Yue Haibing
4f76885213
netns: Make get_net_ns() handle zero refcount net
...
[ Upstream commit ff960f9d3edbe08a736b5a224d91a305ccc946b0 ]
Syzkaller hit a warning:
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 3 PID: 7890 at lib/refcount.c:25 refcount_warn_saturate+0xdf/0x1d0
Modules linked in:
CPU: 3 PID: 7890 Comm: tun Not tainted 6.10.0-rc3-00100-gcaa4f9578aba-dirty #310
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
RIP: 0010:refcount_warn_saturate+0xdf/0x1d0
Code: 41 49 04 31 ff 89 de e8 9f 1e cd fe 84 db 75 9c e8 76 26 cd fe c6 05 b6 41 49 04 01 90 48 c7 c7 b8 8e 25 86 e8 d2 05 b5 fe 90 <0f> 0b 90 90 e9 79 ff ff ff e8 53 26 cd fe 0f b6 1
RSP: 0018:ffff8881067b7da0 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff811c72ac
RDX: ffff8881026a2140 RSI: ffffffff811c72b5 RDI: 0000000000000001
RBP: ffff8881067b7db0 R08: 0000000000000000 R09: 205b5d3730353139
R10: 0000000000000000 R11: 205d303938375420 R12: ffff8881086500c4
R13: ffff8881086500c4 R14: ffff8881086500b0 R15: ffff888108650040
FS: 00007f5b2961a4c0(0000) GS:ffff88823bd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d7ed36fd18 CR3: 00000001482f6000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
? show_regs+0xa3/0xc0
? __warn+0xa5/0x1c0
? refcount_warn_saturate+0xdf/0x1d0
? report_bug+0x1fc/0x2d0
? refcount_warn_saturate+0xdf/0x1d0
? handle_bug+0xa1/0x110
? exc_invalid_op+0x3c/0xb0
? asm_exc_invalid_op+0x1f/0x30
? __warn_printk+0xcc/0x140
? __warn_printk+0xd5/0x140
? refcount_warn_saturate+0xdf/0x1d0
get_net_ns+0xa4/0xc0
? __pfx_get_net_ns+0x10/0x10
open_related_ns+0x5a/0x130
__tun_chr_ioctl+0x1616/0x2370
? __sanitizer_cov_trace_switch+0x58/0xa0
? __sanitizer_cov_trace_const_cmp2+0x1c/0x30
? __pfx_tun_chr_ioctl+0x10/0x10
tun_chr_ioctl+0x2f/0x40
__x64_sys_ioctl+0x11b/0x160
x64_sys_call+0x1211/0x20d0
do_syscall_64+0x9e/0x1d0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5b28f165d7
Code: b3 66 90 48 8b 05 b1 48 2d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 81 48 2d 00 8
RSP: 002b:00007ffc2b59c5e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5b28f165d7
RDX: 0000000000000000 RSI: 00000000000054e3 RDI: 0000000000000003
RBP: 00007ffc2b59c650 R08: 00007f5b291ed8c0 R09: 00007f5b2961a4c0
R10: 0000000029690010 R11: 0000000000000246 R12: 0000000000400730
R13: 00007ffc2b59cf40 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Kernel panic - not syncing: kernel: panic_on_warn set ...
This is trigger as below:
ns0 ns1
tun_set_iff() //dev is tun0
tun->dev = dev
//ip link set tun0 netns ns1
put_net() //ref is 0
__tun_chr_ioctl() //TUNGETDEVNETNS
net = dev_net(tun->dev);
open_related_ns(&net->ns, get_net_ns); //ns1
get_net_ns()
get_net() //addition on 0
Use maybe_get_net() in get_net_ns in case net's ref is zero to fix this
Fixes: 0c3e0e3bb623 ("tun: Add ioctl() TUNGETDEVNETNS cmd to allow obtaining real net ns of tun device")
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20240614131302.2698509-1-yuehaibing@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-19 14:19:08 +01:00
Thadeu Lima de Souza Cascardo
bc6eaae798
net: fix out-of-bounds access in ops_init
...
commit a26ff37e624d12e28077e5b24d2b264f62764ad6 upstream.
net_alloc_generic is called by net_alloc, which is called without any
locking. It reads max_gen_ptrs, which is changed under pernet_ops_rwsem. It
is read twice, first to allocate an array, then to set s.len, which is
later used to limit the bounds of the array access.
It is possible that the array is allocated and another thread is
registering a new pernet ops, increments max_gen_ptrs, which is then used
to set s.len with a larger than allocated length for the variable array.
Fix it by reading max_gen_ptrs only once in net_alloc_generic. If
max_gen_ptrs is later incremented, it will be caught in net_assign_generic.
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Fixes: 073862ba5d24 ("netns: fix net_alloc_generic()")
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240502132006.3430840-1-cascardo@igalia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-11-19 11:32:49 +01:00
