Currently, tcf_action_delete() nulls actions array pointer after putting
and deleting it. However, if tcf_idr_delete_index() returns an error,
pointer to action is not set to null. That results it being released second
time in error handling code of tca_action_gd().
Kasan error:
[ 807.367755]
==================================================================
[ 807.375844] BUG: KASAN: use-after-free in tc_setup_cb_call+0x14e/0x250
[ 807.382763] Read of size 8 at addr ffff88033e636000 by task tc/2732
[ 807.391289] CPU: 0 PID: 2732 Comm: tc Tainted: G W
4.19.0-rc1+ #799
[ 807.399542] Hardware name: Supermicro SYS-2028TP-DECR/X10DRT-P, BIOS 2.0b
03/30/2017
[ 807.407948] Call Trace:
[ 807.410763] dump_stack+0x92/0xeb
[ 807.414456] print_address_description+0x70/0x360
[ 807.419549] kasan_report+0x14d/0x300
[ 807.423582] ? tc_setup_cb_call+0x14e/0x250
[ 807.428150] tc_setup_cb_call+0x14e/0x250
[ 807.432539] ? nla_put+0x65/0xe0
[ 807.436146] fl_dump+0x394/0x3f0 [cls_flower]
[ 807.440890] ? fl_tmplt_dump+0x140/0x140 [cls_flower]
[ 807.446327] ? lock_downgrade+0x320/0x320
[ 807.450702] ? lock_acquire+0xe2/0x220
[ 807.454819] ? is_bpf_text_address+0x5/0x140
[ 807.459475] ? memcpy+0x34/0x50
[ 807.462980] ? nla_put+0x65/0xe0
[ 807.466582] tcf_fill_node+0x341/0x430
[ 807.470717] ? tcf_block_put+0xe0/0xe0
[ 807.474859] tcf_node_dump+0xdb/0xf0
[ 807.478821] fl_walk+0x8e/0x170 [cls_flower]
[ 807.483474] tcf_chain_dump+0x35a/0x4d0
[ 807.487703] ? tfilter_notify+0x170/0x170
[ 807.492091] ? tcf_fill_node+0x430/0x430
[ 807.496411] tc_dump_tfilter+0x362/0x3f0
[ 807.500712] ? tc_del_tfilter+0x850/0x850
[ 807.505104] ? kasan_unpoison_shadow+0x30/0x40
[ 807.509940] ? __mutex_unlock_slowpath+0xcf/0x410
[ 807.515031] netlink_dump+0x263/0x4f0
[ 807.519077] __netlink_dump_start+0x2a0/0x300
[ 807.523817] ? tc_del_tfilter+0x850/0x850
[ 807.528198] rtnetlink_rcv_msg+0x46a/0x6d0
[ 807.532671] ? rtnl_fdb_del+0x3f0/0x3f0
[ 807.536878] ? tc_del_tfilter+0x850/0x850
[ 807.541280] netlink_rcv_skb+0x18d/0x200
[ 807.545570] ? rtnl_fdb_del+0x3f0/0x3f0
[ 807.549773] ? netlink_ack+0x500/0x500
[ 807.553913] netlink_unicast+0x2d0/0x370
[ 807.558212] ? netlink_attachskb+0x340/0x340
[ 807.562855] ? _copy_from_iter_full+0xe9/0x3e0
[ 807.567677] ? import_iovec+0x11e/0x1c0
[ 807.571890] netlink_sendmsg+0x3b9/0x6a0
[ 807.576192] ? netlink_unicast+0x370/0x370
[ 807.580684] ? netlink_unicast+0x370/0x370
[ 807.585154] sock_sendmsg+0x6b/0x80
[ 807.589015] ___sys_sendmsg+0x4a1/0x520
[ 807.593230] ? copy_msghdr_from_user+0x210/0x210
[ 807.598232] ? do_wp_page+0x174/0x880
[ 807.602276] ? __handle_mm_fault+0x749/0x1c10
[ 807.607021] ? __handle_mm_fault+0x1046/0x1c10
[ 807.611849] ? __pmd_alloc+0x320/0x320
[ 807.615973] ? check_chain_key+0x140/0x1f0
[ 807.620450] ? check_chain_key+0x140/0x1f0
[ 807.624929] ? __fget_light+0xbc/0xd0
[ 807.628970] ? __sys_sendmsg+0xd7/0x150
[ 807.633172] __sys_sendmsg+0xd7/0x150
[ 807.637201] ? __ia32_sys_shutdown+0x30/0x30
[ 807.641846] ? up_read+0x53/0x90
[ 807.645442] ? __do_page_fault+0x484/0x780
[ 807.649949] ? do_syscall_64+0x1e/0x2c0
[ 807.654164] do_syscall_64+0x72/0x2c0
[ 807.658198] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 807.663625] RIP: 0033:0x7f42e9870150
[ 807.667568] Code: 8b 15 3c 7d 2b 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb
cd 66 0f 1f 44 00 00 83 3d b9 d5 2b 00 00 75 10 b8 2e 00 00 00 0f 05 <48> 3d 01
f0 ff ff 73 31 c3 48 83 ec 08 e8 be cd 00 00 48 89 04 24
[ 807.687328] RSP: 002b:00007ffdbf595b58 EFLAGS: 00000246 ORIG_RAX:
000000000000002e
[ 807.695564] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f42e9870150
[ 807.703083] RDX: 0000000000000000 RSI: 00007ffdbf595b80 RDI: 0000000000000003
[ 807.710605] RBP: 00007ffdbf599d90 R08: 0000000000679bc0 R09: 000000000000000f
