[PATCH 5.15 047/135] iommu/dart: check return value after calling platform_get_resource()

Greg Kroah-Hartman
2022-05-10T14:00:17Z

From: Yang Yingliang <yangyingliang@huawei.com>

commit a15932f4377062364d22096afe25bc579134a1c3 upstream.

It will cause null-ptr-deref in resource_size(), if platform_get_resource()
returns NULL, move calling resource_size() after devm_ioremap_resource() that
will check 'res' to avoid null-ptr-deref.
And use devm_platform_get_and_ioremap_resource() to simplify code.

Fixes: 46d1fb072e76 ("iommu/dart: Add DART iommu driver")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Sven Peter <sven@svenpeter.dev>
Link: https://lore.kernel.org/r/20220425090826.2532165-1-yangyingliang@huawei.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/iommu/apple-dart.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

--- a/drivers/iommu/apple-dart.c
+++ b/drivers/iommu/apple-dart.c
@@ -832,16 +832,15 @@ static int apple_dart_probe(struct platf
dart->dev = dev;
spin_lock_init(&dart->lock);

- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ dart->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+ if (IS_ERR(dart->regs))
+ return PTR_ERR(dart->regs);
+
if (resource_size(res) < 0x4000) {
dev_err(dev, "MMIO region too small (%pr)\n", res);
return -EINVAL;
}

- dart->regs = devm_ioremap_resource(dev, res);
- if (IS_ERR(dart->regs))
- return PTR_ERR(dart->regs);
-
dart->irq = platform_get_irq(pdev, 0);
if (dart->irq < 0)
return -ENODEV;