From mboxrd@z Thu Jan 1 00:00:00 1970 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 C389F375241; Sat, 28 Feb 2026 17:59:20 +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=1772301560; cv=none; b=nuIQOSZKjrRzYMpOH69f0+3gd1pc3VuFIaSn6/KAYRTcRu2KTYJhzz2kvFqCxYkUzC0iwa83IhpyvuaSfPQSFmsXoOXRX+d8q39rgLsmmNIz/ixmWdI6QUCWf9cTwJjKY141GboESxFAYuPBWitrUBCQZfAcDcGvbz4k0k49TxU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772301560; c=relaxed/simple; bh=sJfuBX6VYbPqMzLg2pC8OYm4UGV1OA4OKUuxO8jfG+4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TuSo/6RXoKDtTl+xEWqdn4zMJlgRbdTzaUPzrQOzHb/arnqFHaJQXdkX6zC360GaNOPwGlAQ5GmRLhCO5qdPB4hC+SIw1B6QTsvMCLbz/yVp011TYiMm9WKnFmCagJDwtQkwnrYU5/i0TQT6Zs7zXj12M+zoCXY9gai3SUUamYY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=szh/88JX; 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="szh/88JX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 08CCBC116D0; Sat, 28 Feb 2026 17:59:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772301560; bh=sJfuBX6VYbPqMzLg2pC8OYm4UGV1OA4OKUuxO8jfG+4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=szh/88JXv7ig/NghYji6VG078MOqKFeev3Pq92CXsQ1q2hPCL5KLV6K8n2qvuZ+jd 60xK0So9rCsv/WS8c9sC/jbAP1lI4f0P5djiZEOcMI96UNDvPgZqpHRHKpaSdVWCTk 9DILfMenqWA9a9EwJcU9tGgSGhynbOKaUFkqPJc2edLB/mYx/0qOQU9nHUpU01wQHp qvl+UEq0sUX7aib4uf9qf/203CSVal3TqtXDwob8AAAnljz5wMr8I8r0Hi4u6WFWR8 xRyHXh8zshEnrn4ih6g9YuoyfeEutTj5yCCNKE8P55XO9f934RLFHdnv24TIu6XyUG XxI5xLltwPdpQ== From: Sasha Levin To: patches@lists.linux.dev Cc: "Masami Hiramatsu (Google)" , stable@vger.kernel.org, Mathieu Desnoyers , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 6.18 744/752] tracing: ring-buffer: Fix to check event length before using Date: Sat, 28 Feb 2026 12:47:35 -0500 Message-ID: <20260228174750.1542406-744-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228174750.1542406-1-sashal@kernel.org> References: <20260228174750.1542406-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: "Masami Hiramatsu (Google)" [ 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 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) Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin --- 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 fdb3153bbf487..54d70bd0a3cb9 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1813,6 +1813,7 @@ 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; @@ -1820,9 +1821,12 @@ 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) { -- 2.51.0