kernel/drivers/net/tun.c, branch linux-4.16.y

net: in virtio_net_hdr only add VLAN_HLEN to csum_start if payload holds vlan

2018-06-25T23:53:55Z

[ Upstream commit fd3a88625844907151737fc3b4201676effa6d27 ] Tun, tap, virtio, packet and uml vector all use struct virtio_net_hdr to communicate packet metadata to userspace. For skbuffs with vlan, the first two return the packet as it may have existed on the wire, inserting the VLAN tag in the user buffer. Then virtio_net_hdr.csum_start needs to be adjusted by VLAN_HLEN bytes. Commit f09e2249c4f5 ("macvtap: restore vlan header on user read") added this feature to macvtap. Commit 3ce9b20f1971 ("macvtap: Fix csum_start when VLAN tags are present") then fixed up csum_start. Virtio, packet and uml do not insert the vlan header in the user buffer. When introducing virtio_net_hdr_from_skb to deduplicate filling in the virtio_net_hdr, the variant from macvtap which adds VLAN_HLEN was applied uniformly, breaking csum offset for packets with vlan on virtio and packet. Make insertion of VLAN_HLEN optional. Convert the callers to pass it when needed. Fixes: e858fae2b0b8f4 ("virtio_net: use common code for virtio_net_hdr and skb GSO conversion") Fixes: 1276f24eeef2 ("packet: use common code for virtio_net_hdr and skb GSO conversion") Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tun: Fix NULL pointer dereference in XDP redirect

