From: Alexey Budankov <alexey.budankov@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Andi Kleen <ak@linux.intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: [PATCH v1] perf/core: take over CAP_SYS_PTRACE creds to CAP_PERFMON cap
Date: Wed, 5 Aug 2020 10:56:56 +0300 [thread overview]
Message-ID: <6e8392ff-4732-0012-2949-e1587709f0f6@linux.intel.com> (raw)
Open access to per-process monitoring for CAP_PERFMON only
privileged processes [1]. Extend ptrace_may_access() check
in perf_events subsystem with perfmon_capable() to simplify
user experience and make monitoring more secure by reducing
attack surface.
[1] https://lore.kernel.org/lkml/7776fa40-6c65-2aa6-1322-eb3a01201000@linux.intel.com/
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
---
kernel/events/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 856d98c36f56..f50d528af444 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11587,7 +11587,7 @@ SYSCALL_DEFINE5(perf_event_open,
goto err_task;
/*
- * Reuse ptrace permission checks for now.
+ * Preserve ptrace permission check for backwards compatibility.
*
* We must hold exec_update_mutex across this and any potential
* perf_install_in_context() call for this new event to
@@ -11595,7 +11595,7 @@ SYSCALL_DEFINE5(perf_event_open,
* perf_event_exit_task() that could imply).
*/
err = -EACCES;
- if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
+ if (!perfmon_capable() && !ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
goto err_cred;
}
--
2.24.1
next reply other threads:[~2020-08-05 7:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-05 7:56 Alexey Budankov [this message]
2020-08-06 12:16 ` [PATCH v1] perf/core: take over CAP_SYS_PTRACE creds to CAP_PERFMON cap Arnaldo Carvalho de Melo
2020-08-06 17:09 ` [tip: perf/urgent] perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability tip-bot2 for Alexey Budankov
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