Hello,
syzbot found the following issue on:
HEAD commit: e3f30ab28ac8 Merge branch 'pktgen-samples-next'
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13249c96300000
kernel config: https://syzkaller.appspot.com/x/.config?x=ef482942966bf763
dashboard link: https://syzkaller.appspot.com/bug?extid=2bef95d3ab4daa10155b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16a29ea9300000
The issue was bisected to:
commit e1dee2c1de2b4dd00eb44004a4bda6326ed07b59
Author: Desmond Cheong Zhi Xi <[email protected]>
Date: Tue Aug 10 04:14:10 2021 +0000
Bluetooth: fix repeated calls to sco_sock_kill
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15030c91300000
final oops: https://syzkaller.appspot.com/x/report.txt?x=17030c91300000
console output: https://syzkaller.appspot.com/x/log.txt?x=13030c91300000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
Fixes: e1dee2c1de2b ("Bluetooth: fix repeated calls to sco_sock_kill")
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in atomic_fetch_add_relaxed include/asm-generic/atomic-instrumented.h:111 [inline]
BUG: KASAN: use-after-free in __refcount_add include/linux/refcount.h:193 [inline]
BUG: KASAN: use-after-free in __refcount_inc include/linux/refcount.h:250 [inline]
BUG: KASAN: use-after-free in refcount_inc include/linux/refcount.h:267 [inline]
BUG: KASAN: use-after-free in sock_hold include/net/sock.h:702 [inline]
BUG: KASAN: use-after-free in sco_sock_timeout+0x64/0x290 net/bluetooth/sco.c:88
Write of size 4 at addr ffff888034b46080 by task kworker/1:0/20
CPU: 1 PID: 20 Comm: kworker/1:0 Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events sco_sock_timeout
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233
__kasan_report mm/kasan/report.c:419 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
atomic_fetch_add_relaxed include/asm-generic/atomic-instrumented.h:111 [inline]
__refcount_add include/linux/refcount.h:193 [inline]
__refcount_inc include/linux/refcount.h:250 [inline]
refcount_inc include/linux/refcount.h:267 [inline]
sock_hold include/net/sock.h:702 [inline]
sco_sock_timeout+0x64/0x290 net/bluetooth/sco.c:88
process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
worker_thread+0x658/0x11f0 kernel/workqueue.c:2422
kthread+0x3e5/0x4d0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Allocated by task 4872:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
____kasan_kmalloc mm/kasan/common.c:472 [inline]
__kasan_kmalloc+0x9b/0xd0 mm/kasan/common.c:522
kmalloc include/linux/slab.h:596 [inline]
sk_prot_alloc+0x110/0x290 net/core/sock.c:1822
sk_alloc+0x32/0xbc0 net/core/sock.c:1875
__netlink_create+0x63/0x2f0 net/netlink/af_netlink.c:640
netlink_create+0x3ad/0x5e0 net/netlink/af_netlink.c:703
__sock_create+0x353/0x790 net/socket.c:1461
sock_create net/socket.c:1512 [inline]
__sys_socket+0xef/0x200 net/socket.c:1554
__do_sys_socket net/socket.c:1563 [inline]
__se_sys_socket net/socket.c:1561 [inline]
__x64_sys_socket+0x6f/0xb0 net/socket.c:1561
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Freed by task 0:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free mm/kasan/common.c:328 [inline]
__kasan_slab_free+0xfb/0x130 mm/kasan/common.c:374
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1628 [inline]
slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1653
slab_free mm/slub.c:3213 [inline]
kfree+0xe4/0x540 mm/slub.c:4267
sk_prot_free net/core/sock.c:1858 [inline]
__sk_destruct+0x6a8/0x900 net/core/sock.c:1943
sk_destruct+0xbd/0xe0 net/core/sock.c:1958
__sk_free+0xef/0x3d0 net/core/sock.c:1969
sk_free+0x78/0xa0 net/core/sock.c:1980
deferred_put_nlk_sk+0x151/0x2f0 net/netlink/af_netlink.c:740
rcu_do_batch kernel/rcu/tree.c:2550 [inline]
rcu_core+0x7ab/0x1380 kernel/rcu/tree.c:2785
__do_softirq+0x29b/0x9c2 kernel/softirq.c:558
Last potentially related work creation:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:348
__call_rcu kernel/rcu/tree.c:3029 [inline]
call_rcu+0xb1/0x750 kernel/rcu/tree.c:3109
netlink_release+0xdd4/0x1dd0 net/netlink/af_netlink.c:812
__sock_release+0xcd/0x280 net/socket.c:649
sock_close+0x18/0x20 net/socket.c:1311
__fput+0x288/0x920 fs/file_table.c:280
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
