iio:health:afe4403 Fix timestamp alignment and prevent data leak. (3f9c6d38) · Commits · 戴 / test

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: ("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>

drivers/iio/health/afe4403.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -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);

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