diff mbox series

[net] mac802154: tx: fix use-after-free

Message ID 20200908104025.4009085-1-edumazet@google.com (mailing list archive)
State Accepted
Headers show
Series [net] mac802154: tx: fix use-after-free | expand

Commit Message

Eric Dumazet Sept. 8, 2020, 10:40 a.m. UTC 
syzbot reported a bug in ieee802154_tx() [1]

A similar issue in ieee802154_xmit_worker() is also fixed in this patch.

[1]
BUG: KASAN: use-after-free in ieee802154_tx+0x3d2/0x480 net/mac802154/tx.c:88
Read of size 4 at addr ffff8880251a8c70 by task syz-executor.3/928

CPU: 0 PID: 928 Comm: syz-executor.3 Not tainted 5.9.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x198/0x1fd lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 ieee802154_tx+0x3d2/0x480 net/mac802154/tx.c:88
 ieee802154_subif_start_xmit+0xbe/0xe4 net/mac802154/tx.c:130
 __netdev_start_xmit include/linux/netdevice.h:4634 [inline]
 netdev_start_xmit include/linux/netdevice.h:4648 [inline]
 dev_direct_xmit+0x4e9/0x6e0 net/core/dev.c:4203
 packet_snd net/packet/af_packet.c:2989 [inline]
 packet_sendmsg+0x2413/0x5290 net/packet/af_packet.c:3014
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:671
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2407
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5b9
Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc98e749c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000002ccc0 RCX: 000000000045d5b9
RDX: 0000000000000000 RSI: 0000000020007780 RDI: 000000000000000b
RBP: 000000000118d020 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cfec
R13: 00007fff690c720f R14: 00007fc98e74a9c0 R15: 000000000118cfec

Allocated by task 928:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
 slab_post_alloc_hook mm/slab.h:518 [inline]
 slab_alloc_node mm/slab.c:3254 [inline]
 kmem_cache_alloc_node+0x136/0x3e0 mm/slab.c:3574
 __alloc_skb+0x71/0x550 net/core/skbuff.c:198
 alloc_skb include/linux/skbuff.h:1094 [inline]
 alloc_skb_with_frags+0x92/0x570 net/core/skbuff.c:5771
 sock_alloc_send_pskb+0x72a/0x880 net/core/sock.c:2348
 packet_alloc_skb net/packet/af_packet.c:2837 [inline]
 packet_snd net/packet/af_packet.c:2932 [inline]
 packet_sendmsg+0x19fb/0x5290 net/packet/af_packet.c:3014
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:671
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2407
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 928:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422
 __cache_free mm/slab.c:3418 [inline]
 kmem_cache_free.part.0+0x74/0x1e0 mm/slab.c:3693
 kfree_skbmem+0xef/0x1b0 net/core/skbuff.c:622
 __kfree_skb net/core/skbuff.c:679 [inline]
 consume_skb net/core/skbuff.c:838 [inline]
 consume_skb+0xcf/0x160 net/core/skbuff.c:832
 __dev_kfree_skb_any+0x9c/0xc0 net/core/dev.c:3107
 fakelb_hw_xmit+0x20e/0x2a0 drivers/net/ieee802154/fakelb.c:81
 drv_xmit_async net/mac802154/driver-ops.h:16 [inline]
 ieee802154_tx+0x282/0x480 net/mac802154/tx.c:81
 ieee802154_subif_start_xmit+0xbe/0xe4 net/mac802154/tx.c:130
 __netdev_start_xmit include/linux/netdevice.h:4634 [inline]
 netdev_start_xmit include/linux/netdevice.h:4648 [inline]
 dev_direct_xmit+0x4e9/0x6e0 net/core/dev.c:4203
 packet_snd net/packet/af_packet.c:2989 [inline]
 packet_sendmsg+0x2413/0x5290 net/packet/af_packet.c:3014
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:671
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2407
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8880251a8c00
 which belongs to the cache skbuff_head_cache of size 224
The buggy address is located 112 bytes inside of
 224-byte region [ffff8880251a8c00, ffff8880251a8ce0)
The buggy address belongs to the page:
page:0000000062b6a4f1 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x251a8
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0000435c88 ffffea00028b6c08 ffff8880a9055d00
raw: 0000000000000000 ffff8880251a80c0 000000010000000c 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880251a8b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880251a8b80: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880251a8c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff8880251a8c80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff8880251a8d00: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb

Fixes: 409c3b0c5f03 ("mac802154: tx: move stats tx increment")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Stefan Schmidt <stefan@datenfreihafen.org>
Cc: linux-wpan@vger.kernel.org
---
 net/mac802154/tx.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

Comments

Stefan Schmidt Sept. 8, 2020, 5:35 p.m. UTC | #1 
Hello Eric.

