[PATCH 4.19 034/101] net: mlx5: Add a missing check on idr_find, free buf

[Greg Kroah-Hartman]

[ Upstream commit 8e949363f017e2011464812a714fb29710fb95b4 ]

idr_find() can return a NULL value to 'flow' which is used without a
check. The patch adds a check to avoid potential NULL pointer dereference.

In case of mlx5_fpga_sbu_conn_sendmsg() failure, free buf allocated
using kzalloc.

Fixes: ab412e1dd7db ("net/mlx5: Accel, add TLS rx offload routines")
Signed-off-by: Aditya Pakki <pakki...@umn.edu>
Reviewed-by: Yuval Shaia <yuval.sh...@oracle.com>
Signed-off-by: Saeed Mahameed <sae...@mellanox.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c 
b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
index 5cf5f2a9d51f..8de64e88c670 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
@@ -217,15 +217,21 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_core_dev *mdev, 
u32 handle, u32 seq,
        void *cmd;
        int ret;
 
+       rcu_read_lock();
+       flow = idr_find(&mdev->fpga->tls->rx_idr, ntohl(handle));
+       rcu_read_unlock();
+
+       if (!flow) {
+               WARN_ONCE(1, "Received NULL pointer for handle\n");
+               return -EINVAL;
+       }
+
        buf = kzalloc(size, GFP_ATOMIC);
        if (!buf)
                return -ENOMEM;
 
        cmd = (buf + 1);
 
-       rcu_read_lock();
-       flow = idr_find(&mdev->fpga->tls->rx_idr, ntohl(handle));
-       rcu_read_unlock();
        mlx5_fpga_tls_flow_to_cmd(flow, cmd);
 
        MLX5_SET(tls_cmd, cmd, swid, ntohl(handle));
@@ -238,6 +244,8 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_core_dev *mdev, u32 
handle, u32 seq,
        buf->complete = mlx_tls_kfree_complete;
 
        ret = mlx5_fpga_sbu_conn_sendmsg(mdev->fpga->tls->conn, buf);
+       if (ret < 0)
+               kfree(buf);
 
        return ret;
 }
-- 
2.19.1