Add to the V4L2 framework helper functions to support drivers when
validating a buffer of V4L2 ISP parameters.
Driver shall use v4l2_isp_params_validate_buffer_size() to verify the
size correctness of the data received from userspace, and after having
copied the data to a kernel-only memory location, complete the
validation by calling v4l2_isp_params_validate_buffer().
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Michael Riesch <michael.riesch@collabora.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
---
MAINTAINERS | 2 +
drivers/media/v4l2-core/Kconfig | 4 ++
drivers/media/v4l2-core/Makefile | 1 +
drivers/media/v4l2-core/v4l2-isp.c | 128 +++++++++++++++++++++++++++++++++++++
include/media/v4l2-isp.h | 91 ++++++++++++++++++++++++++
5 files changed, 226 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index f52237d57710cadff78b297d2b4610b508f55092..5833f82caa7f2f734bb0e1be144ade2109b23988 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -26857,6 +26857,8 @@ M: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
L: linux-media@vger.kernel.org
S: Maintained
F: Documentation/userspace-api/media/v4l/v4l2-isp.rst
+F: drivers/media/v4l2-core/v4l2-isp.c
+F: include/media/v4l2-isp.h
F: include/uapi/linux/media/v4l2-isp.h
VF610 NAND DRIVER
diff --git a/drivers/media/v4l2-core/Kconfig b/drivers/media/v4l2-core/Kconfig
index 331b8e535e5bbf33f22638b2ae8bc764ad5fc407..d50ccac9733cc39a43426ae7e7996dd0b5b45186 100644
--- a/drivers/media/v4l2-core/Kconfig
+++ b/drivers/media/v4l2-core/Kconfig
@@ -82,3 +82,7 @@ config V4L2_CCI_I2C
depends on I2C
select REGMAP_I2C
select V4L2_CCI
+
+config V4L2_ISP
+ tristate
+ depends on VIDEOBUF2_CORE
diff --git a/drivers/media/v4l2-core/Makefile b/drivers/media/v4l2-core/Makefile
index 2177b9d63a8ffc1127c5a70118249a2ff63cd759..329f0eadce994cc1c8580beb435f68fa7e2a7aeb 100644
--- a/drivers/media/v4l2-core/Makefile
+++ b/drivers/media/v4l2-core/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_V4L2_CCI) += v4l2-cci.o
obj-$(CONFIG_V4L2_FLASH_LED_CLASS) += v4l2-flash-led-class.o
obj-$(CONFIG_V4L2_FWNODE) += v4l2-fwnode.o
obj-$(CONFIG_V4L2_H264) += v4l2-h264.o
+obj-$(CONFIG_V4L2_ISP) += v4l2-isp.o
obj-$(CONFIG_V4L2_JPEG_HELPER) += v4l2-jpeg.o
obj-$(CONFIG_V4L2_MEM2MEM_DEV) += v4l2-mem2mem.o
obj-$(CONFIG_V4L2_VP9) += v4l2-vp9.o
diff --git a/drivers/media/v4l2-core/v4l2-isp.c b/drivers/media/v4l2-core/v4l2-isp.c
new file mode 100644
index 0000000000000000000000000000000000000000..35f0b701f1729c3c0ccc34b1c89189b179e0b684
--- /dev/null
+++ b/drivers/media/v4l2-core/v4l2-isp.c
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Video4Linux2 generic ISP parameters and statistics support
+ *
+ * Copyright (C) 2025 Ideas On Board Oy
+ * Author: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
+ */
+
+#include <media/v4l2-isp.h>
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+
+#include <media/videobuf2-core.h>
+
+int v4l2_isp_params_validate_buffer_size(struct device *dev,
+ struct vb2_buffer *vb,
+ size_t max_size)
+{
+ size_t header_size = offsetof(struct v4l2_isp_params_buffer, data);
+ size_t payload_size = vb2_get_plane_payload(vb, 0);
+
+ /* Payload size can't be greater than the destination buffer size */
+ if (payload_size > max_size) {
+ dev_dbg(dev, "Payload size is too large: %zu\n", payload_size);
+ return -EINVAL;
+ }
+
+ /* Payload size can't be smaller than the header size */
+ if (payload_size < header_size) {
+ dev_dbg(dev, "Payload size is too small: %zu\n", payload_size);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_isp_params_validate_buffer_size);
+
+int v4l2_isp_params_validate_buffer(struct device *dev, struct vb2_buffer *vb,
+ const struct v4l2_isp_params_buffer *buffer,
+ const struct v4l2_isp_params_block_info *info,
+ size_t num_blocks)
+{
+ size_t header_size = offsetof(struct v4l2_isp_params_buffer, data);
+ size_t payload_size = vb2_get_plane_payload(vb, 0);
+ size_t block_offset = 0;
+ size_t buffer_size;
+
+ /*
+ * Currently only the first version of the V4L2 ISP parameters format is
+ * supported. We accept both V0 and V1 to support existing drivers
+ * compatible with V4L2 ISP that use either 0 or 1 as their "first
+ * version" identifiers.