exit_task_work include/linux/task_work.h:32 [inline]
do_exit+0xbd4/0x2a60 kernel/exit.c:825
do_group_exit+0x125/0x310 kernel/exit.c:922
__do_sys_exit_group kernel/exit.c:933 [inline]
__se_sys_exit_group kernel/exit.c:931 [inline]
__x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Second to last potentially related work creation:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:348
__call_rcu kernel/rcu/tree.c:3029 [inline]
call_rcu+0xb1/0x750 kernel/rcu/tree.c:3109
netlink_release+0xdd4/0x1dd0 net/netlink/af_netlink.c:812
__sock_release+0xcd/0x280 net/socket.c:649
sock_close+0x18/0x20 net/socket.c:1311
__fput+0x288/0x920 fs/file_table.c:280
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
exit_task_work include/linux/task_work.h:32 [inline]
do_exit+0xbd4/0x2a60 kernel/exit.c:825
do_group_exit+0x125/0x310 kernel/exit.c:922
__do_sys_exit_group kernel/exit.c:933 [inline]
__se_sys_exit_group kernel/exit.c:931 [inline]
__x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
The buggy address belongs to the object at ffff888034b46000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 128 bytes inside of
2048-byte region [ffff888034b46000, ffff888034b46800)
The buggy address belongs to the page:
page:ffffea0000d2d000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34b40
head:ffffea0000d2d000 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea0000c37a00 0000000200000002 ffff888010c42000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 8634, ts 417197903424, free_ts 417180376519
prep_new_page mm/page_alloc.c:2436 [inline]
get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4169
__alloc_pages+0x1b2/0x500 mm/page_alloc.c:5391
alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2244
alloc_slab_page mm/slub.c:1691 [inline]
allocate_slab+0x32e/0x4b0 mm/slub.c:1831
new_slab mm/slub.c:1894 [inline]
new_slab_objects mm/slub.c:2640 [inline]
___slab_alloc+0x473/0x7b0 mm/slub.c:2803
__slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2843
slab_alloc_node mm/slub.c:2925 [inline]
__kmalloc_node_track_caller+0x2e3/0x360 mm/slub.c:4653
kmalloc_reserve net/core/skbuff.c:355 [inline]
__alloc_skb+0xde/0x340 net/core/skbuff.c:426
alloc_skb include/linux/skbuff.h:1116 [inline]
alloc_skb_with_frags+0x93/0x620 net/core/skbuff.c:6073
sock_alloc_send_pskb+0x783/0x910 net/core/sock.c:2475
mld_newpack+0x1df/0x770 net/ipv6/mcast.c:1756
add_grhead+0x265/0x330 net/ipv6/mcast.c:1859
add_grec+0x1053/0x14e0 net/ipv6/mcast.c:1997
mld_send_initial_cr.part.0+0xf6/0x230 net/ipv6/mcast.c:2244
mld_send_initial_cr net/ipv6/mcast.c:1232 [inline]
ipv6_mc_dad_complete+0x1d0/0x690 net/ipv6/mcast.c:2255
addrconf_dad_completed+0xa20/0xd60 net/ipv6/addrconf.c:4181
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1346 [inline]
free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1397
free_unref_page_prepare mm/page_alloc.c:3332 [inline]
free_unref_page+0x19/0x690 mm/page_alloc.c:3411
unfreeze_partials+0x16c/0x1b0 mm/slub.c:2421
put_cpu_partial+0x13d/0x230 mm/slub.c:2457
qlink_free mm/kasan/quarantine.c:146 [inline]
qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272
__kasan_slab_alloc+0x8e/0xa0 mm/kasan/common.c:444
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook mm/slab.h:519 [inline]
slab_alloc_node mm/slub.c:2959 [inline]
slab_alloc mm/slub.c:2967 [inline]
kmem_cache_alloc+0x285/0x4a0 mm/slub.c:2972
getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
getname_flags fs/namei.c:2747 [inline]
user_path_at_empty+0xa1/0x100 fs/namei.c:2747
user_path_at include/linux/namei.h:57 [inline]
vfs_statx+0x142/0x390 fs/stat.c:203
vfs_fstatat fs/stat.c:225 [inline]
vfs_lstat include/linux/fs.h:3386 [inline]
__do_sys_newlstat+0x91/0x110 fs/stat.c:380
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Memory state around the buggy address:
ffff888034b45f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888034b46000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888034b46080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888034b46100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888034b46180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at [email protected].
