From bdf3a3b59a7ab1972e7d2242c9466ba7e79f0004 Mon Sep 17 00:00:00 2001 From: Boris Brezillon Date: Wed, 11 Apr 2018 00:44:30 +0200 Subject: 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 Signed-off-by: Mark Brown --- drivers/spi/spi.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'drivers') diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 3f4666365678..9ab65fb2738e 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -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) -- cgit v1.2.3