* [PATCH] mtd: rawnand: mtk: avoid underflow in mtk_nfc_nand_chip_init()
@ 2020-09-16 19:40 Evgeny Novikov
2020-09-17 16:30 ` Miquel Raynal
0 siblings, 1 reply; 3+ messages in thread
From: Evgeny Novikov @ 2020-09-16 19:40 UTC (permalink / raw)
To: Miquel Raynal
Cc: ldv-project, Vignesh Raghavendra, Gustavo A. R. Silva,
Evgeny Novikov, Richard Weinberger, linux-kernel, Stephen Boyd,
Masahiro Yamada, Boris Brezillon, linux-mtd, Matthias Brugger,
linux-mediatek, linux-arm-kernel
If of_get_property() will set nsels to negative values the driver may
allocate insufficient memory for chip. Moreover, there may be underflow
for devm_kzalloc(). This can result in various bad consequences later.
The patch causes mtk_nfc_nand_chip_init() to fail for negative values of
nsels.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Evgeny Novikov <novikov@ispras.ru>
---
drivers/mtd/nand/raw/mtk_nand.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mtd/nand/raw/mtk_nand.c b/drivers/mtd/nand/raw/mtk_nand.c
index ad1b55dab211..df98a2eec240 100644
--- a/drivers/mtd/nand/raw/mtk_nand.c
+++ b/drivers/mtd/nand/raw/mtk_nand.c
@@ -1376,7 +1376,7 @@ static int mtk_nfc_nand_chip_init(struct device *dev, struct mtk_nfc *nfc,
return -ENODEV;
nsels /= sizeof(u32);
- if (!nsels || nsels > MTK_NAND_MAX_NSELS) {
+ if (nsels <= 0 || nsels > MTK_NAND_MAX_NSELS) {
dev_err(dev, "invalid reg property size %d\n", nsels);
return -EINVAL;
}
--
2.26.2
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] mtd: rawnand: mtk: avoid underflow in mtk_nfc_nand_chip_init()
2020-09-16 19:40 [PATCH] mtd: rawnand: mtk: avoid underflow in mtk_nfc_nand_chip_init() Evgeny Novikov
@ 2020-09-17 16:30 ` Miquel Raynal
2020-09-18 9:33 ` Evgeny Novikov
0 siblings, 1 reply; 3+ messages in thread
From: Miquel Raynal @ 2020-09-17 16:30 UTC (permalink / raw)
To: Evgeny Novikov
Cc: ldv-project, Vignesh Raghavendra, Gustavo A. R. Silva,
Richard Weinberger, linux-kernel, Stephen Boyd, Masahiro Yamada,
Boris Brezillon, linux-mtd, Matthias Brugger, linux-mediatek,
linux-arm-kernel
Hi Evgeny,
Evgeny Novikov <novikov@ispras.ru> wrote on Wed, 16 Sep 2020 22:40:45
+0300:
> If of_get_property() will set nsels to negative values the driver may
Is this really a possible case?
Looking at the OF code, I don't think it can ever happen...
> allocate insufficient memory for chip. Moreover, there may be underflow
> for devm_kzalloc(). This can result in various bad consequences later.
> The patch causes mtk_nfc_nand_chip_init() to fail for negative values of
> nsels.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Evgeny Novikov <novikov@ispras.ru>
> ---
> drivers/mtd/nand/raw/mtk_nand.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/nand/raw/mtk_nand.c b/drivers/mtd/nand/raw/mtk_nand.c
> index ad1b55dab211..df98a2eec240 100644
> --- a/drivers/mtd/nand/raw/mtk_nand.c
> +++ b/drivers/mtd/nand/raw/mtk_nand.c
> @@ -1376,7 +1376,7 @@ static int mtk_nfc_nand_chip_init(struct device *dev, struct mtk_nfc *nfc,
> return -ENODEV;
>
> nsels /= sizeof(u32);
> - if (!nsels || nsels > MTK_NAND_MAX_NSELS) {
> + if (nsels <= 0 || nsels > MTK_NAND_MAX_NSELS) {
> dev_err(dev, "invalid reg property size %d\n", nsels);
> return -EINVAL;
> }
Thanks,
Miquèl
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] mtd: rawnand: mtk: avoid underflow in mtk_nfc_nand_chip_init()
2020-09-17 16:30 ` Miquel Raynal
@ 2020-09-18 9:33 ` Evgeny Novikov
0 siblings, 0 replies; 3+ messages in thread
From: Evgeny Novikov @ 2020-09-18 9:33 UTC (permalink / raw)
To: Miquel Raynal
Cc: ldv-project, Vignesh Raghavendra, Gustavo A. R. Silva,
Richard Weinberger, linux-kernel, Stephen Boyd, Masahiro Yamada,
Boris Brezillon, linux-mtd, Matthias Brugger, linux-mediatek,
linux-arm-kernel
Hi Miquel,
17.09.2020, 19:30, "Miquel Raynal" <miquel.raynal@bootlin.com>:
> Hi Evgeny,
>
> Evgeny Novikov <novikov@ispras.ru> wrote on Wed, 16 Sep 2020 22:40:45
> +0300:
>
>> If of_get_property() will set nsels to negative values the driver may
>
> Is this really a possible case?
>
> Looking at the OF code, I don't think it can ever happen...
I do not know whether this is possible now or it will be possible one day
in the future.
Our tool assumed that this can happen according to the type (int).
Also, I can not find any driver that may suffer from this. Two examples
where negative cases are forbidden intentionally or unintentionally:
- drivers/sbus/char/openprom.c
- drivers/video/fbdev/omap2/omapfb/dss/dsi.c
Best regards,
Evgeny
>> allocate insufficient memory for chip. Moreover, there may be underflow
>> for devm_kzalloc(). This can result in various bad consequences later.
>> The patch causes mtk_nfc_nand_chip_init() to fail for negative values of
>> nsels.
>>
>> Found by Linux Driver Verification project (linuxtesting.org).
>>
>> Signed-off-by: Evgeny Novikov <novikov@ispras.ru>
>> ---
>> drivers/mtd/nand/raw/mtk_nand.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/nand/raw/mtk_nand.c b/drivers/mtd/nand/raw/mtk_nand.c
>> index ad1b55dab211..df98a2eec240 100644
>> --- a/drivers/mtd/nand/raw/mtk_nand.c
>> +++ b/drivers/mtd/nand/raw/mtk_nand.c
>> @@ -1376,7 +1376,7 @@ static int mtk_nfc_nand_chip_init(struct device *dev, struct mtk_nfc *nfc,
>> return -ENODEV;
>>
>> nsels /= sizeof(u32);
>> - if (!nsels || nsels > MTK_NAND_MAX_NSELS) {
>> + if (nsels <= 0 || nsels > MTK_NAND_MAX_NSELS) {
>> dev_err(dev, "invalid reg property size %d\n", nsels);
>> return -EINVAL;
>> }
>
> Thanks,
> Miquèl
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2020-09-16 19:40 [PATCH] mtd: rawnand: mtk: avoid underflow in mtk_nfc_nand_chip_init() Evgeny Novikov
2020-09-17 16:30 ` Miquel Raynal
2020-09-18 9:33 ` Evgeny Novikov
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