WSL2-Linux-Kernel/net
Eric Dumazet 99c07327ae netlink: reset network and mac headers in netlink_dump()
netlink_dump() is allocating an skb, reserves space in it
but forgets to reset network header.

This allows a BPF program, invoked later from sk_filter()
to access uninitialized kernel memory from the reserved
space.

Theorically mac header reset could be omitted, because
it is set to a special initial value.
bpf_internal_load_pointer_neg_helper calls skb_mac_header()
without checking skb_mac_header_was_set().
Relying on skb->len not being too big seems fragile.
We also could add a sanity check in bpf_internal_load_pointer_neg_helper()
to avoid surprises in the future.

syzbot report was:

BUG: KMSAN: uninit-value in ___bpf_prog_run+0xa22b/0xb420 kernel/bpf/core.c:1637
 ___bpf_prog_run+0xa22b/0xb420 kernel/bpf/core.c:1637
 __bpf_prog_run32+0x121/0x180 kernel/bpf/core.c:1796
 bpf_dispatcher_nop_func include/linux/bpf.h:784 [inline]
 __bpf_prog_run include/linux/filter.h:626 [inline]
 bpf_prog_run include/linux/filter.h:633 [inline]
 __bpf_prog_run_save_cb+0x168/0x580 include/linux/filter.h:756
 bpf_prog_run_save_cb include/linux/filter.h:770 [inline]
 sk_filter_trim_cap+0x3bc/0x8c0 net/core/filter.c:150
 sk_filter include/linux/filter.h:905 [inline]
 netlink_dump+0xe0c/0x16c0 net/netlink/af_netlink.c:2276
 netlink_recvmsg+0x1129/0x1c80 net/netlink/af_netlink.c:2002
 sock_recvmsg_nosec net/socket.c:948 [inline]
 sock_recvmsg net/socket.c:966 [inline]
 sock_read_iter+0x5a9/0x630 net/socket.c:1039
 do_iter_readv_writev+0xa7f/0xc70
 do_iter_read+0x52c/0x14c0 fs/read_write.c:786
 vfs_readv fs/read_write.c:906 [inline]
 do_readv+0x432/0x800 fs/read_write.c:943
 __do_sys_readv fs/read_write.c:1034 [inline]
 __se_sys_readv fs/read_write.c:1031 [inline]
 __x64_sys_readv+0xe5/0x120 fs/read_write.c:1031
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Uninit was stored to memory at:
 ___bpf_prog_run+0x96c/0xb420 kernel/bpf/core.c:1558
 __bpf_prog_run32+0x121/0x180 kernel/bpf/core.c:1796
 bpf_dispatcher_nop_func include/linux/bpf.h:784 [inline]
 __bpf_prog_run include/linux/filter.h:626 [inline]
 bpf_prog_run include/linux/filter.h:633 [inline]
 __bpf_prog_run_save_cb+0x168/0x580 include/linux/filter.h:756
 bpf_prog_run_save_cb include/linux/filter.h:770 [inline]
 sk_filter_trim_cap+0x3bc/0x8c0 net/core/filter.c:150
 sk_filter include/linux/filter.h:905 [inline]
 netlink_dump+0xe0c/0x16c0 net/netlink/af_netlink.c:2276
 netlink_recvmsg+0x1129/0x1c80 net/netlink/af_netlink.c:2002
 sock_recvmsg_nosec net/socket.c:948 [inline]
 sock_recvmsg net/socket.c:966 [inline]
 sock_read_iter+0x5a9/0x630 net/socket.c:1039
 do_iter_readv_writev+0xa7f/0xc70
 do_iter_read+0x52c/0x14c0 fs/read_write.c:786
 vfs_readv fs/read_write.c:906 [inline]
 do_readv+0x432/0x800 fs/read_write.c:943
 __do_sys_readv fs/read_write.c:1034 [inline]
 __se_sys_readv fs/read_write.c:1031 [inline]
 __x64_sys_readv+0xe5/0x120 fs/read_write.c:1031
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Uninit was created at:
 slab_post_alloc_hook mm/slab.h:737 [inline]
 slab_alloc_node mm/slub.c:3244 [inline]
 __kmalloc_node_track_caller+0xde3/0x14f0 mm/slub.c:4972
 kmalloc_reserve net/core/skbuff.c:354 [inline]
 __alloc_skb+0x545/0xf90 net/core/skbuff.c:426
 alloc_skb include/linux/skbuff.h:1158 [inline]
 netlink_dump+0x30f/0x16c0 net/netlink/af_netlink.c:2242
 netlink_recvmsg+0x1129/0x1c80 net/netlink/af_netlink.c:2002
 sock_recvmsg_nosec net/socket.c:948 [inline]
 sock_recvmsg net/socket.c:966 [inline]
 sock_read_iter+0x5a9/0x630 net/socket.c:1039
 do_iter_readv_writev+0xa7f/0xc70
 do_iter_read+0x52c/0x14c0 fs/read_write.c:786
 vfs_readv fs/read_write.c:906 [inline]
 do_readv+0x432/0x800 fs/read_write.c:943
 __do_sys_readv fs/read_write.c:1034 [inline]
 __se_sys_readv fs/read_write.c:1031 [inline]
 __x64_sys_readv+0xe5/0x120 fs/read_write.c:1031
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x44/0xae

