From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Arnd Bergmann Subject: [PATCH v2 10/18] m68k: fix access_ok for coldfire Date: Wed, 16 Feb 2022 14:13:24 +0100 Message-Id: <20220216131332.1489939-11-arnd@kernel.org> In-Reply-To: <20220216131332.1489939-1-arnd@kernel.org> References: <20220216131332.1489939-1-arnd@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: Linus Torvalds , Christoph Hellwig , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, arnd@arndb.de, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk Cc: linux@armlinux.org.uk, will@kernel.org, guoren@kernel.org, bcain@codeaurora.org, geert@linux-m68k.org, monstr@monstr.eu, tsbogend@alpha.franken.de, nickhu@andestech.com, green.hu@gmail.com, dinguyen@kernel.org, shorne@gmail.com, deller@gmx.de, mpe@ellerman.id.au, peterz@infradead.org, mingo@redhat.com, mark.rutland@arm.com, hca@linux.ibm.com, dalias@libc.org, davem@davemloft.net, richard@nod.at, x86@kernel.org, jcmvbkbc@gmail.com, ebiederm@xmission.com, akpm@linux-foundation.org, ardb@kernel.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org List-ID: From: Arnd Bergmann While most m68k platforms use separate address spaces for user and kernel space, at least coldfire does not, and the other ones have a TASK_SIZE that is less than the entire 4GB address range. Using the default implementation of __access_ok() stops coldfire user space from trivially accessing kernel memory. Signed-off-by: Arnd Bergmann --- arch/m68k/include/asm/uaccess.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/m68k/include/asm/uaccess.h b/arch/m68k/include/asm/uaccess.h index 79617c0b2f91..8eb625e75452 100644 --- a/arch/m68k/include/asm/uaccess.h +++ b/arch/m68k/include/asm/uaccess.h @@ -12,14 +12,21 @@ #include /* We let the MMU do all checking */ -static inline int access_ok(const void __user *addr, +static inline int access_ok(const void __user *ptr, unsigned long size) { + unsigned long limit = TASK_SIZE; + unsigned long addr = (unsigned long)ptr; + /* * XXX: for !CONFIG_CPU_HAS_ADDRESS_SPACES this really needs to check * for TASK_SIZE! + * Removing this helper is probably sufficient. */ - return 1; + if (IS_ENABLED(CONFIG_CPU_HAS_ADDRESS_SPACES)) + return 1; + + return (size <= limit) && (addr <= (limit - size)); } /* -- 2.29.2