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 C0942262A1 for ; Mon, 16 Oct 2023 14:54:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Scb4ORs8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BCA1DC433CC; Mon, 16 Oct 2023 14:54:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1697468072; bh=jFNqmFYoymMg2QBQFFPwuGOYENu3/ufQDM/wfi5/NR8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Scb4ORs8Brhushd6TEBwTtRG40/Q3zqcycv+PiNnSh6LEb6a6gy82iSxANLKIwl3t eFBBiqLbOiLkRFfoprAGzHUDeevwTPV0312fOAJRV7X5BitoYuq2G0oxogO5Fxzl+s zC9tpgX2WOMYAheCwVULz/tSnCbiaJX93OeOl2Og= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tzung-Bi Shih , Guenter Roeck , Stephen Boyd , Jonathan Cameron Subject: [PATCH 6.5 111/191] iio: cros_ec: fix an use-after-free in cros_ec_sensors_push_data() Date: Mon, 16 Oct 2023 10:41:36 +0200 Message-ID: <20231016084017.977611793@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231016084015.400031271@linuxfoundation.org> References: <20231016084015.400031271@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tzung-Bi Shih commit 7771c8c80d62ad065637ef74ed2962983f6c5f6d upstream. cros_ec_sensors_push_data() reads `indio_dev->active_scan_mask` and calls iio_push_to_buffers_with_timestamp() without making sure the `indio_dev` stays in buffer mode. There is a race if `indio_dev` exits buffer mode right before cros_ec_sensors_push_data() accesses them. An use-after-free on `indio_dev->active_scan_mask` was observed. The call trace: [...] _find_next_bit cros_ec_sensors_push_data cros_ec_sensorhub_event blocking_notifier_call_chain cros_ec_irq_thread It was caused by a race condition: one thread just freed `active_scan_mask` at [1]; while another thread tried to access the memory at [2]. Fix it by calling iio_device_claim_buffer_mode() to ensure the `indio_dev` can't exit buffer mode during cros_ec_sensors_push_data(). [1]: https://elixir.bootlin.com/linux/v6.5/source/drivers/iio/industrialio-buffer.c#L1189 [2]: https://elixir.bootlin.com/linux/v6.5/source/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c#L198 Cc: stable@vger.kernel.org Fixes: aa984f1ba4a4 ("iio: cros_ec: Register to cros_ec_sensorhub when EC supports FIFO") Signed-off-by: Tzung-Bi Shih Reviewed-by: Guenter Roeck Reviewed-by: Stephen Boyd Link: https://lore.kernel.org/r/20230829030622.1571852-1-tzungbi@kernel.org Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c +++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c @@ -190,8 +190,11 @@ int cros_ec_sensors_push_data(struct iio /* * Ignore samples if the buffer is not set: it is needed if the ODR is * set but the buffer is not enabled yet. + * + * Note: iio_device_claim_buffer_mode() returns -EBUSY if the buffer + * is not enabled. */ - if (!iio_buffer_enabled(indio_dev)) + if (iio_device_claim_buffer_mode(indio_dev) < 0) return 0; out = (s16 *)st->samples; @@ -210,6 +213,7 @@ int cros_ec_sensors_push_data(struct iio iio_push_to_buffers_with_timestamp(indio_dev, st->samples, timestamp + delta); + iio_device_release_buffer_mode(indio_dev); return 0; } EXPORT_SYMBOL_GPL(cros_ec_sensors_push_data);