2018-06-11T20:48:18Z

[ Upstream commit 6547e387d7f52f2ba681a229de3c13e5b9e01ee1 ] Calling XDP redirection requires bh disabled. Softirq can call another XDP function and redirection functions, then the percpu static variable ri->map can be overwritten to NULL. This is a generic XDP case called from tun. [ 3535.736058] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 [ 3535.743974] PGD 0 P4D 0 [ 3535.746530] Oops: 0000 [#1] SMP PTI [ 3535.750049] Modules linked in: vhost_net vhost tap tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter sunrpc vfat fat ext4 mbcache jbd2 intel_rapl skx_edac nfit libnvdimm x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm ipmi_ssif irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc ses aesni_intel crypto_simd cryptd enclosure hpwdt hpilo glue_helper ipmi_si pcspkr wmi mei_me ioatdma mei ipmi_devintf shpchp dca ipmi_msghandler lpc_ich acpi_power_meter sch_fq_codel ip_tables xfs libcrc32c sd_mod mgag200 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm smartpqi i40e crc32c_intel scsi_transport_sas tg3 i2c_core ptp pps_core [ 3535.813456] CPU: 5 PID: 1630 Comm: vhost-1614 Not tainted 4.17.0-rc4 #2 [ 3535.820127] Hardware name: HPE ProLiant DL360 Gen10/ProLiant DL360 Gen10, BIOS U32 11/14/2017 [ 3535.828732] RIP: 0010:__xdp_map_lookup_elem+0x5/0x30 [ 3535.833740] RSP: 0018:ffffb4bc47bf7c58 EFLAGS: 00010246 [ 3535.839009] RAX: ffff9fdfcfea1c40 RBX: 0000000000000000 RCX: ffff9fdf27fe3100 [ 3535.846205] RDX: ffff9fdfca769200 RSI: 0000000000000000 RDI: 0000000000000000 [ 3535.853402] RBP: ffffb4bc491d9000 R08: 00000000000045ad R09: 0000000000000ec0 [ 3535.860597] R10: 0000000000000001 R11: ffff9fdf26c3ce4e R12: ffff9fdf9e72c000 [ 3535.867794] R13: 0000000000000000 R14: fffffffffffffff2 R15: ffff9fdfc82cdd00 [ 3535.874990] FS: 0000000000000000(0000) GS:ffff9fdfcfe80000(0000) knlGS:0000000000000000 [ 3535.883152] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3535.888948] CR2: 0000000000000018 CR3: 0000000bde724004 CR4: 00000000007626e0 [ 3535.896145] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 3535.903342] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 3535.910538] PKRU: 55555554 [ 3535.913267] Call Trace: [ 3535.915736] xdp_do_generic_redirect+0x7a/0x310 [ 3535.920310] do_xdp_generic.part.117+0x285/0x370 [ 3535.924970] tun_get_user+0x5b9/0x1260 [tun] [ 3535.929279] tun_sendmsg+0x52/0x70 [tun] [ 3535.933237] handle_tx+0x2ad/0x5f0 [vhost_net] [ 3535.937721] vhost_worker+0xa5/0x100 [vhost] [ 3535.942030] kthread+0xf5/0x130 [ 3535.945198] ? vhost_dev_ioctl+0x3b0/0x3b0 [vhost] [ 3535.950031] ? kthread_bind+0x10/0x10 [ 3535.953727] ret_from_fork+0x35/0x40 [ 3535.957334] Code: 0e 74 15 83 f8 10 75 05 e9 49 aa b3 ff f3 c3 0f 1f 80 00 00 00 00 f3 c3 e9 29 9d b3 ff 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 <8b> 47 18 83 f8 0e 74 0d 83 f8 10 75 05 e9 49 a9 b3 ff 31 c0 c3 [ 3535.976387] RIP: __xdp_map_lookup_elem+0x5/0x30 RSP: ffffb4bc47bf7c58 [ 3535.982883] CR2: 0000000000000018 [ 3535.987096] ---[ end trace 383b299dd1430240 ]--- [ 3536.131325] Kernel panic - not syncing: Fatal exception [ 3536.137484] Kernel Offset: 0x26a00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 3536.281406] ---[ end Kernel panic - not syncing: Fatal exception ]--- And a kernel with generic case fixed still panics in tun driver XDP redirect, because it disabled only preemption, but not bh. [ 2055.128746] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 [ 2055.136662] PGD 0 P4D 0 [ 2055.139219] Oops: 0000 [#1] SMP PTI [ 2055.142736] Modules linked in: vhost_net vhost tap tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter sunrpc vfat fat ext4 mbcache jbd2 intel_rapl skx_edac nfit libnvdimm x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc ses aesni_intel ipmi_ssif crypto_simd enclosure cryptd hpwdt glue_helper ioatdma hpilo wmi dca pcspkr ipmi_si acpi_power_meter ipmi_devintf shpchp mei_me ipmi_msghandler mei lpc_ich sch_fq_codel ip_tables xfs libcrc32c sd_mod mgag200 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm i40e smartpqi tg3 scsi_transport_sas crc32c_intel i2c_core ptp pps_core [ 2055.206142] CPU: 6 PID: 1693 Comm: vhost-1683 Tainted: G W 4.17.0-rc5-fix-tun+ #1 [ 2055.215011] Hardware name: HPE ProLiant DL360 Gen10/ProLiant DL360 Gen10, BIOS U32 11/14/2017 [ 2055.223617] RIP: 0010:__xdp_map_lookup_elem+0x5/0x30 [ 2055.228624] RSP: 0018:ffff998b07607cc0 EFLAGS: 00010246 [ 2055.233892] RAX: ffff8dbd8e235700 RBX: ffff8dbd8ff21c40 RCX: 0000000000000004 [ 2055.241089] RDX: ffff998b097a9000 RSI: 0000000000000000 RDI: 0000000000000000 [ 2055.248286] RBP: 0000000000000000 R08: 00000000000065a8 R09: 0000000000005d80 [ 2055.255483] R10: 0000000000000040 R11: ffff8dbcf0100000 R12: ffff998b097a9000 [ 2055.262681] R13: ffff8dbd8c98c000 R14: 0000000000000000 R15: ffff998b07607d78 [ 2055.269879] FS: 0000000000000000(0000) GS:ffff8dbd8ff00000(0000) knlGS:0000000000000000 [ 2055.278039] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2055.283834] CR2: 0000000000000018 CR3: 0000000c0c8cc005 CR4: 00000000007626e0 [ 2055.291030] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 2055.298227] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 2055.305424] PKRU: 55555554 [ 2055.308153] Call Trace: [ 2055.310624] xdp_do_redirect+0x7b/0x380 [ 2055.314499] tun_get_user+0x10fe/0x12a0 [tun] [ 2055.318895] tun_sendmsg+0x52/0x70 [tun] [ 2055.322852] handle_tx+0x2ad/0x5f0 [vhost_net] [ 2055.327337] vhost_worker+0xa5/0x100 [vhost] [ 2055.331646] kthread+0xf5/0x130 [ 2055.334813] ? vhost_dev_ioctl+0x3b0/0x3b0 [vhost] [ 2055.339646] ? kthread_bind+0x10/0x10 [ 2055.343343] ret_from_fork+0x35/0x40 [ 2055.346950] Code: 0e 74 15 83 f8 10 75 05 e9 e9 aa b3 ff f3 c3 0f 1f 80 00 00 00 00 f3 c3 e9 c9 9d b3 ff 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 <8b> 47 18 83 f8 0e 74 0d 83 f8 10 75 05 e9 e9 a9 b3 ff 31 c0 c3 [ 2055.366004] RIP: __xdp_map_lookup_elem+0x5/0x30 RSP: ffff998b07607cc0 [ 2055.372500] CR2: 0000000000000018 [ 2055.375856] ---[ end trace 2a2dcc5e9e174268 ]--- [ 2055.523626] Kernel panic - not syncing: Fatal exception [ 2055.529796] Kernel Offset: 0x2e000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 2055.677539] ---[ end Kernel panic - not syncing: Fatal exception ]--- v2: - Removed preempt_disable/enable since local_bh_disable will prevent preemption as well, feedback from Jason Wang. Fixes: 761876c857cb ("tap: XDP support") Signed-off-by: Toshiaki Makita Acked-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tuntap: fix use after free during release

