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, Rusty Russell , Linus Torvalds Subject: [PATCH 3.14 11/64] lguest: fix out-by-one error in address checking. Date: Wed, 3 Jun 2015 20:42:39 +0900 Message-Id: <20150603063928.956313316@linuxfoundation.org> In-Reply-To: <20150603063928.472620468@linuxfoundation.org> References: <20150603063928.472620468@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Rusty Russell commit 83a35114d0e4583e6b0ca39502e68b6a92e2910c upstream. This bug has been there since day 1; addresses in the top guest physical page weren't considered valid. You could map that page (the check in check_gpte() is correct), but if a guest tried to put a pagetable there we'd check that address manually when walking it, and kill the guest. Signed-off-by: Rusty Russell Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/lguest/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/lguest/core.c +++ b/drivers/lguest/core.c @@ -176,7 +176,7 @@ static void unmap_switcher(void) bool lguest_address_ok(const struct lguest *lg, unsigned long addr, unsigned long len) { - return (addr+len) / PAGE_SIZE < lg->pfn_limit && (addr+len >= addr); + return addr+len <= lg->pfn_limit * PAGE_SIZE && (addr+len >= addr); } /*