From 0473cbae2137b963bd0eaa74336131cb1d3bc6c3 Mon Sep 17 00:00:00 2001
From: Ben Greear <greearb@candelatech.com>
Date: Wed, 23 Nov 2022 23:02:06 +0200
Subject: [PATCH] wifi: iwlwifi: mvm: fix double free on tx path.
Git-commit: 0473cbae2137b963bd0eaa74336131cb1d3bc6c3
Patch-mainline: v6.2-rc1
References: git-fixes
We see kernel crashes and lockups and KASAN errors related to ax210
firmware crashes. One of the KASAN dumps pointed at the tx path,
and it appears there is indeed a way to double-free an skb.
If iwl_mvm_tx_skb_sta returns non-zero, then the 'skb' sent into the
method will be freed. But, in case where we build TSO skb buffer,
the skb may also be freed in error case. So, return 0 in that particular
error case and do cleanup manually.
Bug: KASAN: use-after-free in __list_del_entry_valid+0x12/0x90
iwlwifi 0000:06:00.0: 0x00000000 | tsf hi
Read of size 8 at addr ffff88813cfa4ba0 by task btserver/9650
Cpu: 4 PID: 9650 Comm: btserver Tainted: G W 5.19.8+ #5
iwlwifi 0000:06:00.0: 0x00000000 | time gp1
Hardware name: Default string Default string/SKYBAY, BIOS 5.12 02/19/2019
Call Trace:
<TASK>
dump_stack_lvl+0x55/0x6d
print_report.cold.12+0xf2/0x684
iwlwifi 0000:06:00.0: 0x1D0915A8 | time gp2
? __list_del_entry_valid+0x12/0x90
kasan_report+0x8b/0x180
iwlwifi 0000:06:00.0: 0x00000001 | uCode revision type
? __list_del_entry_valid+0x12/0x90
__list_del_entry_valid+0x12/0x90
iwlwifi 0000:06:00.0: 0x00000048 | uCode version major
tcp_update_skb_after_send+0x5d/0x170
__tcp_transmit_skb+0xb61/0x15c0
iwlwifi 0000:06:00.0: 0xDAA05125 | uCode version minor
? __tcp_select_window+0x490/0x490
iwlwifi 0000:06:00.0: 0x00000420 | hw version
? trace_kmalloc_node+0x29/0xd0
? __kmalloc_node_track_caller+0x12a/0x260
? memset+0x1f/0x40
? __build_skb_around+0x125/0x150
? __alloc_skb+0x1d4/0x220
? skb_zerocopy_clone+0x55/0x230
iwlwifi 0000:06:00.0: 0x00489002 | board version
? kmalloc_reserve+0x80/0x80
? rcu_read_lock_bh_held+0x60/0xb0
tcp_write_xmit+0x3f1/0x24d0
iwlwifi 0000:06:00.0: 0x034E001C | hcmd
? __check_object_size+0x180/0x350
iwlwifi 0000:06:00.0: 0x24020000 | isr0
tcp_sendmsg_locked+0x8a9/0x1520
iwlwifi 0000:06:00.0: 0x01400000 | isr1
? tcp_sendpage+0x50/0x50
iwlwifi 0000:06:00.0: 0x48F0000A | isr2
? lock_release+0xb9/0x400
? tcp_sendmsg+0x14/0x40
iwlwifi 0000:06:00.0: 0x00C3080C | isr3
? lock_downgrade+0x390/0x390
? do_raw_spin_lock+0x114/0x1d0
iwlwifi 0000:06:00.0: 0x00200000 | isr4
? rwlock_bug.part.2+0x50/0x50
iwlwifi 0000:06:00.0: 0x034A001C | last cmd Id
? rwlock_bug.part.2+0x50/0x50
? lockdep_hardirqs_on_prepare+0xe/0x200
iwlwifi 0000:06:00.0: 0x0000C2F0 | wait_event
? __local_bh_enable_ip+0x87/0xe0
? inet_send_prepare+0x220/0x220
iwlwifi 0000:06:00.0: 0x000000C4 | l2p_control
tcp_sendmsg+0x22/0x40
sock_sendmsg+0x5f/0x70
iwlwifi 0000:06:00.0: 0x00010034 | l2p_duration
__sys_sendto+0x19d/0x250
iwlwifi 0000:06:00.0: 0x00000007 | l2p_mhvalid
? __ia32_sys_getpeername+0x40/0x40
iwlwifi 0000:06:00.0: 0x00000000 | l2p_addr_match
? rcu_read_lock_held_common+0x12/0x50
? rcu_read_lock_sched_held+0x5a/0xd0
? rcu_read_lock_bh_held+0xb0/0xb0
? rcu_read_lock_sched_held+0x5a/0xd0
? rcu_read_lock_sched_held+0x5a/0xd0
? lock_release+0xb9/0x400
? lock_downgrade+0x390/0x390
? ktime_get+0x64/0x130
? ktime_get+0x8d/0x130
? rcu_read_lock_held_common+0x12/0x50
? rcu_read_lock_sched_held+0x5a/0xd0
? rcu_read_lock_held_common+0x12/0x50
? rcu_read_lock_sched_held+0x5a/0xd0
? rcu_read_lock_bh_held+0xb0/0xb0
? rcu_read_lock_bh_held+0xb0/0xb0
__x64_sys_sendto+0x6f/0x80
do_syscall_64+0x34/0xb0
entry_SYSCALL_64_after_hwframe+0x46/0xb0
Rip: 0033:0x7f1d126e4531
Code: 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 35 80 0c 00 41 89 ca 8b 00 85 c0 75 1c 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 67 c3 66 0f 1f 44 00 00 55 48 83 ec 20 48 89
Rsp: 002b:00007ffe21a679d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
