iio: Fix unsafe buffer attributes

PATCH Superseded Matti Vaittinen 2 participants 5 messages Oct 1, 2022 – Oct 2, 2022

Subsystems (7)

IIO Arm/Microchip (AT91) SoC support Analog Devices IIO drivers ChromeOS EC subdrivers +3 more subsystems

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Matti Vaittinen

author

2022-10-01 07:43 UTC #0 lore raw

v2 cover iio: Fix unsafe buffer attributes

IIO The iio_triggered_buffer_setup_ext() has been changed to expect that all attributes given in buffer_attrs array are device-attributes. This expectation has not been forced by the API and not all existing users were checked. Some drivers do 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 address.

This series aims to address both the drivers using IIO_CONST_ATTR() and the API. Use of IIO_CONST_ATTR() has been dropped from drivers for the triggered buffers and the iio_triggered_buffer_setup_ext() is changed to take an array of pointers to struct iio_dev_attr instead of an array of pointers to struct attribute. This should fix the existing users and also prevent similar problem to occur in the future.

I am not super happy about the new macro IIO_STATIC_CONST_DEVICE_ATTR() which unconditionally creates a static function and a static struct iio_dev_attr. OTOH, I do believe static function + static struct iio_dev_attr should be the right thing to do for majority of use cases.

I did also change the struct iio_buffer to have array of pointers to iio_dev_attr in order to avoid yet another copying in side the iio_triggered_buffer_setup_ext(). This change appeared to be somewhat intrusive - and as I lack the hardware to do thorough testing I added the request for testing tag here. Especially testing of adi-axi-adc would be highly appreciated as it is using the industrialio-buffer-dmaengine.

Changelog v2:
- fix also the cros_ec_sensors_core.c
- fix also the industrialio-buffer-dmaengine.c
- add RFT + this cover-letter.

Matti Vaittinen (2):
iio: Add IIO_STATIC_CONST_DEVICE_ATTR
iio: Fix unsafe buffer attributes

 drivers/iio/accel/adxl367.c                    | 16 ++++++++--------
 drivers/iio/accel/adxl372.c                    | 16 ++++++++--------
 drivers/iio/accel/bmc150-accel-core.c          | 18 +++++++++---------
 drivers/iio/adc/at91-sama5d2_adc.c             | 16 ++++++++--------
 .../iio/buffer/industrialio-buffer-dmaengine.c |  4 ++--
 .../iio/buffer/industrialio-triggered-buffer.c |  4 ++--
 drivers/iio/buffer/kfifo_buf.c                 |  2 +-
 .../cros_ec_sensors/cros_ec_sensors_core.c     |  6 +++---
 .../common/hid-sensors/hid-sensor-trigger.c    |  8 ++++----
 drivers/iio/industrialio-buffer.c              | 11 +++++++----
 include/linux/iio/buffer_impl.h                |  2 +-
 include/linux/iio/kfifo_buf.h                  |  3 ++-
 include/linux/iio/sysfs.h                      | 11 +++++++++++
 include/linux/iio/triggered_buffer.h           |  6 +++---
 14 files changed, 69 insertions(+), 54 deletions(-)

base-commit: f76349cf41451c5c42a99f18a9163377e4b364ff

Signature · 14 lines

2.37.3


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]

Matti Vaittinen

author

2022-10-01 07:44 UTC #1 lore raw

PATCH v2 1/2 iio: Add IIO_STATIC_CONST_DEVICE_ATTR

Add IIO_STATIC_CONST_DEVICE_ATTR macro for creating an read-only iio_dev_attr which returns constant value. This macro is intended to be used when replacing the IIO_CONST_ATTR - attributes for triggered buffers because the triggered buffer attributes must be of type iio_dev_attr.

