Messages in this thread | | | Date | Wed, 8 Jan 2020 17:07:13 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v4 2/9] perf/core: open access for CAP_SYS_PERFMON privileged process |
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On Wed, Dec 18, 2019 at 12:25:35PM +0300, Alexey Budankov wrote: > > Open access to perf_events monitoring for CAP_SYS_PERFMON privileged > processes. For backward compatibility reasons access to perf_events > subsystem remains open for CAP_SYS_ADMIN privileged processes but > CAP_SYS_ADMIN usage for secure perf_events monitoring is discouraged > with respect to CAP_SYS_PERFMON capability. > > Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> > --- > include/linux/perf_event.h | 6 +++--- > kernel/events/core.c | 6 +++--- > 2 files changed, 6 insertions(+), 6 deletions(-) > > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index 34c7c6910026..f46acd69425f 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -1285,7 +1285,7 @@ static inline int perf_is_paranoid(void) > > static inline int perf_allow_kernel(struct perf_event_attr *attr) > { > - if (sysctl_perf_event_paranoid > 1 && !capable(CAP_SYS_ADMIN)) > + if (sysctl_perf_event_paranoid > 1 && !perfmon_capable()) > return -EACCES; > > return security_perf_event_open(attr, PERF_SECURITY_KERNEL); > @@ -1293,7 +1293,7 @@ static inline int perf_allow_kernel(struct perf_event_attr *attr) > > static inline int perf_allow_cpu(struct perf_event_attr *attr) > { > - if (sysctl_perf_event_paranoid > 0 && !capable(CAP_SYS_ADMIN)) > + if (sysctl_perf_event_paranoid > 0 && !perfmon_capable()) > return -EACCES; > > return security_perf_event_open(attr, PERF_SECURITY_CPU); > @@ -1301,7 +1301,7 @@ static inline int perf_allow_cpu(struct perf_event_attr *attr) > > static inline int perf_allow_tracepoint(struct perf_event_attr *attr) > { > - if (sysctl_perf_event_paranoid > -1 && !capable(CAP_SYS_ADMIN)) > + if (sysctl_perf_event_paranoid > -1 && !perfmon_capable()) > return -EPERM; > > return security_perf_event_open(attr, PERF_SECURITY_TRACEPOINT);
These are OK I suppose.
> diff --git a/kernel/events/core.c b/kernel/events/core.c > index 059ee7116008..d9db414f2197 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -9056,7 +9056,7 @@ static int perf_kprobe_event_init(struct perf_event *event) > if (event->attr.type != perf_kprobe.type) > return -ENOENT; > > - if (!capable(CAP_SYS_ADMIN)) > + if (!perfmon_capable()) > return -EACCES; > > /*
This one only allows attaching to already extant kprobes, right? It does not allow creation of kprobes.
> @@ -9116,7 +9116,7 @@ static int perf_uprobe_event_init(struct perf_event *event) > if (event->attr.type != perf_uprobe.type) > return -ENOENT; > > - if (!capable(CAP_SYS_ADMIN)) > + if (!perfmon_capable()) > return -EACCES; > > /*
Idem, I presume.
> @@ -11157,7 +11157,7 @@ SYSCALL_DEFINE5(perf_event_open, > } > > if (attr.namespaces) { > - if (!capable(CAP_SYS_ADMIN)) > + if (!perfmon_capable()) > return -EACCES; > }
And given we basically make the entire kernel observable with this CAP, busting namespaces shoulnd't be a problem either.
So yeah, I suppose that works.
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