From: Ahmad Fatoum a.fatoum@pengutronix.de
[ Upstream commit b93eb564869321d0dffaf23fcc5c88112ed62466 ]
The probe function sets priv->chip_data to (void *)priv + sizeof(*priv) with the expectation that priv has enough trailing space.
However, only realtek-smi actually allocated this chip_data space. Do likewise in realtek-mdio to fix out-of-bounds accesses.
These accesses likely went unnoticed so far, because of an (unused) buf[4096] member in struct realtek_priv, which caused kmalloc to round up the allocated buffer to a big enough size, so nothing of value was overwritten. With a different allocator (like in the barebox bootloader port of the driver) or with KASAN, the memory corruption becomes quickly apparent.
Fixes: aac94001067d ("net: dsa: realtek: add new mdio interface for drivers") Reviewed-by: Florian Fainelli f.fainelli@gmail.com Reviewed-by: Luiz Angelo Daros de Luca luizluca@gmail.com Reviewed-by: Alvin Šipraga alsi@bang-olufsen.dk Reviewed-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Ahmad Fatoum a.fatoum@pengutronix.de Link: https://lore.kernel.org/r/20230323103735.2331786-1-a.fatoum@pengutronix.de Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/dsa/realtek/realtek-mdio.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/net/dsa/realtek/realtek-mdio.c b/drivers/net/dsa/realtek/realtek-mdio.c index 3e54fac5f9027..5a8fe707ca25e 100644 --- a/drivers/net/dsa/realtek/realtek-mdio.c +++ b/drivers/net/dsa/realtek/realtek-mdio.c @@ -21,6 +21,7 @@
#include <linux/module.h> #include <linux/of_device.h> +#include <linux/overflow.h> #include <linux/regmap.h>
#include "realtek.h" @@ -152,7 +153,9 @@ static int realtek_mdio_probe(struct mdio_device *mdiodev) if (!var) return -EINVAL;
- priv = devm_kzalloc(&mdiodev->dev, sizeof(*priv), GFP_KERNEL); + priv = devm_kzalloc(&mdiodev->dev, + size_add(sizeof(*priv), var->chip_data_sz), + GFP_KERNEL); if (!priv) return -ENOMEM;