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c20029db28
linux-next/net
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Eric Dumazet c20029db28 net: avoid potential underflow in qdisc_pkt_len_init() with UFO 
After commit 7c6d2ecbda ("net: be more gentle about silly gso
requests coming from user") virtio_net_hdr_to_skb() had sanity check
to detect malicious attempts from user space to cook a bad GSO packet.

Then commit cf9acc90c8 ("net: virtio_net_hdr_to_skb: count
transport header in UFO") while fixing one issue, allowed user space
to cook a GSO packet with the following characteristic :

IPv4 SKB_GSO_UDP, gso_size=3, skb->len = 28.

When this packet arrives in qdisc_pkt_len_init(), we end up
with hdr_len = 28 (IPv4 header + UDP header), matching skb->len

Then the following sets gso_segs to 0 :

gso_segs = DIV_ROUND_UP(skb->len - hdr_len,
                        shinfo->gso_size);

Then later we set qdisc_skb_cb(skb)->pkt_len to back to zero :/

qdisc_skb_cb(skb)->pkt_len += (gso_segs - 1) * hdr_len;

This leads to the following crash in fq_codel [1]

qdisc_pkt_len_init() is best effort, we only want an estimation
of the bytes sent on the wire, not crashing the kernel.

This patch is fixing this particular issue, a following one
adds more sanity checks for another potential bug.

[1]
[   70.724101] BUG: kernel NULL pointer dereference, address: 0000000000000000
[   70.724561] #PF: supervisor read access in kernel mode
[   70.724561] #PF: error_code(0x0000) - not-present page
[   70.724561] PGD 10ac61067 P4D 10ac61067 PUD 107ee2067 PMD 0
[   70.724561] Oops: Oops: 0000 [#1] SMP NOPTI
[   70.724561] CPU: 11 UID: 0 PID: 2163 Comm: b358537762 Not tainted 6.11.0-virtme #991
[   70.724561] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   70.724561] RIP: 0010:fq_codel_enqueue (net/sched/sch_fq_codel.c:120 net/sched/sch_fq_codel.c:168 net/sched/sch_fq_codel.c:230) sch_fq_codel
[ 70.724561] Code: 24 08 49 c1 e1 06 44 89 7c 24 18 45 31 ed 45 31 c0 31 ff 89 44 24 14 4c 03 8b 90 01 00 00 eb 04 39 ca 73 37 4d 8b 39 83 c7 01 <49> 8b 17 49 89 11 41 8b 57 28 45 8b 5f 34 49 c7 07 00 00 00 00 49
All code
========
   0:	24 08                	and    $0x8,%al
   2:	49 c1 e1 06          	shl    $0x6,%r9
   6:	44 89 7c 24 18       	mov    %r15d,0x18(%rsp)
   b:	45 31 ed             	xor    %r13d,%r13d
   e:	45 31 c0             	xor    %r8d,%r8d
  11:	31 ff                	xor    %edi,%edi
  13:	89 44 24 14          	mov    %eax,0x14(%rsp)
  17:	4c 03 8b 90 01 00 00 	add    0x190(%rbx),%r9
  1e:	eb 04                	jmp    0x24
  20:	39 ca                	cmp    %ecx,%edx
  22:	73 37                	jae    0x5b
  24:	4d 8b 39             	mov    (%r9),%r15
  27:	83 c7 01             	add    $0x1,%edi
  2a:*	49 8b 17             	mov    (%r15),%rdx		<-- trapping instruction
  2d:	49 89 11             	mov    %rdx,(%r9)
  30:	41 8b 57 28          	mov    0x28(%r15),%edx
  34:	45 8b 5f 34          	mov    0x34(%r15),%r11d
  38:	49 c7 07 00 00 00 00 	movq   $0x0,(%r15)
  3f:	49                   	rex.WB