+ */
+ if (buffer->version != V4L2_ISP_PARAMS_VERSION_V0 &&
+ buffer->version != V4L2_ISP_PARAMS_VERSION_V1) {
+ dev_dbg(dev,
+ "Unsupported V4L2 ISP parameters format version: %u\n",
+ buffer->version);
+ return -EINVAL;
+ }
+
+ /* Validate the size reported in the header */
+ buffer_size = header_size + buffer->data_size;
+ if (buffer_size != payload_size) {
+ dev_dbg(dev, "Data size %zu and payload size %zu are different\n",
+ buffer_size, payload_size);
+ return -EINVAL;
+ }
+
+ /* Walk the list of ISP configuration blocks and validate them. */
+ buffer_size = buffer->data_size;
+ while (buffer_size >= sizeof(struct v4l2_isp_params_block_header)) {
+ const struct v4l2_isp_params_block_info *block_info;
+ const struct v4l2_isp_params_block_header *block;
+
+ block = (const struct v4l2_isp_params_block_header *)
+ (buffer->data + block_offset);
+
+ if (block->type >= num_blocks) {
+ dev_dbg(dev,
+ "Invalid block type %u at offset %zu\n",
+ block->type, block_offset);
+ return -EINVAL;
+ }
+
+ if (block->size > buffer_size) {
+ dev_dbg(dev, "Premature end of parameters data\n");
+ return -EINVAL;
+ }
+
+ /* It's invalid to specify both ENABLE and DISABLE. */
+ if ((block->flags & (V4L2_ISP_PARAMS_FL_BLOCK_ENABLE |
+ V4L2_ISP_PARAMS_FL_BLOCK_DISABLE)) ==
+ (V4L2_ISP_PARAMS_FL_BLOCK_ENABLE |
+ V4L2_ISP_PARAMS_FL_BLOCK_DISABLE)) {
+ dev_dbg(dev, "Invalid block flags %x at offset %zu\n",
+ block->flags, block_offset);
+ return -EINVAL;
+ }
+
+ /*
+ * Match the block reported size against the info provided
+ * one, but allow the block to only contain the header in
+ * case it is going to be disabled.
+ */
+ block_info = &info[block->type];
+ if (block->size != block_info->size &&
+ (!(block->flags & V4L2_ISP_PARAMS_FL_BLOCK_DISABLE) ||
+ block->size != sizeof(*block))) {
+ dev_dbg(dev,
+ "Invalid block size %u (expected %zu) at offset %zu\n",
+ block->size, block_info->size, block_offset);
+ return -EINVAL;
+ }
+
+ block_offset += block->size;
+ buffer_size -= block->size;
+ }
+
+ if (buffer_size) {
+ dev_dbg(dev, "Unexpected data after the parameters buffer end\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_isp_params_validate_buffer);
diff --git a/include/media/v4l2-isp.h b/include/media/v4l2-isp.h
new file mode 100644
index 0000000000000000000000000000000000000000..8b4695663699e7f176384739cf54ed7fa2c578f8
--- /dev/null
+++ b/include/media/v4l2-isp.h
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Video4Linux2 generic ISP parameters and statistics support
+ *
+ * Copyright (C) 2025 Ideas On Board Oy
+ * Author: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
+ */
+
+#ifndef _V4L2_ISP_H_
+#define _V4L2_ISP_H_
+
+#include <linux/media/v4l2-isp.h>
+
+struct device;
+struct vb2_buffer;
+
+/**
+ * v4l2_isp_params_buffer_size - Calculate size of v4l2_isp_params_buffer
+ * @max_params_size: The total size of the ISP configuration blocks
+ *
+ * Users of the v4l2 extensible parameters will have differing sized data arrays
+ * depending on their specific parameter buffers. Drivers and userspace will
+ * need to be able to calculate the appropriate size of the struct to
+ * accommodate all ISP configuration blocks provided by the platform.
+ * This macro provides a convenient tool for the calculation.
+ */
+#define v4l2_isp_params_buffer_size(max_params_size) \
+ (offsetof(struct v4l2_isp_params_buffer, data) + (max_params_size))
+
+/**
+ * v4l2_isp_params_validate_buffer_size - Validate a V4L2 ISP buffer sizes
+ * @dev: the driver's device pointer
+ * @vb: the videobuf2 buffer
+ * @max_size: the maximum allowed buffer size
+ *
+ * This function performs validation of the size of a V4L2 ISP parameters buffer
+ * before the driver can access the actual data buffer content.
+ *
+ * After the sizes validation, drivers should copy the buffer content to a
+ * kernel-only memory area to prevent userspace from modifying it,
+ * before completing validation using v4l2_isp_params_validate_buffer().
