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Unverified Commit bdf3a3b5 authored Apr 11, 2018 by Boris Brezillon Committed by Mark Brown Apr 26, 2018

spi: Check presence the of ->transfer[_xxx]() before registering a controller



Right now, no checks are done on the presence of a ->transfer[_xxx]()
method, which can lead to a NULL pointer dereference when someone
starts sending something on the bus.

Do the check at registration time and refuse to add the controller if
all ->transfer[_xxx]() pointers are NULL.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

parent 0d7412ed

drivers/spi/spi.c

+21 −0

Original line number	Diff line number	Diff line
		@@ -2068,6 +2068,19 @@ static int of_spi_register_master(struct spi_controller *ctlr)
		}
		#endif

		static int spi_controller_check_ops(struct spi_controller *ctlr)
		{
		/*
		* The controller must at least implement one of the ->transfer()
		* hooks.
		*/
		if (!ctlr->transfer && !ctlr->transfer_one &&
		!ctlr->transfer_one_message)
		return -EINVAL;

		return 0;
		}

		/**
		* spi_register_controller - register SPI master or slave controller
		* @ctlr: initialized master, originally from spi_alloc_master() or
		@@ -2101,6 +2114,14 @@ int spi_register_controller(struct spi_controller *ctlr)
		if (!dev)
		return -ENODEV;

		/*
		* Make sure all necessary hooks are implemented before registering
		* the SPI controller.
		*/
		status = spi_controller_check_ops(ctlr);
		if (status)
		return status;

		if (!spi_controller_is_slave(ctlr)) {
		status = of_spi_register_master(ctlr);
		if (status)