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 D0A2942B3AD; Sat, 28 Feb 2026 17:46:43 +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=1772300803; cv=none; b=joh/RT/a15j9fWXbI5zXCabZSp1nNkXEphcXiwNy/GN0XphfLvc5ICKXyJwnwXFfkT2SOps4zi8J87N9c1bMn/07vtUqSvbILzBMYTr0Xv8xKZry4W+T/ixL2kx+9fzAuycwTrwNix/BYg/9vWtG4vWx0565wZZTFxqKUimA0N0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772300803; c=relaxed/simple; bh=jMounPxqv3isWkbawRiFG1IEvs2hnYQdhs0x/ep8b94=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FRDW/QHQDmdrIBp6dqcFbQG/onrrsJNlOIauX+l8wCUacdBEjoP+o237Hzev2e860mFqzO9BP5oK0LUAA4LFyGOeSEaL/ldG/SgP0xj6nf/mxfnQxb0s9MBFvaY/RsKpFFi+nf8EiUImu+KpryUJynbZKbDDMzFXU7Mbj4bkSvw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=o6667ocq; 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="o6667ocq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 130F3C19425; Sat, 28 Feb 2026 17:46:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772300803; bh=jMounPxqv3isWkbawRiFG1IEvs2hnYQdhs0x/ep8b94=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o6667ocq2xA1hNZtjjuUOWqpkkcUMj+7cWGjPReKscthlxolZEYILTMfXscst5bpp WoMg6qrEXolA2R+fZEVxx/ZtxDTG22hoWOqs2O0029BseDK3ponHOwG9ru7WN7n3BD U7n8u+zABqCaJYigwAsZLk4r02mf2QGyeJP5RqlQPEBA79fyaIVjfETmHlHtTR1Sg7 JMMr9/oOLAuA4xMEm+pVRiYxhti/hAFnAKP+y36C17/oMKgrLS6TF9uo5ZcmySm+eK 5OgyjFzPqMHFuTd2J6IAfTReBbSMkXcx8YTgjG/09BcdIB60zQ0FJM1IvWyp1tQ6LM KGrHt0iXCC8kg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Masami Hiramatsu (Google)" , Mathieu Desnoyers , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 6.19 836/844] tracing: ring-buffer: Fix to check event length before using Date: Sat, 28 Feb 2026 12:32:29 -0500 Message-ID: <20260228173244.1509663-837-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260228173244.1509663-1-sashal@kernel.org> References: <20260228173244.1509663-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org 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 ad08430347b06..2f44063c666f2 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) { -- 2.51.0