linux/net
Eric Dumazet 2b88cba558 net: preserve skb_end_offset() in skb_unclone_keeptruesize()
syzbot found another way to trigger the infamous WARN_ON_ONCE(delta < len)
in skb_try_coalesce() [1]

I was able to root cause the issue to kfence.

When kfence is in action, the following assertion is no longer true:

int size = xxxx;
void *ptr1 = kmalloc(size, gfp);
void *ptr2 = kmalloc(size, gfp);

if (ptr1 && ptr2)
	ASSERT(ksize(ptr1) == ksize(ptr2));

We attempted to fix these issues in the blamed commits, but forgot
that TCP was possibly shifting data after skb_unclone_keeptruesize()
has been used, notably from tcp_retrans_try_collapse().

So we not only need to keep same skb->truesize value,
we also need to make sure TCP wont fill new tailroom
that pskb_expand_head() was able to get from a
addr = kmalloc(...) followed by ksize(addr)

Split skb_unclone_keeptruesize() into two parts:

1) Inline skb_unclone_keeptruesize() for the common case,
   when skb is not cloned.

2) Out of line __skb_unclone_keeptruesize() for the 'slow path'.

WARNING: CPU: 1 PID: 6490 at net/core/skbuff.c:5295 skb_try_coalesce+0x1235/0x1560 net/core/skbuff.c:5295
Modules linked in:
CPU: 1 PID: 6490 Comm: syz-executor161 Not tainted 5.17.0-rc4-syzkaller-00229-g4f12b742eb2b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:skb_try_coalesce+0x1235/0x1560 net/core/skbuff.c:5295
Code: bf 01 00 00 00 0f b7 c0 89 c6 89 44 24 20 e8 62 24 4e fa 8b 44 24 20 83 e8 01 0f 85 e5 f0 ff ff e9 87 f4 ff ff e8 cb 20 4e fa <0f> 0b e9 06 f9 ff ff e8 af b2 95 fa e9 69 f0 ff ff e8 95 b2 95 fa
RSP: 0018:ffffc900063af268 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 00000000ffffffd5 RCX: 0000000000000000
RDX: ffff88806fc05700 RSI: ffffffff872abd55 RDI: 0000000000000003
RBP: ffff88806e675500 R08: 00000000ffffffd5 R09: 0000000000000000
R10: ffffffff872ab659 R11: 0000000000000000 R12: ffff88806dd554e8
R13: ffff88806dd9bac0 R14: ffff88806dd9a2c0 R15: 0000000000000155
FS:  00007f18014f9700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020002000 CR3: 000000006be7a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 tcp_try_coalesce net/ipv4/tcp_input.c:4651 [inline]
 tcp_try_coalesce+0x393/0x920 net/ipv4/tcp_input.c:4630
 tcp_queue_rcv+0x8a/0x6e0 net/ipv4/tcp_input.c:4914
 tcp_data_queue+0x11fd/0x4bb0 net/ipv4/tcp_input.c:5025
 tcp_rcv_established+0x81e/0x1ff0 net/ipv4/tcp_input.c:5947
 tcp_v4_do_rcv+0x65e/0x980 net/ipv4/tcp_ipv4.c:1719
 sk_backlog_rcv include/net/sock.h:1037 [inline]
 __release_sock+0x134/0x3b0 net/core/sock.c:2779
 release_sock+0x54/0x1b0 net/core/sock.c:3311
 sk_wait_data+0x177/0x450 net/core/sock.c:2821
 tcp_recvmsg_locked+0xe28/0x1fd0 net/ipv4/tcp.c:2457
 tcp_recvmsg+0x137/0x610 net/ipv4/tcp.c:2572
 inet_recvmsg+0x11b/0x5e0 net/ipv4/af_inet.c:850
 sock_recvmsg_nosec net/socket.c:948 [inline]
 sock_recvmsg net/socket.c:966 [inline]
 sock_recvmsg net/socket.c:962 [inline]
 ____sys_recvmsg+0x2c4/0x600 net/socket.c:2632
 ___sys_recvmsg+0x127/0x200 net/socket.c:2674
 __sys_recvmsg+0xe2/0x1a0 net/socket.c:2704
 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