2018-05-25T14:46:01Z

[ Upstream commit 7063efd33bb15abc0160347f89eb5aba6b7d000e ] After commit b196d88aba8a ("tun: fix use after free for ptr_ring") we need clean up tx ring during release(). But unfortunately, it tries to do the cleanup blindly after socket were destroyed which will lead another use-after-free. Fix this by doing the cleanup before dropping the last reference of the socket in __tun_detach(). Reported-by: Andrei Vagin Acked-by: Andrei Vagin Fixes: b196d88aba8a ("tun: fix use after free for ptr_ring") Signed-off-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tun: fix use after free for ptr_ring

2018-05-25T14:46:01Z

[ Upstream commit b196d88aba8ac72b775137854121097f4c4c6862 ] We used to initialize ptr_ring during TUNSETIFF, this is because its size depends on the tx_queue_len of netdevice. And we try to clean it up when socket were detached from netdevice. A race were spotted when trying to do uninit during a read which will lead a use after free for pointer ring. Solving this by always initialize a zero size ptr_ring in open() and do resizing during TUNSETIFF, and then we can safely do cleanup during close(). With this, there's no need for the workaround that was introduced by commit 4df0bfc79904 ("tun: fix a memory leak for tfile->tx_array"). Reported-by: syzbot+e8b902c3c3fadf0a9dba@syzkaller.appspotmail.com Cc: Eric Dumazet Cc: Cong Wang Cc: Michael S. Tsirkin Fixes: 1576d9860599 ("tun: switch to use skb array for tx") Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tun: fix vlan packet truncation

2018-04-29T09:35:49Z

[ Upstream commit 81c895072d29cd70eea5be1a8587cd6461c3715a ] Bogus trimming in tun_net_xmit() causes truncated vlan packets. skb->len is correct whether or not skb_vlan_tag_present() is true. There is no more reason to adjust the skb length on xmit in this driver than any other driver. tun_put_user() adds 4 bytes to the total for tagged packets because it transmits the tag inline to userspace. This is similar to a nic transmitting the tag inline on the wire. Reproducing the bug by sending any tagged packet through back-to-back connected tap interfaces: socat TUN,tun-type=tap,iff-up,tun-name=in TUN,tun-type=tap,iff-up,tun-name=out & ip link add link in name in.20 type vlan id 20 ip addr add 10.9.9.9/24 dev in.20 ip link set in.20 up tshark -nxxi in -f arp -c1 2>/dev/null & tshark -nxxi out -f arp -c1 2>/dev/null & ping -c 1 10.9.9.5 >/dev/null 2>&1 The output from the 'in' and 'out' interfaces are different when the bug is present: Capturing on 'in' 0000 ff ff ff ff ff ff 76 cf 76 37 d5 0a 81 00 00 14 ......v.v7...... 0010 08 06 00 01 08 00 06 04 00 01 76 cf 76 37 d5 0a ..........v.v7.. 0020 0a 09 09 09 00 00 00 00 00 00 0a 09 09 05 .............. Capturing on 'out' 0000 ff ff ff ff ff ff 76 cf 76 37 d5 0a 81 00 00 14 ......v.v7...... 0010 08 06 00 01 08 00 06 04 00 01 76 cf 76 37 d5 0a ..........v.v7.. 0020 0a 09 09 09 00 00 00 00 00 00 .......... Fixes: aff3d70a07ff ("tun: allow to attach ebpf socket filter") Cc: Jason Wang Signed-off-by: Bjørn Mork Acked-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

