[PATCH] net/mlx5: DR, Prefer kcalloc over open coded arithmetic
From: Len Baker
Date: Sun Sep 05 2021 - 03:50:20 EST
As noted in the "Deprecated Interfaces, Language Features, Attributes,
and Conventions" documentation [1], size calculations (especially
multiplication) should not be performed in memory allocator (or similar)
function arguments due to the risk of them overflowing. This could lead
to values wrapping around and a smaller allocation being made than the
caller was expecting. Using those allocations could lead to linear
overflows of heap memory and other misbehaviors.
So, refactor the code a bit to use the purpose specific kcalloc()
function instead of the argument size * count in the kzalloc() function.
[1] https://www.kernel.org/doc/html/v5.14/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
Signed-off-by: Len Baker <len.baker@xxxxxxx>
---
.../net/ethernet/mellanox/mlx5/core/steering/dr_action.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_action.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_action.c
index 6475ba35cf6b..e8957dad3bb1 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_action.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_action.c
@@ -716,6 +716,7 @@ mlx5dr_action_create_mult_dest_tbl(struct mlx5dr_domain *dmn,
struct mlx5dr_action *action;
bool reformat_req = false;
u32 num_of_ref = 0;
+ u32 ref_act_cnt;
int ret;
int i;
@@ -724,11 +725,14 @@ mlx5dr_action_create_mult_dest_tbl(struct mlx5dr_domain *dmn,
return NULL;
}
- hw_dests = kzalloc(sizeof(*hw_dests) * num_of_dests, GFP_KERNEL);
+ hw_dests = kcalloc(num_of_dests, sizeof(*hw_dests), GFP_KERNEL);
if (!hw_dests)
return NULL;
- ref_actions = kzalloc(sizeof(*ref_actions) * num_of_dests * 2, GFP_KERNEL);
+ if (unlikely(check_mul_overflow(num_of_dests, 2u, &ref_act_cnt)))
+ goto free_hw_dests;
+
+ ref_actions = kcalloc(ref_act_cnt, sizeof(*ref_actions), GFP_KERNEL);
if (!ref_actions)
goto free_hw_dests;
--
2.25.1