2019-11-07 03:27:28

by Bradley Bolen

Subject: [PATCH v2] 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 | 6 +++---
include/linux/mmc/card.h | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index c880489..fc02124 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)
{
@@ -313,7 +313,7 @@ static void mmc_manage_gp_partitions(struct mmc_card *card, u8 *ext_csd)
{
int idx;
u8 hc_erase_grp_sz, hc_wp_grp_sz;
- unsigned int part_size;
+ u64 part_size;

/*
* General purpose partition feature support --
@@ -362,7 +362,7 @@ static void mmc_manage_gp_partitions(struct mmc_card *card, u8 *ext_csd)
static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd)
{
int err = 0, idx;
- unsigned int part_size;
+ u64 part_size;
struct device_node *np;
bool broken_hpi = false;

diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 9b6336a..b59d35b 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 */
--
2.7.4

2019-11-07 08:33:47

by Avri Altman

Subject: RE: [PATCH v2] 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]>
Looks fine.
Avri

> ---
> drivers/mmc/core/mmc.c | 6 +++---
> include/linux/mmc/card.h | 2 +-
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index
> c880489..fc02124 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)
> {
> @@ -313,7 +313,7 @@ static void mmc_manage_gp_partitions(struct
> mmc_card *card, u8 *ext_csd) {
> int idx;
> u8 hc_erase_grp_sz, hc_wp_grp_sz;
> - unsigned int part_size;
> + u64 part_size;
>
> /*
> * General purpose partition feature support -- @@ -362,7 +362,7 @@
> static void mmc_manage_gp_partitions(struct mmc_card *card, u8 *ext_csd)
> static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd) {
> int err = 0, idx;
> - unsigned int part_size;
> + u64 part_size;
> struct device_node *np;
> bool broken_hpi = false;
>
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h index
> 9b6336a..b59d35b 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 */
> --
> 2.7.4

2019-11-14 11:15:52

by Ulf Hansson

Subject: Re: [PATCH v2] mmc: core: Fix size overflow for mmc partitions

On Thu, 7 Nov 2019 at 04:26, Bradley Bolen <[email protected]> wrote:
>
> 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 | 6 +++---
> include/linux/mmc/card.h | 2 +-
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index c880489..fc02124 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)
> {
> @@ -313,7 +313,7 @@ static void mmc_manage_gp_partitions(struct mmc_card *card, u8 *ext_csd)
> {
> int idx;
> u8 hc_erase_grp_sz, hc_wp_grp_sz;
> - unsigned int part_size;
> + u64 part_size;

There is also a cast to a "size_t" while computing the part_size in
mmc_manage_gp_partitions(). Should we remove that as well?

[...]

Kind regards
Uffe