diff options
| author | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2026-02-16 18:30:15 +0900 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2026-03-04 07:21:46 -0500 |
| commit | 9eb80e54494ef1efef8a64bec4ffa672c9cf411e (patch) | |
| tree | 274ce772c154357608dbab59ed771f1acc67e69f | |
| parent | d9942396845fef2369478c157b26738fe07142f6 (diff) | |
tracing: ring-buffer: Fix to check event length before using
[ Upstream commit 912b0ee248c529a4f45d1e7f568dc1adddbf2a4a ]
Check the event length before adding it for accessing next index in
rb_read_data_buffer(). Since this function is used for validating
possibly broken ring buffers, the length of the event could be broken.
In that case, the new event (e + len) can point a wrong address.
To avoid invalid memory access at boot, check whether the length of
each event is in the possible range before using it.
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 5f3b6e839f3c ("ring-buffer: Validate boot range memory events")
Link: https://patch.msgid.link/177123421541.142205.9414352170164678966.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | kernel/trace/ring_buffer.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index ad08430347b0..2f44063c666f 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1848,6 +1848,7 @@ static int rb_read_data_buffer(struct buffer_data_page *dpage, int tail, int cpu struct ring_buffer_event *event; u64 ts, delta; int events = 0; + int len; int e; *delta_ptr = 0; @@ -1855,9 +1856,12 @@ static int rb_read_data_buffer(struct buffer_data_page *dpage, int tail, int cpu ts = dpage->time_stamp; - for (e = 0; e < tail; e += rb_event_length(event)) { + for (e = 0; e < tail; e += len) { event = (struct ring_buffer_event *)(dpage->data + e); + len = rb_event_length(event); + if (len <= 0 || len > tail - e) + return -1; switch (event->type_len) { |