+ *
+ * The @vb buffer as received from the vb2 .buf_prepare() operation is checked
+ * against @max_size and it's validated to be large enough to accommodate at
+ * least one ISP configuration block.
+ */
+int v4l2_isp_params_validate_buffer_size(struct device *dev,
+ struct vb2_buffer *vb,
+ size_t max_size);
+
+/**
+ * struct v4l2_isp_params_block_info - V4L2 ISP per-block info
+ * @size: the block expected size
+ *
+ * The v4l2_isp_params_block_info collects information of the ISP configuration
+ * blocks for validation purposes. It currently only contains the expected
+ * block size.
+ *
+ * Drivers shall prepare a list of block info, indexed by block type, one for
+ * each supported ISP block and correctly populate them with the expected block
+ * size.
+ */
+struct v4l2_isp_params_block_info {
+ size_t size;
+};
+
+/**
+ * v4l2_isp_params_validate_buffer - Validate a V4L2 ISP parameters buffer
+ * @dev: the driver's device pointer
+ * @vb: the videobuf2 buffer
+ * @buffer: the V4L2 ISP parameters buffer
+ * @info: the list of per-block validation info
+ * @num_blocks: the number of blocks
+ *
+ * This function completes the validation of a V4L2 ISP parameters buffer,
+ * verifying each configuration block correctness before the driver can use
+ * them to program the hardware.
+ *
+ * Drivers should use this function after having validated the correctness of
+ * the vb2 buffer sizes by using the v4l2_isp_params_validate_buffer_size()
+ * helper first. Once the buffer size has been validated, drivers should
+ * perform a copy of the user provided buffer into a kernel-only memory buffer
+ * to prevent userspace from modifying its content after it has been submitted
+ * to the driver, and then call this function to complete validation.
+ */
+int v4l2_isp_params_validate_buffer(struct device *dev, struct vb2_buffer *vb,
+ const struct v4l2_isp_params_buffer *buffer,
+ const struct v4l2_isp_params_block_info *info,
+ size_t num_blocks);
+
+#endif /* _V4L2_ISP_H_ */
--
2.51.0
Hi Jacopo
On 10/20/25 10:24 AM, Jacopo Mondi wrote:
>
> Add to the V4L2 framework helper functions to support drivers when
> validating a buffer of V4L2 ISP parameters.
>
> Driver shall use v4l2_isp_params_validate_buffer_size() to verify the
> size correctness of the data received from userspace, and after having
> copied the data to a kernel-only memory location, complete the
> validation by calling v4l2_isp_params_validate_buffer().
>
> Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Reviewed-by: Michael Riesch <michael.riesch@collabora.com>
> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> ---
> MAINTAINERS | 2 +
> drivers/media/v4l2-core/Kconfig | 4 ++
> drivers/media/v4l2-core/Makefile | 1 +
> drivers/media/v4l2-core/v4l2-isp.c | 128 +++++++++++++++++++++++++++++++++++++
> include/media/v4l2-isp.h | 91 ++++++++++++++++++++++++++
> 5 files changed, 226 insertions(+)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index f52237d57710cadff78b297d2b4610b508f55092..5833f82caa7f2f734bb0e1be144ade2109b23988 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -26857,6 +26857,8 @@ M: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> L: linux-media@vger.kernel.org
> S: Maintained
> F: Documentation/userspace-api/media/v4l/v4l2-isp.rst
> +F: drivers/media/v4l2-core/v4l2-isp.c
> +F: include/media/v4l2-isp.h
> F: include/uapi/linux/media/v4l2-isp.h
>
> VF610 NAND DRIVER
> diff --git a/drivers/media/v4l2-core/Kconfig b/drivers/media/v4l2-core/Kconfig
> index 331b8e535e5bbf33f22638b2ae8bc764ad5fc407..d50ccac9733cc39a43426ae7e7996dd0b5b45186 100644
> --- a/drivers/media/v4l2-core/Kconfig
> +++ b/drivers/media/v4l2-core/Kconfig
> @@ -82,3 +82,7 @@ config V4L2_CCI_I2C
> depends on I2C
> select REGMAP_I2C
> select V4L2_CCI
> +
> +config V4L2_ISP
> + tristate
When configured as module, there's build error:
ERROR: modpost: missing MODULE_LICENSE() in
drivers/media/v4l2-core/v4l2-isp.o
WARNING: modpost: missing MODULE_DESCRIPTION() in
drivers/media/v4l2-core/v4l2-isp.o
It happens when selected from an ISP driver, and ISP driver is a module.
Then module is applied to v4l2-isp too.
