mirror-linux/net/core
Eric Dumazet 23d05d563b net: prevent mss overflow in skb_segment()
Once again syzbot is able to crash the kernel in skb_segment() [1]

GSO_BY_FRAGS is a forbidden value, but unfortunately the following
computation in skb_segment() can reach it quite easily :

	mss = mss * partial_segs;

65535 = 3 * 5 * 17 * 257, so many initial values of mss can lead to
a bad final result.

Make sure to limit segmentation so that the new mss value is smaller
than GSO_BY_FRAGS.

[1]

general protection fault, probably for non-canonical address 0xdffffc000000000e: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077]
CPU: 1 PID: 5079 Comm: syz-executor993 Not tainted 6.7.0-rc4-syzkaller-00141-g1ae4cd3cbdd0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
RIP: 0010:skb_segment+0x181d/0x3f30 net/core/skbuff.c:4551
Code: 83 e3 02 e9 fb ed ff ff e8 90 68 1c f9 48 8b 84 24 f8 00 00 00 48 8d 78 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 8a 21 00 00 48 8b 84 24 f8 00
RSP: 0018:ffffc900043473d0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000010046 RCX: ffffffff886b1597
RDX: 000000000000000e RSI: ffffffff886b2520 RDI: 0000000000000070
RBP: ffffc90004347578 R08: 0000000000000005 R09: 000000000000ffff
R10: 000000000000ffff R11: 0000000000000002 R12: ffff888063202ac0
R13: 0000000000010000 R14: 000000000000ffff R15: 0000000000000046
FS: 0000555556e7e380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020010000 CR3: 0000000027ee2000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
udp6_ufo_fragment+0xa0e/0xd00 net/ipv6/udp_offload.c:109
ipv6_gso_segment+0x534/0x17e0 net/ipv6/ip6_offload.c:120
skb_mac_gso_segment+0x290/0x610 net/core/gso.c:53
__skb_gso_segment+0x339/0x710 net/core/gso.c:124
skb_gso_segment include/net/gso.h:83 [inline]
validate_xmit_skb+0x36c/0xeb0 net/core/dev.c:3626
__dev_queue_xmit+0x6f3/0x3d60 net/core/dev.c:4338
dev_queue_xmit include/linux/netdevice.h:3134 [inline]
packet_xmit+0x257/0x380 net/packet/af_packet.c:276
packet_snd net/packet/af_packet.c:3087 [inline]
packet_sendmsg+0x24c6/0x5220 net/packet/af_packet.c:3119
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg+0xd5/0x180 net/socket.c:745
__sys_sendto+0x255/0x340 net/socket.c:2190
__do_sys_sendto net/socket.c:2202 [inline]
__se_sys_sendto net/socket.c:2198 [inline]
__x64_sys_sendto+0xe0/0x1b0 net/socket.c:2198
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f8692032aa9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff8d685418 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8692032aa9
RDX: 0000000000010048 RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 00000000000f4240 R08: 0000000020000540 R09: 0000000000000014
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff8d685480
R13: 0000000000000001 R14: 00007fff8d685480 R15: 0000000000000003
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:skb_segment+0x181d/0x3f30 net/core/skbuff.c:4551
Code: 83 e3 02 e9 fb ed ff ff e8 90 68 1c f9 48 8b 84 24 f8 00 00 00 48 8d 78 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 8a 21 00 00 48 8b 84 24 f8 00
RSP: 0018:ffffc900043473d0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000010046 RCX: ffffffff886b1597
RDX: 000000000000000e RSI: ffffffff886b2520 RDI: 0000000000000070
RBP: ffffc90004347578 R08: 0000000000000005 R09: 000000000000ffff
R10: 000000000000ffff R11: 0000000000000002 R12: ffff888063202ac0
R13: 0000000000010000 R14: 000000000000ffff R15: 0000000000000046
FS: 0000555556e7e380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020010000 CR3: 0000000027ee2000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Fixes: 3953c46c3a ("sk_buff: allow segmenting based on frag sizes")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20231212164621.4131800-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-12-13 18:26:25 -08:00
..
