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

2021-03-24 Thread Andy Shevchenko
On Wed, Mar 24, 2021 at 04:43:12PM +0100, Roger Pau Monne wrote:
> 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.

I don't think we need a dead code in the kernel. If you have a hardware to show
this issue, I eagerly want to know this!

-- 
With Best Regards,
Andy Shevchenko




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

2021-03-24 Thread Roger Pau Monne
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 
---
Changes since v1:
 - Adjust commit message.
---
Cc: Mika Westerberg 
Cc: Andy Shevchenko 
Cc: Linus Walleij 
Cc: linux-g...@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 = >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,
+ );
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(>dev,
+   "wrong capability offset: %#x\n",
+   offset);
+   return -ENOENT;
+   }
} while (offset);
 
dev_dbg(>dev, "Community%d features: %#08x\n", i, 
community->features);
-- 
2.30.1