Messages in this thread | | | Date | Sat, 8 Jan 2022 19:58:04 +0800 | Subject | Re: [PATCH v2 1/2] powerpc: Fix virt_addr_valid() check | From | Kefeng Wang <> |
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Hi PPC maintainers, ping..
On 2021/12/25 20:06, Kefeng Wang wrote: > When run ethtool eth0, 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(). > > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > --- > arch/powerpc/include/asm/page.h | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h > index 254687258f42..300d4c105a3a 100644 > --- a/arch/powerpc/include/asm/page.h > +++ b/arch/powerpc/include/asm/page.h > @@ -132,7 +132,10 @@ 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; \ > + (unsigned long)(_addr) >= PAGE_OFFSET && pfn_valid(virt_to_pfn(_addr)); \ > +}) > > /* > * On Book-E parts we need __va to parse the device tree and we can't
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