> + depends on VIDEOBUF2_CORE
> diff --git a/drivers/media/v4l2-core/Makefile b/drivers/media/v4l2-core/Makefile
> index 2177b9d63a8ffc1127c5a70118249a2ff63cd759..329f0eadce994cc1c8580beb435f68fa7e2a7aeb 100644
> --- a/drivers/media/v4l2-core/Makefile
> +++ b/drivers/media/v4l2-core/Makefile
> @@ -29,6 +29,7 @@ obj-$(CONFIG_V4L2_CCI) += v4l2-cci.o
> obj-$(CONFIG_V4L2_FLASH_LED_CLASS) += v4l2-flash-led-class.o
> obj-$(CONFIG_V4L2_FWNODE) += v4l2-fwnode.o
> obj-$(CONFIG_V4L2_H264) += v4l2-h264.o
> +obj-$(CONFIG_V4L2_ISP) += v4l2-isp.o
> obj-$(CONFIG_V4L2_JPEG_HELPER) += v4l2-jpeg.o
> obj-$(CONFIG_V4L2_MEM2MEM_DEV) += v4l2-mem2mem.o
> obj-$(CONFIG_V4L2_VP9) += v4l2-vp9.o
> diff --git a/drivers/media/v4l2-core/v4l2-isp.c b/drivers/media/v4l2-core/v4l2-isp.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..35f0b701f1729c3c0ccc34b1c89189b179e0b684
> --- /dev/null
> +++ b/drivers/media/v4l2-core/v4l2-isp.c
> @@ -0,0 +1,128 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Video4Linux2 generic ISP parameters and statistics support
> + *
> + * Copyright (C) 2025 Ideas On Board Oy
> + * Author: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> + */
> +
> +#include <media/v4l2-isp.h>
> +
> +#include <linux/bitops.h>
> +#include <linux/device.h>
> +
> +#include <media/videobuf2-core.h>
> +
> +int v4l2_isp_params_validate_buffer_size(struct device *dev,
> + struct vb2_buffer *vb,
> + size_t max_size)
> +{
> + size_t header_size = offsetof(struct v4l2_isp_params_buffer, data);
> + size_t payload_size = vb2_get_plane_payload(vb, 0);
> +
> + /* Payload size can't be greater than the destination buffer size */
> + if (payload_size > max_size) {
> + dev_dbg(dev, "Payload size is too large: %zu\n", payload_size);
> + return -EINVAL;
> + }
> +
> + /* Payload size can't be smaller than the header size */
> + if (payload_size < header_size) {
> + dev_dbg(dev, "Payload size is too small: %zu\n", payload_size);
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(v4l2_isp_params_validate_buffer_size);
> +
> +int v4l2_isp_params_validate_buffer(struct device *dev, struct vb2_buffer *vb,
> + const struct v4l2_isp_params_buffer *buffer,
> + const struct v4l2_isp_params_block_info *info,
> + size_t num_blocks)
> +{
> + size_t header_size = offsetof(struct v4l2_isp_params_buffer, data);
> + size_t payload_size = vb2_get_plane_payload(vb, 0);
> + size_t block_offset = 0;
> + size_t buffer_size;
> +
> + /*
> + * Currently only the first version of the V4L2 ISP parameters format is
> + * supported. We accept both V0 and V1 to support existing drivers
> + * compatible with V4L2 ISP that use either 0 or 1 as their "first
> + * version" identifiers.
> + */
> + if (buffer->version != V4L2_ISP_PARAMS_VERSION_V0 &&
> + buffer->version != V4L2_ISP_PARAMS_VERSION_V1) {
> + dev_dbg(dev,
> + "Unsupported V4L2 ISP parameters format version: %u\n",
> + buffer->version);
> + return -EINVAL;
> + }
> +
> + /* Validate the size reported in the header */
> + buffer_size = header_size + buffer->data_size;
> + if (buffer_size != payload_size) {
> + dev_dbg(dev, "Data size %zu and payload size %zu are different\n",
> + buffer_size, payload_size);
> + return -EINVAL;
> + }
> +
> + /* Walk the list of ISP configuration blocks and validate them. */
> + buffer_size = buffer->data_size;
> + while (buffer_size >= sizeof(struct v4l2_isp_params_block_header)) {
> + const struct v4l2_isp_params_block_info *block_info;
> + const struct v4l2_isp_params_block_header *block;
> +
> + block = (const struct v4l2_isp_params_block_header *)
> + (buffer->data + block_offset);
> +
> + if (block->type >= num_blocks) {
> + dev_dbg(dev,
> + "Invalid block type %u at offset %zu\n",
> + block->type, block_offset);
> + return -EINVAL;
> + }
> +
> + if (block->size > buffer_size) {
> + dev_dbg(dev, "Premature end of parameters data\n");
> + return -EINVAL;
> + }
> +
> + /* It's invalid to specify both ENABLE and DISABLE. */
> + if ((block->flags & (V4L2_ISP_PARAMS_FL_BLOCK_ENABLE |
> + V4L2_ISP_PARAMS_FL_BLOCK_DISABLE)) ==
> + (V4L2_ISP_PARAMS_FL_BLOCK_ENABLE |
> + V4L2_ISP_PARAMS_FL_BLOCK_DISABLE)) {
> + dev_dbg(dev, "Invalid block flags %x at offset %zu\n",
> + block->flags, block_offset);
> + return -EINVAL;
> + }
> +
> + /*
> + * Match the block reported size against the info provided
> + * one, but allow the block to only contain the header in
> + * case it is going to be disabled.
