linux-kernel - Re: [PATCH v1] mtd: rawnand: meson: check buffer length

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Date:   Tue, 6 Jun 2023 10:37:43 +0300
From:   Arseniy Krasnov <avkrasnov@...rdevices.ru>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
CC:     Liang Yang <liang.yang@...ogic.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Kevin Hilman <khilman@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        <oxffffaa@...il.com>, <kernel@...rdevices.ru>,
        <linux-mtd@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-amlogic@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] mtd: rawnand: meson: check buffer length



On 06.06.2023 10:16, Miquel Raynal wrote:
> Hi Arseniy,
> 
> AVKrasnov@...rdevices.ru wrote on Mon, 5 Jun 2023 22:10:46 +0300:
> 
>> Meson NAND controller has limited buffer length, so check it before
>> command execution to avoid length trim. Also check MTD write size on
>> chip attach.
> 
> Almost there :)

Hello Miquel!

You mean to rephrase it? :)

Thanks, Arseniy

> 
>>
>> Signed-off-by: Arseniy Krasnov <AVKrasnov@...rdevices.ru>
>> ---
>>  drivers/mtd/nand/raw/meson_nand.c | 22 +++++++++++++++++++---
>>  1 file changed, 19 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
>> index 074e14225c06..bfb5363cac23 100644
>> --- a/drivers/mtd/nand/raw/meson_nand.c
>> +++ b/drivers/mtd/nand/raw/meson_nand.c
>> @@ -108,6 +108,8 @@
>>  
>>  #define PER_INFO_BYTE		8
>>  
>> +#define NFC_CMD_RAW_LEN	GENMASK(13, 0)
>> +
>>  struct meson_nfc_nand_chip {
>>  	struct list_head node;
>>  	struct nand_chip nand;
>> @@ -280,7 +282,7 @@ static void meson_nfc_cmd_access(struct nand_chip *nand, int raw, bool dir,
>>  
>>  	if (raw) {
>>  		len = mtd->writesize + mtd->oobsize;
>> -		cmd = (len & GENMASK(13, 0)) | scrambler | DMA_DIR(dir);
>> +		cmd = len | scrambler | DMA_DIR(dir);
>>  		writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>  		return;
>>  	}
>> @@ -544,7 +546,7 @@ static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len)
>>  	if (ret)
>>  		goto out;
>>  
>> -	cmd = NFC_CMD_N2M | (len & GENMASK(13, 0));
>> +	cmd = NFC_CMD_N2M | len;
>>  	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>  
>>  	meson_nfc_drain_cmd(nfc);
>> @@ -568,7 +570,7 @@ static int meson_nfc_write_buf(struct nand_chip *nand, u8 *buf, int len)
>>  	if (ret)
>>  		return ret;
>>  
>> -	cmd = NFC_CMD_M2N | (len & GENMASK(13, 0));
>> +	cmd = NFC_CMD_M2N | len;
>>  	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>>  
>>  	meson_nfc_drain_cmd(nfc);
>> @@ -936,6 +938,9 @@ static int meson_nfc_exec_op(struct nand_chip *nand,
>>  			break;
>>  
>>  		case NAND_OP_DATA_IN_INSTR:
>> +			if (instr->ctx.data.len > NFC_CMD_RAW_LEN)
>> +				return -EINVAL;
> 
> You need to refuse the operation earlier. That's what the check_op
> boolean is about. Maybe you can take inspiration from anfc_check_op()
> in the arasan controller.

Ok! Thanks!

> 
>> +
>>  			buf = meson_nand_op_get_dma_safe_input_buf(instr);
>>  			if (!buf)
>>  				return -ENOMEM;
>> @@ -944,6 +949,9 @@ static int meson_nfc_exec_op(struct nand_chip *nand,
>>  			break;
>>  
>>  		case NAND_OP_DATA_OUT_INSTR:
>> +			if (instr->ctx.data.len > NFC_CMD_RAW_LEN)
>> +				return -EINVAL;
> 
> Same.
> 
>> +
>>  			buf = meson_nand_op_get_dma_safe_output_buf(instr);
>>  			if (!buf)
>>  				return -ENOMEM;
>> @@ -1181,6 +1189,7 @@ static int meson_nand_attach_chip(struct nand_chip *nand)
>>  	struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
>>  	struct mtd_info *mtd = nand_to_mtd(nand);
>>  	int nsectors = mtd->writesize / 1024;
>> +	int raw_writesize;
>>  	int ret;
>>  
>>  	if (!mtd->name) {
>> @@ -1192,6 +1201,13 @@ static int meson_nand_attach_chip(struct nand_chip *nand)
>>  			return -ENOMEM;
>>  	}
>>  
>> +	raw_writesize = mtd->writesize + mtd->oobsize;
>> +	if (raw_writesize > NFC_CMD_RAW_LEN) {
>> +		dev_err(nfc->dev, "too big write size in raw mode: %d > %ld\n",
>> +			raw_writesize, NFC_CMD_RAW_LEN);
>> +		return -EINVAL;
>> +	}
>> +
>>  	if (nand->bbt_options & NAND_BBT_USE_FLASH)
>>  		nand->bbt_options |= NAND_BBT_NO_OOB;
>>  
> 
> 
> Thanks,
> Miquèl