Commit 1a52a094 authored by Thomas Weißschuh's avatar Thomas Weißschuh Committed by Rob Herring (Arm)
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of: address: Unify resource bounds overflow checking 



The members "start" and "end" of struct resource are of type
"resource_size_t" which can be 32bit wide.
Values read from OF however are always 64bit wide.

Refactor the diff overflow checks into a helper function.
Also extend the checks to validate each calculation step.

Signed-off-by: default avatarThomas Weißschuh <thomas.weissschuh@linutronix.de>
Link: https://lore.kernel.org/r/20240906-of-address-overflow-v1-1-19567aaa61da@linutronix.de


[robh: Fix to not return error on 0 sized resource]
Signed-off-by: default avatarRob Herring (Arm) <robh@kernel.org>
parent 22e2bf12

drivers/of/address.c

+24 −19
Original line number Diff line number Diff line
@@ -198,6 +198,23 @@ static u64 of_bus_pci_map(__be32 *addr, const __be32 *range, int na, int ns, 


#endif /* CONFIG_PCI */



static int __of_address_resource_bounds(struct resource *r, u64 start, u64 size)

{

	u64 end = start;



	if (overflows_type(start, r->start))

		return -EOVERFLOW;

	if (size && check_add_overflow(end, size - 1, &end))

		return -EOVERFLOW;

	if (overflows_type(end, r->end))

		return -EOVERFLOW;



	r->start = start;

	r->end = end;



	return 0;

}



/*

 * of_pci_range_to_resource - Create a resource from an of_pci_range

 * @range:	the PCI range that describes the resource
@@ -216,6 +233,7 @@ static u64 of_bus_pci_map(__be32 *addr, const __be32 *range, int na, int ns, 
int of_pci_range_to_resource(struct of_pci_range *range,

			     struct device_node *np, struct resource *res)

{

	u64 start;

	int err;

	res->flags = range->flags;

	res->parent = res->child = res->sibling = NULL;
@@ -232,18 +250,11 @@ int of_pci_range_to_resource(struct of_pci_range *range, 
			err = -EINVAL;

			goto invalid_range;

		}

		res->start = port;

		start = port;

	} else {

		if ((sizeof(resource_size_t) < 8) &&

		    upper_32_bits(range->cpu_addr)) {

			err = -EINVAL;

			goto invalid_range;

		start = range->cpu_addr;

	}



		res->start = range->cpu_addr;

	}

	res->end = res->start + range->size - 1;

	return 0;

	return __of_address_resource_bounds(res, start, range->size);



invalid_range:

	res->start = (resource_size_t)OF_BAD_ADDR;
@@ -259,8 +270,8 @@ EXPORT_SYMBOL(of_pci_range_to_resource); 
 * @res:	pointer to a valid resource that will be updated to

 *              reflect the values contained in the range.

 *

 * Returns ENOENT if the entry is not found or EINVAL if the range cannot be

 * converted to resource.

 * Returns -ENOENT if the entry is not found or -EOVERFLOW if the range

 * cannot be converted to resource.

 */

int of_range_to_resource(struct device_node *np, int index, struct resource *res)

{
@@ -1062,16 +1073,10 @@ static int __of_address_to_resource(struct device_node *dev, int index, int bar_ 
	if (of_mmio_is_nonposted(dev))

		flags |= IORESOURCE_MEM_NONPOSTED;



	if (overflows_type(taddr, r->start))

		return -EOVERFLOW;

	r->start = taddr;

	if (overflows_type(taddr + size - 1, r->end))

		return -EOVERFLOW;

	r->end = taddr + size - 1;

	r->flags = flags;

	r->name = name ? name : dev->full_name;



	return 0;

	return __of_address_resource_bounds(r, taddr, size);

}



/**