[PATCH AUTOSEL 5.17 025/149] mlxsw: spectrum: Guard against invalid local ports

From: Sasha Levin
Date: Fri Apr 01 2022 - 10:28:40 EST


From: Amit Cohen <amcohen@xxxxxxxxxx>

[ Upstream commit bcdfd615f83b4bd04678109bf18022d1476e4bbf ]

When processing events generated by the device's firmware, the driver
protects itself from events reported for non-existent local ports, but
not for the CPU port (local port 0), which exists, but does not have all
the fields as any local port.

This can result in a NULL pointer dereference when trying access
'struct mlxsw_sp_port' fields which are not initialized for CPU port.

Commit 63b08b1f6834 ("mlxsw: spectrum: Protect driver from buggy firmware")
already handled such issue by bailing early when processing a PUDE event
reported for the CPU port.

Generalize the approach by moving the check to a common function and
making use of it in all relevant places.

Signed-off-by: Amit Cohen <amcohen@xxxxxxxxxx>
Signed-off-by: Ido Schimmel <idosch@xxxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/ethernet/mellanox/mlxsw/spectrum.c | 4 +---
drivers/net/ethernet/mellanox/mlxsw/spectrum.h | 7 +++++++
drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c | 3 +--
drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c | 3 +--
4 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index aa411dec62f0..eb1319d63613 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -2148,13 +2148,11 @@ static void mlxsw_sp_pude_event_func(const struct mlxsw_reg_info *reg,
struct mlxsw_sp *mlxsw_sp = priv;
struct mlxsw_sp_port *mlxsw_sp_port;
enum mlxsw_reg_pude_oper_status status;
- unsigned int max_ports;
u16 local_port;

- max_ports = mlxsw_core_max_ports(mlxsw_sp->core);
local_port = mlxsw_reg_pude_local_port_get(pude_pl);

- if (WARN_ON_ONCE(!local_port || local_port >= max_ports))
+ if (WARN_ON_ONCE(!mlxsw_sp_local_port_is_valid(mlxsw_sp, local_port)))
return;
mlxsw_sp_port = mlxsw_sp->ports[local_port];
if (!mlxsw_sp_port)
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.h b/drivers/net/ethernet/mellanox/mlxsw/spectrum.h
index bb2442e1f705..30942b6ffcf9 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.h
@@ -481,6 +481,13 @@ int
mlxsw_sp_port_vlan_classification_set(struct mlxsw_sp_port *mlxsw_sp_port,
bool is_8021ad_tagged,
bool is_8021q_tagged);
+static inline bool
+mlxsw_sp_local_port_is_valid(struct mlxsw_sp *mlxsw_sp, u16 local_port)
+{
+ unsigned int max_ports = mlxsw_core_max_ports(mlxsw_sp->core);
+
+ return local_port < max_ports && local_port;
+}

/* spectrum_buffers.c */
struct mlxsw_sp_hdroom_prio {
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
index 0ff163fbc775..35422e64d89f 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
@@ -568,12 +568,11 @@ void mlxsw_sp1_ptp_got_timestamp(struct mlxsw_sp *mlxsw_sp, bool ingress,
u8 domain_number, u16 sequence_id,
u64 timestamp)
{
- unsigned int max_ports = mlxsw_core_max_ports(mlxsw_sp->core);
struct mlxsw_sp_port *mlxsw_sp_port;
struct mlxsw_sp1_ptp_key key;
u8 types;

- if (WARN_ON_ONCE(local_port >= max_ports))
+ if (WARN_ON_ONCE(!mlxsw_sp_local_port_is_valid(mlxsw_sp, local_port)))
return;
mlxsw_sp_port = mlxsw_sp->ports[local_port];
if (!mlxsw_sp_port)
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
index 65c1724c63b0..bffdb41fc4ed 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c
@@ -2616,7 +2616,6 @@ static void mlxsw_sp_fdb_notify_mac_process(struct mlxsw_sp *mlxsw_sp,
char *sfn_pl, int rec_index,
bool adding)
{
- unsigned int max_ports = mlxsw_core_max_ports(mlxsw_sp->core);
struct mlxsw_sp_port_vlan *mlxsw_sp_port_vlan;
struct mlxsw_sp_bridge_device *bridge_device;
struct mlxsw_sp_bridge_port *bridge_port;
@@ -2630,7 +2629,7 @@ static void mlxsw_sp_fdb_notify_mac_process(struct mlxsw_sp *mlxsw_sp,

mlxsw_reg_sfn_mac_unpack(sfn_pl, rec_index, mac, &fid, &local_port);

- if (WARN_ON_ONCE(local_port >= max_ports))
+ if (WARN_ON_ONCE(!mlxsw_sp_local_port_is_valid(mlxsw_sp, local_port)))
return;
mlxsw_sp_port = mlxsw_sp->ports[local_port];
if (!mlxsw_sp_port) {
--
2.34.1