linux-stable.git/net/llc, branch v4.4.232

llc: make sure applications use ARPHRD_ETHER

2020-07-22T07:10:03+00:00

[ 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 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

llc: fix sk_buff refcounting in llc_conn_state_process()

2020-01-29T09:21:49+00:00

[ Upstream commit 36453c852816f19947ca482a595dffdd2efa4965 ]

If llc_conn_state_process() sees that llc_conn_service() put the skb on
a list, it will drop one fewer references to it.  This is wrong because
the current behavior is that llc_conn_service() never consumes a
reference to the skb.

The code also makes the number of skb references being dropped
conditional on which of ind_prim and cfm_prim are nonzero, yet neither
of these affects how many references are *acquired*.  So there is extra
code that tries to fix this up by sometimes taking another reference.

Remove the unnecessary/broken refcounting logic and instead just add an
skb_get() before the only two places where an extra reference is
actually consumed.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Biggers 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

llc: fix another potential sk_buff leak in llc_ui_sendmsg()

2020-01-29T09:21:49+00:00

[ Upstream commit fc8d5db10cbe1338a52ebc74e7feab9276721774 ]

All callers of llc_conn_state_process() except llc_build_and_send_pkt()
(via llc_ui_sendmsg() -> llc_ui_send_data()) assume that it always
consumes a reference to the skb.  Fix this caller to do the same.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Biggers 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

llc2: Fix return statement of llc_stat_ev_rx_null_dsap_xid_c (and _test_c)

2020-01-12T10:22:50+00:00

[ Upstream commit af1c0e4e00f3cc76cb136ebf2e2c04e8b6446285 ]

When a frame with NULL DSAP is received, llc_station_rcv is called.
In turn, llc_stat_ev_rx_null_dsap_xid_c is called to check if it is a NULL
XID frame. The return statement of llc_stat_ev_rx_null_dsap_xid_c returns 1
when the incoming frame is not a NULL XID frame and 0 otherwise. Hence, a
NULL XID response is returned unexpectedly, e.g. when the incoming frame is
a NULL TEST command.

To fix the error, simply remove the conditional operator.

A similar error in llc_stat_ev_rx_null_dsap_test_c is also fixed.

Signed-off-by: Chan Shu Tak, Alex 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

llc: avoid blocking in llc_sap_close()

2019-11-25T14:53:57+00:00

[ Upstream commit 9708d2b5b7c648e8e0a40d11e8cea12f6277f33c ]

llc_sap_close() is called by llc_sap_put() which
could be called in BH context in llc_rcv(). We can't
block in BH.

There is no reason to block it here, kfree_rcu() should
be sufficient.

Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

llc: fix sk_buff leak in llc_conn_service()

2019-11-06T11:09:22+00:00

commit b74555de21acd791f12c4a1aeaf653dd7ac21133 upstream.

syzbot reported:

    BUG: memory leak
    unreferenced object 0xffff88811eb3de00 (size 224):
       comm "syz-executor559", pid 7315, jiffies 4294943019 (age 10.300s)
       hex dump (first 32 bytes):
         00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
         00 a0 38 24 81 88 ff ff 00 c0 f2 15 81 88 ff ff  ..8$............
       backtrace:
         [<000000008d1c66a1>] kmemleak_alloc_recursive  include/linux/kmemleak.h:55 [inline]
         [<000000008d1c66a1>] slab_post_alloc_hook mm/slab.h:439 [inline]
         [<000000008d1c66a1>] slab_alloc_node mm/slab.c:3269 [inline]
         [<000000008d1c66a1>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579
         [<00000000447d9496>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:198
         [<000000000cdbf82f>] alloc_skb include/linux/skbuff.h:1058 [inline]
         [<000000000cdbf82f>] llc_alloc_frame+0x66/0x110 net/llc/llc_sap.c:54
         [<000000002418b52e>] llc_conn_ac_send_sabme_cmd_p_set_x+0x2f/0x140  net/llc/llc_c_ac.c:777
         [<000000001372ae17>] llc_exec_conn_trans_actions net/llc/llc_conn.c:475  [inline]
         [<000000001372ae17>] llc_conn_service net/llc/llc_conn.c:400 [inline]
         [<000000001372ae17>] llc_conn_state_process+0x1ac/0x640  net/llc/llc_conn.c:75
         [<00000000f27e53c1>] llc_establish_connection+0x110/0x170  net/llc/llc_if.c:109
         [<00000000291b2ca0>] llc_ui_connect+0x10e/0x370 net/llc/af_llc.c:477
         [<000000000f9c740b>] __sys_connect+0x11d/0x170 net/socket.c:1840
         [...]

