From nobody Thu Mar 19 02:05:45 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B73E713AA2F; Mon, 16 Feb 2026 09:30:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771234219; cv=none; b=hpY3N0J1/Gqzjj+BMxgXv3DiiMboKiAP5vKDzezxLL8KuuE4jZpPsF3ACs1Sm2+195WZvh/Vurjn5xH9GHlvF1wqt9dEVNEgyN8NnzyFktJtlJJVUYZ0SlJQS9RkbP4Mz8KTiM1xNFLx0i+P8lSwoEngnKmifXUoDd+bTFaNQII= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771234219; c=relaxed/simple; bh=On3wEf0+yn7vkojIv4yWSrS26SXQspZCTu8heTQRUD0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=nmW+hFUrzwdu4TwUHmB4ldIDZ93e76tX+jvPSofKTF9Q/VcPu31Nj4uX0Yzn6QekYSCs8O9cLlp6gVXNArbI2dzr7N7j5v3oeRvMKp/KqpBes++xSitQNG954X6bSMWl0JDqpeiVWA5lDW5PXxS5Ah7dNFiIL5vLQwsMrDfmwzY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=H3TjRsc4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="H3TjRsc4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1ADEC116C6; Mon, 16 Feb 2026 09:30:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771234219; bh=On3wEf0+yn7vkojIv4yWSrS26SXQspZCTu8heTQRUD0=; h=From:To:Cc:Subject:Date:From; b=H3TjRsc4L3l4HZjeu0D7Py+oyVwZrDbW3qHOAsTzIMr6So3wi1ojvp5oTza4EmT62 dNnaFsiSjyX/qtzYdRCRUJ2lCtM8nSy5CZUMpjiIHcTvaDXFOqWtrX3reUMSwHhuBi epueCJZRA4zQcB4CZKwCNR4HaOoK/nsdafI8n5IxmkN90OZ5G5J6uxatUyIfqJUxBJ 2EjTvdQFszKgKXUVWPIaybDMe7yyonZh8ddX7556FGwTPBBfbnnKki0GCaImkellZ3 2mGYsJ2E5Zqg6STXd2NVxTRP+OH58G7bLaGYhaWsPBJZB2/oGxVuoGXHu8E4GPvwnV 0lr9GmJzaL8Kg== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Masami Hiramatsu Cc: Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH] tracing: ring-buffer: Fix to check event length before using Date: Mon, 16 Feb 2026 18:30:15 +0900 Message-ID: <177123421541.142205.9414352170164678966.stgit@devnote2> X-Mailer: git-send-email 2.43.0 User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) 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. Fixes: 5f3b6e839f3c ("ring-buffer: Validate boot range memory events") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/ring_buffer.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 630221b00838..1ef17d6fd824 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_pag= e *dpage, int tail, int cpu struct ring_buffer_event *event; u64 ts, delta; int events =3D 0; + int len; int e; =20 *delta_ptr =3D 0; @@ -1855,9 +1856,12 @@ static int rb_read_data_buffer(struct buffer_data_pa= ge *dpage, int tail, int cpu =20 ts =3D dpage->time_stamp; =20 - for (e =3D 0; e < tail; e +=3D rb_event_length(event)) { + for (e =3D 0; e < tail; e +=3D len) { =20 event =3D (struct ring_buffer_event *)(dpage->data + e); + len =3D rb_event_length(event); + if (len <=3D 0 || len > tail - e) + return -1; =20 switch (event->type_len) {