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SubjectRe: [PATCH 10/20] fanotify: allow userspace to override max queue depth
Date
On Thursday 28 Oct 2010 22:32:32 Eric Paris wrote:
> fanotify has a defualt max queue depth. This patch allows processes which
> explicitly request it to have an 'unlimited' queue depth. These processes
> need to be very careful to make sure they cannot fall far enough behind
> that they OOM the box. Thus this flag is gated on CAP_SYS_ADMIN.
>
> Signed-off-by: Eric Paris <eparis@redhat.com>
> ---
>
> fs/notify/fanotify/fanotify_user.c | 9 ++++++++-
> include/linux/fanotify.h | 5 +++--
> 2 files changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify_user.c
> b/fs/notify/fanotify/fanotify_user.c index 04f2fe4..43d66d9 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -691,7 +691,14 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags,
> unsigned int, event_f_flags) goto out_put_group;
> }
>
> - group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS;
> + if (flags & FAN_UNLIMITED_QUEUE) {
> + fd = -EPERM;
> + if (!capable(CAP_SYS_ADMIN))
> + goto out_put_group;

Either this capable call is not needed or the one at the top of the syscall
needs to go if you intended to allow non-privileged access.

Tvrtko

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