On Fri, Jun 12, 2015 at 4:23 PM, Alexei Starovoitov <ast@xxxxxxxxxxxx> wrote: > On 6/12/15 3:54 PM, Andy Lutomirski wrote: >> >> On Fri, Jun 12, 2015 at 3:44 PM, Alexei Starovoitov <ast@xxxxxxxxxxxx> >> wrote: >>> >>> On 6/12/15 3:08 PM, Andy Lutomirski wrote: >>>> >>>> >>>> On Fri, Jun 12, 2015 at 2:40 PM, Alexei Starovoitov <ast@xxxxxxxxxxxx> >>>> wrote: >>>>> >>>>> >>>>> eBPF programs attached to kprobes need to filter based on >>>>> current->pid, uid and other fields, so introduce helper functions: >>>>> >>>>> u64 bpf_get_current_pid_tgid(void) >>>>> Return: current->tgid << 32 | current->pid >>>>> >>>>> u64 bpf_get_current_uid_gid(void) >>>>> Return: current_gid << 32 | current_uid >>>> >>>> >>>> >>>> How does this work wrt namespaces, >>> >>> >>> >>> from_kuid(current_user_ns(), uid) >>> >> >> Is current_user_ns() well defined in the context of an eBPF program? > > > What do you mean 'well defined'? > Semantically same as 'current'. Depending on where particular > kprobe is placed, 'current' is either meaningful or not. Program > author needs to know what he's doing. It's a tool. > It's a dangerous tool. Also, shouldn't the returned uid match the namespace of the task that installed the probe, not the task that's being probed? --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
