From: Steven Rostedt <rostedt@goodmis.org>
To: Zhengchuan Liang <zcliangcn@gmail.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Ross Zwisler <zwisler@google.com>,
linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
linux-perf-users@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 1/1] tracing: Require tracepoint permission for perf function filters
Date: Tue, 29 Sep 2026 14:45:01 -0400 [thread overview]
Message-ID: <20260929144501.3b8dcaa1@fedora> (raw)
In-Reply-To: <95d3721fa8d4c7a4577ec14e9d7caec4fd0cefcc.1790553331.git.zcliangcn@gmail.com>
On Sun, 27 Sep 2026 17:00:31 -0700
Zhengchuan Liang <zcliangcn@gmail.com> wrote:
> Count-only perf tracepoint events can be opened without tracepoint
> permission because they do not sample raw event data. Their SET_FILTER
> ioctl still parses .function predicates. Numeric operands call
> kallsyms_lookup_size_offset(), making ioctl success an oracle for
> recovering the randomized kernel text base. Symbolic operands resolve
> hidden symbol addresses and can also match user-controlled event fields
> against those addresses.
>
> Pass the perf origin through filter parsing and require
> perf_allow_tracepoint() before resolving either form of .function
> operand. Ordinary perf count filters and tracefs event filters retain
> their existing behavior.
>
> Fixes: e6745a4da964 ("tracing: Add a way to filter function addresses to function names")
> Cc: stable@vger.kernel.org
> Assisted-by: LLM
> Signed-off-by: Zhengchuan Liang <zcliangcn@gmail.com>
> ---
> kernel/trace/trace_events_filter.c | 39 ++++++++++++++++++++++--------
NAK.
This is a perf issue and not a ftrace issue. It should not touch any
code in kernel/trace/* for the fix.
Looks to me the code that calls ftrace_profile_set_filter() from
kernel/events/core.c should not be allowed by unprivileged users.
-- Steve
prev parent reply other threads:[~2026-09-29 18:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-28 0:00 [PATCH 0/1] perf tracepoint filter exposes the kernel text base Zhengchuan Liang
2026-09-28 0:00 ` [PATCH 1/1] tracing: Require tracepoint permission for perf function filters Zhengchuan Liang
2026-09-28 0:07 ` sashiko-bot
2026-09-29 18:45 ` Steven Rostedt [this message]
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