Signed-off-by Matti Vaittinen <[email protected]>

---
 include/linux/iio/sysfs.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

include/linux/iio/sysfs.h +11 -0

index e51fba66de4b..de5bb125815c 100644
@@ -97,6 +97,17 @@ struct iio_const_attr {
 	= { .string = _string,						\
 	    .dev_attr = __ATTR(_name, S_IRUGO, iio_read_const_attr, NULL)}
 
+#define IIO_STATIC_CONST_DEVICE_ATTR(_name, _string)				\
+	static ssize_t iio_const_dev_attr_show_##_name(			\
+					struct device *dev,		\
+					struct device_attribute *attr,	\
+					char *buf)			\
+	{								\
+		return sysfs_emit(buf, "%s\n", _string);		\
+	}								\
+	static IIO_DEVICE_ATTR(_name, 0444,				\
+			       iio_const_dev_attr_show_##_name, NULL, 0)
+
 /* Generic attributes of onetype or another */
 
 /**

Signature · 14 lines

2.37.3


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]

Matti Vaittinen

author

2022-10-01 07:44 UTC #2 lore raw

PATCH v2 2/2 iio: Fix unsafe buffer attributes

In reply to Matti Vaittinen

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.

Signed-off-by Matti Vaittinen <[email protected]>

Fixes 15097c7a1adc ("iio: buffer: wrap all buffer attributes into iio_dev_attr")

---

v1 => v2:
fix also industrialio-buffer-dmaengine.c and cros_ec_sensors_core.c

The fix is only superficially tested by a ROHM/kionix KX022A driver. Proper testing with real in-tree IIO stuff is _highly_ appreciated.

---
 drivers/iio/accel/adxl367.c                    | 16 ++++++++--------
 drivers/iio/accel/adxl372.c                    | 16 ++++++++--------
 drivers/iio/accel/bmc150-accel-core.c          | 18 +++++++++---------
 drivers/iio/adc/at91-sama5d2_adc.c             | 16 ++++++++--------
 .../iio/buffer/industrialio-buffer-dmaengine.c |  4 ++--
 .../iio/buffer/industrialio-triggered-buffer.c |  4 ++--
 drivers/iio/buffer/kfifo_buf.c                 |  2 +-
 .../cros_ec_sensors/cros_ec_sensors_core.c     |  6 +++---
 .../common/hid-sensors/hid-sensor-trigger.c    |  8 ++++----
 drivers/iio/industrialio-buffer.c              | 11 +++++++----
 include/linux/iio/buffer_impl.h                |  2 +-
 include/linux/iio/kfifo_buf.h                  |  3 ++-
 include/linux/iio/triggered_buffer.h           |  6 +++---
 13 files changed, 58 insertions(+), 54 deletions(-)

drivers/iio/accel/adxl367.c +8 -8

index 47feb375b70b..0922ac0fad9e 100644
@@ -1185,19 +1185,19 @@ static ssize_t adxl367_get_fifo_watermark(struct device *dev,
 	return sysfs_emit(buf, "%d\n", fifo_watermark);
 }
 
-static IIO_CONST_ATTR(hwfifo_watermark_min, "1");
-static IIO_CONST_ATTR(hwfifo_watermark_max,
-		      __stringify(ADXL367_FIFO_MAX_WATERMARK));
+IIO_STATIC_CONST_DEVICE_ATTR(hwfifo_watermark_min, "1");
+IIO_STATIC_CONST_DEVICE_ATTR(hwfifo_watermark_max,
+			     __stringify(ADXL367_FIFO_MAX_WATERMARK));
 static IIO_DEVICE_ATTR(hwfifo_watermark, 0444,
 		       adxl367_get_fifo_watermark, NULL, 0);
 static IIO_DEVICE_ATTR(hwfifo_enabled, 0444,
 		       adxl367_get_fifo_enabled, NULL, 0);
 
-static const struct attribute *adxl367_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.dev_attr.attr,
-	&iio_dev_attr_hwfifo_enabled.dev_attr.attr,
+static const struct iio_dev_attr *adxl367_fifo_attributes[] = {
+	&iio_dev_attr_hwfifo_watermark_min,
+	&iio_dev_attr_hwfifo_watermark_max,
+	&iio_dev_attr_hwfifo_watermark,
+	&iio_dev_attr_hwfifo_enabled,
 	NULL,
 };

drivers/iio/accel/adxl372.c +8 -8

index e3ecbaee61f7..c4193286eb05 100644
@@ -998,19 +998,19 @@ static ssize_t adxl372_get_fifo_watermark(struct device *dev,
 	return sprintf(buf, "%d\n", st->watermark);
 }
 