> + */
> + block_info = &info[block->type];
> + if (block->size != block_info->size &&
> + (!(block->flags & V4L2_ISP_PARAMS_FL_BLOCK_DISABLE) ||
> + block->size != sizeof(*block))) {
> + dev_dbg(dev,
> + "Invalid block size %u (expected %zu) at offset %zu\n",
> + block->size, block_info->size, block_offset);
> + return -EINVAL;
> + }
> +
> + block_offset += block->size;
> + buffer_size -= block->size;
> + }
> +
> + if (buffer_size) {
> + dev_dbg(dev, "Unexpected data after the parameters buffer end\n");
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(v4l2_isp_params_validate_buffer);
> diff --git a/include/media/v4l2-isp.h b/include/media/v4l2-isp.h
> new file mode 100644
> index 0000000000000000000000000000000000000000..8b4695663699e7f176384739cf54ed7fa2c578f8
> --- /dev/null
> +++ b/include/media/v4l2-isp.h
> @@ -0,0 +1,91 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Video4Linux2 generic ISP parameters and statistics support
> + *
> + * Copyright (C) 2025 Ideas On Board Oy
> + * Author: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> + */
> +
> +#ifndef _V4L2_ISP_H_
> +#define _V4L2_ISP_H_
> +
> +#include <linux/media/v4l2-isp.h>
> +
> +struct device;
> +struct vb2_buffer;
> +
> +/**
> + * v4l2_isp_params_buffer_size - Calculate size of v4l2_isp_params_buffer
> + * @max_params_size: The total size of the ISP configuration blocks
> + *
> + * Users of the v4l2 extensible parameters will have differing sized data arrays
> + * depending on their specific parameter buffers. Drivers and userspace will
> + * need to be able to calculate the appropriate size of the struct to
> + * accommodate all ISP configuration blocks provided by the platform.
> + * This macro provides a convenient tool for the calculation.
> + */
> +#define v4l2_isp_params_buffer_size(max_params_size) \
> + (offsetof(struct v4l2_isp_params_buffer, data) + (max_params_size))
> +
> +/**
> + * v4l2_isp_params_validate_buffer_size - Validate a V4L2 ISP buffer sizes
> + * @dev: the driver's device pointer
> + * @vb: the videobuf2 buffer
> + * @max_size: the maximum allowed buffer size
> + *
> + * This function performs validation of the size of a V4L2 ISP parameters buffer
> + * before the driver can access the actual data buffer content.
> + *
> + * After the sizes validation, drivers should copy the buffer content to a
> + * kernel-only memory area to prevent userspace from modifying it,
> + * before completing validation using v4l2_isp_params_validate_buffer().
> + *
> + * The @vb buffer as received from the vb2 .buf_prepare() operation is checked
> + * against @max_size and it's validated to be large enough to accommodate at
> + * least one ISP configuration block.
> + */
> +int v4l2_isp_params_validate_buffer_size(struct device *dev,
> + struct vb2_buffer *vb,
> + size_t max_size);
> +
> +/**
> + * struct v4l2_isp_params_block_info - V4L2 ISP per-block info
> + * @size: the block expected size
> + *
> + * The v4l2_isp_params_block_info collects information of the ISP configuration
> + * blocks for validation purposes. It currently only contains the expected
> + * block size.
> + *
> + * Drivers shall prepare a list of block info, indexed by block type, one for
> + * each supported ISP block and correctly populate them with the expected block
> + * size.
> + */
> +struct v4l2_isp_params_block_info {
> + size_t size;
> +};
> +
> +/**
> + * v4l2_isp_params_validate_buffer - Validate a V4L2 ISP parameters buffer
> + * @dev: the driver's device pointer
> + * @vb: the videobuf2 buffer
> + * @buffer: the V4L2 ISP parameters buffer
> + * @info: the list of per-block validation info
> + * @num_blocks: the number of blocks
> + *
> + * This function completes the validation of a V4L2 ISP parameters buffer,
> + * verifying each configuration block correctness before the driver can use
> + * them to program the hardware.
> + *
> + * Drivers should use this function after having validated the correctness of
> + * the vb2 buffer sizes by using the v4l2_isp_params_validate_buffer_size()
> + * helper first. Once the buffer size has been validated, drivers should
> + * perform a copy of the user provided buffer into a kernel-only memory buffer
> + * to prevent userspace from modifying its content after it has been submitted
> + * to the driver, and then call this function to complete validation.
