[PATCH AUTOSEL 5.6 32/47] mlxsw: spectrum: Fix use-after-free of split/unsplit/type_set in case reload fails

Sasha Levin
2020-05-28T12:08:15Z

From: Jiri Pirko <jiri@mellanox.com>

[ Upstream commit 4340f42f207eacb81e7a6b6bb1e3b6afad9a2e26 ]

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@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/mellanox/mlxsw/spectrum.c | 14 ++++++++++++--
drivers/net/ethernet/mellanox/mlxsw/switchx2.c | 8 ++++++++
2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index 7358b5bc7eb6..58ebabe99876 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -4043,6 +4043,7 @@ static void mlxsw_sp_ports_remove(struct mlxsw_sp *mlxsw_sp)
mlxsw_sp_port_remove(mlxsw_sp, i);
mlxsw_sp_cpu_port_remove(mlxsw_sp);
kfree(mlxsw_sp->ports);
+ mlxsw_sp->ports = NULL;
}

static int mlxsw_sp_ports_create(struct mlxsw_sp *mlxsw_sp)
@@ -4079,6 +4080,7 @@ err_port_create:
mlxsw_sp_cpu_port_remove(mlxsw_sp);
err_cpu_port_create:
kfree(mlxsw_sp->ports);
+ mlxsw_sp->ports = NULL;
return err;
}

@@ -4200,6 +4202,14 @@ static int mlxsw_sp_local_ports_offset(struct mlxsw_core *mlxsw_core,
return mlxsw_core_res_get(mlxsw_core, local_ports_in_x_res_id);
}

+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)
@@ -4213,7 +4223,7 @@ static int mlxsw_sp_port_split(struct mlxsw_core *mlxsw_core, u8 local_port,
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);
@@ -4308,7 +4318,7 @@ static int mlxsw_sp_port_unsplit(struct mlxsw_core *mlxsw_core, u8 local_port,
int offset;
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);
diff --git a/drivers/net/ethernet/mellanox/mlxsw/switchx2.c b/drivers/net/ethernet/mellanox/mlxsw/switchx2.c
index f0e98ec8f1ee..c69232445ab7 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/switchx2.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/switchx2.c
@@ -1259,6 +1259,7 @@ static void mlxsw_sx_ports_remove(struct mlxsw_sx *mlxsw_sx)
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)
@@ -1293,6 +1294,7 @@ 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;
}

@@ -1376,6 +1378,12 @@ static int mlxsw_sx_port_type_set(struct mlxsw_core *mlxsw_core, u8 local_port,
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;

--
2.25.1