Messages in this thread | | | Subject | Re: [PATCHv5 5/7] fanotify: enable close-on-exec on events' fd when requested in fanotify_init() | From | Yann Droneaud <> | Date | Mon, 20 Jan 2014 18:15:30 +0100 |
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Hi Lino,
I've recently sent this patch which may fix a bug in the way fanotify creates its file descriptors.
I failed to noticed you've been working recently on fanotify subsystem and miss the opportunity to add you in the Cc:s.
Please have a look to this patch and help to get it merged.
Le dimanche 05 janvier 2014 à 21:36 +0100, Yann Droneaud a écrit : > According to commit 80af258867648, file descriptor created as part > of file access notification events inherit flags from the event_f_flags > argument passed to syscall fanotify_init(2). > > So while it is legal for userspace to call fanotify_init() with O_CLOEXEC > as part of its second argument, O_CLOEXEC is currently silently ignored. > > Indeed event_f_flags are only given to dentry_open(), which only > seems to care about O_ACCMODE and O_PATH in do_dentry_open(), O_DIRECT > in open_check_o_direct() and O_LARGEFILE in generic_file_open(). > > More, there's no effective check on event_f_flags value that would > catch unknown / unsupported values, unlike the one on f_flags argument > of the syscall (see FAN_ALL_INIT_FLAGS in include/uapi/linux/fanotify.h).
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> But it seems logical to set close-on-exec flag on the file descriptor > if userspace is allowed to request it with O_CLOEXEC. >
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> So this patch replaces call to macro get_unused_fd() by a call to > function get_unused_fd_flags() with event_f_flags value as argument. > This way O_CLOEXEC flag in the second argument of fanotify_init(2) > syscall is interpreted so that close-on-exec get enabled.
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> Cc: Eric Paris <eparis@redhat.com> > Cc: Al Viro <viro@zeniv.linux.org.uk> > Cc: stable@vger.kernel.org > Signed-off-by: Yann Droneaud <ydroneaud@opteya.com> > Link: > http://lkml.kernel.org/r/cover.1388952061.git.ydroneaud@opteya.com > > --- > fs/notify/fanotify/fanotify_user.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c > index 57d7c083cb4b..6d0eaabba02e 100644 > --- a/fs/notify/fanotify/fanotify_user.c > +++ b/fs/notify/fanotify/fanotify_user.c > @@ -71,7 +71,7 @@ static int create_fd(struct fsnotify_group *group, > > pr_debug("%s: group=%p event=%p\n", __func__, group, event); > > - client_fd = get_unused_fd(); > + client_fd = get_unused_fd_flags(group->fanotify_data.f_flags); > if (client_fd < 0) > return client_fd; >
Regards.
-- Yann Droneaud OPTEYA
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