CPU: 0 PID: 3470 Comm: syz-executor751 Not tainted 5.17.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Fixes: db65a3aaf2 ("netlink: Trim skb to alloc size to avoid MSG_TRUNC")
Fixes: 9063e21fb0 ("netlink: autosize skb lengthes")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20220415181442.551228-1-eric.dumazet@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-04-19 15:05:03 +02:00
..
6lowpan net: don't include ndisc.h from ipv6.h 2022-02-04 14:15:11 -08:00
9p xen/grant-table: remove readonly parameter from functions 2022-03-15 20:34:40 -05:00
802
8021q vlan: use correct format characters 2022-03-17 16:34:49 -07:00
appletalk
atm proc: remove PDE_DATA() completely 2022-01-22 08:33:37 +02:00
ax25 ax25: Fix UAF bugs in ax25 timers 2022-03-29 10:24:34 +02:00
batman-adv batman-adv: Use netif_rx(). 2022-03-07 11:40:41 +00:00
bluetooth Bluetooth: call hci_le_conn_failed with hdev lock in hci_le_conn_failed 2022-03-18 17:12:08 +01:00
bpf bpf, test_run: Fix packet size check for live packet mode 2022-03-11 22:01:26 +01:00
bpfilter uaccess: remove CONFIG_SET_FS 2022-02-25 09:36:06 +01:00
bridge net: bridge: mst: Restrict info size queries to bridge ports 2022-03-23 10:32:44 -07:00
caif net: caif: Use netif_rx(). 2022-03-04 12:02:19 +00:00
can can: isotp: stop timeout monitoring when no first frame was sent 2022-04-17 17:21:22 +02:00
ceph libceph: drop else branches in prepare_read_data{,_cont} 2022-03-01 18:26:36 +01:00
core rtnetlink: Fix handling of disabled L3 stats in RTM_GETSTATS replies 2022-04-14 09:01:26 +02:00
dcb net: dcb: disable softirqs in dcbnl_flush_dev() 2022-03-03 08:01:55 -08:00
dccp dccp: remove max48() 2022-01-27 13:53:27 +00:00
decnet net: decnet: use time_is_before_jiffies() instead of open coding it 2022-02-28 13:21:32 +00:00
dns_resolver
dsa net: dsa: hellcreek: Calculate checksums in tagger 2022-04-19 09:49:38 +02:00
ethernet
ethtool ethtool: add support to set/get completion queue event size 2022-02-23 20:33:05 -08:00
hsr net: add per-cpu storage and net->core_stats 2022-03-11 23:17:24 -08:00
ieee802154 net: ipv6: Handle delivery_time in ipv6 defrag 2022-03-03 14:38:48 +00:00
ife
ipv4 net: Handle l3mdev in ip_tunnel_init_flow 2022-04-15 14:27:30 -07:00
ipv6 ipv6: make ip6_rt_gc_expire an atomic_t 2022-04-15 14:28:50 -07:00
iucv s390/iucv: sort out physical vs virtual pointers usage 2022-02-22 16:09:13 -08:00
kcm
key af_key: add __GFP_ZERO flag for compose_sadb_supported in function pfkey_register 2022-03-10 07:39:47 +01:00
l2tp
l3mdev l3mdev: l3mdev_master_upper_ifindex_by_index_rcu should be using netdev_master_upper_dev_get_rcu 2022-04-15 14:27:24 -07:00