Code starting with the faulting instruction
===========================================
   0:	49 8b 17             	mov    (%r15),%rdx
   3:	49 89 11             	mov    %rdx,(%r9)
   6:	41 8b 57 28          	mov    0x28(%r15),%edx
   a:	45 8b 5f 34          	mov    0x34(%r15),%r11d
   e:	49 c7 07 00 00 00 00 	movq   $0x0,(%r15)
  15:	49                   	rex.WB
[   70.724561] RSP: 0018:ffff95ae85e6fb90 EFLAGS: 00000202
[   70.724561] RAX: 0000000002000000 RBX: ffff95ae841de000 RCX: 0000000000000000
[   70.724561] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
[   70.724561] RBP: ffff95ae85e6fbf8 R08: 0000000000000000 R09: ffff95b710a30000
[   70.724561] R10: 0000000000000000 R11: bdf289445ce31881 R12: ffff95ae85e6fc58
[   70.724561] R13: 0000000000000000 R14: 0000000000000040 R15: 0000000000000000
[   70.724561] FS:  000000002c5c1380(0000) GS:ffff95bd7fcc0000(0000) knlGS:0000000000000000
[   70.724561] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   70.724561] CR2: 0000000000000000 CR3: 000000010c568000 CR4: 00000000000006f0
[   70.724561] Call Trace:
[   70.724561]  <TASK>
[   70.724561] ? __die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434)
[   70.724561] ? page_fault_oops (arch/x86/mm/fault.c:715)
[   70.724561] ? exc_page_fault (./arch/x86/include/asm/irqflags.h:26 ./arch/x86/include/asm/irqflags.h:87 ./arch/x86/include/asm/irqflags.h:147 arch/x86/mm/fault.c:1489 arch/x86/mm/fault.c:1539)
[   70.724561] ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:623)
[   70.724561] ? fq_codel_enqueue (net/sched/sch_fq_codel.c:120 net/sched/sch_fq_codel.c:168 net/sched/sch_fq_codel.c:230) sch_fq_codel
[   70.724561] dev_qdisc_enqueue (net/core/dev.c:3784)
[   70.724561] __dev_queue_xmit (net/core/dev.c:3880 (discriminator 2) net/core/dev.c:4390 (discriminator 2))
[   70.724561] ? irqentry_enter (kernel/entry/common.c:237)
[   70.724561] ? sysvec_apic_timer_interrupt (./arch/x86/include/asm/hardirq.h:74 (discriminator 2) arch/x86/kernel/apic/apic.c:1043 (discriminator 2) arch/x86/kernel/apic/apic.c:1043 (discriminator 2))
[   70.724561] ? trace_hardirqs_on (kernel/trace/trace_preemptirq.c:58 (discriminator 4))
[   70.724561] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702)
[   70.724561] ? virtio_net_hdr_to_skb.constprop.0 (./include/linux/virtio_net.h:129 (discriminator 1))
[   70.724561] packet_sendmsg (net/packet/af_packet.c:3145 (discriminator 1) net/packet/af_packet.c:3177 (discriminator 1))
[   70.724561] ? _raw_spin_lock_bh (./arch/x86/include/asm/atomic.h:107 (discriminator 4) ./include/linux/atomic/atomic-arch-fallback.h:2170 (discriminator 4) ./include/linux/atomic/atomic-instrumented.h:1302 (discriminator 4) ./include/asm-generic/qspinlock.h:111 (discriminator 4) ./include/linux/spinlock.h:187 (discriminator 4) ./include/linux/spinlock_api_smp.h:127 (discriminator 4) kernel/locking/spinlock.c:178 (discriminator 4))
[   70.724561] ? netdev_name_node_lookup_rcu (net/core/dev.c:325 (discriminator 1))
[   70.724561] __sys_sendto (net/socket.c:730 (discriminator 1) net/socket.c:745 (discriminator 1) net/socket.c:2210 (discriminator 1))
[   70.724561] ? __sys_setsockopt (./include/linux/file.h:34 net/socket.c:2355)
[   70.724561] __x64_sys_sendto (net/socket.c:2222 (discriminator 1) net/socket.c:2218 (discriminator 1) net/socket.c:2218 (discriminator 1))
[   70.724561] do_syscall_64 (arch/x86/entry/common.c:52 (discriminator 1) arch/x86/entry/common.c:83 (discriminator 1))
[   70.724561] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   70.724561] RIP: 0033:0x41ae09

