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| author | Eric W. Biederman <ebiederm@xmission.com> | 2009-08-27 14:20:04 +0400 |
|---|---|---|
| committer | Eric Paris <eparis@redhat.com> | 2009-08-27 16:02:10 +0400 |
| commit | 0db501bd0610ee0c0aca84d927f90bcccd09e2bd (patch) | |
| tree | 108756b2460edff75bb7bc6c778e1a2c0ff50167 /fs/notify | |
| parent | dead537dd8a1c9495322c1d6f7c780697f474af0 (diff) | |
| download | linux-0db501bd0610ee0c0aca84d927f90bcccd09e2bd.tar.xz | |
inotify: Ensure we alwasy write the terminating NULL.
Before the rewrite copy_event_to_user always wrote a terqminating '\0'
byte to user space after the filename. Since the rewrite that
terminating byte was skipped if your filename is exactly a multiple of
event_size. Ouch!
So add one byte to name_size before we round up and use clear_user to
set userspace to zero like /dev/zero does instead of copying the
strange nul_inotify_event. I can't quite convince myself len_to_zero
will never exceed 16 and even if it doesn't clear_user should be more
efficient and a more accurate reflection of what the code is trying to
do.
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Diffstat (limited to 'fs/notify')
| -rw-r--r-- | fs/notify/inotify/inotify_user.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index ce1f5823e2c2..0e781bc88d1e 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -47,9 +47,6 @@ static struct vfsmount *inotify_mnt __read_mostly; -/* this just sits here and wastes global memory. used to just pad userspace messages with zeros */ -static struct inotify_event nul_inotify_event; - /* these are configurable via /proc/sys/fs/inotify/ */ static int inotify_max_user_instances __read_mostly; static int inotify_max_queued_events __read_mostly; @@ -199,8 +196,10 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group, inotify_free_event_priv(fsn_priv); } - /* round up event->name_len so it is a multiple of event_size */ - name_len = roundup(event->name_len, event_size); + /* round up event->name_len so it is a multiple of event_size + * plus an extra byte for the terminating '\0'. + */ + name_len = roundup(event->name_len + 1, event_size); inotify_event.len = name_len; inotify_event.mask = inotify_mask_to_arg(event->mask); @@ -224,8 +223,8 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group, return -EFAULT; buf += event->name_len; - /* fill userspace with 0's from nul_inotify_event */ - if (copy_to_user(buf, &nul_inotify_event, len_to_zero)) + /* fill userspace with 0's */ + if (clear_user(buf, len_to_zero)) return -EFAULT; buf += len_to_zero; event_size += name_len; |