linux-stable/net
Paolo Abeni 977d293e23 mptcp: ensure tx skbs always have the MPTCP ext
Due to signed/unsigned comparison, the expression:

	info->size_goal - skb->len > 0

evaluates to true when the size goal is smaller than the
skb size. That results in lack of tx cache refill, so that
the skb allocated by the core TCP code lacks the required
MPTCP skb extensions.

Due to the above, syzbot is able to trigger the following WARN_ON():

WARNING: CPU: 1 PID: 810 at net/mptcp/protocol.c:1366 mptcp_sendmsg_frag+0x1362/0x1bc0 net/mptcp/protocol.c:1366
Modules linked in:
CPU: 1 PID: 810 Comm: syz-executor.4 Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:mptcp_sendmsg_frag+0x1362/0x1bc0 net/mptcp/protocol.c:1366
Code: ff 4c 8b 74 24 50 48 8b 5c 24 58 e9 0f fb ff ff e8 13 44 8b f8 4c 89 e7 45 31 ed e8 98 57 2e fe e9 81 f4 ff ff e8 fe 43 8b f8 <0f> 0b 41 bd ea ff ff ff e9 6f f4 ff ff 4c 89 e7 e8 b9 8e d2 f8 e9
RSP: 0018:ffffc9000531f6a0 EFLAGS: 00010216
RAX: 000000000000697f RBX: 0000000000000000 RCX: ffffc90012107000
RDX: 0000000000040000 RSI: ffffffff88eac9e2 RDI: 0000000000000003
RBP: ffff888078b15780 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff88eac017 R11: 0000000000000000 R12: ffff88801de0a280
R13: 0000000000006b58 R14: ffff888066278280 R15: ffff88803c2fe9c0
FS:  00007fd9f866e700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007faebcb2f718 CR3: 00000000267cb000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __mptcp_push_pending+0x1fb/0x6b0 net/mptcp/protocol.c:1547
 mptcp_release_cb+0xfe/0x210 net/mptcp/protocol.c:3003
 release_sock+0xb4/0x1b0 net/core/sock.c:3206
 sk_stream_wait_memory+0x604/0xed0 net/core/stream.c:145
 mptcp_sendmsg+0xc39/0x1bc0 net/mptcp/protocol.c:1749
 inet6_sendmsg+0x99/0xe0 net/ipv6/af_inet6.c:643
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:724
 sock_write_iter+0x2a0/0x3e0 net/socket.c:1057
 call_write_iter include/linux/fs.h:2163 [inline]
 new_sync_write+0x40b/0x640 fs/read_write.c:507
 vfs_write+0x7cf/0xae0 fs/read_write.c:594
 ksys_write+0x1ee/0x250 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665f9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd9f866e188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665f9
RDX: 00000000000e7b78 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038
R13: 0000000000a9fb1f R14: 00007fd9f866e300 R15: 0000000000022000

Fix the issue rewriting the relevant expression to avoid
sign-related problems - note: size_goal is always >= 0.

Additionally, ensure that the skb in the tx cache always carries
the relevant extension.