Fixes: cf9acc90c8 ("net: virtio_net_hdr_to_skb: count transport header in UFO")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jonathan Davies <jonathan.davies@nutanix.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Jonathan Davies <jonathan.davies@nutanix.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-10-01 11:47:05 +02:00
..
6lowpan ipv6: eliminate ndisc_ops_is_useropt() 2024-08-12 17:23:57 -07:00
9p net/9p/usbg: fix CONFIG_USB_GADGET dependency 2024-09-11 15:59:43 +02:00
802 net: fill in MODULE_DESCRIPTION()s under net/802* 2023-10-28 11:29:28 +01:00
8021q netdev_features: remove NETIF_F_ALL_FCOE 2024-09-03 11:36:43 +02:00
appletalk Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-05-09 10:01:01 -07:00
atm atm: clean up a put_user() calls 2024-06-14 19:08:50 -07:00
ax25 ax25: Replace kfree() in ax25_dev_free() with ax25_dev_put() 2024-06-01 15:49:42 -07:00
batman-adv Updates for timers and timekeeping: 2024-09-17 07:25:37 +02:00
bluetooth Bluetooth: hci_sync: Ignore errors from HCI_OP_REMOTE_NAME_REQ_CANCEL 2024-09-10 13:07:24 -04:00
bpf bpf: use type_may_be_null() helper for nullable-param check 2024-09-05 13:29:06 -07:00
bridge netfilter: br_netfilter: Unmask upper DSCP bits in br_nf_pre_routing_finish() 2024-09-09 14:14:52 +01:00
caif net: caif: remove unused name 2024-09-12 20:29:04 -07:00
can Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-09-15 09:13:19 -07:00
ceph libceph: fix crush_choose_firstn() kernel-doc warnings 2024-07-11 16:33:07 +02:00
core net: avoid potential underflow in qdisc_pkt_len_init() with UFO 2024-10-01 11:47:05 +02:00
dcb net: dcb: choose correct policy to parse DCB_ATTR_BCN 2023-08-01 21:07:46 -07:00
dccp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-06-27 12:14:11 -07:00
devlink devlink: Constify the 'table_ops' parameter of devl_dpipe_table_register() 2024-06-05 10:24:57 +01:00
dns_resolver Networking changes for 6.8. 2024-01-11 10:07:29 -08:00
dsa net: dsa: improve shutdown sequence 2024-10-01 09:56:36 +02:00
ethernet netkit: Fix pkt_type override upon netkit pass verdict 2024-05-25 10:48:57 -07:00
ethtool net: ethtool: phy: Don't set the context dev pointer for unfiltered DUMP 2024-09-13 21:40:12 -07:00
handshake net/handshake: use sockfd_put() helper 2024-08-27 16:09:25 -07:00
hsr Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-09-12 17:11:24 -07:00
ieee802154 netdev_features: convert NETIF_F_NETNS_LOCAL to dev->netns_local 2024-09-03 11:36:43 +02:00
ife net: sched: ife: fix potential use-after-free 2023-12-15 10:50:18 +00:00
ipv4 Including fixes from netfilter. 2024-09-26 10:27:10 -07:00
ipv6 netfilter pull request 24-09-26 2024-09-26 15:47:11 +02:00
iucv s390/iucv: Fix vargs handling in iucv_alloc_device() 2024-08-22 13:09:20 -07:00
kcm kcm: Serialise kcm_sendmsg() for the same socket. 2024-08-19 18:36:12 -07:00
key net: fill in MODULE_DESCRIPTION()s for af_key 2024-02-09 14:12:01 -08:00
l2tp l2tp: remove unneeded null check in l2tp_v2_session_get_next 2024-09-04 16:39:32 -07:00
l3mdev
lapb
llc llc: Constify struct llc_sap_state_trans 2024-07-15 08:51:19 -07:00
mac80211 wifi: mac80211: use two-phase skb reclamation in ieee80211_do_stop() 2024-09-09 11:45:06 +02:00
mac802154 net: mac802154: Fix racy device stats updates by DEV_STATS_INC() and DEV_STATS_ADD() 2024-06-03 11:20:56 +02:00
mctp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-08-22 17:06:18 -07:00
mpls net: mpls: delete redundant judgment statements 2024-08-23 14:27:46 +01:00
mptcp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-09-12 17:11:24 -07:00
ncsi net/ncsi: Fix the multi thread manner of NCSI driver 2024-06-01 16:21:44 -07:00
netfilter netfilter: nfnetlink_queue: remove old clash resolution logic 2024-09-26 13:03:03 +02:00
netlabel netlabel: fix RCU annotation for IPv4 options on socket creation 2024-05-13 14:58:12 -07:00
netlink net: netlink: Remove the dump_cb_mutex field from struct netlink_sock 2024-08-26 10:35:16 +01:00
netrom net/netrom: prefer strscpy over strcpy 2024-08-29 12:33:07 -07:00
nfc Quite smaller than usual. Notably it includes the fix for the unix 2024-05-23 12:49:37 -07:00
nsh nsh: Restore skb->{protocol,data,mac_header} for outer header in nsh_gso_segment(). 2024-04-26 12:20:01 +02:00
openvswitch netdev_features: convert NETIF_F_NETNS_LOCAL to dev->netns_local 2024-09-03 11:36:43 +02:00
packet net: add support for skbs with unreadable frags 2024-09-11 20:44:31 -07:00
phonet sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
psample net: psample: fix flag being set in wrong skb 2024-07-11 18:11:31 -07:00
qrtr net: qrtr: Update packets cloning when broadcasting 2024-09-24 10:48:16 +02:00
rds net: rds: add option for GCOV profiling 2024-08-09 13:18:46 +01:00
rfkill wifi: rfkill: Correct parameter type for rfkill_set_hw_state_reason() 2024-08-27 10:28:55 +02:00
rose net: change proto and proto_ops accept type 2024-05-13 18:19:09 -06:00
rxrpc rxrpc: Remove unused function declarations 2024-08-02 17:17:34 -07:00
sched sch_cake: constify inverse square root cache 2024-09-10 18:31:52 -07:00
sctp sctp: Unmask upper DSCP bits in sctp_v4_get_dst() 2024-09-09 14:14:53 +01:00
smc net/smc: add sysctl for smc_limit_hs 2024-09-10 12:11:04 +02:00
strparser
sunrpc SUNRPC: replace program list with program array 2024-09-23 15:03:30 -04:00
switchdev net: bridge: switchdev: Improve error message for port_obj_add/del functions 2024-05-08 12:19:12 +01:00
tipc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-09-15 09:13:19 -07:00
tls net: tls: wait for async completion on last message 2024-09-06 18:20:55 -07:00
unix af_unix: Don't return OOB skb in manage_oob(). 2024-09-09 17:14:27 -07:00
vmw_vsock virtio: features, fixes, cleanups 2024-09-26 08:43:17 -07:00
wireless wifi: cfg80211: fix two more possible UBSAN-detected off-by-one errors 2024-09-09 11:43:21 +02:00
x25 net: change proto and proto_ops accept type 2024-05-13 18:19:09 -06:00
xdp bpf-next-6.12 2024-09-21 09:27:50 -07:00
xfrm ipsec-next-2024-09-10 2024-09-10 19:00:47 -07:00
compat.c file: stop exposing receive_fd_user() 2023-12-12 14:24:14 +01:00
devres.c
Kconfig memory-provider: disable building dmabuf mp on !CONFIG_PAGE_POOL 2024-09-13 11:41:45 -07:00
Kconfig.debug
Makefile af_unix: Remove CONFIG_UNIX_SCM. 2024-01-31 16:41:16 -08:00
socket.c struct fd layout change (and conversion to accessor helpers) 2024-09-23 09:35:36 -07:00
sysctl_net.c sysctl: Remove check for sentinel element in ctl_table arrays 2024-06-13 10:50:52 +02:00