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-and-tested-by: [email protected]
Tested on:
commit: e3f30ab2 Merge branch 'pktgen-samples-next'
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git
kernel config: https://syzkaller.appspot.com/x/.config?x=ef482942966bf763
dashboard link: https://syzkaller.appspot.com/bug?extid=2bef95d3ab4daa10155b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
patch: https://syzkaller.appspot.com/x/patch.diff?x=108523fe300000
Note: testing is done by a robot and is best-effort only.
On 29/8/21 4:29 pm, Hillf Danton wrote:
> On Fri, 27 Aug 2021 15:58:34 +0800 Desmond Cheong Zhi Xi wrote:
>> On 27/8/21 9:19 am, Hillf Danton wrote:
>>> On Thu, 26 Aug 2021 09:29:24 -0700
>>>> syzbot found the following issue on:
>>>>
>>>> HEAD commit: e3f30ab28ac8 Merge branch 'pktgen-samples-next'
>>>> git tree: net-next
>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=13249c96300000
>>>> kernel config: https://syzkaller.appspot.com/x/.config?x=ef482942966bf763
>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=2bef95d3ab4daa10155b
>>>> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
>>>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16a29ea9300000
>>>>
>>>> The issue was bisected to:
>>>>
>>>> commit e1dee2c1de2b4dd00eb44004a4bda6326ed07b59
>>>> Author: Desmond Cheong Zhi Xi <[email protected]>
>>>> Date: Tue Aug 10 04:14:10 2021 +0000
>>>>
>>>> Bluetooth: fix repeated calls to sco_sock_kill
>
> To fix the uaf, grab another hold to sock to make the timeout work safe.
>
> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git e3f30ab28ac8
>
> --- a/net/bluetooth/sco.c
> +++ b/net/bluetooth/sco.c
> @@ -190,15 +190,14 @@ static void sco_conn_del(struct hci_conn
> sco_conn_unlock(conn);
>
> if (sk) {
> - sock_hold(sk);
> lock_sock(sk);
> sco_sock_clear_timer(sk);
> sco_chan_del(sk, err);
> release_sock(sk);
> - sock_put(sk);
>
> /* Ensure no more work items will run before freeing conn. */
> cancel_delayed_work_sync(&conn->timeout_work);
> + sock_put(sk);
Hi Hillf,
Saw that this passed the reproducer. But on closer inspection, I think
what's happening is that sco_conn_del is never run.
So the extra sock_hold prevents a UAF, but that's because now the
reference count never goes to 0. In my opinion, something closer to your
previous proposal (+ also addressing other calls to __sco_sock_close)
where we call cancel_delayed_work_sync after the channel is deleted
would address the root cause better.
Just my two cents.
