v4:
- add upper limit check
v3:
- update changelog and remove a redundant cast
arch/powerpc/include/asm/page.h | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 254687258f42..7a1ba27a7285 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -132,7 +132,11 @@ static inline bool pfn_valid(unsigned long pfn)
#define virt_to_page(kaddr) pfn_to_page(virt_to_pfn(kaddr))
#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
-#define virt_addr_valid(kaddr) pfn_valid(virt_to_pfn(kaddr))
+#define virt_addr_valid(vaddr) ({ \
+ unsigned long _addr = (unsigned long)vaddr; \
+ _addr >= PAGE_OFFSET && _addr < (unsigned long)high_memory && \
+ pfn_valid(virt_to_pfn(_addr)); \
+})
/*
* On Book-E parts we need __va to parse the device tree and we can't
--
2.26.2
next prev parent reply other threads:[~2022-02-16 11:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-16 12:11 [PATCH v4 1/2] Revert "powerpc: Set max_mapnr correctly" Kefeng Wang
2022-02-16 12:11 ` Kefeng Wang [this message]
2022-03-26 7:55 ` Kefeng Wang
2022-03-28 14:12 ` Christophe Leroy
2022-03-29 11:32 ` Kefeng Wang
2022-04-04 12:31 ` Michael Ellerman
2022-04-06 2:21 ` Kefeng Wang
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