From: Tzung-Bi Shih <tzungbi@kernel.org>
To: bleung@chromium.org, groeck@chromium.org, jic23@kernel.org,
lars@metafoo.de
Cc: chrome-platform@lists.linux.dev, tzungbi@kernel.org,
gwendal@chromium.org, linux-iio@vger.kernel.org,
dianders@chromium.org, swboyd@chromium.org,
stable@vger.kernel.org
Subject: [PATCH v2] iio: cros_ec: fix an use-after-free in cros_ec_sensors_push_data()
Date: Tue, 29 Aug 2023 11:06:22 +0800 [thread overview]
Message-ID: <20230829030622.1571852-1-tzungbi@kernel.org> (raw)
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 <tzungbi@kernel.org>
---
Changes from v1(https://patchwork.kernel.org/project/linux-iio/patch/20230828094339.1248472-1-tzungbi@kernel.org/):
- Use iio_device_{claim|release}_buffer_mode() instead of accessing `mlock`.
drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
index b72d39fc2434..6bfe5d6847e7 100644
--- 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_dev *indio_dev,
/*
* 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_dev *indio_dev,
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);
--
2.42.0.rc2.253.gd59a3bf2b4-goog
next reply other threads:[~2023-08-29 3:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-29 3:06 Tzung-Bi Shih [this message]
2023-08-29 20:47 ` [PATCH v2] iio: cros_ec: fix an use-after-free in cros_ec_sensors_push_data() Stephen Boyd
2023-08-29 20:50 ` Guenter Roeck
2023-09-03 11:34 ` Jonathan Cameron
2023-11-13 3:23 ` patchwork-bot+chrome-platform
2023-11-13 3:42 ` patchwork-bot+chrome-platform
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230829030622.1571852-1-tzungbi@kernel.org \
--to=tzungbi@kernel.org \
--cc=bleung@chromium.org \
--cc=chrome-platform@lists.linux.dev \
--cc=dianders@chromium.org \
--cc=groeck@chromium.org \
--cc=gwendal@chromium.org \
--cc=jic23@kernel.org \
--cc=lars@metafoo.de \
--cc=linux-iio@vger.kernel.org \
--cc=stable@vger.kernel.org \
--cc=swboyd@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).