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authorJiri Olsa <jolsa@kernel.org>2014-07-16 14:33:29 +0200
committerIngo Molnar <mingo@kernel.org>2014-07-28 10:01:38 +0200
commitf4be073db878d0e79f74bc36f1642847781791a0 (patch)
tree27af2c38ab25f889f0e850ce856aaf41a15add57 /kernel/trace
parent5030c69755416d19516c0a61cd988a0e0062e041 (diff)
perf: Check permission only for parent tracepoint event
There's no need to check cloned event's permission once the parent was already checked. Also the code is checking 'current' process permissions, which is not owner process for cloned events, thus could end up with wrong permission check result. Reported-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com> Tested-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1405079782-8139-1-git-send-email-jolsa@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace_event_perf.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 5d12bb407b44..4b9c114ee9de 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -30,6 +30,18 @@ static int perf_trace_event_perm(struct ftrace_event_call *tp_event,
return ret;
}
+ /*
+ * We checked and allowed to create parent,
+ * allow children without checking.
+ */
+ if (p_event->parent)
+ return 0;
+
+ /*
+ * It's ok to check current process (owner) permissions in here,
+ * because code below is called only via perf_event_open syscall.
+ */
+
/* The ftrace function trace is allowed only for root. */
if (ftrace_event_is_function(tp_event)) {
if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))