Thread (4 messages) flat view 4 messages, 4 authors, 2022-02-05

RE: [PATCH] iio: stmpe-adc: Use correctly sized arguments for bit field

From: David Laight <hidden>
Date: 2022-02-05 13:38:52
Also in: linux-hardening, linux-iio, lkml

From: Yury Norov
Sent: 04 February 2022 04:30

On Wed, Dec 15, 2021 at 03:25:13PM -0800, Kees Cook wrote:
quoted
The find.h APIs are designed to be used only on unsigned long arguments.
This can technically result in a over-read, but it is harmless in this
case. Regardless, fix it to avoid the warning seen under -Warray-bounds,
which we'd like to enable globally:
...
quoted
Signed-off-by: Kees Cook <redacted>
---
 drivers/iio/adc/stmpe-adc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/adc/stmpe-adc.c b/drivers/iio/adc/stmpe-adc.c
index fba659bfdb40..d2d405388499 100644
--- a/drivers/iio/adc/stmpe-adc.c
+++ b/drivers/iio/adc/stmpe-adc.c
@@ -256,6 +256,7 @@ static int stmpe_adc_probe(struct platform_device *pdev)
 	struct stmpe_adc *info;
 	struct device_node *np;
 	u32 norequest_mask = 0;
+	unsigned long bits;
 	int irq_temp, irq_adc;
 	int num_chan = 0;
 	int i = 0;
@@ -309,8 +310,8 @@ static int stmpe_adc_probe(struct platform_device *pdev)

 	of_property_read_u32(np, "st,norequest-mask", &norequest_mask);

-	for_each_clear_bit(i, (unsigned long *) &norequest_mask,
-			   (STMPE_ADC_LAST_NR + 1)) {
+	bits = norequest_mask;
This would not work on 64-bit BE architecture. It should use bitmap_from_arr32()
The old version was wrong on 64 bit BE, Kees version is probably ok.

But changing norequest_mask to 'unsigned long' is probably neater.
OTOH using the bitmap functions on single words is just bloat.

	David

-
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