5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Andrew Lunn andrew@lunn.ch
[ Upstream commit b063b1924fd9bf0bc157cf644764dc2151d04ccc ]
When performing a C22 operation, check that the bus driver actually provides the methods, and return -EOPNOTSUPP if not. C45 only busses do exist, and in future their C22 methods will be NULL.
Signed-off-by: Andrew Lunn andrew@lunn.ch Signed-off-by: Michael Walle michael@walle.cc Signed-off-by: Jakub Kicinski kuba@kernel.org Stable-dep-of: 0e629694126c ("net/mdiobus: Fix potential out-of-bounds read/write access") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/phy/mdio_bus.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c index fdf8221f46fa5..e5c25beae21e0 100644 --- a/drivers/net/phy/mdio_bus.c +++ b/drivers/net/phy/mdio_bus.c @@ -565,7 +565,10 @@ int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
WARN_ON_ONCE(!mutex_is_locked(&bus->mdio_lock));
- retval = bus->read(bus, addr, regnum); + if (bus->read) + retval = bus->read(bus, addr, regnum); + else + retval = -EOPNOTSUPP;
trace_mdio_access(bus, 1, addr, regnum, retval, retval);
@@ -590,7 +593,10 @@ int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
WARN_ON_ONCE(!mutex_is_locked(&bus->mdio_lock));
- err = bus->write(bus, addr, regnum, val); + if (bus->write) + err = bus->write(bus, addr, regnum, val); + else + err = -EOPNOTSUPP;
trace_mdio_access(bus, 0, addr, regnum, val, err);