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mlxsw: spectrum_buffers: Fix memory corruptions on Spectrum-4 systems
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[ Upstream commit c28947d ]

The following two shared buffer operations make use of the Shared Buffer
Status Register (SBSR):

 # devlink sb occupancy snapshot pci/0000:01:00.0
 # devlink sb occupancy clearmax pci/0000:01:00.0

The register has two masks of 256 bits to denote on which ingress /
egress ports the register should operate on. Spectrum-4 has more than
256 ports, so the register was extended by cited commit with a new
'port_page' field.

However, when filling the register's payload, the driver specifies the
ports as absolute numbers and not relative to the first port of the port
page, resulting in memory corruptions [1].

Fix by specifying the ports relative to the first port of the port page.

[1]
BUG: KASAN: slab-use-after-free in mlxsw_sp_sb_occ_snapshot+0xb6d/0xbc0
Read of size 1 at addr ffff8881068cb00f by task devlink/1566
[...]
Call Trace:
 <TASK>
 dump_stack_lvl+0xc6/0x120
 print_report+0xce/0x670
 kasan_report+0xd7/0x110
 mlxsw_sp_sb_occ_snapshot+0xb6d/0xbc0
 mlxsw_devlink_sb_occ_snapshot+0x75/0xb0
 devlink_nl_sb_occ_snapshot_doit+0x1f9/0x2a0
 genl_family_rcv_msg_doit+0x20c/0x300
 genl_rcv_msg+0x567/0x800
 netlink_rcv_skb+0x170/0x450
 genl_rcv+0x2d/0x40
 netlink_unicast+0x547/0x830
 netlink_sendmsg+0x8d4/0xdb0
 __sys_sendto+0x49b/0x510
 __x64_sys_sendto+0xe5/0x1c0
 do_syscall_64+0xc1/0x1d0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
[...]
Allocated by task 1:
 kasan_save_stack+0x33/0x60
 kasan_save_track+0x14/0x30
 __kasan_kmalloc+0x8f/0xa0
 copy_verifier_state+0xbc2/0xfb0
 do_check_common+0x2c51/0xc7e0
 bpf_check+0x5107/0x9960
 bpf_prog_load+0xf0e/0x2690
 __sys_bpf+0x1a61/0x49d0
 __x64_sys_bpf+0x7d/0xc0
 do_syscall_64+0xc1/0x1d0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 1:
 kasan_save_stack+0x33/0x60
 kasan_save_track+0x14/0x30
 kasan_save_free_info+0x3b/0x60
 poison_slab_object+0x109/0x170
 __kasan_slab_free+0x14/0x30
 kfree+0xca/0x2b0
 free_verifier_state+0xce/0x270
 do_check_common+0x4828/0xc7e0
 bpf_check+0x5107/0x9960
 bpf_prog_load+0xf0e/0x2690
 __sys_bpf+0x1a61/0x49d0
 __x64_sys_bpf+0x7d/0xc0
 do_syscall_64+0xc1/0x1d0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fixes: f8538ae ("mlxsw: Add support for more than 256 ports in SBSR register")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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@idosch @gregkh
idosch authored and gregkh committed Jul 5, 2024
1 parent 2dfaf2c commit bfa86a9
Showing 1 changed file with 14 additions and 6 deletions.
20 changes: 14 additions & 6 deletions drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1607,8 +1607,8 @@ static void mlxsw_sp_sb_sr_occ_query_cb(struct mlxsw_core *mlxsw_core,
int mlxsw_sp_sb_occ_snapshot(struct mlxsw_core *mlxsw_core,
unsigned int sb_index)
{
u16 local_port, local_port_1, first_local_port, last_local_port;
struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
u16 local_port, local_port_1, last_local_port;
struct mlxsw_sp_sb_sr_occ_query_cb_ctx cb_ctx;
u8 masked_count, current_page = 0;
unsigned long cb_priv = 0;
Expand All @@ -1628,6 +1628,7 @@ int mlxsw_sp_sb_occ_snapshot(struct mlxsw_core *mlxsw_core,
masked_count = 0;
mlxsw_reg_sbsr_pack(sbsr_pl, false);
mlxsw_reg_sbsr_port_page_set(sbsr_pl, current_page);
first_local_port = current_page * MLXSW_REG_SBSR_NUM_PORTS_IN_PAGE;
last_local_port = current_page * MLXSW_REG_SBSR_NUM_PORTS_IN_PAGE +
MLXSW_REG_SBSR_NUM_PORTS_IN_PAGE - 1;

Expand All @@ -1645,9 +1646,12 @@ int mlxsw_sp_sb_occ_snapshot(struct mlxsw_core *mlxsw_core,
if (local_port != MLXSW_PORT_CPU_PORT) {
/* Ingress quotas are not supported for the CPU port */
mlxsw_reg_sbsr_ingress_port_mask_set(sbsr_pl,
local_port, 1);
local_port - first_local_port,
1);
}
mlxsw_reg_sbsr_egress_port_mask_set(sbsr_pl, local_port, 1);
mlxsw_reg_sbsr_egress_port_mask_set(sbsr_pl,
local_port - first_local_port,
1);
for (i = 0; i < mlxsw_sp->sb_vals->pool_count; i++) {
err = mlxsw_sp_sb_pm_occ_query(mlxsw_sp, local_port, i,
&bulk_list);
Expand Down Expand Up @@ -1684,7 +1688,7 @@ int mlxsw_sp_sb_occ_max_clear(struct mlxsw_core *mlxsw_core,
unsigned int sb_index)
{
struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
u16 local_port, last_local_port;
u16 local_port, first_local_port, last_local_port;
LIST_HEAD(bulk_list);
unsigned int masked_count;
u8 current_page = 0;
Expand All @@ -1702,6 +1706,7 @@ int mlxsw_sp_sb_occ_max_clear(struct mlxsw_core *mlxsw_core,
masked_count = 0;
mlxsw_reg_sbsr_pack(sbsr_pl, true);
mlxsw_reg_sbsr_port_page_set(sbsr_pl, current_page);
first_local_port = current_page * MLXSW_REG_SBSR_NUM_PORTS_IN_PAGE;
last_local_port = current_page * MLXSW_REG_SBSR_NUM_PORTS_IN_PAGE +
MLXSW_REG_SBSR_NUM_PORTS_IN_PAGE - 1;

Expand All @@ -1719,9 +1724,12 @@ int mlxsw_sp_sb_occ_max_clear(struct mlxsw_core *mlxsw_core,
if (local_port != MLXSW_PORT_CPU_PORT) {
/* Ingress quotas are not supported for the CPU port */
mlxsw_reg_sbsr_ingress_port_mask_set(sbsr_pl,
local_port, 1);
local_port - first_local_port,
1);
}
mlxsw_reg_sbsr_egress_port_mask_set(sbsr_pl, local_port, 1);
mlxsw_reg_sbsr_egress_port_mask_set(sbsr_pl,
local_port - first_local_port,
1);
for (i = 0; i < mlxsw_sp->sb_vals->pool_count; i++) {
err = mlxsw_sp_sb_pm_occ_clear(mlxsw_sp, local_port, i,
&bulk_list);
Expand Down

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