From 54246b9034da08087ceb2083478c0d13403e12b4 Mon Sep 17 00:00:00 2001 From: Matti Vaittinen Date: Mon, 3 Oct 2022 11:11:33 +0300 Subject: iio: at91-sama5d2_adc: Fix unsafe buffer attributes The iio_triggered_buffer_setup_ext() was changed by commit 15097c7a1adc ("iio: buffer: wrap all buffer attributes into iio_dev_attr") to silently expect that all attributes given in buffer_attrs array are device-attributes. This expectation was not forced by the API - and some drivers did register attributes created by IIO_CONST_ATTR(). The added attribute "wrapping" does not copy the pointer to stored string constant and when the sysfs file is read the kernel will access to invalid location. Change the IIO_CONST_ATTRs from the driver to IIO_DEVICE_ATTR in order to prevent the invalid memory access. Signed-off-by: Matti Vaittinen Fixes: 15097c7a1adc ("iio: buffer: wrap all buffer attributes into iio_dev_attr") Tested-by: Claudiu Beznea Link: https://lore.kernel.org/r/be69775aa302159f088b8b91894e6ec449bca65b.1664782676.git.mazziesaccount@gmail.com Signed-off-by: Jonathan Cameron --- drivers/iio/adc/at91-sama5d2_adc.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) (limited to 'drivers/iio/adc') diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c index 4294d6539cdb..33e251552214 100644 --- a/drivers/iio/adc/at91-sama5d2_adc.c +++ b/drivers/iio/adc/at91-sama5d2_adc.c @@ -2193,17 +2193,30 @@ static ssize_t at91_adc_get_watermark(struct device *dev, return scnprintf(buf, PAGE_SIZE, "%d\n", st->dma_st.watermark); } +static ssize_t hwfifo_watermark_min_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%s\n", "2"); +} + +static ssize_t hwfifo_watermark_max_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%s\n", AT91_HWFIFO_MAX_SIZE_STR); +} + static IIO_DEVICE_ATTR(hwfifo_enabled, 0444, at91_adc_get_fifo_state, NULL, 0); static IIO_DEVICE_ATTR(hwfifo_watermark, 0444, at91_adc_get_watermark, NULL, 0); - -static IIO_CONST_ATTR(hwfifo_watermark_min, "2"); -static IIO_CONST_ATTR(hwfifo_watermark_max, AT91_HWFIFO_MAX_SIZE_STR); +static IIO_DEVICE_ATTR_RO(hwfifo_watermark_min, 0); +static IIO_DEVICE_ATTR_RO(hwfifo_watermark_max, 0); static const struct attribute *at91_adc_fifo_attributes[] = { - &iio_const_attr_hwfifo_watermark_min.dev_attr.attr, - &iio_const_attr_hwfifo_watermark_max.dev_attr.attr, + &iio_dev_attr_hwfifo_watermark_min.dev_attr.attr, + &iio_dev_attr_hwfifo_watermark_max.dev_attr.attr, &iio_dev_attr_hwfifo_watermark.dev_attr.attr, &iio_dev_attr_hwfifo_enabled.dev_attr.attr, NULL, -- cgit v1.2.3