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Subject[PATCH 4.19 18/96] net/mlx5: FPGA, tls, idr remove on flow delete
Date
From: Saeed Mahameed <saeedm@mellanox.com>

[ Upstream commit df3a8344d404a810b4aadbf19b08c8232fbaa715 ]

Flow is kfreed on mlx5_fpga_tls_del_flow but kept in the idr data
structure, this is risky and can cause use-after-free, since the
idr_remove is delayed until tls_send_teardown_cmd completion.

Instead of delaying idr_remove, in this patch we do it on
mlx5_fpga_tls_del_flow, before actually kfree(flow).

Added synchronize_rcu before kfree(flow)

Fixes: ab412e1dd7db ("net/mlx5: Accel, add TLS rx offload routines")
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 | 43 +++++++--------------
1 file changed, 15 insertions(+), 28 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fpga/tls.c
@@ -148,14 +148,16 @@ static int mlx5_fpga_tls_alloc_swid(stru
return ret;
}

-static void mlx5_fpga_tls_release_swid(struct idr *idr,
- spinlock_t *idr_spinlock, u32 swid)
+static void *mlx5_fpga_tls_release_swid(struct idr *idr,
+ spinlock_t *idr_spinlock, u32 swid)
{
unsigned long flags;
+ void *ptr;

spin_lock_irqsave(idr_spinlock, flags);
- idr_remove(idr, swid);
+ ptr = idr_remove(idr, swid);
spin_unlock_irqrestore(idr_spinlock, flags);
+ return ptr;
}

static void mlx_tls_kfree_complete(struct mlx5_fpga_conn *conn,
@@ -165,20 +167,12 @@ static void mlx_tls_kfree_complete(struc
kfree(buf);
}

-struct mlx5_teardown_stream_context {
- struct mlx5_fpga_tls_command_context cmd;
- u32 swid;
-};
-
static void
mlx5_fpga_tls_teardown_completion(struct mlx5_fpga_conn *conn,
struct mlx5_fpga_device *fdev,
struct mlx5_fpga_tls_command_context *cmd,
struct mlx5_fpga_dma_buf *resp)
{
- struct mlx5_teardown_stream_context *ctx =
- container_of(cmd, struct mlx5_teardown_stream_context, cmd);
-
if (resp) {
u32 syndrome = MLX5_GET(tls_resp, resp->sg[0].data, syndrome);

@@ -186,14 +180,6 @@ mlx5_fpga_tls_teardown_completion(struct
mlx5_fpga_err(fdev,
"Teardown stream failed with syndrome = %d",
syndrome);
- else if (MLX5_GET(tls_cmd, cmd->buf.sg[0].data, direction_sx))
- mlx5_fpga_tls_release_swid(&fdev->tls->tx_idr,
- &fdev->tls->tx_idr_spinlock,
- ctx->swid);
- else
- mlx5_fpga_tls_release_swid(&fdev->tls->rx_idr,
- &fdev->tls->rx_idr_spinlock,
- ctx->swid);
}
mlx5_fpga_tls_put_command_ctx(cmd);
}
@@ -253,7 +239,7 @@ int mlx5_fpga_tls_resync_rx(struct mlx5_
static void mlx5_fpga_tls_send_teardown_cmd(struct mlx5_core_dev *mdev,
void *flow, u32 swid, gfp_t flags)
{
- struct mlx5_teardown_stream_context *ctx;
+ struct mlx5_fpga_tls_command_context *ctx;
struct mlx5_fpga_dma_buf *buf;
void *cmd;

@@ -261,7 +247,7 @@ static void mlx5_fpga_tls_send_teardown_
if (!ctx)
return;

- buf = &ctx->cmd.buf;
+ buf = &ctx->buf;
cmd = (ctx + 1);
MLX5_SET(tls_cmd, cmd, command_type, CMD_TEARDOWN_STREAM);
MLX5_SET(tls_cmd, cmd, swid, swid);
@@ -272,8 +258,7 @@ static void mlx5_fpga_tls_send_teardown_
buf->sg[0].data = cmd;
buf->sg[0].size = MLX5_TLS_COMMAND_SIZE;

- ctx->swid = swid;
- mlx5_fpga_tls_cmd_send(mdev->fpga, &ctx->cmd,
+ mlx5_fpga_tls_cmd_send(mdev->fpga, ctx,
mlx5_fpga_tls_teardown_completion);
}

@@ -283,13 +268,14 @@ void mlx5_fpga_tls_del_flow(struct mlx5_
struct mlx5_fpga_tls *tls = mdev->fpga->tls;
void *flow;

- rcu_read_lock();
if (direction_sx)
- flow = idr_find(&tls->tx_idr, swid);
+ flow = mlx5_fpga_tls_release_swid(&tls->tx_idr,
+ &tls->tx_idr_spinlock,
+ swid);
else
- flow = idr_find(&tls->rx_idr, swid);
-
- rcu_read_unlock();
+ flow = mlx5_fpga_tls_release_swid(&tls->rx_idr,
+ &tls->rx_idr_spinlock,
+ swid);

if (!flow) {
mlx5_fpga_err(mdev->fpga, "No flow information for swid %u\n",
@@ -297,6 +283,7 @@ void mlx5_fpga_tls_del_flow(struct mlx5_
return;
}

+ synchronize_rcu(); /* before kfree(flow) */
mlx5_fpga_tls_send_teardown_cmd(mdev, flow, swid, flags);
}


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