KASAN: use-after-free Read in rxrpc_get_skb
Hillf Danton
hdanton at sina.com
Tue Jan 26 04:02:17 EST 2021
On Mon, 25 Jan 2021 00:52:19 -0800
> syzbot found the following issue on:
>
> HEAD commit: 7d68e382 bpf: Permit size-0 datasec
> git tree: bpf-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=17e024c8d00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7843b8af99dff
> dashboard link: https://syzkaller.appspot.com/bug?extid=3d1c772efafd3c38d007
> compiler: gcc (GCC) 10.1.0-syz 20200507
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+3d1c772efafd3c38d007 at syzkaller.appspotmail.com
>
> ==================================================================
> BUG: KASAN: use-after-free in rxrpc_get_skb+0x1ce/0x1e0 net/rxrpc/skbuff.c:50
> Read of size 1 at addr ffff8880117ae8ed by task kworker/1:4/9736
>
> CPU: 1 PID: 9736 Comm: kworker/1:4 Not tainted 5.11.0-rc3-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Workqueue: krxrpcd rxrpc_process_call
> Call Trace:
> __dump_stack lib/dump_stack.c:79 [inline]
> dump_stack+0x107/0x163 lib/dump_stack.c:120
> print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:230
> __kasan_report mm/kasan/report.c:396 [inline]
> kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413
> rxrpc_get_skb+0x1ce/0x1e0 net/rxrpc/skbuff.c:50
> rxrpc_resend net/rxrpc/call_event.c:263 [inline]
> rxrpc_process_call+0x1619/0x1f60 net/rxrpc/call_event.c:412
> process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
> worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
> kthread+0x3b1/0x4a0 kernel/kthread.c:292
> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
>
> Allocated by task 20353:
> 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:401 [inline]
> ____kasan_kmalloc.constprop.0+0x82/0xa0 mm/kasan/common.c:429
> kasan_slab_alloc include/linux/kasan.h:205 [inline]
> slab_post_alloc_hook mm/slab.h:512 [inline]
> slab_alloc_node mm/slub.c:2891 [inline]
> kmem_cache_alloc_node+0x1e0/0x470 mm/slub.c:2927
> __alloc_skb+0x71/0x5a0 net/core/skbuff.c:198
> alloc_skb include/linux/skbuff.h:1100 [inline]
> alloc_skb_with_frags+0x93/0x5d0 net/core/skbuff.c:5887
> sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2348
> rxrpc_send_data+0xb51/0x2bf0 net/rxrpc/sendmsg.c:358
> rxrpc_do_sendmsg+0xc03/0x1350 net/rxrpc/sendmsg.c:744
> rxrpc_sendmsg+0x420/0x630 net/rxrpc/af_rxrpc.c:560
> sock_sendmsg_nosec net/socket.c:652 [inline]
> sock_sendmsg+0xcf/0x120 net/socket.c:672
> ____sys_sendmsg+0x6e8/0x810 net/socket.c:2345
> ___sys_sendmsg+0xf3/0x170 net/socket.c:2399
> __sys_sendmsg+0xe5/0x1b0 net/socket.c:2432
> do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> Freed by task 20353:
> 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:356
> ____kasan_slab_free+0xe1/0x110 mm/kasan/common.c:362
> kasan_slab_free include/linux/kasan.h:188 [inline]
> slab_free_hook mm/slub.c:1547 [inline]
> slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1580
> slab_free mm/slub.c:3142 [inline]
> kmem_cache_free+0x82/0x350 mm/slub.c:3158
> kfree_skbmem+0xef/0x1b0 net/core/skbuff.c:633
> __kfree_skb net/core/skbuff.c:690 [inline]
> kfree_skb net/core/skbuff.c:707 [inline]
> kfree_skb+0x140/0x3f0 net/core/skbuff.c:701
> rxrpc_free_skb+0x11d/0x150 net/rxrpc/skbuff.c:78
> rxrpc_cleanup_ring net/rxrpc/call_object.c:485 [inline]
> rxrpc_release_call+0x5dd/0x860 net/rxrpc/call_object.c:552
> rxrpc_release_calls_on_socket+0x21c/0x300 net/rxrpc/call_object.c:579
> rxrpc_release_sock net/rxrpc/af_rxrpc.c:885 [inline]
> rxrpc_release+0x263/0x5a0 net/rxrpc/af_rxrpc.c:916
> __sock_release+0xcd/0x280 net/socket.c:597
> sock_close+0x18/0x20 net/socket.c:1256
> __fput+0x283/0x920 fs/file_table.c:280
> task_work_run+0xdd/0x190 kernel/task_work.c:140
> exit_task_work include/linux/task_work.h:30 [inline]
> do_exit+0xc5c/0x2ae0 kernel/exit.c:825
> do_group_exit+0x125/0x310 kernel/exit.c:922
> get_signal+0x3e9/0x20a0 kernel/signal.c:2770
> arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811
> handle_signal_work kernel/entry/common.c:147 [inline]
> exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
> exit_to_user_mode_prepare+0x148/0x250 kernel/entry/common.c:201
> __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
> syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> The buggy address belongs to the object at ffff8880117ae8c0
> which belongs to the cache skbuff_head_cache of size 232
> The buggy address is located 45 bytes inside of
> 232-byte region [ffff8880117ae8c0, ffff8880117ae9a8)
> The buggy address belongs to the page:
> page:000000006d18c7f7 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x117ae
> flags: 0xfff00000000200(slab)
> raw: 00fff00000000200 dead000000000100 dead000000000122 ffff8881406f7c80
> raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
> ffff8880117ae780: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8880117ae800: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
> >ffff8880117ae880: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
> ^
> ffff8880117ae900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8880117ae980: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
Wait for kworker to complete. Another option is cancel_work_sync().
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -549,6 +549,7 @@ void rxrpc_release_call(struct rxrpc_soc
if (call->security)
call->security->free_call_crypto(call);
+ flush_work(&call->processor);
rxrpc_cleanup_ring(call);
_leave("");
}
More information about the linux-afs
mailing list