[PATCH 5.4 031/142] mlxsw: spectrum: Fix use-after-free of split/unsplit/type_set in case reload fails

[Greg Kroah-Hartman]

From: Jiri Pirko <j...@mellanox.com>

commit 4340f42f207eacb81e7a6b6bb1e3b6afad9a2e26 upstream.

In case of reload fail, the mlxsw_sp->ports contains a pointer to a
freed memory (either by reload_down() or reload_up() error path).
Fix this by initializing the pointer to NULL and checking it before
dereferencing in split/unsplit/type_set callpaths.

Fixes: 24cc68ad6c46 ("mlxsw: core: Add support for reload")
Reported-by: Danielle Ratson <daniel...@mellanox.com>
Signed-off-by: Jiri Pirko <j...@mellanox.com>
Signed-off-by: Ido Schimmel <ido...@mellanox.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/net/ethernet/mellanox/mlxsw/spectrum.c |   14 ++++++++++++--
 drivers/net/ethernet/mellanox/mlxsw/switchx2.c |    8 ++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -3932,6 +3932,7 @@ static void mlxsw_sp_ports_remove(struct
        mlxsw_sp_cpu_port_remove(mlxsw_sp);
        kfree(mlxsw_sp->port_to_module);
        kfree(mlxsw_sp->ports);
+       mlxsw_sp->ports = NULL;
 }
 
 static int mlxsw_sp_ports_create(struct mlxsw_sp *mlxsw_sp)
@@ -3986,6 +3987,7 @@ err_cpu_port_create:
        kfree(mlxsw_sp->port_to_module);
 err_port_to_module_alloc:
        kfree(mlxsw_sp->ports);
+       mlxsw_sp->ports = NULL;
        return err;
 }
 
@@ -4040,6 +4042,14 @@ static void mlxsw_sp_port_unsplit_create
        }
 }
 
+static struct mlxsw_sp_port *
+mlxsw_sp_port_get_by_local_port(struct mlxsw_sp *mlxsw_sp, u8 local_port)
+{
+       if (mlxsw_sp->ports && mlxsw_sp->ports[local_port])
+               return mlxsw_sp->ports[local_port];
+       return NULL;
+}
+
 static int mlxsw_sp_port_split(struct mlxsw_core *mlxsw_core, u8 local_port,
                               unsigned int count,
                               struct netlink_ext_ack *extack)
@@ -4058,7 +4068,7 @@ static int mlxsw_sp_port_split(struct ml
        local_ports_in_1x = MLXSW_CORE_RES_GET(mlxsw_core, LOCAL_PORTS_IN_1X);
        local_ports_in_2x = MLXSW_CORE_RES_GET(mlxsw_core, LOCAL_PORTS_IN_2X);
 
-       mlxsw_sp_port = mlxsw_sp->ports[local_port];
+       mlxsw_sp_port = mlxsw_sp_port_get_by_local_port(mlxsw_sp, local_port);
        if (!mlxsw_sp_port) {
                dev_err(mlxsw_sp->bus_info->dev, "Port number \"%d\" does not 
exist\n",
                        local_port);
@@ -4136,7 +4146,7 @@ static int mlxsw_sp_port_unsplit(struct
        local_ports_in_1x = MLXSW_CORE_RES_GET(mlxsw_core, LOCAL_PORTS_IN_1X);
        local_ports_in_2x = MLXSW_CORE_RES_GET(mlxsw_core, LOCAL_PORTS_IN_2X);
 
-       mlxsw_sp_port = mlxsw_sp->ports[local_port];
+       mlxsw_sp_port = mlxsw_sp_port_get_by_local_port(mlxsw_sp, local_port);
        if (!mlxsw_sp_port) {
                dev_err(mlxsw_sp->bus_info->dev, "Port number \"%d\" does not 
exist\n",
                        local_port);
--- a/drivers/net/ethernet/mellanox/mlxsw/switchx2.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/switchx2.c
@@ -1258,6 +1258,7 @@ static void mlxsw_sx_ports_remove(struct
                if (mlxsw_sx_port_created(mlxsw_sx, i))
                        mlxsw_sx_port_remove(mlxsw_sx, i);
        kfree(mlxsw_sx->ports);
+       mlxsw_sx->ports = NULL;
 }
 
 static int mlxsw_sx_ports_create(struct mlxsw_sx *mlxsw_sx)
@@ -1292,6 +1293,7 @@ err_port_module_info_get:
                if (mlxsw_sx_port_created(mlxsw_sx, i))
                        mlxsw_sx_port_remove(mlxsw_sx, i);
        kfree(mlxsw_sx->ports);
+       mlxsw_sx->ports = NULL;
        return err;
 }
 
@@ -1375,6 +1377,12 @@ static int mlxsw_sx_port_type_set(struct
        u8 module, width;
        int err;
 
+       if (!mlxsw_sx->ports || !mlxsw_sx->ports[local_port]) {
+               dev_err(mlxsw_sx->bus_info->dev, "Port number \"%d\" does not 
exist\n",
+                       local_port);
+               return -EINVAL;
+       }
+
        if (new_type == DEVLINK_PORT_TYPE_AUTO)
                return -EOPNOTSUPP;