linux-stable.git/net/core/dev.c, branch linux-5.0.y

net-gro: fix use-after-free read in napi_gro_frags()

2019-06-04T06:01:27+00:00

[ Upstream commit a4270d6795b0580287453ea55974d948393e66ef ]

If a network driver provides to napi_gro_frags() an
skb with a page fragment of exactly 14 bytes, the call
to gro_pull_from_frag0() will 'consume' the fragment
by calling skb_frag_unref(skb, 0), and the page might
be freed and reused.

Reading eth->h_proto at the end of napi_frags_skb() might
read mangled data, or crash under specific debugging features.

BUG: KASAN: use-after-free in napi_frags_skb net/core/dev.c:5833 [inline]
BUG: KASAN: use-after-free in napi_gro_frags+0xc6f/0xd10 net/core/dev.c:5841
Read of size 2 at addr ffff88809366840c by task syz-executor599/8957

CPU: 1 PID: 8957 Comm: syz-executor599 Not tainted 5.2.0-rc1+ #32
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188
 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 kasan_report+0x12/0x20 mm/kasan/common.c:614
 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/generic_report.c:142
 napi_frags_skb net/core/dev.c:5833 [inline]
 napi_gro_frags+0xc6f/0xd10 net/core/dev.c:5841
 tun_get_user+0x2f3c/0x3ff0 drivers/net/tun.c:1991
 tun_chr_write_iter+0xbd/0x156 drivers/net/tun.c:2037
 call_write_iter include/linux/fs.h:1872 [inline]
 do_iter_readv_writev+0x5f8/0x8f0 fs/read_write.c:693
 do_iter_write fs/read_write.c:970 [inline]
 do_iter_write+0x184/0x610 fs/read_write.c:951
 vfs_writev+0x1b3/0x2f0 fs/read_write.c:1015
 do_writev+0x15b/0x330 fs/read_write.c:1058

Fixes: a50e233c50db ("net-gro: restore frag0 optimization")
Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: avoid weird emergency message

2019-05-25T16:21:52+00:00

[ Upstream commit d7c04b05c9ca14c55309eb139430283a45c4c25f ]

When host is under high stress, it is very possible thread
running netdev_wait_allrefs() returns from msleep(250)
10 seconds late.

This leads to these messages in the syslog :

[...] unregister_netdevice: waiting for syz_tun to become free. Usage count = 0

If the device refcount is zero, the wait is over.

Signed-off-by: Eric Dumazet 
Reported-by: syzbot 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

failover: allow name change on IFF_UP slave interfaces

2019-04-27T07:37:26+00:00

[ Upstream commit 8065a779f17e94536a1c4dcee4f9d88011672f97 ]

When a netdev appears through hot plug then gets enslaved by a failover
master that is already up and running, the slave will be opened
right away after getting enslaved. Today there's a race that userspace
(udev) may fail to rename the slave if the kernel (net_failover)
opens the slave earlier than when the userspace rename happens.
Unlike bond or team, the primary slave of failover can't be renamed by
userspace ahead of time, since the kernel initiated auto-enslavement is
unable to, or rather, is never meant to be synchronized with the rename
request from userspace.

As the failover slave interfaces are not designed to be operated
directly by userspace apps: IP configuration, filter rules with
regard to network traffic passing and etc., should all be done on master
interface. In general, userspace apps only care about the
name of master interface, while slave names are less important as long
as admin users can see reliable names that may carry
other information describing the netdev. For e.g., they can infer that
"ens3nsby" is a standby slave of "ens3", while for a
name like "eth0" they can't tell which master it belongs to.

Historically the name of IFF_UP interface can't be changed because
there might be admin script or management software that is already
relying on such behavior and assumes that the slave name can't be
changed once UP. But failover is special: with the in-kernel
auto-enslavement mechanism, the userspace expectation for device
enumeration and bring-up order is already broken. Previously initramfs
and various userspace config tools were modified to bypass failover
slaves because of auto-enslavement and duplicate MAC address. Similarly,
in case that users care about seeing reliable slave name, the new type
of failover slaves needs to be taken care of specifically in userspace
anyway.

It's less risky to lift up the rename restriction on failover slave
which is already UP. Although it's possible this change may potentially
break userspace component (most likely configuration scripts or
management software) that assumes slave name can't be changed while
UP, it's relatively a limited and controllable set among all userspace
components, which can be fixed specifically to listen for the rename
events on failover slaves. Userspace component interacting with slaves
is expected to be changed to operate on failover master interface
instead, as the failover slave is dynamic in nature which may come and
go at any point.  The goal is to make the role of failover slaves less
relevant, and userspace components should only deal with failover master
in the long run.