Rax: ffffffffffffffda RBX: 000000000000ffdc RCX: 00007f1d126e4531
Rdx: 0000000000010000 RSI: 000000000374acf0 RDI: 0000000000000014
Rbp: 00007ffe21a67ac0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000010
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 </TASK>
Allocated by task 9650:
kasan_save_stack+0x1c/0x40
__kasan_slab_alloc+0x6d/0x90
kmem_cache_alloc_node+0xf3/0x2b0
__alloc_skb+0x191/0x220
tcp_stream_alloc_skb+0x3f/0x330
tcp_sendmsg_locked+0x67c/0x1520
tcp_sendmsg+0x22/0x40
sock_sendmsg+0x5f/0x70
__sys_sendto+0x19d/0x250
__x64_sys_sendto+0x6f/0x80
do_syscall_64+0x34/0xb0
entry_SYSCALL_64_after_hwframe+0x46/0xb0
Freed by task 9650:
kasan_save_stack+0x1c/0x40
kasan_set_track+0x21/0x30
kasan_set_free_info+0x20/0x30
__kasan_slab_free+0x102/0x170
kmem_cache_free+0xc8/0x3e0
iwl_mvm_mac_itxq_xmit+0x124/0x270 [iwlmvm]
ieee80211_queue_skb+0x874/0xd10 [mac80211]
ieee80211_xmit_fast+0xf80/0x1180 [mac80211]
__ieee80211_subif_start_xmit+0x287/0x680 [mac80211]
ieee80211_subif_start_xmit+0xcd/0x730 [mac80211]
dev_hard_start_xmit+0xf6/0x420
__dev_queue_xmit+0x165b/0x1b50
ip_finish_output2+0x66e/0xfb0
__ip_finish_output+0x487/0x6d0
ip_output+0x11c/0x350
__ip_queue_xmit+0x36b/0x9d0
__tcp_transmit_skb+0xb35/0x15c0
tcp_write_xmit+0x3f1/0x24d0
tcp_sendmsg_locked+0x8a9/0x1520
tcp_sendmsg+0x22/0x40
sock_sendmsg+0x5f/0x70
__sys_sendto+0x19d/0x250
__x64_sys_sendto+0x6f/0x80
do_syscall_64+0x34/0xb0
entry_SYSCALL_64_after_hwframe+0x46/0xb0
The buggy address belongs to the object at ffff88813cfa4b40
which belongs to the cache skbuff_fclone_cache of size 472
The buggy address is located 96 bytes inside of
472-byte region [ffff88813cfa4b40, ffff88813cfa4d18)
The buggy address belongs to the physical page:
page:ffffea0004f3e900 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88813cfa6c40 pfn:0x13cfa4
head:ffffea0004f3e900 order:2 compound_mapcount:0 compound_pincount:0
Flags: 0x5fff8000010200(slab|head|node=0|zone=2|lastcpupid=0x3fff)
Raw: 005fff8000010200 ffffea0004656b08 ffffea0008e8cf08 ffff8881081a5240
Raw: ffff88813cfa6c40 0000000000170015 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88813cfa4a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88813cfa4b00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>ffff88813cfa4b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88813cfa4c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88813cfa4c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Fixes: 08f7d8b69aaf ("iwlwifi: mvm: bring back mvm GSO code")
Link: https://lore.kernel.org/linux-wireless/20220928193057.16132-1-greearb@candelatech.com/
Tested-by: Amol Jawale <amol.jawale@candelatech.com>
Signed-off-by: Ben Greear <greearb@candelatech.com>
Link: https://lore.kernel.org/r/20221123225313.21b1ee31d666.I3b3ba184433dd2a544d91eeeda29b467021824ae@changeid
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/net/wireless/intel/iwlwifi/mvm/tx.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/tx.c b/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
index f460332333a7..fadaa683a416 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
@@ -1215,6 +1215,7 @@ int iwl_mvm_tx_skb_sta(struct iwl_mvm *mvm, struct sk_buff *skb,
struct sk_buff_head mpdus_skbs;
unsigned int payload_len;
int ret;
+ struct sk_buff *orig_skb = skb;
if (WARN_ON_ONCE(!mvmsta))
return -1;
@@ -1247,8 +1248,17 @@ int iwl_mvm_tx_skb_sta(struct iwl_mvm *mvm, struct sk_buff *skb,
ret = iwl_mvm_tx_mpdu(mvm, skb, &info, sta);
if (ret) {
+ /* Free skbs created as part of TSO logic that have not yet been dequeued */
__skb_queue_purge(&mpdus_skbs);
- return ret;
+ /* skb here is not necessarily same as skb that entered this method,
+ * so free it explicitly.
+ */
+ if (skb == orig_skb)
+ ieee80211_free_txskb(mvm->hw, skb);
+ else
+ kfree_skb(skb);
+ /* there was error, but we consumed skb one way or another, so return 0 */
+ return 0;
}
}
--
2.35.3