From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7AB9FC433C1 for ; Fri, 26 Mar 2021 00:03:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5337A61A0A for ; Fri, 26 Mar 2021 00:03:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229981AbhCZACz (ORCPT ); Thu, 25 Mar 2021 20:02:55 -0400 Received: from mga11.intel.com ([192.55.52.93]:15386 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229733AbhCZACp (ORCPT ); Thu, 25 Mar 2021 20:02:45 -0400 IronPort-SDR: j8JrjOHIpOKEpMKxaSpKeLIGSDVDu408q4RLfIVBtZJVn6Mk4MB4rcYIZVUT6Z5651nicAG7O0 HpneMyGSNVmw== X-IronPort-AV: E=McAfee;i="6000,8403,9934"; a="187748033" X-IronPort-AV: E=Sophos;i="5.81,278,1610438400"; d="scan'208";a="187748033" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Mar 2021 17:02:43 -0700 IronPort-SDR: wN2owymOr8LuNbROqRY5grqOI0GqflWynmkq92DqloOFlO9DkdfPS4k+ss2TfBJymhpfMtG3Gn hBOppYjcZfwg== X-IronPort-AV: E=Sophos;i="5.81,278,1610438400"; d="scan'208";a="416265839" Received: from agluck-desk2.sc.intel.com ([10.3.52.146]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Mar 2021 17:02:43 -0700 From: Tony Luck To: Borislav Petkov Cc: Tony Luck , x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andy Lutomirski , Aili Yao , =?UTF-8?q?HORIGUCHI=20NAOYA=28=20=E5=A0=80=E5=8F=A3=E3=80=80=E7=9B=B4=E4=B9=9F=29?= Subject: [PATCH 2/4] mce/iter: Check for copyin failure & return error up stack Date: Thu, 25 Mar 2021 17:02:33 -0700 Message-Id: <20210326000235.370514-3-tony.luck@intel.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210326000235.370514-1-tony.luck@intel.com> References: <20210326000235.370514-1-tony.luck@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Check for failure from low level copy from user code. Doing this requires some type changes from the unsigned "size_t" so some signed type (so that "if (xxx < 0)" works!). I picked "loff_t" but there may be some other more appropriate type. Very likely more places need to be changed. These changes based on a machine check copying user data for a write(2) system call to an xfs file system where the stack trace looks like: [ 149.445163] ? copyin+0x2d/0x40 [ 149.448687] ? iov_iter_copy_from_user_atomic+0xd6/0x3a0 [ 149.454625] ? iomap_write_actor+0xc7/0x190 [ 149.459319] ? iomap_apply+0x12a/0x440 [ 149.463508] ? iomap_write_begin+0x530/0x530 [ 149.468276] ? iomap_write_begin+0x530/0x530 [ 149.473041] ? iomap_file_buffered_write+0x62/0x90 [ 149.478390] ? iomap_write_begin+0x530/0x530 [ 149.483157] ? xfs_file_buffered_write+0xe0/0x340 [xfs] [ 149.489393] ? new_sync_write+0x122/0x1b0 [ 149.493879] ? vfs_write+0x20a/0x350 [ 149.497888] ? ksys_write+0x5f/0xe0 [ 149.501784] ? do_syscall_64+0x33/0x40 --- Needs to be bundled with other patches for bisection safety --- fs/iomap/buffered-io.c | 8 +++++++- include/linux/uio.h | 2 +- lib/iov_iter.c | 15 +++++++++++++-- 3 files changed, 21 insertions(+), 4 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 414769a6ad11..6cc28e3f32ff 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -757,7 +757,7 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct page *page; unsigned long offset; /* Offset into pagecache page */ unsigned long bytes; /* Bytes to write to page */ - size_t copied; /* Bytes copied from user */ + loff_t copied; /* Bytes copied from user */ offset = offset_in_page(pos); bytes = min_t(unsigned long, PAGE_SIZE - offset, @@ -791,6 +791,12 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); + if (copied < 0) { + unlock_page(page); + put_page(page); + return copied; + } + copied = iomap_write_end(inode, pos, bytes, copied, page, iomap, srcmap); diff --git a/include/linux/uio.h b/include/linux/uio.h index 27ff8eb786dc..c2d82e8e309c 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -111,7 +111,7 @@ static inline struct iovec iov_iter_iovec(const struct iov_iter *iter) }; } -size_t iov_iter_copy_from_user_atomic(struct page *page, +loff_t iov_iter_copy_from_user_atomic(struct page *page, struct iov_iter *i, unsigned long offset, size_t bytes); void iov_iter_advance(struct iov_iter *i, size_t bytes); void iov_iter_revert(struct iov_iter *i, size_t bytes); diff --git a/lib/iov_iter.c b/lib/iov_iter.c index f66c62aa7154..57e2f81c51ee 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -16,13 +16,18 @@ #define PIPE_PARANOIA /* for now */ #define iterate_iovec(i, n, __v, __p, skip, STEP) { \ - size_t left; \ + loff_t left; \ size_t wanted = n; \ __p = i->iov; \ __v.iov_len = min(n, __p->iov_len - skip); \ if (likely(__v.iov_len)) { \ __v.iov_base = __p->iov_base + skip; \ left = (STEP); \ + if (left < 0) { \ + wanted = left; \ + n = 0; \ + goto err; \ + } \ __v.iov_len -= left; \ skip += __v.iov_len; \ n -= __v.iov_len; \ @@ -36,10 +41,16 @@ continue; \ __v.iov_base = __p->iov_base; \ left = (STEP); \ + if (left < 0) { \ + wanted = left; \ + n = 0; \ + break; \ + } \ __v.iov_len -= left; \ skip = __v.iov_len; \ n -= __v.iov_len; \ } \ +err: \ n = wanted - n; \ } @@ -975,7 +986,7 @@ size_t iov_iter_zero(size_t bytes, struct iov_iter *i) } EXPORT_SYMBOL(iov_iter_zero); -size_t iov_iter_copy_from_user_atomic(struct page *page, +loff_t iov_iter_copy_from_user_atomic(struct page *page, struct iov_iter *i, unsigned long offset, size_t bytes) { char *kaddr = kmap_atomic(page), *p = kaddr + offset; -- 2.29.2