| From 21bb2bbe58a4872910b61a2e50408d77752eb97c Mon Sep 17 00:00:00 2001 |
| From: Jonathan Cameron <Jonathan.Cameron@huawei.com> |
| Date: Sun, 17 May 2020 18:29:56 +0100 |
| Subject: [PATCH] iio:health:afe4403 Fix timestamp alignment and prevent data |
| leak. |
| |
| commit 3f9c6d38797e9903937b007a341dad0c251765d6 upstream. |
| |
| One of a class of bugs pointed out by Lars in a recent review. |
| iio_push_to_buffers_with_timestamp assumes the buffer used is aligned |
| to the size of the timestamp (8 bytes). This is not guaranteed in |
| this driver which uses a 32 byte array of smaller elements on the stack. |
| As Lars also noted this anti pattern can involve a leak of data to |
| userspace and that indeed can happen here. We close both issues by |
| moving to a suitable structure in the iio_priv() data with alignment |
| explicitly requested. This data is allocated with kzalloc so no |
| data can leak appart from previous readings. |
| |
| Fixes: eec96d1e2d31 ("iio: health: Add driver for the TI AFE4403 heart monitor") |
| Reported-by: Lars-Peter Clausen <lars@metafoo.de> |
| Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> |
| Acked-by: Andrew F. Davis <afd@ti.com> |
| Cc: <Stable@vger.kernel.org> |
| Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/iio/health/afe4403.c b/drivers/iio/health/afe4403.c |
| index e9f87e42ff4f..a3507624b30f 100644 |
| --- a/drivers/iio/health/afe4403.c |
| +++ b/drivers/iio/health/afe4403.c |
| @@ -65,6 +65,7 @@ static const struct reg_field afe4403_reg_fields[] = { |
| * @regulator: Pointer to the regulator for the IC |
| * @trig: IIO trigger for this device |
| * @irq: ADC_RDY line interrupt number |
| + * @buffer: Used to construct data layout to push into IIO buffer. |
| */ |
| struct afe4403_data { |
| struct device *dev; |
| @@ -74,6 +75,8 @@ struct afe4403_data { |
| struct regulator *regulator; |
| struct iio_trigger *trig; |
| int irq; |
| + /* Ensure suitable alignment for timestamp */ |
| + s32 buffer[8] __aligned(8); |
| }; |
| |
| enum afe4403_chan_id { |
| @@ -309,7 +312,6 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private) |
| struct iio_dev *indio_dev = pf->indio_dev; |
| struct afe4403_data *afe = iio_priv(indio_dev); |
| int ret, bit, i = 0; |
| - s32 buffer[8]; |
| u8 tx[4] = {AFE440X_CONTROL0, 0x0, 0x0, AFE440X_CONTROL0_READ}; |
| u8 rx[3]; |
| |
| @@ -326,7 +328,7 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private) |
| if (ret) |
| goto err; |
| |
| - buffer[i++] = get_unaligned_be24(&rx[0]); |
| + afe->buffer[i++] = get_unaligned_be24(&rx[0]); |
| } |
| |
| /* Disable reading from the device */ |
| @@ -335,7 +337,8 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private) |
| if (ret) |
| goto err; |
| |
| - iio_push_to_buffers_with_timestamp(indio_dev, buffer, pf->timestamp); |
| + iio_push_to_buffers_with_timestamp(indio_dev, afe->buffer, |
| + pf->timestamp); |
| err: |
| iio_trigger_notify_done(indio_dev->trig); |
| |
| -- |
| 2.27.0 |
| |