| Message ID | c93309dc-b920-f5fa-f997-e8b2faf47b88@linux.intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Introduce CAP_SYS_PERFMON to secure system performance monitoring and observability | expand |
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.
On 08.01.2020 19:07, Peter Zijlstra wrote: > 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. This unblocks creation of local trace kprobes and uprobes by CAP_SYS_PERFMON privileged process, exactly the same as for CAP_SYS_ADMIN privileged process. > >> @@ -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. >
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); 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; /* @@ -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; /* @@ -11157,7 +11157,7 @@ SYSCALL_DEFINE5(perf_event_open, } if (attr.namespaces) { - if (!capable(CAP_SYS_ADMIN)) + if (!perfmon_capable()) return -EACCES; }
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(-)