Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933523AbcCGXut (ORCPT ); Mon, 7 Mar 2016 18:50:49 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:44392 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933056AbcCGXtF (ORCPT ); Mon, 7 Mar 2016 18:49:05 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johannes Thumshirn , Hannes Reinecke , Jens Axboe Subject: [PATCH 3.14 01/36] bio: return EINTR if copying to user space got interrupted Date: Mon, 7 Mar 2016 15:45:44 -0800 Message-Id: <20160307234600.606154897@linuxfoundation.org> X-Mailer: git-send-email 2.7.2 In-Reply-To: <20160307234600.344036091@linuxfoundation.org> References: <20160307234600.344036091@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1767 Lines: 52 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hannes Reinecke commit 2d99b55d378c996b9692a0c93dd25f4ed5d58934 upstream. Commit 35dc248383bbab0a7203fca4d722875bc81ef091 introduced a check for current->mm to see if we have a user space context and only copies data if we do. Now if an IO gets interrupted by a signal data isn't copied into user space any more (as we don't have a user space context) but user space isn't notified about it. This patch modifies the behaviour to return -EINTR from bio_uncopy_user() to notify userland that a signal has interrupted the syscall, otherwise it could lead to a situation where the caller may get a buffer with no data returned. This can be reproduced by issuing SG_IO ioctl()s in one thread while constantly sending signals to it. Fixes: 35dc248 [SCSI] sg: Fix user memory corruption when SG_IO is interrupted by a signal Signed-off-by: Johannes Thumshirn Signed-off-by: Hannes Reinecke Cc: stable@vger.kernel.org # v.3.11+ Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/bio.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/fs/bio.c +++ b/fs/bio.c @@ -1096,9 +1096,12 @@ int bio_uncopy_user(struct bio *bio) ret = __bio_copy_iov(bio, bmd->sgvecs, bmd->nr_sgvecs, bio_data_dir(bio) == READ, 0, bmd->is_our_pages); - else if (bmd->is_our_pages) - bio_for_each_segment_all(bvec, bio, i) - __free_page(bvec->bv_page); + else { + ret = -EINTR; + if (bmd->is_our_pages) + bio_for_each_segment_all(bvec, bio, i) + __free_page(bvec->bv_page); + } } kfree(bmd); bio_put(bio);