> }
>
> hcon->sco_data = NULL;
> @@ -212,6 +211,8 @@ static void __sco_chan_add(struct sco_co
>
> sco_pi(sk)->conn = conn;
> conn->sk = sk;
> + /* make timeout_work safe; will be put in sco_conn_del() */
> + sock_hold(sk);
>
> INIT_DELAYED_WORK(&conn->timeout_work, sco_sock_timeout);
>
> --
>
On 29/8/21 10:53 pm, Desmond Cheong Zhi Xi wrote:
> On 29/8/21 4:29 pm, Hillf Danton wrote:
>> On Fri, 27 Aug 2021 15:58:34 +0800 Desmond Cheong Zhi Xi wrote:
>>> On 27/8/21 9:19 am, Hillf Danton wrote:
>>>> On Thu, 26 Aug 2021 09:29:24 -0700
>>>>> syzbot found the following issue on:
>>>>>
>>>>> HEAD commit:??? e3f30ab28ac8 Merge branch 'pktgen-samples-next'
>>>>> git tree:?????? net-next
>>>>> console output:
>>>>> https://syzkaller.appspot.com/x/log.txt?x=13249c96300000
>>>>> kernel config:
>>>>> https://syzkaller.appspot.com/x/.config?x=ef482942966bf763
>>>>> dashboard link:
>>>>> https://syzkaller.appspot.com/bug?extid=2bef95d3ab4daa10155b
>>>>> compiler:?????? gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU
>>>>> Binutils for Debian) 2.35.1
>>>>> syz repro:
>>>>> https://syzkaller.appspot.com/x/repro.syz?x=16a29ea9300000
>>>>>
>>>>> The issue was bisected to:
>>>>>
>>>>> commit e1dee2c1de2b4dd00eb44004a4bda6326ed07b59
>>>>> Author: Desmond Cheong Zhi Xi <[email protected]>
>>>>> Date:?? Tue Aug 10 04:14:10 2021 +0000
>>>>>
>>>>> ????? Bluetooth: fix repeated calls to sco_sock_kill
>>
>> To fix the uaf, grab another hold to sock to make the timeout work safe.
>>
>> #syz test:
>> git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git
>> e3f30ab28ac8
>>
>> --- a/net/bluetooth/sco.c
>> +++ b/net/bluetooth/sco.c
>> @@ -190,15 +190,14 @@ static void sco_conn_del(struct hci_conn
>> ????? sco_conn_unlock(conn);
>> ????? if (sk) {
>> -??????? sock_hold(sk);
>> ????????? lock_sock(sk);
>> ????????? sco_sock_clear_timer(sk);
>> ????????? sco_chan_del(sk, err);
>> ????????? release_sock(sk);
>> -??????? sock_put(sk);
>> ????????? /* Ensure no more work items will run before freeing conn. */
>> ????????? cancel_delayed_work_sync(&conn->timeout_work);
>> +??????? sock_put(sk);
>
> Hi Hillf,
>
> Saw that this passed the reproducer. But on closer inspection, I think
> what's happening is that sco_conn_del is never run.
>
> So the extra sock_hold prevents a UAF, but that's because now the
> reference count never goes to 0. In my opinion, something closer to your
> previous proposal (+ also addressing other calls to __sco_sock_close)
> where we call cancel_delayed_work_sync after the channel is deleted
> would address the root cause better.
>
> Just my two cents.
>
Ok I went back to make a more thorough audit. Even without calling
cancel_delayed_work_sync, sco_sock_timeout should not cause a UAF.
I believe the real issue is that we can allocate a connection twice in
sco_connect. This means that the first connection gets lost and we're
unable to clean it up properly.
Thoughts on this?
