2022-01-26 01:20:49

by Gustavo A. R. Silva

Subject: [PATCH][next] mlxsw: spectrum_kvdl: Use struct_size() helper in kzalloc()

Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worst scenario, could lead to heap overflows.

Also, address the following sparse warnings:
drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c:229:24: warning: using sizeof on a flexible structure

Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c
index a9fff8adc75e..d20e794e01ca 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c
@@ -213,7 +213,6 @@ mlxsw_sp1_kvdl_part_init(struct mlxsw_sp *mlxsw_sp,
struct mlxsw_sp1_kvdl_part *part;
bool need_update = true;
unsigned int nr_entries;
- size_t usage_size;
u64 resource_size;
int err;

@@ -225,8 +224,8 @@ mlxsw_sp1_kvdl_part_init(struct mlxsw_sp *mlxsw_sp,
}

nr_entries = div_u64(resource_size, info->alloc_size);
- usage_size = BITS_TO_LONGS(nr_entries) * sizeof(unsigned long);
- part = kzalloc(sizeof(*part) + usage_size, GFP_KERNEL);
+ part = kzalloc(struct_size(part, usage, BITS_TO_LONGS(nr_entries)),
+ GFP_KERNEL);
if (!part)
return ERR_PTR(-ENOMEM);

--
2.27.0

2022-01-26 20:25:52

by Ido Schimmel

Subject: Re: [PATCH][next] mlxsw: spectrum_kvdl: Use struct_size() helper in kzalloc()

On Tue, Jan 25, 2022 at 11:01:28AM -0600, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version,
> in order to avoid any potential type mistakes or integer overflows that,
> in the worst scenario, could lead to heap overflows.
>
> Also, address the following sparse warnings:
> drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c:229:24: warning: using sizeof on a flexible structure
>
> Link: https://github.com/KSPP/linux/issues/174
> Signed-off-by: Gustavo A. R. Silva <[email protected]>

Reviewed-by: Ido Schimmel <[email protected]>

Thanks

2022-01-26 21:07:21

by Petr Machata

Subject: Re: [PATCH][next] mlxsw: spectrum_kvdl: Use struct_size() helper in kzalloc()

"Gustavo A. R. Silva" <[email protected]> writes:

> Make use of the struct_size() helper instead of an open-coded version,
> in order to avoid any potential type mistakes or integer overflows that,
> in the worst scenario, could lead to heap overflows.
>
> Also, address the following sparse warnings:
> drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c:229:24: warning: using sizeof on a flexible structure
>
> Link: https://github.com/KSPP/linux/issues/174
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
> ---
> drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c
> index a9fff8adc75e..d20e794e01ca 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c
> @@ -213,7 +213,6 @@ mlxsw_sp1_kvdl_part_init(struct mlxsw_sp *mlxsw_sp,
> struct mlxsw_sp1_kvdl_part *part;
> bool need_update = true;
> unsigned int nr_entries;
> - size_t usage_size;
> u64 resource_size;
> int err;
>
> @@ -225,8 +224,8 @@ mlxsw_sp1_kvdl_part_init(struct mlxsw_sp *mlxsw_sp,
> }
>
> nr_entries = div_u64(resource_size, info->alloc_size);
> - usage_size = BITS_TO_LONGS(nr_entries) * sizeof(unsigned long);
> - part = kzalloc(sizeof(*part) + usage_size, GFP_KERNEL);
> + part = kzalloc(struct_size(part, usage, BITS_TO_LONGS(nr_entries)),
> + GFP_KERNEL);
> if (!part)
> return ERR_PTR(-ENOMEM);

Reviewed-by: Petr Machata <[email protected]>