vhost_net: examine pointer types during un-producing

2018-03-09T17:02:59Z

After commit fc72d1d54dd9 ("tuntap: XDP transmission"), we can actually queueing XDP pointers in the pointer ring, so we should examine the pointer type before freeing the pointer. Fixes: fc72d1d54dd9 ("tuntap: XDP transmission") Reported-by: Michael S. Tsirkin Acked-by: Michael S. Tsirkin Signed-off-by: Jason Wang Signed-off-by: David S. Miller

tuntap: correctly add the missing XDP flush

2018-02-26T18:49:49Z

We don't flush batched XDP packets through xdp_do_flush_map(), this will cause packets stall at TX queue. Consider we don't do XDP on NAPI poll(), the only possible fix is to call xdp_do_flush_map() immediately after xdp_do_redirect(). Note, this in fact won't try to batch packets through devmap, we could address in the future. Reported-by: Christoffer Dall Fixes: 761876c857cb ("tap: XDP support") Signed-off-by: Jason Wang Signed-off-by: David S. Miller

tuntap: disable preemption during XDP processing

2018-02-26T18:49:48Z

Except for tuntap, all other drivers' XDP was implemented at NAPI poll() routine in a bh. This guarantees all XDP operation were done at the same CPU which is required by e.g BFP_MAP_TYPE_PERCPU_ARRAY. But for tuntap, we do it in process context and we try to protect XDP processing by RCU reader lock. This is insufficient since CONFIG_PREEMPT_RCU can preempt the RCU reader critical section which breaks the assumption that all XDP were processed in the same CPU. Fixing this by simply disabling preemption during XDP processing. Fixes: 761876c857cb ("tap: XDP support") Signed-off-by: Jason Wang Signed-off-by: David S. Miller

Revert "tuntap: add missing xdp flush"

2018-02-26T18:49:48Z

This reverts commit 762c330d670e3d4b795cf7a8d761866fdd1eef49. The reason is we try to batch packets for devmap which causes calling xdp_do_flush() in the process context. Simply disabling preemption may not work since process may move among processors which lead xdp_do_flush() to miss some flushes on some processors. So simply revert the patch, a follow-up patch will add the xdp flush correctly. Reported-by: Christoffer Dall Fixes: 762c330d670e ("tuntap: add missing xdp flush") Signed-off-by: Jason Wang Signed-off-by: David S. Miller

tun: fix tun_napi_alloc_frags() frag allocator

2018-02-16T21:20:46Z

While fuzzing arm64 v4.16-rc1 with Syzkaller, I've been hitting a misaligned atomic in __skb_clone: atomic_inc(&(skb_shinfo(skb)->dataref)); where dataref doesn't have the required natural alignment, and the atomic operation faults. e.g. i often see it aligned to a single byte boundary rather than a four byte boundary. AFAICT, the skb_shared_info is misaligned at the instant it's allocated in __napi_alloc_skb() __napi_alloc_skb() Problem is caused by tun_napi_alloc_frags() using napi_alloc_frag() with user provided seg sizes, leading to other users of this API getting unaligned page fragments. Since we would like to not necessarily add paddings or alignments to the frags that tun_napi_alloc_frags() attaches to the skb, switch to another page frag allocator. As a bonus skb_page_frag_refill() can use GFP_KERNEL allocations, meaning that we can not deplete memory reserves as easily. Fixes: 90e33d459407 ("tun: enable napi_gro_frags() for TUN/TAP driver") Signed-off-by: Eric Dumazet Reported-by: Mark Rutland Tested-by: Mark Rutland Signed-off-by: David S. Miller