[PATCH 5.14 146/334] devlink: Break parameter notification sequence to be before/after unload/load driver

From: Greg Kroah-Hartman
Date: Mon Sep 13 2021 - 10:34:52 EST

From: Leon Romanovsky <leonro@xxxxxxxxxx>

[ Upstream commit 05a7f4a8dff19999ca8a83a35ff4782689de7bfc ]

The change of namespaces during devlink reload calls to driver unload
before it accesses devlink parameters. The commands below causes to
use-after-free bug when trying to get flow steering mode.

* ip netns add n1
* devlink dev reload pci/0000:00:09.0 netns n1

==================================================================
BUG: KASAN: use-after-free in mlx5_devlink_fs_mode_get+0x96/0xa0 [mlx5_core]
Read of size 4 at addr ffff888009d04308 by task devlink/275

CPU: 6 PID: 275 Comm: devlink Not tainted 5.12.0-rc2+ #2853
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Call Trace:
dump_stack+0x93/0xc2
print_address_description.constprop.0+0x18/0x140
? mlx5_devlink_fs_mode_get+0x96/0xa0 [mlx5_core]
? mlx5_devlink_fs_mode_get+0x96/0xa0 [mlx5_core]
kasan_report.cold+0x7c/0xd8
? mlx5_devlink_fs_mode_get+0x96/0xa0 [mlx5_core]
mlx5_devlink_fs_mode_get+0x96/0xa0 [mlx5_core]
devlink_nl_param_fill+0x1c8/0xe80
? __free_pages_ok+0x37a/0x8a0
? devlink_flash_update_timeout_notify+0xd0/0xd0
? lock_acquire+0x1a9/0x6d0
? fs_reclaim_acquire+0xb7/0x160
? lock_is_held_type+0x98/0x110
? 0xffffffff81000000
? lock_release+0x1f9/0x6c0
? fs_reclaim_release+0xa1/0xf0
? lock_downgrade+0x6d0/0x6d0
? lock_is_held_type+0x98/0x110
? lock_is_held_type+0x98/0x110
? memset+0x20/0x40
? __build_skb_around+0x1f8/0x2b0
devlink_param_notify+0x6d/0x180
devlink_reload+0x1c3/0x520
? devlink_remote_reload_actions_performed+0x30/0x30
? mutex_trylock+0x24b/0x2d0
? devlink_nl_cmd_reload+0x62b/0x1070
devlink_nl_cmd_reload+0x66d/0x1070
? devlink_reload+0x520/0x520
? devlink_get_from_attrs+0x1bc/0x260
? devlink_nl_pre_doit+0x64/0x4d0
genl_family_rcv_msg_doit+0x1e9/0x2f0
? mutex_lock_io_nested+0x1130/0x1130
? genl_family_rcv_msg_attrs_parse.constprop.0+0x240/0x240
? security_capable+0x51/0x90
genl_rcv_msg+0x27f/0x4a0
? genl_get_cmd+0x3c0/0x3c0
? lock_acquire+0x1a9/0x6d0
? devlink_reload+0x520/0x520
? lock_release+0x6c0/0x6c0
netlink_rcv_skb+0x11d/0x340
? genl_get_cmd+0x3c0/0x3c0
? netlink_ack+0x9f0/0x9f0
? lock_release+0x1f9/0x6c0
genl_rcv+0x24/0x40
netlink_unicast+0x433/0x700
? netlink_attachskb+0x730/0x730
? _copy_from_iter_full+0x178/0x650
? __alloc_skb+0x113/0x2b0
netlink_sendmsg+0x6f1/0xbd0
? netlink_unicast+0x700/0x700
? lock_is_held_type+0x98/0x110
? netlink_unicast+0x700/0x700
sock_sendmsg+0xb0/0xe0
__sys_sendto+0x193/0x240
? __x64_sys_getpeername+0xb0/0xb0
? do_sys_openat2+0x10b/0x370
? __up_read+0x1a1/0x7b0
? do_user_addr_fault+0x219/0xdc0
? __x64_sys_openat+0x120/0x1d0
? __x64_sys_open+0x1a0/0x1a0
__x64_sys_sendto+0xdd/0x1b0
? syscall_enter_from_user_mode+0x1d/0x50
do_syscall_64+0x2d/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fc69d0af14a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 15 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 76 c3 0f 1f 44 00 00 55 48 83 ec 30 44 89 4c
RSP: 002b:00007ffc1d8292f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007fc69d0af14a
RDX: 0000000000000038 RSI: 0000555f57c56440 RDI: 0000000000000003
RBP: 0000555f57c56410 R08: 00007fc69d17b200 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 146:
kasan_save_stack+0x1b/0x40
__kasan_kmalloc+0x99/0xc0
mlx5_init_fs+0xf0/0x1c50 [mlx5_core]
mlx5_load+0xd2/0x180 [mlx5_core]
mlx5_init_one+0x2f6/0x450 [mlx5_core]
probe_one+0x47d/0x6e0 [mlx5_core]
pci_device_probe+0x2a0/0x4a0
really_probe+0x20a/0xc90
driver_probe_device+0xd8/0x380
device_driver_attach+0x1df/0x250
__driver_attach+0xff/0x240
bus_for_each_dev+0x11e/0x1a0
bus_add_driver+0x309/0x570
driver_register+0x1ee/0x380
0xffffffffa06b8062
do_one_initcall+0xd5/0x410
do_init_module+0x1c8/0x760
load_module+0x6d8b/0x9650
__do_sys_finit_module+0x118/0x1b0
do_syscall_64+0x2d/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 275:
kasan_save_stack+0x1b/0x40
kasan_set_track+0x1c/0x30
kasan_set_free_info+0x20/0x30
__kasan_slab_free+0x102/0x140
slab_free_freelist_hook+0x74/0x1b0
kfree+0xd7/0x2a0
mlx5_unload+0x16/0xb0 [mlx5_core]
mlx5_unload_one+0xae/0x120 [mlx5_core]
mlx5_devlink_reload_down+0x1bc/0x380 [mlx5_core]
devlink_reload+0x141/0x520
devlink_nl_cmd_reload+0x66d/0x1070
genl_family_rcv_msg_doit+0x1e9/0x2f0
genl_rcv_msg+0x27f/0x4a0
netlink_rcv_skb+0x11d/0x340
genl_rcv+0x24/0x40
netlink_unicast+0x433/0x700
netlink_sendmsg+0x6f1/0xbd0
sock_sendmsg+0xb0/0xe0
__sys_sendto+0x193/0x240
__x64_sys_sendto+0xdd/0x1b0
do_syscall_64+0x2d/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff888009d04300
which belongs to the cache kmalloc-128 of size 128
The buggy address is located 8 bytes inside of
128-byte region [ffff888009d04300, ffff888009d04380)
The buggy address belongs to the page:
page:0000000086a64ecc refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888009d04000 pfn:0x9d04
head:0000000086a64ecc order:1 compound_mapcount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 ffffea0000203980 0000000200000002 ffff8880050428c0
raw: ffff888009d04000 000000008020001d 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff888009d04200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888009d04280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888009d04300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888009d04380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888009d04400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