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git e3f30ab28ac8
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -578,9 +578,6 @@ static int sco_sock_connect(struct socket *sock, struct sockaddr *addr, int alen
addr->sa_family != AF_BLUETOOTH)
return -EINVAL;
- if (sk->sk_state != BT_OPEN && sk->sk_state != BT_BOUND)
- return -EBADFD;
-
if (sk->sk_type != SOCK_SEQPACKET)
return -EINVAL;
@@ -591,6 +588,13 @@ static int sco_sock_connect(struct socket *sock, struct sockaddr *addr, int alen
lock_sock(sk);
+ if (sk->sk_state != BT_OPEN && sk->sk_state != BT_BOUND) {
+ hci_dev_unlock(hdev);
+ hci_dev_put(hdev);
+ err = -EBADFD;
+ goto done;
+ }
+
/* Set destination address and psm */
bacpy(&sco_pi(sk)->dst, &sa->sco_bdaddr);
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Write in sco_sock_timeout
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:116 [inline]
BUG: KASAN: use-after-free in __refcount_add include/linux/refcount.h:193 [inline]
BUG: KASAN: use-after-free in __refcount_inc include/linux/refcount.h:250 [inline]
BUG: KASAN: use-after-free in refcount_inc include/linux/refcount.h:267 [inline]
BUG: KASAN: use-after-free in sock_hold include/net/sock.h:726 [inline]
BUG: KASAN: use-after-free in sco_sock_timeout+0x64/0x290 net/bluetooth/sco.c:89
Write of size 4 at addr ffff88801d165080 by task kworker/0:1/8
CPU: 0 PID: 8 Comm: kworker/0:1 Not tainted 5.17.0-rc4-syzkaller-01424-g922ea87ff6f2-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events sco_sock_timeout
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255
__kasan_report mm/kasan/report.c:442 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:116 [inline]
__refcount_add include/linux/refcount.h:193 [inline]
__refcount_inc include/linux/refcount.h:250 [inline]
refcount_inc include/linux/refcount.h:267 [inline]
sock_hold include/net/sock.h:726 [inline]
sco_sock_timeout+0x64/0x290 net/bluetooth/sco.c:89
process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
worker_thread+0x657/0x1110 kernel/workqueue.c:2454
kthread+0x2e9/0x3a0 kernel/kthread.c:377
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Allocated by task 4059:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:436 [inline]
____kasan_kmalloc mm/kasan/common.c:515 [inline]
____kasan_kmalloc mm/kasan/common.c:474 [inline]
__kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524
kmalloc include/linux/slab.h:586 [inline]
sk_prot_alloc+0x110/0x290 net/core/sock.c:1936
sk_alloc+0x32/0xa80 net/core/sock.c:1989
sco_sock_alloc.constprop.0+0x31/0x330 net/bluetooth/sco.c:484
sco_sock_create+0xd5/0x1b0 net/bluetooth/sco.c:523
bt_sock_create+0x17c/0x340 net/bluetooth/af_bluetooth.c:130
__sock_create+0x353/0x790 net/socket.c:1468
sock_create net/socket.c:1519 [inline]
__sys_socket+0xef/0x200 net/socket.c:1561
__do_sys_socket net/socket.c:1570 [inline]
__se_sys_socket net/socket.c:1568 [inline]
__x64_sys_socket+0x6f/0xb0 net/socket.c:1568
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Freed by task 4060:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track+0x21/0x30 mm/kasan/common.c:45
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free+0x126/0x160 mm/kasan/common.c:328
kasan_slab_free include/linux/kasan.h:236 [inline]
slab_free_hook mm/slub.c:1728 [inline]
slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754
slab_free mm/slub.c:3509 [inline]
kfree+0xd0/0x390 mm/slub.c:4562
sk_prot_free net/core/sock.c:1972 [inline]
__sk_destruct+0x6c0/0x920 net/core/sock.c:2058
sk_destruct+0x131/0x180 net/core/sock.c:2076
__sk_free+0xef/0x3d0 net/core/sock.c:2087
sk_free+0x78/0xa0 net/core/sock.c:2098
sock_put include/net/sock.h:1926 [inline]
sco_sock_kill+0x18d/0x1b0 net/bluetooth/sco.c:403
sco_sock_release+0x162/0x2d0 net/bluetooth/sco.c:1260
__sock_release+0xcd/0x280 net/socket.c:650
sock_close+0x18/0x20 net/socket.c:1318
__fput+0x286/0x9f0 fs/file_table.c:317
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
