Messages in this thread | | | Date | Wed, 7 Aug 2019 20:05:35 +0200 | From | Christian Brauner <> | Subject | Re: [PATCH v3 1/2] fork: extend clone3() to support CLONE_SET_TID |
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On Wed, Aug 07, 2019 at 06:08:56PM +0200, Oleg Nesterov wrote: > On 08/06, Adrian Reber wrote: > > > > @@ -2573,6 +2575,14 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, > > .tls = args.tls, > > }; > > > > + if (size == sizeof(struct clone_args)) { > > + /* Only check permissions if set_tid is actually set. */ > > + if (args.set_tid && > > + !ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN)) > > and I just noticed this uses pid_ns = task_active_pid_ns() ... > > is it correct? > > I feel I am totally confused, but should we use the same > p->nsproxy->pid_ns_for_children passed to alloc_pid?
We need to have CAP_SYS_ADMIN in the owning user namespace of the target pidns for the pidns in which we spawn the new process. The value for pid_ns_for_children could've been altered by either passing CLONE_NEWPID or by having called unshare(CLONE_NEWPID) before. So yes, pid_ns_for_children is what we want.
Sorry again for the delay in my responses. On vacation atm.
Christian
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