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f0c928d878
linux/net
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Eric Dumazet f0c928d878 tcp: fix a race in inet_diag_dump_icsk() 
Alexei reported use after frees in inet_diag_dump_icsk() [1]

Because we use refcount_set() when various sockets are setup and
inserted into ehash, we also need to make sure inet_diag_dump_icsk()
wont race with the refcount_set() operations.

Jonathan Lemon sent a patch changing net_twsk_hashdance() but
other spots would need risky changes.

Instead, fix inet_diag_dump_icsk() as this bug came with
linux-4.10 only.

[1] Quoting Alexei :

First something iterating over sockets finds already freed tw socket:

refcount_t: increment on 0; use-after-free.
WARNING: CPU: 2 PID: 2738 at lib/refcount.c:153 refcount_inc+0x26/0x30
RIP: 0010:refcount_inc+0x26/0x30
RSP: 0018:ffffc90004c8fbc0 EFLAGS: 00010282
RAX: 000000000000002b RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88085ee9d680 RSI: ffff88085ee954c8 RDI: ffff88085ee954c8
RBP: ffff88010ecbd2c0 R08: 0000000000000000 R09: 000000000000174c
R10: ffffffff81e7c5a0 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8806ba9bf210 R14: ffffffff82304600 R15: ffff88010ecbd328
FS:  00007f81f5a7d700(0000) GS:ffff88085ee80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f81e2a95000 CR3: 000000069b2eb006 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 inet_diag_dump_icsk+0x2b3/0x4e0 [inet_diag]  // sock_hold(sk); in net/ipv4/inet_diag.c:1002
 ? kmalloc_large_node+0x37/0x70
 ? __kmalloc_node_track_caller+0x1cb/0x260
 ? __alloc_skb+0x72/0x1b0
 ? __kmalloc_reserve.isra.40+0x2e/0x80
 __inet_diag_dump+0x3b/0x80 [inet_diag]
 netlink_dump+0x116/0x2a0
 netlink_recvmsg+0x205/0x3c0
 sock_read_iter+0x89/0xd0
 __vfs_read+0xf7/0x140
 vfs_read+0x8a/0x140
 SyS_read+0x3f/0xa0
 do_syscall_64+0x5a/0x100

then a minute later twsk timer fires and hits two bad refcnts
for this freed socket:

refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 31 PID: 0 at lib/refcount.c:228 refcount_dec+0x2e/0x40
Modules linked in:
RIP: 0010:refcount_dec+0x2e/0x40
RSP: 0018:ffff88085f5c3ea8 EFLAGS: 00010296
RAX: 000000000000002c RBX: ffff88010ecbd2c0 RCX: 000000000000083f
RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000003f
RBP: ffffc90003c77280 R08: 0000000000000000 R09: 00000000000017d3
R10: ffffffff81e7c5a0 R11: 0000000000000000 R12: ffffffff82ad2d80
R13: ffffffff8182de00 R14: ffff88085f5c3ef8 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88085f5c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbe42685250 CR3: 0000000002209001 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 inet_twsk_kill+0x9d/0xc0  // inet_twsk_bind_unhash(tw, hashinfo);
 call_timer_fn+0x29/0x110
 run_timer_softirq+0x36b/0x3a0

refcount_t: underflow; use-after-free.
WARNING: CPU: 31 PID: 0 at lib/refcount.c:187 refcount_sub_and_test+0x46/0x50
RIP: 0010:refcount_sub_and_test+0x46/0x50
RSP: 0018:ffff88085f5c3eb8 EFLAGS: 00010296
RAX: 0000000000000026 RBX: ffff88010ecbd2c0 RCX: 000000000000083f
RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000003f
RBP: ffff88010ecbd358 R08: 0000000000000000 R09: 000000000000185b
R10: ffffffff81e7c5a0 R11: 0000000000000000 R12: ffff88010ecbd358
R13: ffffffff8182de00 R14: ffff88085f5c3ef8 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88085f5c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbe42685250 CR3: 0000000002209001 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 inet_twsk_put+0x12/0x20  // inet_twsk_put(tw);
 call_timer_fn+0x29/0x110
 run_timer_softirq+0x36b/0x3a0