Reported-and-tested-by: syzbot+263a248eec3e875baa7b@syzkaller.appspotmail.com
Fixes: 1094c6fe72 ("mptcp: fix possible divide by zero")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-22 14:39:41 +01:00
..
6lowpan
9p net/9p: increase default msize to 128k 2021-09-05 08:36:44 +09:00
802 net: 802: remove dead leftover after ipx driver removal 2021-08-13 16:30:35 -07:00
8021q dev_ioctl: split out ndo_eth_ioctl 2021-07-27 20:11:45 +01:00
appletalk
atm
ax25 ax25: use skb_expand_head 2021-08-03 11:21:39 +01:00
batman-adv Kbuild updates for v5.15 2021-09-03 15:33:47 -07:00
bluetooth TTY / Serial patches for 5.15-rc1 2021-09-01 09:51:16 -07:00
bpf bpf: Refactor BPF_PROG_RUN into a function 2021-08-17 00:45:07 +02:00
bpfilter
bridge net: bridge: mcast: fix vlan port router deadlock 2021-09-03 13:43:19 +01:00
caif net-caif: avoid user-triggerable WARN_ON(1) 2021-09-14 12:51:15 +01:00
can net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
ceph
core napi: fix race inside napi_enable 2021-09-20 09:41:29 +01:00
dcb
dccp dccp: don't duplicate ccid when cloning dccp sock 2021-09-08 11:28:35 +01:00
decnet net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
dns_resolver
dsa net: dsa: don't allocate the slave_mii_bus using devres 2021-09-21 13:52:16 +01:00
ethernet move netdev_boot_setup into Space.c 2021-08-03 13:05:26 +01:00
ethtool ethtool: extend coalesce setting uAPI with CQE mode 2021-08-24 07:38:29 -07:00
hsr
ieee802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-08-13 06:41:22 -07:00
ife
ipv4 nexthop: Fix division by zero while replacing a resilient group 2021-09-20 09:45:14 +01:00
ipv6 ipv6: delay fib6_sernum increase in fib6_add 2021-09-13 13:00:53 +01:00
iucv net/iucv: Replace deprecated CPU-hotplug functions. 2021-08-09 10:13:32 +01:00
kcm
key
l2tp net/l2tp: Fix reference count leak in l2tp_udp_recv_core 2021-09-09 11:00:20 +01:00
l3mdev
lapb
llc net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
mac80211 mac80211: parse transmit power envelope element 2021-08-26 10:18:56 +02:00
mac802154 ieee802154: Remove redundant initialization of variable ret 2021-09-07 14:06:08 +01:00
mctp mctp: perform route destruction under RCU read lock 2021-09-08 11:29:16 +01:00
mpls mpls: defer ttl decrement in mpls_forward() 2021-07-23 17:17:56 +01:00
mptcp mptcp: ensure tx skbs always have the MPTCP ext 2021-09-22 14:39:41 +01:00
ncsi net/ncsi: add get MAC address command to get Intel i210 MAC address 2021-09-01 17:18:56 -07:00
netfilter Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2021-09-03 16:20:37 -07:00
netlabel net: fix NULL pointer reference in cipso_v4_doi_free 2021-08-30 12:23:18 +01:00
netlink net: netlink: Remove unused function 2021-07-30 18:35:47 +02:00
netrom net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
nfc net: in_irq() cleanup 2021-08-13 14:09:19 -07:00
nsh
openvswitch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-08-19 18:09:18 -07:00
packet net/packet: clarify source of pr_*() messages 2021-09-10 10:00:59 +01:00
phonet net: Remove redundant if statements 2021-08-05 13:27:50 +01:00
psample
qrtr net: qrtr: revert check in qrtr_endpoint_post() 2021-09-02 11:37:02 +01:00
rds net/rds: dma_map_sg is entitled to merge entries 2021-08-18 15:35:50 -07:00
rfkill
rose
rxrpc net: RxRPC: make dependent Kconfig symbols be shown indented 2021-08-18 10:12:11 +01:00
sched fq_codel: reject silly quantum parameters 2021-09-04 10:49:46 +01:00
sctp sctp: move the active_key update after sh_keys is added 2021-08-03 11:43:43 +01:00
smc net/smc: fix 'workqueue leaked lock' in smc_conn_abort_work 2021-09-21 10:54:16 +01:00
strparser
sunrpc Critical bug fixes: 2021-09-08 15:55:42 -07:00
switchdev net: make switchdev_bridge_port_{,unoffload} loosely coupled with the bridge 2021-08-04 12:35:07 +01:00
tipc tipc: increase timeout in tipc_sk_enqueue() 2021-09-13 12:43:10 +01:00
tls
unix net/af_unix: fix a data-race in unix_dgram_poll 2021-09-09 10:57:52 +01:00
vmw_vsock af_vsock: rename variables in receive loop 2021-09-06 02:25:16 -04:00
wireless cfg80211: use wiphy DFS domain if it is self-managed 2021-08-26 11:04:55 +02:00
x25
xdp
xfrm Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ 2021-08-27 11:16:29 +01:00
compat.c
devres.c
Kconfig mctp: Add MCTP base 2021-07-29 15:06:49 +01:00
Makefile mctp: Add MCTP base 2021-07-29 15:06:49 +01:00
socket.c Core: 2021-08-31 16:43:06 -07:00
sysctl_net.c