Eric Dumazet 989b0ff35f net: prevent mss overflow in skb_segment() ... commit 23d05d563b upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2024-02-23 09:12:51 +01:00
..
bpf_sk_storage.c	bpf: Add length check for SK_DIAG_BPF_STORAGE_REQ_MAP_FD parsing	2023-08-11 12:08:12 +02:00
datagram.c	net: datagram: fix data-races in datagram_poll()	2023-05-24 17:32:32 +01:00
dev.c	net: fix removing a namespace with conflicting altnames	2024-01-31 16:17:04 -08:00
dev.h	net: fix removing a namespace with conflicting altnames	2024-01-31 16:17:04 -08:00
dev_addr_lists.c
dev_addr_lists_test.c
dev_ioctl.c
drop_monitor.c	drop_monitor: Require 'CAP_SYS_ADMIN' when joining "events" group	2023-12-13 18:39:12 +01:00
dst.c	ipv6: remove max_size check inline with ipv4	2024-01-15 18:54:51 +01:00
dst_cache.c
failover.c
fib_notifier.c
fib_rules.c
filter.c	bpf: sockmap, updating the sg structure should also update curr	2023-12-13 18:39:11 +01:00
flow_dissector.c	net/core: Fix ETH_P_1588 flow dissector	2023-10-06 14:56:36 +02:00
flow_offload.c
gen_estimator.c
gen_stats.c
gro.c	skb: Do mix page pool and page referenced frags in GRO	2023-02-09 11:28:05 +01:00
gro_cells.c
hwbm.c
link_watch.c
lwt_bpf.c	lwt: Fix return values of BPF xmit ops	2023-09-13 09:42:33 +02:00
lwtunnel.c	xfrm: lwtunnel: squelch kernel warning in case XFRM encap type is not available	2022-10-12 10:45:51 +02:00
Makefile	devlink: move code to a dedicated directory	2023-08-30 16:11:00 +02:00
neighbour.c	neighbour: Don't let neigh_forced_gc() disable preemption for long	2024-01-20 11:50:07 +01:00
net-procfs.c
net-sysfs.c
net-sysfs.h
net-traces.c
net_namespace.c	net: fix UaF in netns ops registration error path	2023-02-01 08:34:43 +01:00
netclassid_cgroup.c
netevent.c
netpoll.c	net: don't let netpoll invoke NAPI if in xmit context	2023-04-13 16:55:21 +02:00
netprio_cgroup.c
of_net.c
page_pool.c	net: page_pool: add missing free_percpu when page_pool_init fail	2023-11-20 11:52:16 +01:00
pktgen.c	net: pktgen: Fix interface flags printing	2023-10-25 12:03:08 +02:00
ptp_classifier.c
request_sock.c	tcp: make sure init the accept_queue's spinlocks once	2024-01-31 16:17:03 -08:00
rtnetlink.c	Revert "net: rtnetlink: Enslave device before bringing it up"	2024-01-25 15:27:43 -08:00
scm.c	io_uring/af_unix: disable sending io_uring over sockets	2023-12-13 18:39:17 +01:00
secure_seq.c
selftests.c
skbuff.c	net: prevent mss overflow in skb_segment()	2024-02-23 09:12:51 +01:00
skmsg.c	bpf, sockmap: af_unix stream sockets need to hold ref for pair sock	2024-01-10 17:10:32 +01:00
sock.c	udp: fix busy polling	2024-01-31 16:17:04 -08:00
sock_destructor.h
sock_diag.c
sock_map.c	bpf: syzkaller found null ptr deref in unix_bpf proto add	2024-01-10 17:10:36 +01:00
sock_reuseport.c	soreuseport: Fix socket selection for SO_INCOMING_CPU.	2022-12-31 13:32:04 +01:00
stream.c	net: Return error from sk_stream_wait_connect() if sk_wait_event() fails	2024-01-01 12:38:56 +00:00
sysctl_net_core.c
timestamping.c
tso.c
utils.c
xdp.c