[PATCH v2 2/2] intel/pinctrl: check capability offset is between MMIO region

Roger Pau Monne
2021-03-24T15:44:31Z

When parsing the capability list make sure the offset is between the
MMIO region mapped in 'regs', or else the kernel hits a page fault.

Adding the check is harmless, and prevents buggy or broken systems
from crashing the kernel if the capability linked list is somehow
broken.

Fixes: 91d898e51e60 ('pinctrl: intel: Convert capability list to features')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Changes since v1:
- Adjust commit message.
---
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Andy Shevchenko <andy@kernel.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-gpio@vger.kernel.org
---
drivers/pinctrl/intel/pinctrl-intel.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/pinctrl/intel/pinctrl-intel.c b/drivers/pinctrl/intel/pinctrl-intel.c
index 59d13342caf6..d45a6994b2a3 100644
--- a/drivers/pinctrl/intel/pinctrl-intel.c
+++ b/drivers/pinctrl/intel/pinctrl-intel.c
@@ -1481,16 +1481,22 @@ static int intel_pinctrl_probe(struct platform_device *pdev,

for (i = 0; i < pctrl->ncommunities; i++) {
struct intel_community *community = &pctrl->communities[i];
+ struct resource *res;
void __iomem *regs;
+ size_t size;
u32 offset;
u32 value;

*community = pctrl->soc->communities[i];

- regs = devm_platform_ioremap_resource(pdev, community->barno);
+ regs = devm_platform_get_and_ioremap_resource(pdev,
+ community->barno,
+ &res);
if (IS_ERR(regs))
return PTR_ERR(regs);

+ size = res->end - res->start;
+
/* Determine community features based on the revision */
value = readl(regs + REVID);
if (value == ~0u)
@@ -1521,6 +1527,12 @@ static int intel_pinctrl_probe(struct platform_device *pdev,
break;
}
offset = (value & CAPLIST_NEXT_MASK) >> CAPLIST_NEXT_SHIFT;
+ if (offset >= size) {
+ dev_err(&pdev->dev,
+ "wrong capability offset: %#x\n",
+ offset);
+ return -ENOENT;
+ }
} while (offset);

dev_dbg(&pdev->dev, "Community%d features: %#08x\n", i, community->features);
--
2.30.1