CVE-2026-43087 in Linux
Resumen
por VulDB • 2026-05-20
Enabling interrupts on pins that haven't been configured yet can lead to unexpected behavior, especially when the interrupt handler is invoked before the driver has fully initialized its internal state. This can cause issues such as accessing uninitialized data structures or triggering nested interrupts that don't have corresponding handlers.
To fix this issue, we need to ensure that all pin interrupts are disabled during the initialization phase of the MCP23S08 driver. This can be achieved by writing a value of `0` to the `MCP_GPINTEN` register, which disables interrupts for all pins.
Here's how you can implement this fix:
1. **Identify the Initialization Function**: Locate the function in the MCP23S08 driver where the initialization occurs. This is typically the probe function or a dedicated initialization function called from the probe function.
2. **Write to the GPINTEN Register**: Add a line of code to write `0` to the `MCP_GPINTEN` register. This will disable interrupts for all pins.
Here's an example of how this might look in the code:
```c #include <linux/regmap.h> #include <linux/gpio/driver.h> #include <linux/interrupt.h> #include <linux/spi/spi.h> #include <linux/of.h> #include <linux/of_gpio.h> #include <linux/module.h>
/* Include necessary headers and definitions for MCP23S08 */
static int mcp23s08_probe(struct spi_device *spi) {
struct mcp23s08 *mcp; int ret;
/* Allocate and initialize the MCP23S08 structure */ mcp = devm_kzalloc(&spi->dev, sizeof(*mcp), GFP_KERNEL); if (!mcp) return -ENOMEM;
/* Initialize other fields of the MCP23S08 structure */
/* Disable all pin interrupts during initialization */ ret = regmap_write(mcp->regmap, MCP_GPINTEN, 0); if (ret) {
dev_err(&spi->dev, "Failed to disable interrupts: %d\n", ret); return ret; }
/* Continue with other initialization steps */
/* Register the GPIO chip */ ret = gpiochip_add_data(&mcp->gpio_chip, mcp); if (ret) {
dev_err(&spi->dev, "Failed to add GPIO chip: %d\n", ret); return ret; }
return 0; }
/* Other functions and definitions for the MCP23S08 driver */
static const struct spi_device_id mcp23s08_id_table[] = {
{ "mcp23s08", 0 },
{ "mcp23s17", 0 },
{ /* sentinel */ }
}; MODULE_DEVICE_TABLE(spi, mcp23s08_id_table);
static struct spi_driver mcp23s08_driver = {
.driver = {
.name = "mcp23s08", .of_match_table = of_match_ptr(mcp23s08_of_match), }, .probe = mcp23s08_probe, .id_table = mcp23s08_id_table, }; module_spi_driver(mcp23s08_driver);
MODULE_LICENSE("GPL"); MODULE_AUTHOR("Your Name <[email protected]>"); MODULE_DESCRIPTION("MCP23S08 SPI GPIO Expander Driver"); ```
In this example, the `mcp23s08_probe` function is modified to include a call to `regmap_write` to disable all pin interrupts by writing `0` to the `MCP_GPINTEN` register. This ensures that no interrupts are triggered until the driver has fully initialized and configured the pins as needed.
Make sure to replace placeholder comments and code with actual implementation details specific to your driver and hardware setup.
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