Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Will Deacon , Mark Rutland , Catalin Marinas Subject: [PATCH 3.18 08/27] arm64: ensure __dump_instr() checks addr_limit Date: Mon, 6 Nov 2017 12:27:53 +0100 Message-Id: <20171106112736.940804309@linuxfoundation.org> In-Reply-To: <20171106112736.529730803@linuxfoundation.org> References: <20171106112736.529730803@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mark Rutland commit 7a7003b1da010d2b0d1dc8bf21c10f5c73b389f1 upstream. It's possible for a user to deliberately trigger __dump_instr with a chosen kernel address. Let's avoid problems resulting from this by using get_user() rather than __get_user(), ensuring that we don't erroneously access kernel memory. Where we use __dump_instr() on kernel text, we already switch to KERNEL_DS, so this shouldn't adversely affect those cases. Fixes: 60ffc30d5652810d ("arm64: Exception handling") Acked-by: Will Deacon Signed-off-by: Mark Rutland Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/traps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -115,7 +115,7 @@ static void dump_instr(const char *lvl, for (i = -4; i < 1; i++) { unsigned int val, bad; - bad = __get_user(val, &((u32 *)addr)[i]); + bad = get_user(val, &((u32 *)addr)[i]); if (!bad) p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);