Fixes: c4777efa75 ("net: add and use skb_unclone_keeptruesize() helper")
Fixes: 097b9146c0 ("net: fix up truesize of cloned skb in skb_prepare_for_shift()")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-22 19:43:50 -08:00
..
6lowpan net: don't include ndisc.h from ipv6.h 2022-02-04 14:15:11 -08:00
9p virtio,vdpa,qemu_fw_cfg: features, cleanups, fixes 2022-01-18 10:05:48 +02:00
802 net: 802: Use memset_startat() to clear struct fields 2021-11-19 11:23:23 +00:00
8021q vlan: move dev_put into vlan_dev_uninit 2022-02-09 13:33:39 +00:00
appletalk
atm proc: remove PDE_DATA() completely 2022-01-22 08:33:37 +02:00
ax25 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-10 17:29:56 -08:00
batman-adv ipv6: make mc_forwarding atomic 2022-02-05 15:20:34 +00:00
bluetooth bluetooth-next pull request for net-next: 2022-01-28 13:39:07 -08:00
bpf bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide 2022-02-09 11:40:45 -08:00
bpfilter
bridge bridge: switch br_net_exit to batch mode 2022-02-19 16:20:12 +00:00
caif caif: cleanup double word in comment 2022-02-07 12:06:54 +00:00
can Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-10 17:29:56 -08:00
ceph libceph: optionally use bounce buffer on recv path in crc mode 2022-02-02 18:50:36 +01:00
core net: preserve skb_end_offset() in skb_unclone_keeptruesize() 2022-02-22 19:43:50 -08:00
dcb
dccp dccp: remove max48() 2022-01-27 13:53:27 +00:00
decnet Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2021-12-31 14:35:40 +00:00
dns_resolver
dsa net: phy: phylink: fix DSA mac_select_pcs() introduction 2022-02-22 16:57:08 -08:00
ethernet gro: remove rcu_read_lock/rcu_read_unlock from gro_complete handlers 2021-11-24 17:21:42 -08:00
ethtool ethtool: add header/data split indication 2022-01-28 14:43:47 +00:00
hsr net: hsr: fix hsr build error when lockdep is not enabled 2022-02-21 20:43:10 -08:00
ieee802154 Merge tag 'ieee802154-for-davem-2022-02-10' of git://git.kernel.org/pub/scm/linux/kernel/git/sschmidt/wpan-next 2022-02-10 14:28:04 +00:00
ife
ipv4 ipv4: Invalidate neighbour for broadcast address upon address addition 2022-02-21 11:44:30 +00:00
ipv6 ipv6: tcp: consistently use MAX_TCP_HEADER 2022-02-22 17:27:18 -08:00
iucv s390/iucv: sort out physical vs virtual pointers usage 2022-02-22 16:09:13 -08:00
kcm net: Don't include filter.h from net/sock.h 2021-12-29 08:48:14 -08:00
key
l2tp l2tp: add netns refcount tracker to l2tp_dfs_seq_data 2021-12-10 06:38:27 -08:00
l3mdev
lapb
llc sock: Use sock_owned_by_user_nocheck() instead of sk_lock.owned. 2021-12-10 19:43:00 -08:00
mac80211 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-17 11:44:20 -08:00
mac802154
mctp mctp: add address validity checking for packet receive 2022-02-18 21:24:29 -08:00
mpls net: mpls: Fix GCC 12 warning 2022-02-10 15:29:39 +00:00
mptcp mptcp: don't save tcp data_ready and write space callbacks 2022-02-16 20:52:06 -08:00
ncsi all: replace find_next{,_zero}_bit with find_first{,_zero}_bit where appropriate 2022-01-15 08:47:31 -08:00
netfilter Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-17 11:44:20 -08:00
netlabel lsm: security_task_getsecid_subj() -> security_current_getsecid_subj() 2021-11-22 17:52:47 -05:00
netlink net: Don't include filter.h from net/sock.h 2021-12-29 08:48:14 -08:00
netrom netrom: fix api breakage in nr_setsockopt() 2022-01-07 14:11:05 +00:00
nfc Networking fixes for 5.17-rc1, including fixes from netfilter, bpf. 2022-01-20 10:57:05 +02:00
nsh
openvswitch net/sched: Enable tc skb ext allocation on chain miss only when needed 2022-02-05 10:12:53 +00:00
packet af_packet: fix data-race in packet_setsockopt / packet_setsockopt 2022-02-01 20:21:10 -08:00
phonet phonet/pep: refuse to enable an unbound pipe 2021-12-20 11:49:51 +00:00
psample
qrtr bus: mhi: core: Add an API for auto queueing buffers for DL channel 2021-12-17 17:17:14 +01:00
rds Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-12-16 16:13:19 -08:00
rfkill rfkill: allow to get the software rfkill state 2021-12-20 11:02:38 +01:00
rose net: Don't include filter.h from net/sock.h 2021-12-29 08:48:14 -08:00
rxrpc rxrpc: Adjust retransmission backoff 2022-01-22 02:03:24 +00:00
sched Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-17 11:44:20 -08:00
sctp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-01-05 14:36:10 -08:00
smc net/smc: unlock on error paths in __smc_setsockopt() 2022-02-19 18:54:43 +00:00
strparser bpf: sockmap, strparser, and tls are reusing qdisc_skb_cb and colliding 2021-11-09 01:05:28 +01:00
sunrpc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-10 17:29:56 -08:00
switchdev net: switchdev: introduce switchdev_handle_port_obj_{add,del} for foreign interfaces 2022-02-16 11:21:04 +00:00
tipc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-17 11:44:20 -08:00
tls tls: cap the output scatter list to something reasonable 2022-02-04 10:14:07 +00:00
unix Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2022-01-24 15:42:29 -08:00
vmw_vsock vsock: remove vsock from connected table when connect is interrupted by a signal 2022-02-17 08:56:02 -08:00
wireless Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-02-17 11:44:20 -08:00
x25 net: x25: drop harmless check of !more 2021-12-09 18:35:11 -08:00
xdp i40e: xsk: Move tmp desc array from driver to pool 2022-01-27 17:25:32 +01:00
xfrm xfrm: Don't accidentally set RTO_ONLINK in decode_session4() 2022-01-11 20:36:08 -08:00
compat.c
devres.c
Kconfig net: kunit: add a test for dev_addr_lists 2021-11-20 12:25:57 +00:00
Kconfig.debug net: add networking namespace refcount tracker 2021-12-10 06:38:26 -08:00
Makefile
socket.c net: fix documentation for kernel_getsockname 2022-02-14 14:01:19 +00:00
sysctl_net.c sections: move and rename core_kernel_data() to is_kernel_core_data() 2021-11-09 10:02:50 -08:00