[ 807.718127] R10: 00000000000005e7 R11: 0000000000000246 R12: 00007ffdbf599d88
[ 807.725651] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 807.735048] Allocated by task 2687:
[ 807.738902] kasan_kmalloc+0xa0/0xd0
[ 807.742852] __kmalloc+0x118/0x2d0
[ 807.746615] tcf_idr_create+0x44/0x320
[ 807.750738] tcf_nat_init+0x41e/0x530 [act_nat]
[ 807.755638] tcf_action_init_1+0x4e0/0x650
[ 807.760104] tcf_action_init+0x1ce/0x2d0
[ 807.764395] tcf_exts_validate+0x1d8/0x200
[ 807.768861] fl_change+0x55a/0x26b4 [cls_flower]
[ 807.773845] tc_new_tfilter+0x748/0xa20
[ 807.778051] rtnetlink_rcv_msg+0x56a/0x6d0
[ 807.782517] netlink_rcv_skb+0x18d/0x200
[ 807.786804] netlink_unicast+0x2d0/0x370
[ 807.791095] netlink_sendmsg+0x3b9/0x6a0
[ 807.795387] sock_sendmsg+0x6b/0x80
[ 807.799240] ___sys_sendmsg+0x4a1/0x520
[ 807.803445] __sys_sendmsg+0xd7/0x150
[ 807.807473] do_syscall_64+0x72/0x2c0
[ 807.811506] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 807.818776] Freed by task 2728:
[ 807.822283] __kasan_slab_free+0x122/0x180
[ 807.826752] kfree+0xf4/0x2f0
[ 807.830080] __tcf_action_put+0x5a/0xb0
[ 807.834281] tcf_action_put_many+0x46/0x70
[ 807.838747] tca_action_gd+0x232/0xc40
[ 807.842862] tc_ctl_action+0x215/0x230
[ 807.846977] rtnetlink_rcv_msg+0x56a/0x6d0
[ 807.851444] netlink_rcv_skb+0x18d/0x200
[ 807.855731] netlink_unicast+0x2d0/0x370
[ 807.860021] netlink_sendmsg+0x3b9/0x6a0
[ 807.864312] sock_sendmsg+0x6b/0x80
[ 807.868166] ___sys_sendmsg+0x4a1/0x520
[ 807.872372] __sys_sendmsg+0xd7/0x150
[ 807.876401] do_syscall_64+0x72/0x2c0
[ 807.880431] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 807.887704] The buggy address belongs to the object at ffff88033e636000
which belongs to the cache kmalloc-256 of size 256
[ 807.900909] The buggy address is located 0 bytes inside of
256-byte region [ffff88033e636000, ffff88033e636100)
[ 807.913155] The buggy address belongs to the page:
[ 807.918322] page:ffffea000cf98d80 count:1 mapcount:0
mapping:ffff88036f80ee00 index:0x0 compound_mapcount: 0
[ 807.928831] flags: 0x5fff8000008100(slab|head)
[ 807.933647] raw: 005fff8000008100 ffffea000db44f00 0000000400000004
ffff88036f80ee00
[ 807.942050] raw: 0000000000000000 0000000080190019 00000001ffffffff
0000000000000000
[ 807.950456] page dumped because: kasan: bad access detected
[ 807.958240] Memory state around the buggy address:
[ 807.963405] ffff88033e635f00: fc fc fc fc fb fb fb fb fb fb fb fc fc fc fc
fb
[ 807.971288] ffff88033e635f80: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc
fc
[ 807.979166] >ffff88033e636000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
fb
[ 807.994882] ^
[ 807.998477] ffff88033e636080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
fb
[ 808.006352] ffff88033e636100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb
fb
[ 808.014230]
==================================================================
[ 808.022108] Disabling lock debugging due to kernel taint
Fixes: edfaf94fa705 ("net_sched: improve and refactor tcf_action_put_many()")
Signed-off-by: Vlad Buslov <vla...@mellanox.com>
---
net/sched/act_api.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 398c752ff529..b8540bcaa8fc 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -1175,6 +1175,7 @@ static int tcf_action_delete(struct net *net, struct
tc_action *actions[])
struct tcf_idrinfo *idrinfo = a->idrinfo;
u32 act_index = a->tcfa_index;
+ actions[i] = NULL;
if (tcf_action_put(a)) {
/* last reference, action was deleted concurrently */
module_put(ops->owner);
@@ -1186,7 +1187,6 @@ static int tcf_action_delete(struct net *net, struct
tc_action *actions[])
if (ret < 0)
return ret;
}
- actions[i] = NULL;
}
return 0;
}
--
2.7.5
