From patchwork Wed Jan 16 15:55:33 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Herton Ronaldo Krzesinski X-Patchwork-Id: 212710 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from chlorine.canonical.com (chlorine.canonical.com [91.189.94.204]) by ozlabs.org (Postfix) with ESMTP id 678852C0092 for ; Thu, 17 Jan 2013 03:06:47 +1100 (EST) Received: from localhost ([127.0.0.1] helo=chlorine.canonical.com) by chlorine.canonical.com with esmtp (Exim 4.71) (envelope-from ) id 1TvVVd-0004Y4-Cr; Wed, 16 Jan 2013 16:06:37 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by chlorine.canonical.com with esmtp (Exim 4.71) (envelope-from ) id 1TvVUx-00049V-Uw for kernel-team@lists.ubuntu.com; Wed, 16 Jan 2013 16:05:56 +0000 Received: from [177.132.109.150] (helo=canonical.com) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1TvVUx-0006u0-1d; Wed, 16 Jan 2013 16:05:55 +0000 From: Herton Ronaldo Krzesinski To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com 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 Cc: Russell King , Al Viro X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.13 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: kernel-team-bounces@lists.ubuntu.com Errors-To: kernel-team-bounces@lists.ubuntu.com 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;