From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932396Ab3APQGE (ORCPT ); Wed, 16 Jan 2013 11:06:04 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:36317 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932341Ab3APQF6 (ORCPT ); Wed, 16 Jan 2013 11:05:58 -0500 From: Herton Ronaldo Krzesinski To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Al Viro , Russell King , Herton Ronaldo Krzesinski Subject: [PATCH 133/222] ARM: missing ->mmap_sem around find_vma() in swp_emulate.c Date: Wed, 16 Jan 2013 13:55:33 -0200 Message-Id: <1358351822-7675-134-git-send-email-herton.krzesinski@canonical.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1358351822-7675-1-git-send-email-herton.krzesinski@canonical.com> References: <1358351822-7675-1-git-send-email-herton.krzesinski@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7.3 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit 7bf9b7bef881aac820bf1f2e9951a17b09bd7e04 upstream. find_vma() is *not* safe when somebody else is removing vmas. Not just the return value might get bogus just as you are getting it (this instance doesn't try to dereference the resulting vma), the search itself can get buggered in rather spectacular ways. IOW, ->mmap_sem really, really is not optional here. Signed-off-by: Al Viro Signed-off-by: Russell King Signed-off-by: Herton Ronaldo Krzesinski --- arch/arm/kernel/swp_emulate.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm/kernel/swp_emulate.c b/arch/arm/kernel/swp_emulate.c index df74518..ab1017b 100644 --- a/arch/arm/kernel/swp_emulate.c +++ b/arch/arm/kernel/swp_emulate.c @@ -109,10 +109,12 @@ static void set_segfault(struct pt_regs *regs, unsigned long addr) { siginfo_t info; + down_read(¤t->mm->mmap_sem); if (find_vma(current->mm, addr) == NULL) info.si_code = SEGV_MAPERR; else info.si_code = SEGV_ACCERR; + up_read(¤t->mm->mmap_sem); info.si_signo = SIGSEGV; info.si_errno = 0; -- 1.7.9.5