get_signal+0x1de2/0x2490 kernel/signal.c:2631
arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868
handle_signal_work kernel/entry/common.c:148 [inline]
exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
Last potentially related work creation:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
__kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348
__call_rcu kernel/rcu/tree.c:3026 [inline]
call_rcu+0xb1/0x740 kernel/rcu/tree.c:3106
netlink_release+0xf08/0x1db0 net/netlink/af_netlink.c:813
__sock_release+0xcd/0x280 net/socket.c:650
sock_close+0x18/0x20 net/socket.c:1318
__fput+0x286/0x9f0 fs/file_table.c:317
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
Second to last potentially related work creation:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
__kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348
__call_rcu kernel/rcu/tree.c:3026 [inline]
call_rcu+0xb1/0x740 kernel/rcu/tree.c:3106
netlink_release+0xf08/0x1db0 net/netlink/af_netlink.c:813
__sock_release+0xcd/0x280 net/socket.c:650
sock_close+0x18/0x20 net/socket.c:1318
__fput+0x286/0x9f0 fs/file_table.c:317
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
The buggy address belongs to the object at ffff88801d165000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 128 bytes inside of
2048-byte region [ffff88801d165000, ffff88801d165800)
The buggy address belongs to the page:
page:ffffea0000745800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1d160
head:ffffea0000745800 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea000070c000 dead000000000002 ffff888010c42000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 54, ts 8464675040, free_ts 0
prep_new_page mm/page_alloc.c:2434 [inline]
get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
__alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389
alloc_pages+0x1aa/0x310 mm/mempolicy.c:2271
alloc_slab_page mm/slub.c:1799 [inline]
allocate_slab+0x27f/0x3c0 mm/slub.c:1944
new_slab mm/slub.c:2004 [inline]
___slab_alloc+0xbe1/0x12b0 mm/slub.c:3018
__slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105
slab_alloc_node mm/slub.c:3196 [inline]
slab_alloc mm/slub.c:3238 [inline]
__kmalloc+0x372/0x450 mm/slub.c:4420
kmalloc include/linux/slab.h:586 [inline]
kzalloc include/linux/slab.h:715 [inline]
scsi_alloc_target+0x132/0xc60 drivers/scsi/scsi_scan.c:498
__scsi_scan_target+0x13a/0xdb0 drivers/scsi/scsi_scan.c:1632
scsi_scan_channel drivers/scsi/scsi_scan.c:1737 [inline]
scsi_scan_channel+0x148/0x1e0 drivers/scsi/scsi_scan.c:1713
scsi_scan_host_selected+0x2df/0x3b0 drivers/scsi/scsi_scan.c:1766
do_scsi_scan_host+0x1e8/0x260 drivers/scsi/scsi_scan.c:1905
do_scan_async+0x3e/0x500 drivers/scsi/scsi_scan.c:1915
async_run_entry_fn+0x9d/0x550 kernel/async.c:127
process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
worker_thread+0x657/0x1110 kernel/workqueue.c:2454
page_owner free stack trace missing
Memory state around the buggy address:
ffff88801d164f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88801d165000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801d165080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88801d165100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88801d165180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Tested on:
commit: 922ea87f ionic: use vmalloc include
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/
console output: https://syzkaller.appspot.com/x/log.txt?x=144f85da700000
kernel config: https://syzkaller.appspot.com/x/.config?x=d63ad23bb09039e8
dashboard link: https://syzkaller.appspot.com/bug?extid=2bef95d3ab4daa10155b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=16e9136c700000
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: use-after-free Write in sco_sock_timeout
Bluetooth: hci0: command 0x0419 tx timeout
Bluetooth: hci0: command 0x0405 tx timeout
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:116 [inline]
