From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-fw-6002.amazon.com ([52.95.49.90]:40113 "EHLO smtp-fw-6002.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932306AbdKPToG (ORCPT ); Thu, 16 Nov 2017 14:44:06 -0500 From: Stefan Nuernberger To: stable@vger.kernel.org Cc: Amit Shah , David Woodhouse , Will Woods Subject: [PATCH] fanotify: fix -EOVERFLOW with large files on 64-bit Date: Thu, 16 Nov 2017 20:43:53 +0100 Message-Id: <20171116194353.20100-1-snu@amazon.com> Sender: stable-owner@vger.kernel.org List-ID: From: Will Woods commit 1e2ee49f7f1b79f0b14884fe6a602f0411b39552 upstream. On 64-bit systems, O_LARGEFILE is automatically added to flags inside the open() syscall (also openat(), blkdev_open(), etc). Userspace therefore defines O_LARGEFILE to be 0 - you can use it, but it's a no-op. Everything should be O_LARGEFILE by default. But: when fanotify does create_fd() it uses dentry_open(), which skips all that. And userspace can't set O_LARGEFILE in fanotify_init() because it's defined to 0. So if fanotify gets an event regarding a large file, the read() will just fail with -EOVERFLOW. This patch adds O_LARGEFILE to fanotify_init()'s event_f_flags on 64-bit systems, using the same test as open()/openat()/etc. Addresses https://bugzilla.redhat.com/show_bug.cgi?id=696821 Signed-off-by: Will Woods Acked-by: Eric Paris Reviewed-by: Jan Kara Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [snu: Backported to 3.2 / 3.10: adjusted context] Signed-off-by: Stefan Nuernberger Reviewed-by: Pawel Wieczorkiewicz Reviewed-by: Simon Veith Cc: # 3.2.x and 3.10.x --- fs/notify/fanotify/fanotify_user.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index d57995e1cfd7..dd3d9d13a4c4 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -712,6 +712,9 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) group->fanotify_data.user = user; atomic_inc(&user->fanotify_listeners); + if (force_o_largefile()) + event_f_flags |= O_LARGEFILE; + group->fanotify_data.f_flags = event_f_flags; #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS mutex_init(&group->fanotify_data.access_mutex); -- 2.15.0