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authorWill Woods <wwoods@redhat.com>2014-05-06 12:50:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-05-06 13:04:59 -0700
commit1e2ee49f7f1b79f0b14884fe6a602f0411b39552 (patch)
tree06e78cfe43e34b040d713585cca950e507d45260 /fs/notify
parent41a212859a4dd583d3aa032cdd3efa564c4f189f (diff)
downloadlinux-1e2ee49f7f1b79f0b14884fe6a602f0411b39552.tar.gz
fanotify: fix -EOVERFLOW with large files on 64-bit
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 <wwoods@redhat.com>
Acked-by: Eric Paris <eparis@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/notify')
-rw-r--r--fs/notify/fanotify/fanotify_user.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 4e565c814309..732648b270dc 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -698,6 +698,8 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
 	}
 	group->overflow_event = &oevent->fse;
 
+	if (force_o_largefile())
+		event_f_flags |= O_LARGEFILE;
 	group->fanotify_data.f_flags = event_f_flags;
 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
 	spin_lock_init(&group->fanotify_data.access_lock);