[V2] mtd: sharpslpart: fix overflow on block_adr calculation

Message ID 20171108161323.30662-1-colin.king@canonical.com
State New
Delegated to: Richard Weinberger
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  • [V2] mtd: sharpslpart: fix overflow on block_adr calculation
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Commit Message

Colin King Nov. 8, 2017, 4:13 p.m.
From: Colin Ian King <colin.king@canonical.com>

Multiplying block_num and mtd->erasesize may potentially overflow
as they are both unsigned ints and so the multiplication is evaluated
in unsigned int arithmetic.  Cast block_adr to off_t to ensure
multiplication is off_t sized to avoid any potential overflow.

Detected by CoverityScan, CID#1461264 ("Unintentional integer overflow")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/mtd/parsers/sharpslpart.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Andrea Adami Nov. 10, 2017, 4:35 p.m. | #1
On Wed, Nov 8, 2017 at 5:13 PM, Colin King <colin.king@canonical.com> wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> Multiplying block_num and mtd->erasesize may potentially overflow
> as they are both unsigned ints and so the multiplication is evaluated
> in unsigned int arithmetic.  Cast block_adr to off_t to ensure
> multiplication is off_t sized to avoid any potential overflow.
>
> Detected by CoverityScan, CID#1461264 ("Unintentional integer overflow")
>
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/mtd/parsers/sharpslpart.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/parsers/sharpslpart.c b/drivers/mtd/parsers/sharpslpart.c
> index 5fe0079ea5ed..0ddb79ac390d 100644
> --- a/drivers/mtd/parsers/sharpslpart.c
> +++ b/drivers/mtd/parsers/sharpslpart.c
> @@ -192,7 +192,7 @@ static int sharpsl_nand_init_ftl(struct mtd_info *mtd, struct sharpsl_ftl *ftl)
>
>         /* create physical-logical table */
>         for (block_num = 0; block_num < phymax; block_num++) {
> -               block_adr = block_num * mtd->erasesize;
> +               block_adr = (loff_t)block_num * mtd->erasesize;
>
>                 if (mtd_block_isbad(mtd, block_adr))
>                         continue;
> @@ -244,7 +244,7 @@ static int sharpsl_nand_read_laddr(struct mtd_info *mtd,
>                 return -EINVAL;
>
>         block_num = ftl->log2phy[log_num];
> -       block_adr = block_num * mtd->erasesize;
> +       block_adr = (loff_t)block_num * mtd->erasesize;
>         block_ofs = mtd_mod_by_eb((u32)from, mtd);
>
>         err = mtd_read(mtd, block_adr + block_ofs, len, &retlen, buf);
> --
> 2.14.1
>

Thanks for spotting this,

Acked-by: Andrea Adami <andrea.adami@gmail.com>

Patch

diff --git a/drivers/mtd/parsers/sharpslpart.c b/drivers/mtd/parsers/sharpslpart.c
index 5fe0079ea5ed..0ddb79ac390d 100644
--- a/drivers/mtd/parsers/sharpslpart.c
+++ b/drivers/mtd/parsers/sharpslpart.c
@@ -192,7 +192,7 @@  static int sharpsl_nand_init_ftl(struct mtd_info *mtd, struct sharpsl_ftl *ftl)
 
 	/* create physical-logical table */
 	for (block_num = 0; block_num < phymax; block_num++) {
-		block_adr = block_num * mtd->erasesize;
+		block_adr = (loff_t)block_num * mtd->erasesize;
 
 		if (mtd_block_isbad(mtd, block_adr))
 			continue;
@@ -244,7 +244,7 @@  static int sharpsl_nand_read_laddr(struct mtd_info *mtd,
 		return -EINVAL;
 
 	block_num = ftl->log2phy[log_num];
-	block_adr = block_num * mtd->erasesize;
+	block_adr = (loff_t)block_num * mtd->erasesize;
 	block_ofs = mtd_mod_by_eb((u32)from, mtd);
 
 	err = mtd_read(mtd, block_adr + block_ofs, len, &retlen, buf);