-static IIO_CONST_ATTR(hwfifo_watermark_min, "1");
-static IIO_CONST_ATTR(hwfifo_watermark_max,
-		      __stringify(ADXL372_FIFO_SIZE));
+IIO_STATIC_CONST_DEVICE_ATTR(hwfifo_watermark_min, "1");
+IIO_STATIC_CONST_DEVICE_ATTR(hwfifo_watermark_max,
+			     __stringify(ADXL372_FIFO_SIZE));
 static IIO_DEVICE_ATTR(hwfifo_watermark, 0444,
 		       adxl372_get_fifo_watermark, NULL, 0);
 static IIO_DEVICE_ATTR(hwfifo_enabled, 0444,
 		       adxl372_get_fifo_enabled, NULL, 0);
 
-static const struct attribute *adxl372_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.dev_attr.attr,
-	&iio_dev_attr_hwfifo_enabled.dev_attr.attr,
+static const struct iio_dev_attr *adxl372_fifo_attributes[] = {
+	&iio_dev_attr_hwfifo_watermark_min,
+	&iio_dev_attr_hwfifo_watermark_max,
+	&iio_dev_attr_hwfifo_watermark,
+	&iio_dev_attr_hwfifo_enabled,
 	NULL,
 };

drivers/iio/accel/bmc150-accel-core.c +9 -9

index 57e8a8350cd1..110591804b4c 100644
@@ -925,19 +925,19 @@ static const struct iio_chan_spec_ext_info bmc150_accel_ext_info[] = {
 	{ }
 };
 
-static IIO_CONST_ATTR(hwfifo_watermark_min, "1");
-static IIO_CONST_ATTR(hwfifo_watermark_max,
-		      __stringify(BMC150_ACCEL_FIFO_LENGTH));
+IIO_STATIC_CONST_DEVICE_ATTR(hwfifo_watermark_min, "1");
+IIO_STATIC_CONST_DEVICE_ATTR(hwfifo_watermark_max,
+			     __stringify(BMC150_ACCEL_FIFO_LENGTH));
 static IIO_DEVICE_ATTR(hwfifo_enabled, S_IRUGO,
 		       bmc150_accel_get_fifo_state, NULL, 0);
 static IIO_DEVICE_ATTR(hwfifo_watermark, S_IRUGO,
 		       bmc150_accel_get_fifo_watermark, NULL, 0);
 
-static const struct attribute *bmc150_accel_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.dev_attr.attr,
-	&iio_dev_attr_hwfifo_enabled.dev_attr.attr,
+static const struct iio_dev_attr *bmc150_accel_fifo_attributes[] = {
+	&iio_dev_attr_hwfifo_watermark_min,
+	&iio_dev_attr_hwfifo_watermark_max,
+	&iio_dev_attr_hwfifo_watermark,
+	&iio_dev_attr_hwfifo_enabled,
 	NULL,
 };

@@ -1665,7 +1665,7 @@ int bmc150_accel_core_probe(struct device *dev, struct regmap *regmap, int irq,
 			    enum bmc150_type type, const char *name,
 			    bool block_supported)
 {
-	const struct attribute **fifo_attrs;
+	const struct iio_dev_attr **fifo_attrs;
 	struct bmc150_accel_data *data;
 	struct iio_dev *indio_dev;
 	int ret;

drivers/iio/adc/at91-sama5d2_adc.c +8 -8

index 279430c1d88c..f994366b0778 100644
@@ -1846,8 +1846,8 @@ static IIO_DEVICE_ATTR(hwfifo_enabled, 0444,
 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);
+IIO_STATIC_CONST_DEVICE_ATTR(hwfifo_watermark_min, "2");
+IIO_STATIC_CONST_DEVICE_ATTR(hwfifo_watermark_max, AT91_HWFIFO_MAX_SIZE_STR);
 
 static IIO_CONST_ATTR(oversampling_ratio_available,
 		      __stringify(AT91_OSR_1SAMPLES) " "