Fixes: 67db3e4bfb ("tcp: no longer hold ehash lock while calling tcp_get_info()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Alexei Starovoitov <ast@kernel.org>
Cc: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-12-20 19:23:22 -08:00
..
6lowpan
9p Merge branch 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-11-03 10:35:52 -07:00
802
8021q netpoll: allow cleanup to be synchronous 2018-10-19 17:01:43 -07:00
appletalk
atm Revert "net: simplify sock_poll_wait" 2018-10-23 10:57:06 -07:00
ax25
batman-adv batman-adv: Expand merged fragment buffer for full packet 2018-11-12 10:41:29 +01:00
bluetooth Merge branch 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-11-01 19:58:52 -07:00
bpf bpf: refactor bpf_test_run() to separate own failures and test program result 2018-12-01 12:33:58 -08:00
bpfilter net: bpfilter: Set user mode helper's command line 2018-10-22 19:37:36 -07:00
bridge net: bridge: fix vlan stats use-after-free on destruction 2018-11-17 21:38:44 -08:00
caif Revert "net: simplify sock_poll_wait" 2018-10-23 10:57:06 -07:00
can net: add missing SOF_TIMESTAMPING_OPT_ID support 2018-12-17 23:27:00 -08:00
ceph libceph: fall back to sendmsg for slab pages 2018-11-19 17:59:47 +01:00
core neighbor: NTF_PROXY is a valid ndm_flag for a dump request 2018-12-19 17:30:47 -08:00
dcb
dccp Revert "net: simplify sock_poll_wait" 2018-10-23 10:57:06 -07:00
decnet
dns_resolver dns: Allow the dns resolver to retrieve a server set 2018-10-04 09:40:52 -07:00
dsa net: dsa: Fix tagging attribute location 2018-11-30 17:17:39 -08:00
ethernet
hsr
ieee802154
ife
ipv4 tcp: fix a race in inet_diag_dump_icsk() 2018-12-20 19:23:22 -08:00
ipv6 ipv6: frags: Fix bogus skb->sk in reassembled packets 2018-12-20 16:31:36 -08:00
iucv Revert "net: simplify sock_poll_wait" 2018-10-23 10:57:06 -07:00
kcm
key
l2tp l2tp: fix a sock refcnt leak in l2tp_tunnel_register 2018-11-14 22:49:31 -08:00
l3mdev
lapb
llc llc: do not use sk_eat_skb() 2018-10-22 19:59:20 -07:00
mac80211 mac80211: free skb fraglist before freeing the skb 2018-12-19 09:40:17 +01:00
mac802154 mac802154: Remove VLA usage of skcipher 2018-09-28 12:46:07 +08:00
mpls net/mpls: Handle kernel side filtering of route dumps 2018-10-16 00:14:07 -07:00
ncsi net/ncsi: Add NCSI Broadcom OEM command 2018-10-17 22:14:54 -07:00
netfilter netfilter: nf_conncount: use rb_link_node_rcu() instead of rb_link_node() 2018-12-13 01:14:58 +01:00
netlabel
netlink net: netlink: rename NETLINK_DUMP_STRICT_CHK -> NETLINK_GET_STRICT_CHK 2018-12-14 11:44:31 -08:00
netrom
nfc Merge branch 'work.tty-ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-10-24 14:43:41 +01:00
nsh
openvswitch openvswitch: fix spelling mistake "execeeds" -> "exceeds" 2018-11-30 13:18:09 -08:00
packet net: add missing SOF_TIMESTAMPING_OPT_ID support 2018-12-17 23:27:00 -08:00
phonet
psample
qrtr
rds rds: Fix warning. 2018-12-19 20:53:18 -08:00
rfkill
rose
rxrpc rxrpc: Fix life check 2018-11-15 11:35:40 -08:00
sched net/sched: cls_flower: Remove old entries from rhashtable 2018-12-19 16:36:55 -08:00
sctp sctp: initialize sin6_flowinfo for ipv6 addrs in sctp_inet6addr_event 2018-12-10 11:53:42 -08:00
smc net/smc: fix TCP fallback socket release 2018-12-18 22:02:51 -08:00
strparser bpf, sockmap: convert to generic sk_msg interface 2018-10-15 12:23:19 -07:00
sunrpc SUNRPC: Remove xprt_connect_status() 2018-12-18 11:04:10 -05:00
switchdev
tipc tipc: check group dests after tipc_wait_for_cond() 2018-12-18 15:44:23 -08:00
tls net/tls: allocate tls context using GFP_ATOMIC 2018-12-19 16:28:50 -08:00
unix Revert "net: simplify sock_poll_wait" 2018-10-23 10:57:06 -07:00
vmw_vsock VSOCK: Send reset control packet when socket is partially bound 2018-12-18 11:53:42 -08:00
wimax
wireless nl80211: fix memory leak if validate_pae_over_nl80211() fails 2018-12-19 09:40:17 +01:00
x25 net/x25: handle call collisions 2018-11-29 14:25:36 -08:00
xdp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-10-19 11:03:06 -07:00
xfrm Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec 2018-12-18 11:43:26 -08:00
compat.c
Kconfig bpf, sockmap: convert to generic sk_msg interface 2018-10-15 12:23:19 -07:00
Makefile
socket.c socket: do a generic_file_splice_read when proto_ops has no splice_read 2018-11-17 21:34:11 -08:00
sysctl_net.c