BUG: KASAN: use-after-free in __refcount_add include/linux/refcount.h:193 [inline]
BUG: KASAN: use-after-free in __refcount_inc include/linux/refcount.h:250 [inline]
BUG: KASAN: use-after-free in refcount_inc include/linux/refcount.h:267 [inline]
BUG: KASAN: use-after-free in sock_hold include/net/sock.h:726 [inline]
BUG: KASAN: use-after-free in sco_sock_timeout+0x64/0x290 net/bluetooth/sco.c:89
Write of size 4 at addr ffff888074aac080 by task kworker/1:2/141
CPU: 1 PID: 141 Comm: kworker/1:2 Not tainted 5.17.0-rc4-syzkaller-01424-g922ea87ff6f2-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events sco_sock_timeout
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255
__kasan_report mm/kasan/report.c:442 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:116 [inline]
__refcount_add include/linux/refcount.h:193 [inline]
__refcount_inc include/linux/refcount.h:250 [inline]
refcount_inc include/linux/refcount.h:267 [inline]
sock_hold include/net/sock.h:726 [inline]
sco_sock_timeout+0x64/0x290 net/bluetooth/sco.c:89
process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
worker_thread+0x657/0x1110 kernel/workqueue.c:2454
kthread+0x2e9/0x3a0 kernel/kthread.c:377
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
Allocated by task 4058:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:45 [inline]
set_alloc_info mm/kasan/common.c:436 [inline]
____kasan_kmalloc mm/kasan/common.c:515 [inline]
____kasan_kmalloc mm/kasan/common.c:474 [inline]
__kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524
kmalloc include/linux/slab.h:586 [inline]
sk_prot_alloc+0x110/0x290 net/core/sock.c:1936
sk_alloc+0x32/0xa80 net/core/sock.c:1989
sco_sock_alloc.constprop.0+0x31/0x330 net/bluetooth/sco.c:484
sco_sock_create+0xd5/0x1b0 net/bluetooth/sco.c:523
bt_sock_create+0x17c/0x340 net/bluetooth/af_bluetooth.c:130
__sock_create+0x353/0x790 net/socket.c:1468
sock_create net/socket.c:1519 [inline]
__sys_socket+0xef/0x200 net/socket.c:1561
__do_sys_socket net/socket.c:1570 [inline]
__se_sys_socket net/socket.c:1568 [inline]
__x64_sys_socket+0x6f/0xb0 net/socket.c:1568
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Freed by task 4059:
kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
kasan_set_track+0x21/0x30 mm/kasan/common.c:45
kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
____kasan_slab_free mm/kasan/common.c:366 [inline]
____kasan_slab_free+0x126/0x160 mm/kasan/common.c:328
kasan_slab_free include/linux/kasan.h:236 [inline]
slab_free_hook mm/slub.c:1728 [inline]
slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1754
slab_free mm/slub.c:3509 [inline]
kfree+0xd0/0x390 mm/slub.c:4562
sk_prot_free net/core/sock.c:1972 [inline]
__sk_destruct+0x6c0/0x920 net/core/sock.c:2058
sk_destruct+0x131/0x180 net/core/sock.c:2076
__sk_free+0xef/0x3d0 net/core/sock.c:2087
sk_free+0x78/0xa0 net/core/sock.c:2098
sock_put include/net/sock.h:1926 [inline]
sco_sock_kill+0x18d/0x1b0 net/bluetooth/sco.c:403
sco_sock_release+0x155/0x2c0 net/bluetooth/sco.c:1260
__sock_release+0xcd/0x280 net/socket.c:650
sock_close+0x18/0x20 net/socket.c:1318
__fput+0x286/0x9f0 fs/file_table.c:317
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
get_signal+0x1de2/0x2490 kernel/signal.c:2631
arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868
handle_signal_work kernel/entry/common.c:148 [inline]
exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
The buggy address belongs to the object at ffff888074aac000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 128 bytes inside of
2048-byte region [ffff888074aac000, ffff888074aac800)
The buggy address belongs to the page:
page:ffffea0001d2aa00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x74aa8
head:ffffea0001d2aa00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea000078ac00 dead000000000002 ffff888010c42000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3593, ts 45984233319, free_ts 45950800073
prep_new_page mm/page_alloc.c:2434 [inline]