The bug is that most callers of llc_conn_send_pdu() assume it consumes a
reference to the skb, when actually due to commit b85ab56c3f81 ("llc:
properly handle dev_queue_xmit() return value") it doesn't.

Revert most of that commit, and instead make the few places that need
llc_conn_send_pdu() to *not* consume a reference call skb_get() before.

Fixes: b85ab56c3f81 ("llc: properly handle dev_queue_xmit() return value")
Reported-by: syzbot+6b825a6494a04cc0e3f7@syzkaller.appspotmail.com
Signed-off-by: Eric Biggers 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

llc: fix sk_buff leak in llc_sap_state_process()

2019-11-06T11:09:22+00:00

commit c6ee11c39fcc1fb55130748990a8f199e76263b4 upstream.

syzbot reported:

    BUG: memory leak
    unreferenced object 0xffff888116270800 (size 224):
       comm "syz-executor641", pid 7047, jiffies 4294947360 (age 13.860s)
       hex dump (first 32 bytes):
         00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
         00 20 e1 2a 81 88 ff ff 00 40 3d 2a 81 88 ff ff  . .*.....@=*....
       backtrace:
         [<000000004d41b4cc>] kmemleak_alloc_recursive  include/linux/kmemleak.h:55 [inline]
         [<000000004d41b4cc>] slab_post_alloc_hook mm/slab.h:439 [inline]
         [<000000004d41b4cc>] slab_alloc_node mm/slab.c:3269 [inline]
         [<000000004d41b4cc>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579
         [<00000000506a5965>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:198
         [<000000001ba5a161>] alloc_skb include/linux/skbuff.h:1058 [inline]
         [<000000001ba5a161>] alloc_skb_with_frags+0x5f/0x250  net/core/skbuff.c:5327
         [<0000000047d9c78b>] sock_alloc_send_pskb+0x269/0x2a0  net/core/sock.c:2225
         [<000000003828fe54>] sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2242
         [<00000000e34d94f9>] llc_ui_sendmsg+0x10a/0x540 net/llc/af_llc.c:933
         [<00000000de2de3fb>] sock_sendmsg_nosec net/socket.c:652 [inline]
         [<00000000de2de3fb>] sock_sendmsg+0x54/0x70 net/socket.c:671
         [<000000008fe16e7a>] __sys_sendto+0x148/0x1f0 net/socket.c:1964
	 [...]

The bug is that llc_sap_state_process() always takes an extra reference
to the skb, but sometimes neither llc_sap_next_state() nor
llc_sap_state_process() itself drops this reference.

Fix it by changing llc_sap_next_state() to never consume a reference to
the skb, rather than sometimes do so and sometimes not.  Then remove the
extra skb_get() and kfree_skb() from llc_sap_state_process().

Reported-by: syzbot+6bf095f9becf5efef645@syzkaller.appspotmail.com
Reported-by: syzbot+31c16aa4202dace3812e@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Biggers 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

llc: fix skb leak in llc_build_and_send_ui_pkt()

2019-06-11T10:24:06+00:00

[ Upstream commit 8fb44d60d4142cd2a440620cd291d346e23c131e ]

If llc_mac_hdr_init() returns an error, we must drop the skb
since no llc_build_and_send_ui_pkt() caller will take care of this.

