Messages in this thread | | | Subject | Re: [PATCH v4 2/9] perf/core: open access for CAP_SYS_PERFMON privileged process | From | Alexey Budankov <> | Date | Fri, 3 Apr 2020 17:28:59 +0300 |
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On 01.04.2020 23:49, Alexey Budankov wrote: > Hi Peter, > > 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. >> >>> @@ -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. > > Could this have you explicit Reviewed-by or Acked-by tag > so the changes could be driven into the kernel? > Latest v7 is here: > https://lore.kernel.org/lkml/c8de937a-0b3a-7147-f5ef-69f467e87a13@linux.intel.com/
Posted v8 with all acquired tags so far: https://lore.kernel.org/lkml/f96f8f8a-e65c-3f36-dc85-fc3f5191e8c5@linux.intel.com/
Thanks, Alexey
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