Makefile net: add skb_segment kunit test 2023-10-11 10:39:01 +01:00
bpf_sk_storage.c bpf: Add length check for SK_DIAG_BPF_STORAGE_REQ_MAP_FD parsing 2023-07-27 10:07:56 -07:00
datagram.c iov_iter, net: Move hash_and_copy_to_iter() to net/ 2023-10-09 09:35:14 +02:00
dev.c bpf: Fix dev's rx stats for bpf_redirect_peer traffic 2023-11-20 10:15:16 -08:00
dev.h bpf-next-for-netdev 2023-10-26 20:02:41 -07:00
dev_addr_lists.c
dev_addr_lists_test.c net: fill in MODULE_DESCRIPTION()s under net/core 2023-10-28 11:29:27 +01:00
dev_ioctl.c net: dsa: Use conduit and user terms 2023-10-24 13:08:14 -07:00
drop_monitor.c drop_monitor: Require 'CAP_SYS_ADMIN' when joining "events" group 2023-12-07 09:54:02 -08:00
dst.c net: dst: remove unnecessary input parameter in dst_alloc and dst_init 2023-09-12 11:42:25 +02:00
dst_cache.c
failover.c
fib_notifier.c
fib_rules.c
filter.c bpf: sockmap, updating the sg structure should also update curr 2023-12-07 09:52:29 -08:00
flow_dissector.c net/core: Fix ETH_P_1588 flow dissector 2023-09-15 10:40:04 +01:00
flow_offload.c tc: flower: Enable offload support IPSEC SPI field. 2023-08-02 10:09:32 +01:00
gen_estimator.c treewide: Convert del_timer*() to timer_shutdown*() 2022-12-25 13:38:09 -08:00
gen_stats.c
gro.c gro: move the tc_ext comparison to a helper 2023-06-18 18:08:35 +01:00
gro_cells.c
gso.c net: move gso declarations and functions to their own files 2023-06-10 00:11:41 -07:00
gso_test.c net: gso_test: support CONFIG_MAX_SKB_FRAGS up to 45 2023-11-13 11:04:38 +00:00
hwbm.c
link_watch.c
lwt_bpf.c lwt: Fix return values of BPF xmit ops 2023-08-18 16:05:26 +02:00
lwtunnel.c
neighbour.c neighbour: Don't let neigh_forced_gc() disable preemption for long 2023-12-08 10:37:43 +00:00
net-procfs.c net-sysfs: display two backlog queue len separately 2023-03-22 12:03:52 +01:00
net-sysfs.c net: move struct netdev_rx_queue out of netdevice.h 2023-08-03 08:38:07 -07:00
net-sysfs.h
net-traces.c udp6: add a missing call into udp_fail_queue_rcv_skb tracepoint 2023-07-07 09:16:52 +01:00
net_namespace.c lib/ref_tracker: improve printing stats 2023-06-05 15:28:42 -07:00
netclassid_cgroup.c cgroup, netclassid: on modifying netclassid in cgroup, only consider the main process. 2023-10-16 16:36:53 -07:00
netdev-genl-gen.c net: ynl: prefix uAPI header include with uapi/ 2023-05-26 10:30:14 +01:00
netdev-genl-gen.h net: ynl: prefix uAPI header include with uapi/ 2023-05-26 10:30:14 +01:00
netdev-genl.c bpf: expose information about supported xdp metadata kfunc 2023-09-15 11:26:58 -07:00
netevent.c
netpoll.c netpoll: allocate netdev tracker right away 2023-06-15 08:21:11 +01:00
netprio_cgroup.c
of_net.c net: Explicitly include correct DT includes 2023-07-27 20:33:16 -07:00
page_pool.c net: page_pool: add missing free_percpu when page_pool_init fail 2023-11-02 12:27:53 +01:00
pktgen.c As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
ptp_classifier.c
request_sock.c
rtnetlink.c rtnetlink: Add MDB get support 2023-10-27 10:51:42 +01:00
scm.c io_uring/af_unix: disable sending io_uring over sockets 2023-12-09 21:20:33 +00:00
secure_seq.c
selftests.c net: fill in MODULE_DESCRIPTION()s under net/core 2023-10-28 11:29:27 +01:00
skbuff.c net: prevent mss overflow in skb_segment() 2023-12-13 18:26:25 -08:00
skmsg.c bpf, sockmap: af_unix stream sockets need to hold ref for pair sock 2023-11-30 00:25:16 +01:00
sock.c for-6.7/io_uring-sockopt-2023-10-30 2023-11-01 11:16:34 -10:00
sock_destructor.h
sock_diag.c
sock_map.c bpf, sockmap: Reject sk_msg egress redirects to non-TCP sockets 2023-09-29 17:11:07 +02:00
sock_reuseport.c
stream.c tcp: allow again tcp_disconnect() when threads are waiting 2023-10-13 16:49:32 -07:00
sysctl_net_core.c networking: Update to register_net_sysctl_sz 2023-08-15 15:26:18 -07:00
timestamping.c
tso.c
utils.c
xdp.c bpf: Add __bpf_kfunc_{start,end}_defs macros 2023-11-01 22:33:53 -07:00