On Tue, May 31, 2022 at 08:25:26AM -0700, Prasad Sodagudi wrote: > I am working on an IoT solution and would like to understand security impact > of these two CONFIG_SPI_SPIDEV and CONFIG_I2C_CHARDEV interfaces of Linux. > If a driver is developed from userspace for /dev/spiX.Y or /dev/i2c > interfaces, are there any security concerns ? Well, you have to ensure that only userspace processes that you want to have access to the spidev and I2C interfaces actually have access to them which is something that could go wrong. For I2C you IIRC don't have a mechanism to partition devices between different users since it all goes through /dev/i2c rather than per device userspace devices. > Userspace driver is to control external SPI slave on board. I heard that > these interfaces allows access to any of these type of devices on board. > How to avoid accessing any of these type of unwanted device access from > userspace ? Can Selinux or any mechanism control access to other these type > of devices from user-space ? You can use all the usual permission mechanisms to control access to devices (probably using udev to set up permissions when things are instantiated). I'd expect this to include SELinux.
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