@@ -1863,11 +1863,11 @@ static const struct attribute_group at91_adc_attribute_group = {
 	.attrs = at91_adc_attributes,
 };
 
-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.dev_attr.attr,
-	&iio_dev_attr_hwfifo_enabled.dev_attr.attr,
+static const struct iio_dev_attr *at91_adc_fifo_attributes[] = {
+	&iio_dev_attr_hwfifo_watermark_min,
+	&iio_dev_attr_hwfifo_watermark_max,
+	&iio_dev_attr_hwfifo_watermark,
+	&iio_dev_attr_hwfifo_enabled,
 	NULL,
 };

@@ -1884,7 +1884,7 @@ static int at91_adc_buffer_and_trigger_init(struct device *dev,
 					    struct iio_dev *indio)
 {
 	struct at91_adc_state *st = iio_priv(indio);
-	const struct attribute **fifo_attrs;
+	const struct iio_dev_attr **fifo_attrs;
 	int ret;
 
 	if (st->selected_trig->hw_trig)

drivers/iio/buffer/industrialio-buffer-dmaengine.c +2 -2

index f744b62a636a..5f85ba38e6f6 100644
@@ -142,8 +142,8 @@ static ssize_t iio_dmaengine_buffer_get_length_align(struct device *dev,
 static IIO_DEVICE_ATTR(length_align_bytes, 0444,
 		       iio_dmaengine_buffer_get_length_align, NULL, 0);
 
-static const struct attribute *iio_dmaengine_buffer_attrs[] = {
-	&iio_dev_attr_length_align_bytes.dev_attr.attr,
+static const struct iio_dev_attr *iio_dmaengine_buffer_attrs[] = {
+	&iio_dev_attr_length_align_bytes,
 	NULL,
 };

drivers/iio/buffer/industrialio-triggered-buffer.c +2 -2

index 8d4fc97d1005..c7671b1f5ead 100644
@@ -41,7 +41,7 @@ int iio_triggered_buffer_setup_ext(struct iio_dev *indio_dev,
 	irqreturn_t (*thread)(int irq, void *p),
 	enum iio_buffer_direction direction,
 	const struct iio_buffer_setup_ops *setup_ops,
-	const struct attribute **buffer_attrs)
+	const struct iio_dev_attr **buffer_attrs)
 {
 	struct iio_buffer *buffer;
 	int ret;

@@ -110,7 +110,7 @@ int devm_iio_triggered_buffer_setup_ext(struct device *dev,
 					irqreturn_t (*thread)(int irq, void *p),
 					enum iio_buffer_direction direction,
 					const struct iio_buffer_setup_ops *ops,
-					const struct attribute **buffer_attrs)
+					const struct iio_dev_attr **buffer_attrs)
 {
 	int ret;

drivers/iio/buffer/kfifo_buf.c +1 -1

index 35d8b4077376..05b285f0eb22 100644
@@ -270,7 +270,7 @@ static struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
 int devm_iio_kfifo_buffer_setup_ext(struct device *dev,
 				    struct iio_dev *indio_dev,
 				    const struct iio_buffer_setup_ops *setup_ops,
-				    const struct attribute **buffer_attrs)
+				    const struct iio_dev_attr **buffer_attrs)
 {
 	struct iio_buffer *buffer;

drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c +3 -3

index 05a28d353e34..943e9e14d1e9 100644
@@ -172,9 +172,9 @@ static ssize_t hwfifo_watermark_max_show(struct device *dev,
 
 static IIO_DEVICE_ATTR_RO(hwfifo_watermark_max, 0);
 
-static const struct attribute *cros_ec_sensor_fifo_attributes[] = {
-	&iio_dev_attr_hwfifo_timeout.dev_attr.attr,
-	&iio_dev_attr_hwfifo_watermark_max.dev_attr.attr,
+static const struct iio_dev_attr *cros_ec_sensor_fifo_attributes[] = {
+	&iio_dev_attr_hwfifo_timeout,
+	&iio_dev_attr_hwfifo_watermark_max,
 	NULL,
 };

drivers/iio/common/hid-sensors/hid-sensor-trigger.c +4 -4

index 1151434038d4..ad8910e6ad59 100644
@@ -75,9 +75,9 @@ static IIO_DEVICE_ATTR(hwfifo_timeout, 0644,
 static IIO_DEVICE_ATTR(hwfifo_enabled, 0444,
 		       _hid_sensor_get_fifo_state, NULL, 0);
 