BUG: memory leak
unreferenced object 0xffff8881202b6800 (size 2048):
  comm "syz-executor907", pid 7074, jiffies 4294943781 (age 8.590s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    1a 00 07 40 00 00 00 00 00 00 00 00 00 00 00 00  ...@............
  backtrace:
    [<00000000e25b5abe>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
    [<00000000e25b5abe>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<00000000e25b5abe>] slab_alloc mm/slab.c:3326 [inline]
    [<00000000e25b5abe>] __do_kmalloc mm/slab.c:3658 [inline]
    [<00000000e25b5abe>] __kmalloc+0x161/0x2c0 mm/slab.c:3669
    [<00000000a1ae188a>] kmalloc include/linux/slab.h:552 [inline]
    [<00000000a1ae188a>] sk_prot_alloc+0xd6/0x170 net/core/sock.c:1608
    [<00000000ded25bbe>] sk_alloc+0x35/0x2f0 net/core/sock.c:1662
    [<000000002ecae075>] llc_sk_alloc+0x35/0x170 net/llc/llc_conn.c:950
    [<00000000551f7c47>] llc_ui_create+0x7b/0x140 net/llc/af_llc.c:173
    [<0000000029027f0e>] __sock_create+0x164/0x250 net/socket.c:1430
    [<000000008bdec225>] sock_create net/socket.c:1481 [inline]
    [<000000008bdec225>] __sys_socket+0x69/0x110 net/socket.c:1523
    [<00000000b6439228>] __do_sys_socket net/socket.c:1532 [inline]
    [<00000000b6439228>] __se_sys_socket net/socket.c:1530 [inline]
    [<00000000b6439228>] __x64_sys_socket+0x1e/0x30 net/socket.c:1530
    [<00000000cec820c1>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:301
    [<000000000c32554f>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88811d750d00 (size 224):
  comm "syz-executor907", pid 7074, jiffies 4294943781 (age 8.600s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 f0 0c 24 81 88 ff ff 00 68 2b 20 81 88 ff ff  ...$.....h+ ....
  backtrace:
    [<0000000053026172>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
    [<0000000053026172>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<0000000053026172>] slab_alloc_node mm/slab.c:3269 [inline]
    [<0000000053026172>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579
    [<00000000fa8f3c30>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:198
    [<00000000d96fdafb>] alloc_skb include/linux/skbuff.h:1058 [inline]
    [<00000000d96fdafb>] alloc_skb_with_frags+0x5f/0x250 net/core/skbuff.c:5327
    [<000000000a34a2e7>] sock_alloc_send_pskb+0x269/0x2a0 net/core/sock.c:2225
    [<00000000ee39999b>] sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2242
    [<00000000e034d810>] llc_ui_sendmsg+0x10a/0x540 net/llc/af_llc.c:933
    [<00000000c0bc8445>] sock_sendmsg_nosec net/socket.c:652 [inline]
    [<00000000c0bc8445>] sock_sendmsg+0x54/0x70 net/socket.c:671
    [<000000003b687167>] __sys_sendto+0x148/0x1f0 net/socket.c:1964
    [<00000000922d78d9>] __do_sys_sendto net/socket.c:1976 [inline]
    [<00000000922d78d9>] __se_sys_sendto net/socket.c:1972 [inline]
    [<00000000922d78d9>] __x64_sys_sendto+0x2a/0x30 net/socket.c:1972
    [<00000000cec820c1>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:301
    [<000000000c32554f>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

llc: do not use sk_eat_skb()

2018-12-01T08:46:34+00:00

commit 604d415e2bd642b7e02c80e719e0396b9d4a77a6 upstream.

syzkaller triggered a use-after-free [1], caused by a combination of
skb_get() in llc_conn_state_process() and usage of sk_eat_skb()

sk_eat_skb() is assuming the skb about to be freed is only used by
the current thread. TCP/DCCP stacks enforce this because current
thread holds the socket lock.

llc_conn_state_process() wants to make sure skb does not disappear,
and holds a reference on the skb it manipulates. But as soon as this
skb is added to socket receive queue, another thread can consume it.

This means that llc must use regular skb_unlink() and kfree_skb()
so that both producer and consumer can safely work on the same skb.

[1]
BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
BUG: KASAN: use-after-free in refcount_read include/linux/refcount.h:43 [inline]
BUG: KASAN: use-after-free in skb_unref include/linux/skbuff.h:967 [inline]
BUG: KASAN: use-after-free in kfree_skb+0xb7/0x580 net/core/skbuff.c:655
Read of size 4 at addr ffff8801d1f6fba4 by task ksoftirqd/1/18

