[PATCH v9 10/27] resource: harden resource_contains

alejandro.lucero-palau
2024-12-30T21:45:17Z

From: Alejandro Lucero <alucerop@amd.com>

While resource_contains checks for IORESOURCE_UNSET flag for the
resources given, if r1 was initialized with 0 size, the function
returns a false positive. This is so because resource start and
end fields are unsigned with end initialised to size - 1 by current
resource macros.

Make the function to check for the resource size for both resources
since r2 with size 0 should not be considered as valid for the function
purpose.

Signed-off-by: Alejandro Lucero <alucerop@amd.com>
Suggested-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
include/linux/ioport.h | 2 ++
1 file changed, 2 insertions(+)

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 5385349f0b8a..7ba31a222536 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -296,6 +296,8 @@ static inline unsigned long resource_ext_type(const struct resource *res)
/* True iff r1 completely contains r2 */
static inline bool resource_contains(const struct resource *r1, const struct resource *r2)
{
+ if (!resource_size(r1) || !resource_size(r2))
+ return false;
if (resource_type(r1) != resource_type(r2))
return false;
if (r1->flags & IORESOURCE_UNSET || r2->flags & IORESOURCE_UNSET)
--
2.17.1