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From: Richard Weinberger <richard@nod.at>
To: "Michał Kępień" <kernel@kempniu.pl>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>,
	 Vignesh Raghavendra <vigneshr@ti.com>,
	 Boris Brezillon <boris.brezillon@collabora.com>,
	 linux-mtd <linux-mtd@lists.infradead.org>,
	 linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 4/4] mtdchar: add MEMREAD ioctl
Date: Thu, 3 Feb 2022 10:18:56 +0100 (CET)	[thread overview]
Message-ID: <1173246756.12597.1643879936765.JavaMail.zimbra@nod.at> (raw)
In-Reply-To: <20220125104822.8420-5-kernel@kempniu.pl>

Michał,

----- Ursprüngliche Mail -----
> Von: "Michał Kępień" <kernel@kempniu.pl>
> An: "Miquel Raynal" <miquel.raynal@bootlin.com>, "richard" <richard@nod.at>, "Vignesh Raghavendra" <vigneshr@ti.com>
> CC: "Boris Brezillon" <boris.brezillon@collabora.com>, "linux-mtd" <linux-mtd@lists.infradead.org>, "linux-kernel"
> <linux-kernel@vger.kernel.org>
> Gesendet: Dienstag, 25. Januar 2022 11:48:22
> Betreff: [PATCH v3 4/4] mtdchar: add MEMREAD ioctl

> +	if (req.start + req.len > mtd->size) {

I think this can overflow since both req.start and req.len are u64.
So an evil-doer might bypass this check.

> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	datbuf_len = min_t(size_t, req.len, mtd->erasesize);
> +	if (datbuf_len > 0) {
> +		datbuf = kmalloc(datbuf_len, GFP_KERNEL);

If mtd->erasesize is large (which is not uncommon these days) you might
request more from kmalloc() than it can serve.
Maybe kvmalloc() makes more sense?

> +		if (!datbuf) {
> +			ret = -ENOMEM;
> +			goto out;
> +		}
> +	}
> +
> +	oobbuf_len = min_t(size_t, req.ooblen, mtd->erasesize);
> +	if (oobbuf_len > 0) {
> +		oobbuf = kmalloc(oobbuf_len, GFP_KERNEL);

Same.

Thanks,
//richard

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

WARNING: multiple messages have this Message-ID (diff)
From: Richard Weinberger <richard@nod.at>
To: "Michał Kępień" <kernel@kempniu.pl>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Boris Brezillon <boris.brezillon@collabora.com>,
	linux-mtd <linux-mtd@lists.infradead.org>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 4/4] mtdchar: add MEMREAD ioctl
Date: Thu, 3 Feb 2022 10:18:56 +0100 (CET)	[thread overview]
Message-ID: <1173246756.12597.1643879936765.JavaMail.zimbra@nod.at> (raw)
In-Reply-To: <20220125104822.8420-5-kernel@kempniu.pl>

Michał,

----- Ursprüngliche Mail -----
> Von: "Michał Kępień" <kernel@kempniu.pl>
> An: "Miquel Raynal" <miquel.raynal@bootlin.com>, "richard" <richard@nod.at>, "Vignesh Raghavendra" <vigneshr@ti.com>
> CC: "Boris Brezillon" <boris.brezillon@collabora.com>, "linux-mtd" <linux-mtd@lists.infradead.org>, "linux-kernel"
> <linux-kernel@vger.kernel.org>
> Gesendet: Dienstag, 25. Januar 2022 11:48:22
> Betreff: [PATCH v3 4/4] mtdchar: add MEMREAD ioctl

> +	if (req.start + req.len > mtd->size) {

I think this can overflow since both req.start and req.len are u64.
So an evil-doer might bypass this check.

> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	datbuf_len = min_t(size_t, req.len, mtd->erasesize);
> +	if (datbuf_len > 0) {
> +		datbuf = kmalloc(datbuf_len, GFP_KERNEL);

If mtd->erasesize is large (which is not uncommon these days) you might
request more from kmalloc() than it can serve.
Maybe kvmalloc() makes more sense?

> +		if (!datbuf) {
> +			ret = -ENOMEM;
> +			goto out;
> +		}
> +	}
> +
> +	oobbuf_len = min_t(size_t, req.ooblen, mtd->erasesize);
> +	if (oobbuf_len > 0) {
> +		oobbuf = kmalloc(oobbuf_len, GFP_KERNEL);

Same.

Thanks,
//richard

  reply	other threads:[~2022-02-03  9:19 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-25 10:48 [PATCH v3 0/4] mtdchar: add MEMREAD ioctl Michał Kępień
2022-01-25 10:48 ` Michał Kępień
2022-01-25 10:48 ` [PATCH v3 1/4] mtd: track maximum number of bitflips for each read request Michał Kępień
2022-01-25 10:48   ` Michał Kępień
2022-01-25 10:48 ` [PATCH v3 2/4] mtd: always initialize 'stats' in struct mtd_oob_ops Michał Kępień
2022-01-25 10:48   ` Michał Kępień
2022-01-25 10:48 ` [PATCH v3 3/4] mtd: add ECC error accounting for each read request Michał Kępień
2022-01-25 10:48   ` Michał Kępień
2022-01-25 10:48 ` [PATCH v3 4/4] mtdchar: add MEMREAD ioctl Michał Kępień
2022-01-25 10:48   ` Michał Kępień
2022-02-03  9:18   ` Richard Weinberger [this message]
2022-02-03  9:18     ` Richard Weinberger
2022-02-03  9:46     ` Miquel Raynal
2022-02-03  9:46       ` Miquel Raynal
2022-02-03 10:13       ` Richard Weinberger
2022-02-03 10:13         ` Richard Weinberger
2022-02-14 11:18         ` Michał Kępień
2022-02-14 11:18           ` Michał Kępień
2022-02-14 11:15     ` Michał Kępień
2022-02-14 11:15       ` Michał Kępień

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