From: Boris Brezillon <boris.brezillon@bootlin.com>
Date: Wed, 11 Apr 2018 00:44:30 +0200
Subject: spi: Check presence the of ->transfer[_xxx]() before registering a
controller
Git-commit: bdf3a3b59a7ab1972e7d2242c9466ba7e79f0004
Patch-mainline: v4.18-rc1
References: fate#326572
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>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
drivers/spi/spi.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
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)
--
2.11.0