Fixes: 30c8bd5aa8b2 ("net: Introduce generic failover module")
Signed-off-by: Si-Wei Liu 
Reviewed-by: Liran Alon 
Acked-by: Sridhar Samudrala 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: core: netif_receive_skb_list: unlist skb before passing to pt->func

2019-04-17T06:39:43+00:00

[ Upstream commit 9a5a90d167b0e5fe3d47af16b68fd09ce64085cd ]

__netif_receive_skb_list_ptype() leaves skb->next poisoned before passing
it to pt_prev->func handler, what may produce (in certain cases, e.g. DSA
setup) crashes like:

[ 88.606777] CPU 0 Unable to handle kernel paging request at virtual address 0000000e, epc == 80687078, ra == 8052cc7c
[ 88.618666] Oops[#1]:
[ 88.621196] CPU: 0 PID: 0 Comm: swapper Not tainted 5.1.0-rc2-dlink-00206-g4192a172-dirty #1473
[ 88.630885] $ 0 : 00000000 10000400 00000002 864d7850
[ 88.636709] $ 4 : 87c0ddf0 864d7800 87c0ddf0 00000000
[ 88.642526] $ 8 : 00000000 49600000 00000001 00000001
[ 88.648342] $12 : 00000000 c288617b dadbee27 25d17c41
[ 88.654159] $16 : 87c0ddf0 85cff080 80790000 fffffffd
[ 88.659975] $20 : 80797b20 ffffffff 00000001 864d7800
[ 88.665793] $24 : 00000000 8011e658
[ 88.671609] $28 : 80790000 87c0dbc0 87cabf00 8052cc7c
[ 88.677427] Hi : 00000003
[ 88.680622] Lo : 7b5b4220
[ 88.683840] epc : 80687078 vlan_dev_hard_start_xmit+0x1c/0x1a0
[ 88.690532] ra : 8052cc7c dev_hard_start_xmit+0xac/0x188
[ 88.696734] Status: 10000404	IEp
[ 88.700422] Cause : 50000008 (ExcCode 02)
[ 88.704874] BadVA : 0000000e
[ 88.708069] PrId : 0001a120 (MIPS interAptiv (multi))
[ 88.713005] Modules linked in:
[ 88.716407] Process swapper (pid: 0, threadinfo=(ptrval), task=(ptrval), tls=00000000)
[ 88.725219] Stack : 85f61c28 00000000 0000000e 80780000 87c0ddf0 85cff080 80790000 8052cc7c
[ 88.734529] 87cabf00 00000000 00000001 85f5fb40 807b0000 864d7850 87cabf00 807d0000
[ 88.743839] 864d7800 8655f600 00000000 85cff080 87c1c000 0000006a 00000000 8052d96c
[ 88.753149] 807a0000 8057adb8 87c0dcc8 87c0dc50 85cfff08 00000558 87cabf00 85f58c50
[ 88.762460] 00000002 85f58c00 864d7800 80543308 fffffff4 00000001 85f58c00 864d7800
[ 88.771770] ...
[ 88.774483] Call Trace:
[ 88.777199] [<80687078>] vlan_dev_hard_start_xmit+0x1c/0x1a0
[ 88.783504] [<8052cc7c>] dev_hard_start_xmit+0xac/0x188
[ 88.789326] [<8052d96c>] __dev_queue_xmit+0x6e8/0x7d4
[ 88.794955] [<805a8640>] ip_finish_output2+0x238/0x4d0
[ 88.800677] [<805ab6a0>] ip_output+0xc8/0x140
[ 88.805526] [<805a68f4>] ip_forward+0x364/0x560
[ 88.810567] [<805a4ff8>] ip_rcv+0x48/0xe4
[ 88.815030] [<80528d44>] __netif_receive_skb_one_core+0x44/0x58
[ 88.821635] [<8067f220>] dsa_switch_rcv+0x108/0x1ac
[ 88.827067] [<80528f80>] __netif_receive_skb_list_core+0x228/0x26c
[ 88.833951] [<8052ed84>] netif_receive_skb_list+0x1d4/0x394
[ 88.840160] [<80355a88>] lunar_rx_poll+0x38c/0x828
[ 88.845496] [<8052fa78>] net_rx_action+0x14c/0x3cc
[ 88.850835] [<806ad300>] __do_softirq+0x178/0x338
[ 88.856077] [<8012a2d4>] irq_exit+0xbc/0x100
[ 88.860846] [<802f8b70>] plat_irq_dispatch+0xc0/0x144
[ 88.866477] [<80105974>] handle_int+0x14c/0x158
[ 88.871516] [<806acfb0>] r4k_wait+0x30/0x40
[ 88.876462] Code: afb10014 8c8200a0 00803025 <9443000c> 94a20468 00000000 10620042 00a08025 9605046a
[ 88.887332]
[ 88.888982] ---[ end trace eb863d007da11cf1 ]---
[ 88.894122] Kernel panic - not syncing: Fatal exception in interrupt
[ 88.901202] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

Fix this by pulling skb off the sublist and zeroing skb->next pointer
before calling ptype callback.

