From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from wtarreau.pck.nerim.net ([62.212.114.60]:9284 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755428AbbILXMh (ORCPT ); Sat, 12 Sep 2015 19:12:37 -0400 Message-Id: <20150912225607.641348841@1wt.eu> Date: Sun, 13 Sep 2015 00:56:31 +0200 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Rusty Russell , Linus Torvalds , Ben Hutchings , Willy Tarreau Subject: [PATCH 2.6.32 25/62] lguest: fix out-by-one error in address checking. MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 In-Reply-To: <08d3b586eb2e764308c3de9ee398a17c@local> Sender: stable-owner@vger.kernel.org List-ID: 2.6.32-longterm 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: Ben Hutchings (cherry picked from commit a8f5259269671acb4f0bdb6e0a53974aa5b351ff) Signed-off-by: Willy Tarreau --- drivers/lguest/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c index 8744d24..42ad32c 100644 --- a/drivers/lguest/core.c +++ b/drivers/lguest/core.c @@ -170,7 +170,7 @@ 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); } /* -- 1.7.12.2.21.g234cd45.dirty