> + */
> +int v4l2_isp_params_validate_buffer(struct device *dev, struct vb2_buffer *vb,
> + const struct v4l2_isp_params_buffer *buffer,
> + const struct v4l2_isp_params_block_info *info,
> + size_t num_blocks);
> +
> +#endif /* _V4L2_ISP_H_ */
>
> --
> 2.51.0
>
HI Antoine
On Thu, Nov 13, 2025 at 09:19:10AM +0100, Antoine Bouyer wrote:
>
> Hi Jacopo
>
> On 10/20/25 10:24 AM, Jacopo Mondi wrote:
> >
> > Add to the V4L2 framework helper functions to support drivers when
> > validating a buffer of V4L2 ISP parameters.
> >
> > Driver shall use v4l2_isp_params_validate_buffer_size() to verify the
> > size correctness of the data received from userspace, and after having
> > copied the data to a kernel-only memory location, complete the
> > validation by calling v4l2_isp_params_validate_buffer().
> >
> > Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
> > Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> > Reviewed-by: Michael Riesch <michael.riesch@collabora.com>
> > Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> > ---
> > MAINTAINERS | 2 +
> > drivers/media/v4l2-core/Kconfig | 4 ++
> > drivers/media/v4l2-core/Makefile | 1 +
> > drivers/media/v4l2-core/v4l2-isp.c | 128 +++++++++++++++++++++++++++++++++++++
> > include/media/v4l2-isp.h | 91 ++++++++++++++++++++++++++
> > 5 files changed, 226 insertions(+)
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index f52237d57710cadff78b297d2b4610b508f55092..5833f82caa7f2f734bb0e1be144ade2109b23988 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -26857,6 +26857,8 @@ M: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> > L: linux-media@vger.kernel.org
> > S: Maintained
> > F: Documentation/userspace-api/media/v4l/v4l2-isp.rst
> > +F: drivers/media/v4l2-core/v4l2-isp.c
> > +F: include/media/v4l2-isp.h
> > F: include/uapi/linux/media/v4l2-isp.h
> >
> > VF610 NAND DRIVER
> > diff --git a/drivers/media/v4l2-core/Kconfig b/drivers/media/v4l2-core/Kconfig
> > index 331b8e535e5bbf33f22638b2ae8bc764ad5fc407..d50ccac9733cc39a43426ae7e7996dd0b5b45186 100644
> > --- a/drivers/media/v4l2-core/Kconfig
> > +++ b/drivers/media/v4l2-core/Kconfig
> > @@ -82,3 +82,7 @@ config V4L2_CCI_I2C
> > depends on I2C
> > select REGMAP_I2C
> > select V4L2_CCI
> > +
> > +config V4L2_ISP
> > + tristate
>
> When configured as module, there's build error:
>
> ERROR: modpost: missing MODULE_LICENSE() in
> drivers/media/v4l2-core/v4l2-isp.o
> WARNING: modpost: missing MODULE_DESCRIPTION() in
> drivers/media/v4l2-core/v4l2-isp.o
>
> It happens when selected from an ISP driver, and ISP driver is a module.
> Then module is applied to v4l2-isp too.
Thanks for reporting it! I was about to send a pull request -.-'
I can reproduce locally
ERROR: modpost: missing MODULE_LICENSE() in drivers/media/v4l2-core/v4l2-isp.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/media/v4l2-core/v4l2-isp.o
make[3]: *** [../scripts/Makefile.modpost:147: Module.symvers] Error 1
And I've fixed it by adding:
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jacopo Mondi <jacopo.mondi@ideasonboard.com");
MODULE_DESCRIPTION("V4L2 generic ISP parameters and statistics helpers");
Thank you!