-static const struct attribute *hid_sensor_fifo_attributes[] = {
-	&iio_dev_attr_hwfifo_timeout.dev_attr.attr,
-	&iio_dev_attr_hwfifo_enabled.dev_attr.attr,
+static const struct iio_dev_attr *hid_sensor_fifo_attributes[] = {
+	&iio_dev_attr_hwfifo_timeout,
+	&iio_dev_attr_hwfifo_enabled,
 	NULL,
 };

@@ -231,7 +231,7 @@ static const struct iio_trigger_ops hid_sensor_trigger_ops = {
 int hid_sensor_setup_trigger(struct iio_dev *indio_dev, const char *name,
 				struct hid_sensor_common *attrb)
 {
-	const struct attribute **fifo_attrs;
+	const struct iio_dev_attr **fifo_attrs;
 	int ret;
 	struct iio_trigger *trig;

drivers/iio/industrialio-buffer.c +7 -4

index acc2b6c05d57..cc7ebafae571 100644
@@ -1599,6 +1599,7 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
 {
 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 	struct iio_dev_attr *p;
+	const struct iio_dev_attr *id_attr;
 	struct attribute **attr;
 	int ret, i, attrn, scan_el_attrcount, buffer_attrcount;
 	const struct iio_chan_spec *channels;

@@ -1608,6 +1609,7 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
 		while (buffer->attrs[buffer_attrcount] != NULL)
 			buffer_attrcount++;
 	}
+	buffer_attrcount += ARRAY_SIZE(iio_buffer_attrs);
 
 	scan_el_attrcount = 0;
 	INIT_LIST_HEAD(&buffer->buffer_attr_list);

@@ -1650,7 +1652,7 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
 		}
 	}
 
-	attrn = buffer_attrcount + scan_el_attrcount + ARRAY_SIZE(iio_buffer_attrs);
+	attrn = buffer_attrcount + scan_el_attrcount;
 	attr = kcalloc(attrn + 1, sizeof(*attr), GFP_KERNEL);
 	if (!attr) {
 		ret = -ENOMEM;

@@ -1665,10 +1667,11 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
 		attr[2] = &dev_attr_watermark_ro.attr;
 
 	if (buffer->attrs)
-		memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
-		       sizeof(struct attribute *) * buffer_attrcount);
+		for (i = 0, id_attr = buffer->attrs[i];
+		     (id_attr = buffer->attrs[i]); i++)
+			attr[ARRAY_SIZE(iio_buffer_attrs) + i] =
+				(struct attribute *)&id_attr->dev_attr.attr;
 
-	buffer_attrcount += ARRAY_SIZE(iio_buffer_attrs);
 	buffer->buffer_group.attrs = attr;
 
 	for (i = 0; i < buffer_attrcount; i++) {

include/linux/iio/buffer_impl.h +1 -1

index e2ca8ea23e19..89c3fd7c29ca 100644
@@ -123,7 +123,7 @@ struct iio_buffer {
 	struct attribute_group buffer_group;
 
 	/* @attrs: Standard attributes of the buffer. */
-	const struct attribute **attrs;
+	const struct iio_dev_attr **attrs;
 
 	/* @demux_bounce: Buffer for doing gather from incoming scan. */
 	void *demux_bounce;

include/linux/iio/kfifo_buf.h +2 -1

index 8a83fb58232d..22874da0c8be 100644
@@ -5,6 +5,7 @@
 struct iio_buffer;
 struct iio_buffer_setup_ops;
 struct iio_dev;
+struct iio_dev_attr;
 struct device;
 
 struct iio_buffer *iio_kfifo_allocate(void);

@@ -13,7 +14,7 @@ void iio_kfifo_free(struct iio_buffer *r);
 int devm_iio_kfifo_buffer_setup_ext(struct device *dev,
 				    struct iio_dev *indio_dev,
 				    const struct iio_buffer_setup_ops *setup_ops,
-				    const struct attribute **buffer_attrs);
+				    const struct iio_dev_attr **buffer_attrs);
 
