[PATCH 4.4 22/58] llc: make sure applications use ARPHRD_ETHER

From: Greg Kroah-Hartman
Date: Mon Jul 20 2020 - 11:38:04 EST

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From: Eric Dumazet <edumazet@xxxxxxxxxx>

[ Upstream commit a9b1110162357689a34992d5c925852948e5b9fd ]

syzbot was to trigger a bug by tricking AF_LLC with
non sensible addr->sllc_arphrd

It seems clear LLC requires an Ethernet device.

Back in commit abf9d537fea2 ("llc: add support for SO_BINDTODEVICE")
Octavian Purdila added possibility for application to use a zero
value for sllc_arphrd, convert it to ARPHRD_ETHER to not cause
regressions on existing applications.

BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:199 [inline]
BUG: KASAN: use-after-free in list_empty include/linux/list.h:268 [inline]
BUG: KASAN: use-after-free in waitqueue_active include/linux/wait.h:126 [inline]
BUG: KASAN: use-after-free in wq_has_sleeper include/linux/wait.h:160 [inline]
BUG: KASAN: use-after-free in skwq_has_sleeper include/net/sock.h:2092 [inline]
BUG: KASAN: use-after-free in sock_def_write_space+0x642/0x670 net/core/sock.c:2813
Read of size 8 at addr ffff88801e0b4078 by task ksoftirqd/3/27

CPU: 3 PID: 27 Comm: ksoftirqd/3 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
__kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
kasan_report+0x12/0x20 mm/kasan/common.c:639
__asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
__read_once_size include/linux/compiler.h:199 [inline]
list_empty include/linux/list.h:268 [inline]
waitqueue_active include/linux/wait.h:126 [inline]
wq_has_sleeper include/linux/wait.h:160 [inline]
skwq_has_sleeper include/net/sock.h:2092 [inline]
sock_def_write_space+0x642/0x670 net/core/sock.c:2813
sock_wfree+0x1e1/0x260 net/core/sock.c:1958
skb_release_head_state+0xeb/0x260 net/core/skbuff.c:652
skb_release_all+0x16/0x60 net/core/skbuff.c:663
__kfree_skb net/core/skbuff.c:679 [inline]
consume_skb net/core/skbuff.c:838 [inline]
consume_skb+0xfb/0x410 net/core/skbuff.c:832
__dev_kfree_skb_any+0xa4/0xd0 net/core/dev.c:2967
dev_kfree_skb_any include/linux/netdevice.h:3650 [inline]
e1000_unmap_and_free_tx_resource.isra.0+0x21b/0x3a0 drivers/net/ethernet/intel/e1000/e1000_main.c:1963
e1000_clean_tx_irq drivers/net/ethernet/intel/e1000/e1000_main.c:3854 [inline]
e1000_clean+0x4cc/0x1d10 drivers/net/ethernet/intel/e1000/e1000_main.c:3796
napi_poll net/core/dev.c:6532 [inline]
net_rx_action+0x508/0x1120 net/core/dev.c:6600
__do_softirq+0x262/0x98c kernel/softirq.c:292
run_ksoftirqd kernel/softirq.c:603 [inline]
run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595
smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165
kthread+0x361/0x430 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 8247:
save_stack+0x23/0x90 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
__kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:521
slab_post_alloc_hook mm/slab.h:584 [inline]
slab_alloc mm/slab.c:3320 [inline]
kmem_cache_alloc+0x121/0x710 mm/slab.c:3484
sock_alloc_inode+0x1c/0x1d0 net/socket.c:240
alloc_inode+0x68/0x1e0 fs/inode.c:230
new_inode_pseudo+0x19/0xf0 fs/inode.c:919
sock_alloc+0x41/0x270 net/socket.c:560
__sock_create+0xc2/0x730 net/socket.c:1384
sock_create net/socket.c:1471 [inline]
__sys_socket+0x103/0x220 net/socket.c:1513
__do_sys_socket net/socket.c:1522 [inline]
__se_sys_socket net/socket.c:1520 [inline]
__ia32_sys_socket+0x73/0xb0 net/socket.c:1520
do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline]
do_fast_syscall_32+0x27b/0xe16 arch/x86/entry/common.c:408
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 17:
save_stack+0x23/0x90 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
kasan_set_free_info mm/kasan/common.c:335 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
__cache_free mm/slab.c:3426 [inline]
kmem_cache_free+0x86/0x320 mm/slab.c:3694
sock_free_inode+0x20/0x30 net/socket.c:261
i_callback+0x44/0x80 fs/inode.c:219
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2183 [inline]
rcu_core+0x570/0x1540 kernel/rcu/tree.c:2408
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2417
__do_softirq+0x262/0x98c kernel/softirq.c:292

The buggy address belongs to the object at ffff88801e0b4000
which belongs to the cache sock_inode_cache of size 1152
The buggy address is located 120 bytes inside of
1152-byte region [ffff88801e0b4000, ffff88801e0b4480)
The buggy address belongs to the page:
page:ffffea0000782d00 refcount:1 mapcount:0 mapping:ffff88807aa59c40 index:0xffff88801e0b4ffd
raw: 00fffe0000000200 ffffea00008e6c88 ffffea0000782d48 ffff88807aa59c40
raw: ffff88801e0b4ffd ffff88801e0b4000 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88801e0b3f00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
ffff88801e0b3f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801e0b4000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88801e0b4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88801e0b4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Fixes: abf9d537fea2 ("llc: add support for SO_BINDTODEVICE")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/llc/af_llc.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -271,6 +271,10 @@ static int llc_ui_autobind(struct socket

if (!sock_flag(sk, SOCK_ZAPPED))
goto out;
+ if (!addr->sllc_arphrd)
+ addr->sllc_arphrd = ARPHRD_ETHER;
+ if (addr->sllc_arphrd != ARPHRD_ETHER)
+ goto out;
rc = -ENODEV;
if (sk->sk_bound_dev_if) {
llc->dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if);
@@ -328,15 +332,15 @@ static int llc_ui_bind(struct socket *so
if (unlikely(!sock_flag(sk, SOCK_ZAPPED) || addrlen != sizeof(*addr)))
goto out;
rc = -EAFNOSUPPORT;
- if (unlikely(addr->sllc_family != AF_LLC))
+ if (!addr->sllc_arphrd)
+ addr->sllc_arphrd = ARPHRD_ETHER;
+ if (unlikely(addr->sllc_family != AF_LLC || addr->sllc_arphrd != ARPHRD_ETHER))
goto out;
rc = -ENODEV;
rcu_read_lock();
if (sk->sk_bound_dev_if) {
llc->dev = dev_get_by_index_rcu(&init_net, sk->sk_bound_dev_if);
if (llc->dev) {
- if (!addr->sllc_arphrd)
- addr->sllc_arphrd = llc->dev->type;
if (is_zero_ether_addr(addr->sllc_mac))
memcpy(addr->sllc_mac, llc->dev->dev_addr,
IFHWADDRLEN);

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