>
> > + depends on VIDEOBUF2_CORE
> > diff --git a/drivers/media/v4l2-core/Makefile b/drivers/media/v4l2-core/Makefile
> > index 2177b9d63a8ffc1127c5a70118249a2ff63cd759..329f0eadce994cc1c8580beb435f68fa7e2a7aeb 100644
> > --- a/drivers/media/v4l2-core/Makefile
> > +++ b/drivers/media/v4l2-core/Makefile
> > @@ -29,6 +29,7 @@ obj-$(CONFIG_V4L2_CCI) += v4l2-cci.o
> > obj-$(CONFIG_V4L2_FLASH_LED_CLASS) += v4l2-flash-led-class.o
> > obj-$(CONFIG_V4L2_FWNODE) += v4l2-fwnode.o
> > obj-$(CONFIG_V4L2_H264) += v4l2-h264.o
> > +obj-$(CONFIG_V4L2_ISP) += v4l2-isp.o
> > obj-$(CONFIG_V4L2_JPEG_HELPER) += v4l2-jpeg.o
> > obj-$(CONFIG_V4L2_MEM2MEM_DEV) += v4l2-mem2mem.o
> > obj-$(CONFIG_V4L2_VP9) += v4l2-vp9.o
> > diff --git a/drivers/media/v4l2-core/v4l2-isp.c b/drivers/media/v4l2-core/v4l2-isp.c
> > new file mode 100644
> > index 0000000000000000000000000000000000000000..35f0b701f1729c3c0ccc34b1c89189b179e0b684
> > --- /dev/null
> > +++ b/drivers/media/v4l2-core/v4l2-isp.c
> > @@ -0,0 +1,128 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * Video4Linux2 generic ISP parameters and statistics support
> > + *
> > + * Copyright (C) 2025 Ideas On Board Oy
> > + * Author: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> > + */
> > +
> > +#include <media/v4l2-isp.h>
> > +
> > +#include <linux/bitops.h>
> > +#include <linux/device.h>
> > +
> > +#include <media/videobuf2-core.h>
> > +
> > +int v4l2_isp_params_validate_buffer_size(struct device *dev,
> > + struct vb2_buffer *vb,
> > + size_t max_size)
> > +{
> > + size_t header_size = offsetof(struct v4l2_isp_params_buffer, data);
> > + size_t payload_size = vb2_get_plane_payload(vb, 0);
> > +
> > + /* Payload size can't be greater than the destination buffer size */
> > + if (payload_size > max_size) {
> > + dev_dbg(dev, "Payload size is too large: %zu\n", payload_size);
> > + return -EINVAL;
> > + }
> > +
> > + /* Payload size can't be smaller than the header size */
> > + if (payload_size < header_size) {
> > + dev_dbg(dev, "Payload size is too small: %zu\n", payload_size);
> > + return -EINVAL;
> > + }
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(v4l2_isp_params_validate_buffer_size);
> > +
> > +int v4l2_isp_params_validate_buffer(struct device *dev, struct vb2_buffer *vb,
> > + const struct v4l2_isp_params_buffer *buffer,
> > + const struct v4l2_isp_params_block_info *info,
> > + size_t num_blocks)
> > +{
> > + size_t header_size = offsetof(struct v4l2_isp_params_buffer, data);
> > + size_t payload_size = vb2_get_plane_payload(vb, 0);
> > + size_t block_offset = 0;
> > + size_t buffer_size;
> > +
> > + /*
> > + * Currently only the first version of the V4L2 ISP parameters format is
> > + * supported. We accept both V0 and V1 to support existing drivers
> > + * compatible with V4L2 ISP that use either 0 or 1 as their "first
> > + * version" identifiers.
> > + */
> > + if (buffer->version != V4L2_ISP_PARAMS_VERSION_V0 &&
> > + buffer->version != V4L2_ISP_PARAMS_VERSION_V1) {
> > + dev_dbg(dev,
> > + "Unsupported V4L2 ISP parameters format version: %u\n",
> > + buffer->version);
> > + return -EINVAL;
> > + }
> > +
> > + /* Validate the size reported in the header */
> > + buffer_size = header_size + buffer->data_size;
> > + if (buffer_size != payload_size) {
> > + dev_dbg(dev, "Data size %zu and payload size %zu are different\n",
> > + buffer_size, payload_size);
> > + return -EINVAL;
> > + }
> > +
> > + /* Walk the list of ISP configuration blocks and validate them. */
> > + buffer_size = buffer->data_size;
> > + while (buffer_size >= sizeof(struct v4l2_isp_params_block_header)) {
> > + const struct v4l2_isp_params_block_info *block_info;
> > + const struct v4l2_isp_params_block_header *block;
> > +
> > + block = (const struct v4l2_isp_params_block_header *)
> > + (buffer->data + block_offset);
> > +
> > + if (block->type >= num_blocks) {
> > + dev_dbg(dev,
> > + "Invalid block type %u at offset %zu\n",
> > + block->type, block_offset);
> > + return -EINVAL;
> > + }
> > +
> > + if (block->size > buffer_size) {
> > + dev_dbg(dev, "Premature end of parameters data\n");
> > + return -EINVAL;
> > + }
> > +
> > + /* It's invalid to specify both ENABLE and DISABLE. */
> > + if ((block->flags & (V4L2_ISP_PARAMS_FL_BLOCK_ENABLE |
> > + V4L2_ISP_PARAMS_FL_BLOCK_DISABLE)) ==
> > + (V4L2_ISP_PARAMS_FL_BLOCK_ENABLE |
> > + V4L2_ISP_PARAMS_FL_BLOCK_DISABLE)) {
> > + dev_dbg(dev, "Invalid block flags %x at offset %zu\n",
> > + block->flags, block_offset);
> > + return -EINVAL;
> > + }
> > +
> > + /*
> > + * Match the block reported size against the info provided
> > + * one, but allow the block to only contain the header in
> > + * case it is going to be disabled.