 #define devm_iio_kfifo_buffer_setup(dev, indio_dev, setup_ops)	\
 	devm_iio_kfifo_buffer_setup_ext((dev), (indio_dev), (setup_ops), NULL)

include/linux/iio/triggered_buffer.h +3 -3

index 7490b05fc5b2..29e1fe146879 100644
@@ -5,8 +5,8 @@
 #include <linux/iio/buffer.h>
 #include <linux/interrupt.h>
 
-struct attribute;
 struct iio_dev;
+struct iio_dev_attr;
 struct iio_buffer_setup_ops;
 
 int iio_triggered_buffer_setup_ext(struct iio_dev *indio_dev,

@@ -14,7 +14,7 @@ int iio_triggered_buffer_setup_ext(struct iio_dev *indio_dev,
 	irqreturn_t (*thread)(int irq, void *p),
 	enum iio_buffer_direction direction,
 	const struct iio_buffer_setup_ops *setup_ops,
-	const struct attribute **buffer_attrs);
+	const struct iio_dev_attr **buffer_attrs);
 void iio_triggered_buffer_cleanup(struct iio_dev *indio_dev);
 
 #define iio_triggered_buffer_setup(indio_dev, h, thread, setup_ops)		\

@@ -28,7 +28,7 @@ int devm_iio_triggered_buffer_setup_ext(struct device *dev,
 					irqreturn_t (*thread)(int irq, void *p),
 					enum iio_buffer_direction direction,
 					const struct iio_buffer_setup_ops *ops,
-					const struct attribute **buffer_attrs);
+					const struct iio_dev_attr **buffer_attrs);
 
 #define devm_iio_triggered_buffer_setup(dev, indio_dev, h, thread, setup_ops)	\
 	devm_iio_triggered_buffer_setup_ext((dev), (indio_dev), (h), (thread),	\

Signature · 14 lines

2.37.3


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]

Jonathan Cameron

maintainer

2022-10-02 13:56 UTC #3 lore raw

Quoted 6 lines · On Sat, 1 Oct 2022 10:44:23 +0300 Matti Vaittinen <[email protected]>…

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().

Quoted 6 lines

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.
Signed-off-by Matti Vaittinen <[email protected]>
Fixes 15097c7a1adc ("iio: buffer: wrap all buffer attributes into iio_dev_attr")

Hi Matti,

This feels like we are doing too much in one go.
I would start with fixes for each individual driver, then once those are in we come around again and do the refactor.

So for the first patch set (one per driver) just siwtch to yor new dev_attr but still use a struct attribute * array.
Second series then does the refactor so we don't introduce any new instances in future. More churn but the code to backport is more tightly confined.

Thanks,

Jonathan

Quoted 8 lines

---
v1 => v2:
fix also industrialio-buffer-dmaengine.c and cros_ec_sensors_core.c
The fix is only superficially tested by a ROHM/kionix KX022A driver. Proper testing with real in-tree IIO stuff is _highly_ appreciated.

Matti Vaittinen

author

2022-10-02 14:25 UTC #4 lore raw

Quoted 18 lines · Jonathan Cameron

Quoted 6 lines · On Sat, 1 Oct 2022 10:44:23 +0300 Matti Vaittinen <[email protected]>…
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().
Quoted 6 lines
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.
Signed-off-by Matti Vaittinen <[email protected]>
Fixes 15097c7a1adc ("iio: buffer: wrap all buffer attributes into iio_dev_attr")
Hi Matti,

Quoted 8 lines

This feels like we are doing too much in one go.
I would start with fixes for each individual driver, then once those are in we come around again and do the refactor.
So for the first patch set (one per driver) just siwtch to yor new dev_attr but still use a struct attribute * array.
Second series then does the refactor so we don't introduce any new instances in future. More churn but the code to backport is more tightly confined.

Agreed. Besides, backporting the fix to stable will be much easier that way. I'll split this for v3. Thanks for the input!

Yours,

	--Matti

Signature · 5 lines

Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

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