2019-10-31 01:18:17

by Bradley Bolen

Subject: [PATCH] mmc: core: Fix size overflow for mmc partitions

With large eMMC cards, it is possible to create general purpose
partitions that are bigger than 4GB. The size member of the mmc_part
struct is only an unsigned int which overflows for gp partitions larger
than 4GB. Change this to a u64 to handle the overflow.

Signed-off-by: Bradley Bolen <[email protected]>
---
drivers/mmc/core/mmc.c | 4 ++--
include/linux/mmc/card.h | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index c8804895595f..4e89cf6524a1 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -297,7 +297,7 @@ static void mmc_manage_enhanced_area(struct mmc_card *card, u8 *ext_csd)
}
}

-static void mmc_part_add(struct mmc_card *card, unsigned int size,
+static void mmc_part_add(struct mmc_card *card, u64 size,
unsigned int part_cfg, char *name, int idx, bool ro,
int area_type)
{
@@ -345,7 +345,7 @@ static void mmc_manage_gp_partitions(struct mmc_card *card, u8 *ext_csd)
ext_csd[EXT_CSD_GP_SIZE_MULT + idx * 3];
part_size *= (size_t)(hc_erase_grp_sz *
hc_wp_grp_sz);
- mmc_part_add(card, part_size << 19,
+ mmc_part_add(card, (u64)part_size << 19,
EXT_CSD_PART_CONFIG_ACC_GP0 + idx,
"gp%d", idx, false,
MMC_BLK_DATA_AREA_GP);
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 9b6336ad3266..b59d35bb50ba 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -226,7 +226,7 @@ struct mmc_queue_req;
* MMC Physical partitions
*/
struct mmc_part {
- unsigned int size; /* partition size (in bytes) */
+ u64 size; /* partition size (in bytes) */
unsigned int part_cfg; /* partition type */
char name[MAX_MMC_PART_NAME_LEN];
bool force_ro; /* to make boot parts RO by default */
--
2.17.1

2019-11-04 13:41:01

by Avri Altman

Subject: RE: [PATCH] mmc: core: Fix size overflow for mmc partitions

>
>
> With large eMMC cards, it is possible to create general purpose partitions that
> are bigger than 4GB. The size member of the mmc_part struct is only an
> unsigned int which overflows for gp partitions larger than 4GB. Change this to a
> u64 to handle the overflow.
>
> Signed-off-by: Bradley Bolen <[email protected]>
> ---
> drivers/mmc/core/mmc.c | 4 ++--
> include/linux/mmc/card.h | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index
> c8804895595f..4e89cf6524a1 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -297,7 +297,7 @@ static void mmc_manage_enhanced_area(struct
> mmc_card *card, u8 *ext_csd)
> }
> }
>
> -static void mmc_part_add(struct mmc_card *card, unsigned int size,
> +static void mmc_part_add(struct mmc_card *card, u64 size,
> unsigned int part_cfg, char *name, int idx, bool ro,
> int area_type)
> {
> @@ -345,7 +345,7 @@ static void mmc_manage_gp_partitions(struct
> mmc_card *card, u8 *ext_csd)
> ext_csd[EXT_CSD_GP_SIZE_MULT + idx * 3];
> part_size *= (size_t)(hc_erase_grp_sz *
Need to adjust part_size as well.

Thanks,
Avri
> hc_wp_grp_sz);
> - mmc_part_add(card, part_size << 19,
> + mmc_part_add(card, (u64)part_size << 19,
> EXT_CSD_PART_CONFIG_ACC_GP0 + idx,
> "gp%d", idx, false,
> MMC_BLK_DATA_AREA_GP); diff --git
> a/include/linux/mmc/card.h b/include/linux/mmc/card.h index
> 9b6336ad3266..b59d35bb50ba 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -226,7 +226,7 @@ struct mmc_queue_req;
> * MMC Physical partitions
> */
> struct mmc_part {
> - unsigned int size; /* partition size (in bytes) */
> + u64 size; /* partition size (in bytes) */
> unsigned int part_cfg; /* partition type */
> char name[MAX_MMC_PART_NAME_LEN];
> bool force_ro; /* to make boot parts RO by default */
> --
> 2.17.1