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iio:health:afe4403 Fix timestamp alignment and prevent data leak.
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: eec96d1e2d
("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>
This commit is contained in:
parent
b791d1bdf9
commit
3f9c6d3879
1 changed files with 6 additions and 3 deletions
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@ -65,6 +65,7 @@ static const struct reg_field afe4403_reg_fields[] = {
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* @regulator: Pointer to the regulator for the IC
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* @trig: IIO trigger for this device
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* @irq: ADC_RDY line interrupt number
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* @buffer: Used to construct data layout to push into IIO buffer.
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*/
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struct afe4403_data {
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struct device *dev;
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@ -74,6 +75,8 @@ struct afe4403_data {
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struct regulator *regulator;
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struct iio_trigger *trig;
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int irq;
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/* Ensure suitable alignment for timestamp */
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s32 buffer[8] __aligned(8);
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};
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enum afe4403_chan_id {
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@ -309,7 +312,6 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private)
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struct iio_dev *indio_dev = pf->indio_dev;
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struct afe4403_data *afe = iio_priv(indio_dev);
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int ret, bit, i = 0;
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s32 buffer[8];
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u8 tx[4] = {AFE440X_CONTROL0, 0x0, 0x0, AFE440X_CONTROL0_READ};
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u8 rx[3];
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@ -326,7 +328,7 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private)
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if (ret)
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goto err;
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buffer[i++] = get_unaligned_be24(&rx[0]);
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afe->buffer[i++] = get_unaligned_be24(&rx[0]);
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}
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/* Disable reading from the device */
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@ -335,7 +337,8 @@ static irqreturn_t afe4403_trigger_handler(int irq, void *private)
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if (ret)
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goto err;
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iio_push_to_buffers_with_timestamp(indio_dev, buffer, pf->timestamp);
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iio_push_to_buffers_with_timestamp(indio_dev, afe->buffer,
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pf->timestamp);
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err:
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iio_trigger_notify_done(indio_dev->trig);
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