554fe75c1b
Following scenario easily break driver logic and crash the kernel:
1. Add rule with mirred actions to same device.
2. Delete this rule.
In described scenario rule is not added to database and on deletion
driver access invalid entry.
Example:
$ tc filter add dev ens1f0_0 ingress protocol ip prio 1 \
flower skip_sw \
action mirred egress mirror dev ens1f0_1 pipe \
action mirred egress redirect dev ens1f0_1
$ tc filter del dev ens1f0_0 ingress protocol ip prio 1
Dmesg output:
[ 376.634396] mlx5_core 0000:82:00.0: mlx5_cmd_check:756:(pid 3439): DESTROY_FLOW_GROUP(0x934) op_mod(0x0) failed, status bad resource state(0x9), syndrome (0x563e2f)
[ 376.654983] mlx5_core 0000:82:00.0: del_hw_flow_group:567:(pid 3439): flow steering can't destroy fg 89 of ft 3145728
[ 376.673433] kasan: CONFIG_KASAN_INLINE enabled
[ 376.683769] kasan: GPF could be caused by NULL-ptr deref or user memory access
[ 376.695229] general protection fault: 0000 [#1] PREEMPT SMP KASAN PTI
[ 376.705069] CPU: 7 PID: 3439 Comm: tc Not tainted 5.4.0-rc5+ #76
[ 376.714959] Hardware name: Supermicro SYS-2028TP-DECTR/X10DRT-PT, BIOS 2.0a 08/12/2016
[ 376.726371] RIP: 0010:mlx5_del_flow_rules+0x105/0x960 [mlx5_core]
[ 376.735817] Code: 01 00 00 00 48 83 eb 08 e8 28 d9 ff ff 4c 39 e3 75 d8 4c 8d bd c0 02 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 84 04 00 00 48 8d 7d 28 8b 9 d
[ 376.761261] RSP: 0018:ffff888847c56db8 EFLAGS: 00010202
[ 376.770054] RAX: dffffc0000000000 RBX: ffff8888582a6da0 RCX: ffff888847c56d60
[ 376.780743] RDX: 0000000000000058 RSI: 0000000000000008 RDI: 0000000000000282
[ 376.791328] RBP: 0000000000000000 R08: fffffbfff0c60ea6 R09: fffffbfff0c60ea6
[ 376.802050] R10: fffffbfff0c60ea5 R11: ffffffff8630752f R12: ffff8888582a6da0
[ 376.812798] R13: dffffc0000000000 R14: ffff8888582a6da0 R15: 00000000000002c0
[ 376.823445] FS: 00007f675f9a8840(0000) GS:ffff88886d200000(0000) knlGS:0000000000000000
[ 376.834971] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 376.844179] CR2: 00000000007d9640 CR3: 00000007d3f26003 CR4: 00000000001606e0
[ 376.854843] Call Trace:
[ 376.868542] __mlx5_eswitch_del_rule+0x49/0x300 [mlx5_core]
[ 376.877735] mlx5e_tc_del_fdb_flow+0x6ec/0x9e0 [mlx5_core]
[ 376.921549] mlx5e_flow_put+0x2b/0x50 [mlx5_core]
[ 376.929813] mlx5e_delete_flower+0x5b6/0xbd0 [mlx5_core]
[ 376.973030] tc_setup_cb_reoffload+0x29/0xc0
[ 376.980619] fl_reoffload+0x50a/0x770 [cls_flower]
[ 377.015087] tcf_block_playback_offloads+0xbd/0x250
[ 377.033400] tcf_block_setup+0x1b2/0xc60
[ 377.057247] tcf_block_offload_cmd+0x195/0x240
[ 377.098826] tcf_block_offload_unbind+0xe7/0x180
[ 377.107056] __tcf_block_put+0xe5/0x400
[ 377.114528] ingress_destroy+0x3d/0x60 [sch_ingress]
[ 377.122894] qdisc_destroy+0xf1/0x5a0
[ 377.129993] qdisc_graft+0xa3d/0xe50
[ 377.151227] tc_get_qdisc+0x48e/0xa20
[ 377.165167] rtnetlink_rcv_msg+0x35d/0x8d0
[ 377.199528] netlink_rcv_skb+0x11e/0x340
[ 377.219638] netlink_unicast+0x408/0x5b0
[ 377.239913] netlink_sendmsg+0x71b/0xb30
[ 377.267505] sock_sendmsg+0xb1/0xf0
[ 377.273801] ___sys_sendmsg+0x635/0x900
[ 377.312784] __sys_sendmsg+0xd3/0x170
[ 377.338693] do_syscall_64+0x95/0x460
[ 377.344833] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 377.352321] RIP: 0033:0x7f675e58e090
To avoid this, for every mirred action check if output device was
already processed. If so - drop rule with EOPNOTSUPP error.
Signed-off-by: Dmytro Linkin <dmitrolin@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.