[PATCH 4.19 18/95] mlxsw: spectrum: Fix use-after-free of split/unsplit/type_set in case reload fails

From: Greg Kroah-Hartman
Date: Mon Jun 01 2020 - 14:03:30 EST


From: Jiri Pirko <jiri@xxxxxxxxxxxx>

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 <danieller@xxxxxxxxxxxx>
Signed-off-by: Jiri Pirko <jiri@xxxxxxxxxxxx>
Signed-off-by: Ido Schimmel <idosch@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
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
@@ -3126,6 +3126,7 @@ static void mlxsw_sp_ports_remove(struct
mlxsw_sp_port_remove(mlxsw_sp, i);
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)
@@ -3174,6 +3175,7 @@ err_port_module_info_get:
kfree(mlxsw_sp->port_to_module);
err_port_to_module_alloc:
kfree(mlxsw_sp->ports);
+ mlxsw_sp->ports = NULL;
return err;
}

@@ -3228,6 +3230,14 @@ 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)
@@ -3238,7 +3248,7 @@ static int mlxsw_sp_port_split(struct ml
int i;
int err;

- 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);
@@ -3305,7 +3315,7 @@ static int mlxsw_sp_port_unsplit(struct
unsigned int count;
int i;

- 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
@@ -1289,6 +1289,7 @@ 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)
@@ -1323,6 +1324,7 @@ 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;
}

@@ -1406,6 +1408,12 @@ 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;