CPU: 1 PID: 18 Comm: ksoftirqd/1 Not tainted 4.19.0-rc8+ #295
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c4/0x2b6 lib/dump_stack.c:113
 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
 refcount_read include/linux/refcount.h:43 [inline]
 skb_unref include/linux/skbuff.h:967 [inline]
 kfree_skb+0xb7/0x580 net/core/skbuff.c:655
 llc_sap_state_process+0x9b/0x550 net/llc/llc_sap.c:224
 llc_sap_rcv+0x156/0x1f0 net/llc/llc_sap.c:297
 llc_sap_handler+0x65e/0xf80 net/llc/llc_sap.c:438
 llc_rcv+0x79e/0xe20 net/llc/llc_input.c:208
 __netif_receive_skb_one_core+0x14d/0x200 net/core/dev.c:4913
 __netif_receive_skb+0x2c/0x1e0 net/core/dev.c:5023
 process_backlog+0x218/0x6f0 net/core/dev.c:5829
 napi_poll net/core/dev.c:6249 [inline]
 net_rx_action+0x7c5/0x1950 net/core/dev.c:6315
 __do_softirq+0x30c/0xb03 kernel/softirq.c:292
 run_ksoftirqd+0x94/0x100 kernel/softirq.c:653
 smpboot_thread_fn+0x68b/0xa00 kernel/smpboot.c:164
 kthread+0x35a/0x420 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413

Allocated by task 18:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc_node+0x144/0x730 mm/slab.c:3644
 __alloc_skb+0x119/0x770 net/core/skbuff.c:193
 alloc_skb include/linux/skbuff.h:995 [inline]
 llc_alloc_frame+0xbc/0x370 net/llc/llc_sap.c:54
 llc_station_ac_send_xid_r net/llc/llc_station.c:52 [inline]
 llc_station_rcv+0x1dc/0x1420 net/llc/llc_station.c:111
 llc_rcv+0xc32/0xe20 net/llc/llc_input.c:220
 __netif_receive_skb_one_core+0x14d/0x200 net/core/dev.c:4913
 __netif_receive_skb+0x2c/0x1e0 net/core/dev.c:5023
 process_backlog+0x218/0x6f0 net/core/dev.c:5829
 napi_poll net/core/dev.c:6249 [inline]
 net_rx_action+0x7c5/0x1950 net/core/dev.c:6315
 __do_softirq+0x30c/0xb03 kernel/softirq.c:292

Freed by task 16383:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x83/0x290 mm/slab.c:3756
 kfree_skbmem+0x154/0x230 net/core/skbuff.c:582
 __kfree_skb+0x1d/0x20 net/core/skbuff.c:642
 sk_eat_skb include/net/sock.h:2366 [inline]
 llc_ui_recvmsg+0xec2/0x1610 net/llc/af_llc.c:882
 sock_recvmsg_nosec net/socket.c:794 [inline]
 sock_recvmsg+0xd0/0x110 net/socket.c:801
 ___sys_recvmsg+0x2b6/0x680 net/socket.c:2278
 __sys_recvmmsg+0x303/0xb90 net/socket.c:2390
 do_sys_recvmmsg+0x181/0x1a0 net/socket.c:2466
 __do_sys_recvmmsg net/socket.c:2484 [inline]
 __se_sys_recvmmsg net/socket.c:2480 [inline]
 __x64_sys_recvmmsg+0xbe/0x150 net/socket.c:2480
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8801d1f6fac0
 which belongs to the cache skbuff_head_cache of size 232
The buggy address is located 228 bytes inside of
 232-byte region [ffff8801d1f6fac0, ffff8801d1f6fba8)
The buggy address belongs to the page:
page:ffffea000747dbc0 count:1 mapcount:0 mapping:ffff8801d9be7680 index:0xffff8801d1f6fe80
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea0007346e88 ffffea000705b108 ffff8801d9be7680
raw: ffff8801d1f6fe80 ffff8801d1f6f0c0 000000010000000b 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d1f6fa80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8801d1f6fb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801d1f6fb80: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
                               ^
 ffff8801d1f6fc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d1f6fc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

llc: use refcount_inc_not_zero() for llc_sap_find()

2018-08-22T05:48:35+00:00

[ Upstream commit 0dcb82254d65f72333aa50ad626d1e9665ad093b ]

llc_sap_put() decreases the refcnt before deleting sap
from the global list. Therefore, there is a chance
llc_sap_find() could find a sap with zero refcnt
in this global list.

Close this race condition by checking if refcnt is zero
or not in llc_sap_find(), if it is zero then it is being
removed so we can just treat it as gone.

Reported-by: 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman