diff options
| author | Jakub Sitnicki <jakub@cloudflare.com> | 2019-01-28 10:13:35 +0100 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2019-01-29 00:05:03 +0100 |
| commit | 1d79895aef18fa05789995d86d523c9b2ee58a02 (patch) | |
| tree | 50fcf2e81b0200b2ff9ddafc69f702dd3430da98 | |
| parent | 8c79b35693380d856dcbbc21629682a90f26ca62 (diff) | |
sk_msg: Always cancel strp work before freeing the psock
Despite having stopped the parser, we still need to deinitialize it
by calling strp_done so that it cancels its work. Otherwise the worker
thread can run after we have freed the parser, and attempt to access
its workqueue resulting in a use-after-free:
==================================================================
BUG: KASAN: use-after-free in pwq_activate_delayed_work+0x1b/0x1d0
Read of size 8 at addr ffff888069975240 by task kworker/u2:2/93
CPU: 0 PID: 93 Comm: kworker/u2:2 Not tainted 5.0.0-rc2-00335-g28f9d1a3d4fe-dirty #14
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-2.fc27 04/01/2014
Workqueue: (null) (kstrp)
Call Trace:
print_address_description+0x6e/0x2b0
? pwq_activate_delayed_work+0x1b/0x1d0
kasan_report+0xfd/0x177
? pwq_activate_delayed_work+0x1b/0x1d0
? pwq_activate_delayed_work+0x1b/0x1d0
pwq_activate_delayed_work+0x1b/0x1d0
? process_one_work+0x4aa/0x660
pwq_dec_nr_in_flight+0x9b/0x100
worker_thread+0x82/0x680
? process_one_work+0x660/0x660
kthread+0x1b9/0x1e0
? __kthread_create_on_node+0x250/0x250
ret_from_fork+0x1f/0x30
Allocated by task 111:
sk_psock_init+0x3c/0x1b0
sock_map_link.isra.2+0x103/0x4b0
sock_map_update_common+0x94/0x270
sock_map_update_elem+0x145/0x160
__se_sys_bpf+0x152e/0x1e10
do_syscall_64+0xb2/0x3e0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Freed by task 112:
kfree+0x7f/0x140
process_one_work+0x40b/0x660
worker_thread+0x82/0x680
kthread+0x1b9/0x1e0
ret_from_fork+0x1f/0x30
The buggy address belongs to the object at ffff888069975180
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 192 bytes inside of
512-byte region [ffff888069975180, ffff888069975380)
The buggy address belongs to the page:
page:ffffea0001a65d00 count:1 mapcount:0 mapping:ffff88806d401280 index:0x0 compound_mapcount: 0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 dead000000000100 dead000000000200 ffff88806d401280
raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff888069975100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888069975180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888069975200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888069975280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888069975300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Reported-by: Marek Majkowski <marek@cloudflare.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/netdev/CAJPywTLwgXNEZ2dZVoa=udiZmtrWJ0q5SuBW64aYs0Y1khXX3A@mail.gmail.com
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
| -rw-r--r-- | net/core/skmsg.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/net/core/skmsg.c b/net/core/skmsg.c index d6d5c20d7044..8c826603bf36 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -545,8 +545,7 @@ static void sk_psock_destroy_deferred(struct work_struct *gc) struct sk_psock *psock = container_of(gc, struct sk_psock, gc); /* No sk_callback_lock since already detached. */ - if (psock->parser.enabled) - strp_done(&psock->parser.strp); + strp_done(&psock->parser.strp); cancel_work_sync(&psock->work); |