lapb
llc llc: only change llc->dev when bind() succeeds 2022-03-25 16:55:41 -07:00
mac80211 mac80211: fix ht_capa printout in debugfs 2022-04-11 11:57:27 +02:00
mac802154
mctp mctp: Use output netdev to allocate skb headroom 2022-04-01 12:04:15 +01:00
mpls net: mpls: Fix GCC 12 warning 2022-02-10 15:29:39 +00:00
mptcp Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-03-23 10:53:49 -07:00
ncsi all: replace find_next{,_zero}_bit with find_first{,_zero}_bit where appropriate 2022-01-15 08:47:31 -08:00
netfilter netfilter: nf_tables: nft_parse_register can return a negative value 2022-04-12 11:36:37 +02:00
netlabel netlabel: fix out-of-bounds memory accesses 2022-03-21 10:59:11 +00:00
netlink netlink: reset network and mac headers in netlink_dump() 2022-04-19 15:05:03 +02:00
netrom
nfc nfc: nci: add flush_workqueue to prevent uaf 2022-04-13 14:44:44 +01:00
nsh
openvswitch openvswitch: fix OOB access in reserve_sfa_size() 2022-04-15 11:50:02 +01:00
packet net/packet: fix packet_sock xmit return value checking 2022-04-15 11:17:30 +01:00
phonet phonet: Use netif_rx(). 2022-03-07 11:40:41 +00:00
psample
qrtr
rds
rfkill rfkill: make new event layout opt-in 2022-03-18 13:09:17 +02:00
rose
rxrpc rxrpc: Restore removed timer deletion 2022-04-15 10:54:49 +01:00
sched net/sched: cls_u32: fix possible leak in u32_init_knode() 2022-04-15 14:26:11 -07:00
sctp sctp: Initialize daddr on peeled off socket 2022-04-11 20:33:10 -07:00
smc net/smc: Fix sock leak when release after smc_shutdown() 2022-04-15 11:14:38 +01:00
strparser
sunrpc NFSD bug fixes for 5.18-rc: 2022-04-12 14:23:19 -10:00
switchdev net: switchdev: remove lag_mod_cb from switchdev_handle_fdb_event_to_device 2022-02-24 21:31:43 -08:00
tipc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-03-23 10:53:49 -07:00
tls net/tls: fix slab-out-of-bounds bug in decrypt_internal 2022-04-01 11:53:35 +01:00
unix Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-03-23 10:53:49 -07:00
vmw_vsock vsock/virtio: enable VQs early on probe 2022-03-24 18:36:36 -07:00
wireless cfg80211: hold bss_lock while updating nontrans_list 2022-04-11 11:55:36 +02:00
x25 net/x25: Fix null-ptr-deref caused by x25_disconnect 2022-03-26 11:48:16 -07:00
xdp xsk: Do not write NULL in SW ring at allocation failure 2022-03-28 19:56:28 -07:00
xfrm xfrm: Pass flowi_oif or l3mdev as oif to xfrm_dst_lookup 2022-04-04 13:32:56 +02:00
Kconfig page_pool: Add allocation stats 2022-03-03 09:55:28 +00:00
Kconfig.debug
Makefile
compat.c
devres.c
socket.c fs: allocate inode by using alloc_inode_sb() 2022-03-22 15:57:03 -07:00
sysctl_net.c