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mlxsw: spectrum_kvdl: Use struct_size() helper in kzalloc()

PATCH In review Gustavo A. R. Silva 3 participants 3 messages Jan 25, 2022 – Jan 26, 2022

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Networking Network drivers Mellanox Ethernet switch drivers
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Gustavo A. R. Silva

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#0 lore raw

PATCH 1/1 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(-)
drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c +2 -3
index a9fff8adc75e..d20e794e01ca 100644
@@ -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);
Signature · 1 line
2.27.0
Reviewed-by on v1 1/1
#1 lore raw
Quoted 9 lines · Gustavo A. R. Silva

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

maintainer Reviewed-by on v1 1/1
#2 lore raw
In reply to Gustavo A. R. Silva
Quoted 26 lines · Gustavo A. R. Silva

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(-)
drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c +0 -1
index a9fff8adc75e..d20e794e01ca 100644
@@ -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;

drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c mlxsw_sp1_kvdl_part_init(struct mlxsw_sp *mlxsw_sp, · line 230

Quoted 9 lines
drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c +2 -2
@@ -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]>