The right solution to devlink reload is to notify about deletion of
parameters, unload driver, change net namespaces, load driver and notify
about addition of parameters.

Fixes: 070c63f20f6c ("net: devlink: allow to change namespaces during reload")
Reviewed-by: Parav Pandit <parav@xxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/core/devlink.c | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 85032626de24..3963b1bc1e59 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -3801,10 +3801,12 @@ static void devlink_param_notify(struct devlink *devlink,
struct devlink_param_item *param_item,
enum devlink_command cmd);

-static void devlink_reload_netns_change(struct devlink *devlink,
- struct net *dest_net)
+static void devlink_ns_change_notify(struct devlink *devlink,
+ struct net *dest_net, struct net *curr_net,
+ bool new)
{
struct devlink_param_item *param_item;
+ enum devlink_command cmd;

/* Userspace needs to be notified about devlink objects
* removed from original and entering new network namespace.
@@ -3812,17 +3814,18 @@ static void devlink_reload_netns_change(struct devlink *devlink,
* reload process so the notifications are generated separatelly.
*/

- list_for_each_entry(param_item, &devlink->param_list, list)
- devlink_param_notify(devlink, 0, param_item,
- DEVLINK_CMD_PARAM_DEL);
- devlink_notify(devlink, DEVLINK_CMD_DEL);
+ if (!dest_net || net_eq(dest_net, curr_net))
+ return;

- __devlink_net_set(devlink, dest_net);
+ if (new)
+ devlink_notify(devlink, DEVLINK_CMD_NEW);

- devlink_notify(devlink, DEVLINK_CMD_NEW);
+ cmd = new ? DEVLINK_CMD_PARAM_NEW : DEVLINK_CMD_PARAM_DEL;
list_for_each_entry(param_item, &devlink->param_list, list)
- devlink_param_notify(devlink, 0, param_item,
- DEVLINK_CMD_PARAM_NEW);
+ devlink_param_notify(devlink, 0, param_item, cmd);
+
+ if (!new)
+ devlink_notify(devlink, DEVLINK_CMD_DEL);
}

static bool devlink_reload_supported(const struct devlink_ops *ops)
@@ -3902,6 +3905,7 @@ static int devlink_reload(struct devlink *devlink, struct net *dest_net,
u32 *actions_performed, struct netlink_ext_ack *extack)
{
u32 remote_reload_stats[DEVLINK_RELOAD_STATS_ARRAY_SIZE];
+ struct net *curr_net;
int err;

if (!devlink->reload_enabled)
@@ -3909,18 +3913,22 @@ static int devlink_reload(struct devlink *devlink, struct net *dest_net,

memcpy(remote_reload_stats, devlink->stats.remote_reload_stats,
sizeof(remote_reload_stats));
+
+ curr_net = devlink_net(devlink);
+ devlink_ns_change_notify(devlink, dest_net, curr_net, false);
err = devlink->ops->reload_down(devlink, !!dest_net, action, limit, extack);
if (err)
return err;

- if (dest_net && !net_eq(dest_net, devlink_net(devlink)))
- devlink_reload_netns_change(devlink, dest_net);
+ if (dest_net && !net_eq(dest_net, curr_net))
+ __devlink_net_set(devlink, dest_net);

err = devlink->ops->reload_up(devlink, action, limit, actions_performed, extack);
devlink_reload_failed_set(devlink, !!err);
if (err)
return err;

+ devlink_ns_change_notify(devlink, dest_net, curr_net, true);
WARN_ON(!(*actions_performed & BIT(action)));
/* Catch driver on updating the remote action within devlink reload */
WARN_ON(memcmp(remote_reload_stats, devlink->stats.remote_reload_stats,
--
2.30.2