From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Gerald Schaefer , Heiko Carstens , Martin Schwidefsky Subject: [PATCH 3.12 153/212] s390/uaccess: add missing page table walk range check Date: Mon, 2 Dec 2013 11:15:44 -0800 Message-Id: <20131202191304.535673023@linuxfoundation.org> In-Reply-To: <20131202191248.517975703@linuxfoundation.org> References: <20131202191248.517975703@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Heiko Carstens commit 71a86ef055f569b93bc6901f007bdf447dbf515f upstream. When translating a user space address, the address must be checked against the ASCE limit of the process. If the address is larger than the maximum address that is reachable with the ASCE, an ASCE type exception must be generated. The current code simply ignored the higher order bits. This resulted in an address wrap around in user space instead of an exception in user space. Reviewed-by: Gerald Schaefer Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- arch/s390/lib/uaccess_pt.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/s390/lib/uaccess_pt.c +++ b/arch/s390/lib/uaccess_pt.c @@ -78,11 +78,14 @@ static size_t copy_in_kernel(size_t coun * contains the (negative) exception code. */ #ifdef CONFIG_64BIT + static unsigned long follow_table(struct mm_struct *mm, unsigned long address, int write) { unsigned long *table = (unsigned long *)__pa(mm->pgd); + if (unlikely(address > mm->context.asce_limit - 1)) + return -0x38UL; switch (mm->context.asce_bits & _ASCE_TYPE_MASK) { case _ASCE_TYPE_REGION1: table = table + ((address >> 53) & 0x7ff);