get_page_from_freelist+0xa72/0x2f50 mm/page_alloc.c:4165
__alloc_pages+0x1b2/0x500 mm/page_alloc.c:5389
alloc_pages+0x1aa/0x310 mm/mempolicy.c:2271
alloc_slab_page mm/slub.c:1799 [inline]
allocate_slab+0x27f/0x3c0 mm/slub.c:1944
new_slab mm/slub.c:2004 [inline]
___slab_alloc+0xbe1/0x12b0 mm/slub.c:3018
__slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105
slab_alloc_node mm/slub.c:3196 [inline]
slab_alloc mm/slub.c:3238 [inline]
__kmalloc+0x372/0x450 mm/slub.c:4420
kmalloc include/linux/slab.h:586 [inline]
kzalloc include/linux/slab.h:715 [inline]
__register_sysctl_table+0x112/0x1090 fs/proc/proc_sysctl.c:1335
__devinet_sysctl_register+0x156/0x280 net/ipv4/devinet.c:2588
devinet_sysctl_register net/ipv4/devinet.c:2628 [inline]
devinet_sysctl_register+0x160/0x230 net/ipv4/devinet.c:2618
inetdev_init+0x286/0x580 net/ipv4/devinet.c:279
inetdev_event+0xa8a/0x15d0 net/ipv4/devinet.c:1536
notifier_call_chain+0xb5/0x200 kernel/notifier.c:84
call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1939
call_netdevice_notifiers_extack net/core/dev.c:1951 [inline]
call_netdevice_notifiers net/core/dev.c:1965 [inline]
register_netdevice+0x1102/0x15a0 net/core/dev.c:9696
veth_newlink+0x59c/0xa90 drivers/net/veth.c:1725
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1352 [inline]
free_pcp_prepare+0x374/0x870 mm/page_alloc.c:1404
free_unref_page_prepare mm/page_alloc.c:3325 [inline]
free_unref_page+0x19/0x690 mm/page_alloc.c:3404
__unfreeze_partials+0x320/0x340 mm/slub.c:2536
qlink_free mm/kasan/quarantine.c:157 [inline]
qlist_free_all+0x6d/0x160 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446
kasan_slab_alloc include/linux/kasan.h:260 [inline]
slab_post_alloc_hook mm/slab.h:732 [inline]
slab_alloc_node mm/slub.c:3230 [inline]
slab_alloc mm/slub.c:3238 [inline]
kmem_cache_alloc_trace+0x258/0x3d0 mm/slub.c:3255
kmalloc include/linux/slab.h:581 [inline]
kzalloc include/linux/slab.h:715 [inline]
ref_tracker_alloc+0x14c/0x550 lib/ref_tracker.c:85
__netdev_tracker_alloc include/linux/netdevice.h:3860 [inline]
dev_hold_track include/linux/netdevice.h:3889 [inline]
dev_hold_track include/linux/netdevice.h:3884 [inline]
netdev_queue_add_kobject net/core/net-sysfs.c:1650 [inline]
netdev_queue_update_kobjects+0x1a7/0x4e0 net/core/net-sysfs.c:1705
register_queue_kobjects net/core/net-sysfs.c:1766 [inline]
netdev_register_kobject+0x35a/0x430 net/core/net-sysfs.c:2012
register_netdevice+0xd9d/0x15a0 net/core/dev.c:9663
veth_newlink+0x405/0xa90 drivers/net/veth.c:1694
__rtnl_newlink+0x107c/0x1760 net/core/rtnetlink.c:3483
rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3531
rtnetlink_rcv_msg+0x413/0xb80 net/core/rtnetlink.c:5598
netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
Memory state around the buggy address:
ffff888074aabf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888074aac000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888074aac080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888074aac100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888074aac180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Tested on:
commit: 922ea87f ionic: use vmalloc include
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/
console output: https://syzkaller.appspot.com/x/log.txt?x=118926a2700000
kernel config: https://syzkaller.appspot.com/x/.config?x=d63ad23bb09039e8
dashboard link: https://syzkaller.appspot.com/bug?extid=2bef95d3ab4daa10155b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=130215b6700000
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-and-tested-by: [email protected]
Tested on:
commit: 922ea87f ionic: use vmalloc include
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/
kernel config: https://syzkaller.appspot.com/x/.config?x=3f802340579dda19
dashboard link: https://syzkaller.appspot.com/bug?extid=2bef95d3ab4daa10155b
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=134f85da700000
Note: testing is done by a robot and is best-effort only.