> > + */
> > + block_info = &info[block->type];
> > + if (block->size != block_info->size &&
> > + (!(block->flags & V4L2_ISP_PARAMS_FL_BLOCK_DISABLE) ||
> > + block->size != sizeof(*block))) {
> > + dev_dbg(dev,
> > + "Invalid block size %u (expected %zu) at offset %zu\n",
> > + block->size, block_info->size, block_offset);
> > + return -EINVAL;
> > + }
> > +
> > + block_offset += block->size;
> > + buffer_size -= block->size;
> > + }
> > +
> > + if (buffer_size) {
> > + dev_dbg(dev, "Unexpected data after the parameters buffer end\n");
> > + return -EINVAL;
> > + }
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(v4l2_isp_params_validate_buffer);
> > diff --git a/include/media/v4l2-isp.h b/include/media/v4l2-isp.h
> > new file mode 100644
> > index 0000000000000000000000000000000000000000..8b4695663699e7f176384739cf54ed7fa2c578f8
> > --- /dev/null
> > +++ b/include/media/v4l2-isp.h
> > @@ -0,0 +1,91 @@
> > +/* SPDX-License-Identifier: GPL-2.0-or-later */
> > +/*
> > + * Video4Linux2 generic ISP parameters and statistics support
> > + *
> > + * Copyright (C) 2025 Ideas On Board Oy
> > + * Author: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> > + */
> > +
> > +#ifndef _V4L2_ISP_H_
> > +#define _V4L2_ISP_H_
> > +
> > +#include <linux/media/v4l2-isp.h>
> > +
> > +struct device;
> > +struct vb2_buffer;
> > +
> > +/**
> > + * v4l2_isp_params_buffer_size - Calculate size of v4l2_isp_params_buffer
> > + * @max_params_size: The total size of the ISP configuration blocks
> > + *
> > + * Users of the v4l2 extensible parameters will have differing sized data arrays
> > + * depending on their specific parameter buffers. Drivers and userspace will
> > + * need to be able to calculate the appropriate size of the struct to
> > + * accommodate all ISP configuration blocks provided by the platform.
> > + * This macro provides a convenient tool for the calculation.
> > + */
> > +#define v4l2_isp_params_buffer_size(max_params_size) \
> > + (offsetof(struct v4l2_isp_params_buffer, data) + (max_params_size))
> > +
> > +/**
> > + * v4l2_isp_params_validate_buffer_size - Validate a V4L2 ISP buffer sizes
> > + * @dev: the driver's device pointer
> > + * @vb: the videobuf2 buffer
> > + * @max_size: the maximum allowed buffer size
> > + *
> > + * This function performs validation of the size of a V4L2 ISP parameters buffer
> > + * before the driver can access the actual data buffer content.
> > + *
> > + * After the sizes validation, drivers should copy the buffer content to a
> > + * kernel-only memory area to prevent userspace from modifying it,
> > + * before completing validation using v4l2_isp_params_validate_buffer().
> > + *
> > + * The @vb buffer as received from the vb2 .buf_prepare() operation is checked
> > + * against @max_size and it's validated to be large enough to accommodate at
> > + * least one ISP configuration block.
> > + */
> > +int v4l2_isp_params_validate_buffer_size(struct device *dev,
> > + struct vb2_buffer *vb,
> > + size_t max_size);
> > +
> > +/**
> > + * struct v4l2_isp_params_block_info - V4L2 ISP per-block info
> > + * @size: the block expected size
> > + *
> > + * The v4l2_isp_params_block_info collects information of the ISP configuration
> > + * blocks for validation purposes. It currently only contains the expected
> > + * block size.
> > + *
> > + * Drivers shall prepare a list of block info, indexed by block type, one for
> > + * each supported ISP block and correctly populate them with the expected block
> > + * size.
> > + */
> > +struct v4l2_isp_params_block_info {
> > + size_t size;
> > +};
> > +
> > +/**
> > + * v4l2_isp_params_validate_buffer - Validate a V4L2 ISP parameters buffer
> > + * @dev: the driver's device pointer
> > + * @vb: the videobuf2 buffer
> > + * @buffer: the V4L2 ISP parameters buffer
> > + * @info: the list of per-block validation info
> > + * @num_blocks: the number of blocks
> > + *
> > + * This function completes the validation of a V4L2 ISP parameters buffer,
> > + * verifying each configuration block correctness before the driver can use
> > + * them to program the hardware.
> > + *
> > + * Drivers should use this function after having validated the correctness of
> > + * the vb2 buffer sizes by using the v4l2_isp_params_validate_buffer_size()
> > + * helper first. Once the buffer size has been validated, drivers should
> > + * perform a copy of the user provided buffer into a kernel-only memory buffer
> > + * to prevent userspace from modifying its content after it has been submitted
> > + * to the driver, and then call this function to complete validation.
> > + */
> > +int v4l2_isp_params_validate_buffer(struct device *dev, struct vb2_buffer *vb,
> > + const struct v4l2_isp_params_buffer *buffer,
> > + const struct v4l2_isp_params_block_info *info,
> > + size_t num_blocks);
> > +
> > +#endif /* _V4L2_ISP_H_ */
> >
> > --
> > 2.51.0
> >
>
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