From f4be073db878d0e79f74bc36f1642847781791a0 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 16 Jul 2014 14:33:29 +0200 Subject: [PATCH] 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 Tested-by: Alexander Yarygin Signed-off-by: Jiri Olsa Signed-off-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Corey Ashford Cc: Frederic Weisbecker Cc: Paul Mackerras Cc: Linus Torvalds Cc: Steven Rostedt Link: http://lkml.kernel.org/r/1405079782-8139-1-git-send-email-jolsa@kernel.org Signed-off-by: Ingo Molnar --- kernel/trace/trace_event_perf.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) 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)) -- 2.30.2