On 08.09.20 12:40, Eric Dumazet wrote:
> syzbot reported a bug in ieee802154_tx() [1]
> 
> A similar issue in ieee802154_xmit_worker() is also fixed in this patch.
> 

[ snip]

> 
> Fixes: 409c3b0c5f03 ("mac802154: tx: move stats tx increment")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: syzbot <syzkaller@googlegroups.com>
> Cc: Alexander Aring <alex.aring@gmail.com>
> Cc: Stefan Schmidt <stefan@datenfreihafen.org>
> Cc: linux-wpan@vger.kernel.org
> ---
>   net/mac802154/tx.c | 8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/net/mac802154/tx.c b/net/mac802154/tx.c
> index ab52811523e992f33f0855cdb711a2752b602e15..c829e4a7532564d401c0d2d1f90f56c2fe030b2c 100644
> --- a/net/mac802154/tx.c
> +++ b/net/mac802154/tx.c
> @@ -34,11 +34,11 @@ void ieee802154_xmit_worker(struct work_struct *work)
>   	if (res)
>   		goto err_tx;
>   
> -	ieee802154_xmit_complete(&local->hw, skb, false);
> -
>   	dev->stats.tx_packets++;
>   	dev->stats.tx_bytes += skb->len;
>   
> +	ieee802154_xmit_complete(&local->hw, skb, false);
> +
>   	return;
>   
>   err_tx:
> @@ -78,6 +78,8 @@ ieee802154_tx(struct ieee802154_local *local, struct sk_buff *skb)
>   
>   	/* async is priority, otherwise sync is fallback */
>   	if (local->ops->xmit_async) {
> +		unsigned int len = skb->len;
> +
>   		ret = drv_xmit_async(local, skb);
>   		if (ret) {
>   			ieee802154_wake_queue(&local->hw);
> @@ -85,7 +87,7 @@ ieee802154_tx(struct ieee802154_local *local, struct sk_buff *skb)
>   		}
>   
>   		dev->stats.tx_packets++;
> -		dev->stats.tx_bytes += skb->len;
> +		dev->stats.tx_bytes += len;
>   	} else {
>   		local->tx_skb = skb;
>   		queue_work(local->workqueue, &local->tx_work);
> 

Thanks for catching this!

This patch has been applied to the wpan tree and will be
part of the next pull request to net. Thanks!

regards
Stefan Schmidt
diff mbox series

Patch

diff --git a/net/mac802154/tx.c b/net/mac802154/tx.c
index ab52811523e992f33f0855cdb711a2752b602e15..c829e4a7532564d401c0d2d1f90f56c2fe030b2c 100644
--- a/net/mac802154/tx.c
+++ b/net/mac802154/tx.c
@@ -34,11 +34,11 @@  void ieee802154_xmit_worker(struct work_struct *work)
 	if (res)
 		goto err_tx;
 
-	ieee802154_xmit_complete(&local->hw, skb, false);
-
 	dev->stats.tx_packets++;
 	dev->stats.tx_bytes += skb->len;
 
+	ieee802154_xmit_complete(&local->hw, skb, false);
+
 	return;
 
 err_tx:
@@ -78,6 +78,8 @@  ieee802154_tx(struct ieee802154_local *local, struct sk_buff *skb)
 
 	/* async is priority, otherwise sync is fallback */
 	if (local->ops->xmit_async) {
+		unsigned int len = skb->len;
+
 		ret = drv_xmit_async(local, skb);
 		if (ret) {
 			ieee802154_wake_queue(&local->hw);
@@ -85,7 +87,7 @@  ieee802154_tx(struct ieee802154_local *local, struct sk_buff *skb)
 		}
 
 		dev->stats.tx_packets++;
-		dev->stats.tx_bytes += skb->len;
+		dev->stats.tx_bytes += len;
 	} else {
 		local->tx_skb = skb;
 		queue_work(local->workqueue, &local->tx_work);