[PATCH] IB/mlx5: Fix a possible null-pointer dereference in set_roce_addr()

[Tuo Li <islituo@gmail.com>]

The pointer gid is checked at the beginning of set_roce_addr(). However,
if it is NULL, the function continues execution and may dereference gid
when calling mlx5_core_roce_gid_set():

  return mlx5_core_roce_gid_set(..., gid->raw, ...)

This can lead to a null-pointer dereference. To prevent this, add an else
branch that return -EINVAL when gid is NULL, and remove the redundant gid
check in the IB_GID_TYPE_ROCE_UDP_ENCAP case.

Signed-off-by: Tuo Li <islituo@gmail.com>
---
 drivers/infiniband/hw/mlx5/main.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 40284bbb45d6..d68a58d249d4 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -645,6 +645,8 @@ int set_roce_addr(struct mlx5_ib_dev *dev, u32 port_num,
 		ret = rdma_read_gid_l2_fields(attr, &vlan_id, &mac[0]);
 		if (ret)
 			return ret;
+	} else {
+		return -EINVAL;
 	}
 
 	switch (gid_type) {
@@ -653,7 +655,7 @@ int set_roce_addr(struct mlx5_ib_dev *dev, u32 port_num,
 		break;
 	case IB_GID_TYPE_ROCE_UDP_ENCAP:
 		roce_version = MLX5_ROCE_VERSION_2;
-		if (gid && ipv6_addr_v4mapped((void *)gid))
+		if (ipv6_addr_v4mapped((void *)gid))
 			roce_l3_type = MLX5_ROCE_L3_TYPE_IPV4;
 		else
 			roce_l3_type = MLX5_ROCE_L3_TYPE_IPV6;
-- 
2.43.0