Fixes: 88eb1944e18c ("net: core: propagate SKB lists through packet_type lookup")
Reviewed-by: Edward Cree 
Signed-off-by: Alexander Lobakin 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

net: Fix for_each_netdev_feature on Big endian

2019-02-16T04:23:50+00:00

The features attribute is of type u64 and stored in the native endianes on
the system. The for_each_set_bit() macro takes a pointer to a 32 bit array
and goes over the bits in this area. On little Endian systems this also
works with an u64 as the most significant bit is on the highest address,
but on big endian the words are swapped. When we expect bit 15 here we get
bit 47 (15 + 32).

This patch converts it more or less to its own for_each_set_bit()
implementation which works on 64 bit integers directly. This is then
completely in host endianness and should work like expected.

Fixes: fd867d51f ("net/core: generic support for disabling netdev features down stack")
Signed-off-by: Hauke Mehrtens 
Signed-off-by: David S. Miller

net: set default network namespace in init_dummy_netdev()

2019-01-29T19:29:55+00:00

Assign a default net namespace to netdevs created by init_dummy_netdev().
Fixes a NULL pointer dereference caused by busy-polling a socket bound to
an iwlwifi wireless device, which bumps the per-net BUSYPOLLRXPACKETS stat
if napi_poll() received packets:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000190
  IP: napi_busy_loop+0xd6/0x200
  Call Trace:
    sock_poll+0x5e/0x80
    do_sys_poll+0x324/0x5a0
    SyS_poll+0x6c/0xf0
    do_syscall_64+0x6b/0x1f0
    entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Fixes: 7db6b048da3b ("net: Commonize busy polling code to focus on napi_id instead of socket")
Signed-off-by: Josh Elsasser 
Signed-off-by: David S. Miller

jump_label: move 'asm goto' support test to Kconfig

2019-01-06T00:46:51+00:00

Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label".

The jump label is controlled by HAVE_JUMP_LABEL, which is defined
like this:

  #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
  # define HAVE_JUMP_LABEL
  #endif

We can improve this by testing 'asm goto' support in Kconfig, then
make JUMP_LABEL depend on CC_HAS_ASM_GOTO.

Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will
match to the real kernel capability.

Signed-off-by: Masahiro Yamada 
Acked-by: Michael Ellerman  (powerpc)
Tested-by: Sedat Dilek

net: use indirect call wrappers at GRO network layer

2018-12-15T21:23:02+00:00

This avoids an indirect calls for L3 GRO receive path, both
for ipv4 and ipv6, if the latter is not compiled as a module.

Note that when IPv6 is compiled as builtin, it will be checked first,
so we have a single additional compare for the more common path.

v1 -> v2:
 - adapted to INDIRECT_CALL_ changes

Signed-off-by: Paolo Abeni 
Signed-off-by: David S. Miller

net: dev: Issue NETDEV_PRE_CHANGEADDR

2018-12-14T02:41:38+00:00

When a device address is about to be changed, or an address added to the
list of device HW addresses, it is necessary to ensure that all
interested parties can support the address. Therefore, send the
NETDEV_PRE_CHANGEADDR notification, and if anyone bails on it, do not
change the address.

Signed-off-by: Petr Machata 
Acked-by: Jiri Pirko 
Reviewed-by: Ido Schimmel 
Signed-off-by: David S. Miller

net: dev: Add NETDEV_PRE_CHANGEADDR

2018-12-14T02:41:38+00:00

The NETDEV_CHANGEADDR notification is emitted after a device address
changes. Extending this message to allow vetoing is certainly possible,
but several other notification types have instead adopted a simple
two-stage approach: first a "pre" notification is sent to make sure all
interested parties are OK with a change that's about to be done. Then
the change is done, and afterwards a "post" notification is sent.

This dual approach is easier to use: when the change is vetoed, nothing
has changed yet, and it's therefore unnecessary to roll anything back.
Therefore adopt it for NETDEV_CHANGEADDR as well.

To that end, add NETDEV_PRE_CHANGEADDR and an info structure to go along
with it.

Signed-off-by: Petr Machata 
Acked-by: Jiri Pirko 
Reviewed-by: Ido Schimmel 
Signed-off-by: David S. Miller