[PATCH 4.19 16/96] net/mlx5: FPGA, tls, hold rcu read lock a bit longer

Greg Kroah-Hartman
2019-04-24T17:50:12Z

From: Saeed Mahameed <saeedm@mellanox.com>

[ Upstream commit 31634bf5dcc418b5b2cacd954394c0c4620db6a2 ]

To avoid use-after-free, hold the rcu read lock until we are done copying
flow data into the command buffer.

Fixes: ab412e1dd7db ("net/mlx5: Accel, add TLS rx offload routines")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
@@ -217,22 +217,22 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_
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));
+ if (unlikely(!flow)) {
+ rcu_read_unlock();
+ WARN_ONCE(1, "Received NULL pointer for handle\n");
+ kfree(buf);
+ return -EINVAL;
+ }
mlx5_fpga_tls_flow_to_cmd(flow, cmd);
+ rcu_read_unlock();

MLX5_SET(tls_cmd, cmd, swid, ntohl(handle));
MLX5_SET64(tls_cmd, cmd, tls_rcd_sn, be64_to_cpu(rcd_sn));